Dissertations / Theses on the topic 'Biogas from livestock waste'

The purpose of this feasibility study has been to guide decision makers in the implementation of abiogas project for the region of Sønderborg, Denmark. The project has been part of Feasibility studies envisioned in the Master Plan for Sønderborg to go carbon neutral by 2029. The study tried to evolve abest alternative for the city and gives a ready document to refer all aspects of biogas. The intensive industrial farming in Sønderborg needs to evolve to compare favorably with the situationin other regions of Denmark. The interests of various stakeholders in the waste cycle should be alignedwith that of farming. Interesting developments in the Bioenergy space hold promise for farmers to usetheir capacities for additional or alternative livelihood in energy. The focus to promote biogas as part ofDanish energy strategy and multiply capacity over the next 3 years has attracted numerous biogas proposals all over Denmark. This study had started off with identifying and estimating very obvious substrate sources. At verymoderate assumptions the value of methane in these sources has been estimated at 9 million m3. Thispotential could easily be increased if economically feasible substrates like energy crops and algae areadded. The SWOT analysis of pig farming in the region brings out the perspectives of farming direction in the near future. The 5 scenarios developed help the decision maker understand the various aspects thatneed to be carefully considered when planning the plant. The best case scenario for the city would bethe energy mosaic scenario which would integrate the high tech focus of local industry, a renewable energy source and a showcase project to make the region stand out among the other regions focused inthe climate change debate. The technological system analysis should help decision makers understand the stakeholders and the various dimensions in biogas that although complicated are manageable. The business case approach to identify utilization of energy and its costs gives a clear picture on the need for using the energy in CHP.The present focus by potential investors on government subsidies to calculate profitability needs to be understood in the context of other similar plants accepting present subsidy levels and the societal benefits, which unfortunately cannot be valued in money terms. At the center of all this is the need for proper stakeholder management within a bound timeframe asidentified by the “Create acceptance process”. The various tools and data are all present in this study,that only need to be arranged and presented by the company eventually handling the strict Projectmanagement goals of this project.

www.ima.kth.se

Tesis por compendio
[ES] El acceso a fuentes de energía moderna en las áreas rurales de la región andina es uno de los factores principales para disminuir la pobreza ya que su acceso proporcionaría beneficios ambientales, económicos y sociales. Pese a los esfuerzos de buscar fuentes alternativas para subsanar el déficit energético, aún existen millones de personas que sufren la falta de accesibilidad a fuentes de energía moderna, situación que se debe a los altos niveles de pobreza bajo los cuales se encuentran inmersos. Junto a este inconveniente se suma el enorme incremento de residuos agrícolas en las comunidades andinas. Residuos que provienen de las actividades agrícolas, y que podrían ser perjudiciales para el medio ambiente si no se toman medidas adecuadas. Lamentablemente, en muchos países en desarrollo donde se generan grandes cantidades de estos residuos, se sabe poco sobre sus posibles riesgos y beneficios si no se gestionan adecuadamente. Uno de los enfoques más interesantes para abordar esta problemática, es el desarrollo de la gestión sostenible de los residuos orgánicos agrícolas de la región, transformándolos en recursos para la generación de energía renovable (biogás) y fertilizantes orgánicos (digestato). Esta solución permitiría dar una valorización energética a los residuos de la agricultura de la zona, sobre la cual basan su economía, y a la vez contribuiría a una mayor gestión de los residuos evitando el incremento de la contaminación ambiental. Con la finalidad de contribuir al desarrollo energético y mejorar el paradigma de la gestión de residuos en el área andina de Guaranda (Ecuador), la presente Tesis Doctoral aborda la evaluación del potencial bioquímico de metano (BMP) de los residuos orgánicos agrícolas de la región. Se realiza una cuantificación sistemática de la producción de biogás mediante la transformación bioquímica de residuos orgánicos agrícolas, que comprenden: sustratos principales (residuos de estiércol de vicuña, llama y cuy, y residuos de matadero de ganado vacuno) y cosustratos (residuos de paja de amaranto, quinua y trigo). El objetivo general de esta investigación de doctorado se ha llevado a cabo en cuatro fases: (I) Caracterización de la materia prima mediante el análisis elemental y proximal a través de los cuáles se estimó el rendimiento teórico y la biodegradabilidad de los sustratos y cosustratos, (II) Rendimiento de la codigestión de residuos orgánicos agrícolas con mezclas de lodos de aguas residuales en biodigestores batch, (III) Análisis de los efectos sinérgicos y antagónicos durante la monodigestión y codigestión de las materias primas y (IV) Evaluación de la cinética microbiana de la digestión anaerobia mediante los modelos de Gompertz modificado, transferencia, ecuación logística, modelo del cono y Richards modificado. En la caracterización fisicoquímica se determinó que las relaciones SV/ST de los sustratos y cosustratos oscilaron entre 58 y 77% con una relación C/N entre 12 y 102, lo que indicó que estos residuos son materias primas adecuadas para la producción de metano. En todos los ensayos un aumento de la cantidad de inóculo mejoró la biodegradabilidad de los sustratos y por consiguiente la producción metano; así, en la monodigestión se tuvo incrementos de hasta 90% y en la codigestión incrementos del 71%. Todas las mezclas produjeron efectos sinérgicos, donde los mayores porcentajes de metano se dieron cuando las mezclas de residuos de amaranto, quinua y trigo fueron del 50 y 75% de sólidos volátiles. Independientemente de la SIR1:1 y la SIR 1:2 se mejoró la producción de metano de la codigestión al incrementar el porcentaje de cosustrato especialmente de residuos de amaranto y quinua. Los mejores resultados de todos los ensayos realizados se obtuvieron en los biodigestores compuestos por residuos de matadero y residuos de quinua, donde se obtuvieron producciones de metano entre 581 y 555 ml
[CA] L'accés a fonts d'energia moderna en les àrees rurals de la regió andina és un dels factors principals per a disminuir la pobresa ja que el seu accés proporcionaria beneficis ambientals, econòmics i socials. Malgrat els esforços de buscar fonts alternatives per a esmenar el dèficit energètic, encara existeixen milions de persones que pateixen la falta d'accessibilitat a fonts d'energia moderna, situació que es deu als alts nivells de pobresa sota els quals es troben immersos. Al costat d'aquest inconvenient se suma l'enorme increment de residus agrícoles en les comunitats andines. Residus que provenen de les activitats agrícoles, i que podrien ser perjudicials per al medi ambient si no es prenen mesures adequades. Lamentablement, en molts països en desenvolupament on es generen grans quantitats d'aquests residus, se sap poc sobre els seus possibles riscos i beneficis si no es gestionen adequadament. Un dels enfocaments més interessants per a abordar aquesta problemàtica, és el desenvolupament de la gestió sostenible dels residus orgànics agrícoles de la regió, transformant-los en recursos per a la generació d'energia renovable (biogàs) i fertilitzants orgànics (digestato). Aquesta solució permetria donar una valorització energètica als residus de l'agricultura de la zona, sobre la qual basen la seua economia, i alhora contribuiria a una major gestió dels residus evitant l'increment de la contaminació ambiental. Amb la finalitat de contribuir al desenvolupament energètic i millorar el paradigma de la gestió de residus en l'àrea andina de Guaranda (l'Equador), la present Tesi Doctoral aborda l'avaluació del potencial bioquímic de metà (BMP) dels residus orgànics agrícoles de la regió. Es realitza una quantificació sistemàtica de la producció de biogàs mitjançant la transformació bioquímica de residus orgànics agrícoles que comprenen: substrats principals (residus de fem de vicunya, flama i cuy, i residus d'escorxador de bestiar boví), *cosustratos (residus de palla d'amarant, quinua i blat). L'objectiu general d'aquesta investigació de doctorat s'ha dut a terme en quatre fases: (I) caracterització de la matèria primera mitjançant l'anàlisi elemental i proximal a través dels quals es va estimar el rendiment teòric i la biodegradabilitat dels substrats i cosustratos, (II) Rendiment de la codigestión de residus orgànics agrícoles amb mescles de llots d'aigües residuals en biodigestores batch, (III) Anàlisis dels efectes sinèrgics i antagònics durant la monodigestión i codigestión de les matèries primeres i (IV) Avaluació de la cinètica microbiana de la digestió anaeròbia mitjançant els models de Gompertz modificat, transferència, equació logística, model del con i Richards modificat. En la caracterització fisicoquímica es va determinar que les relacions SV/ST dels substrats i cosustratos van oscil·lar entre 58 i 77% amb una relació C/N entre 12 i 102, la qual cosa va indicar que aquests residus són matèries primeres adequades per a la producció de metà. En tots els assajos un augment de la quantitat d'inòcul va millorar la biodegradabilitat dels substrats i per consegüent la producció metà; així, en la monodigestión es va tindre increments de fins a 90% i en la codigestión increments del 71%. Totes les mescles van produir efectes sinèrgics, on els majors percentatges de metà es van donar quan les mescles de residus d'amarant, quinua i blat van ser del 50 i 75% de sòlids volàtils. Independentment de la SIR1:1 i la SIR 1:2 es va millorar la producció de metà de la codigestión en incrementar el percentatge de cosustrato especialment de residus d'amarant i quinua. Els millors resultats de tots els assajos realitzats es van obtindre en els biodigestores compostos per residus d'escorxador i residus de quinua, on es van obtindre produccions de metà entre 581 i 555 ml/g VS.
[EN] Access to modern energy sources in rural areas of the Andean region is one of the main factors to reduce poverty, since its access would provide environmental, economic and social benefits. Despite efforts to find alternative sources to correct the energy deficit, there are still millions of people who suffer from the lack of accessibility to modern energy sources, a situation that is due to the high levels of poverty under which they are immersed. Along with this inconvenience is added the enormous increase in agricultural residues in the Andean communities. Waste that comes from agricultural activities, and that could be harmful to the environment if adequate measures are not taken. Unfortunately, in many developing countries where large amounts of these wastes are generated, little is known about their potential risks and benefits if not managed properly. One of the most interesting approaches to address this problem is the development of sustainable management of agricultural organic waste in the region, transforming it into resources for the generation of renewable energy (biogas) and organic fertilizers (digestate). This solution would allow to give an energetic recovery to the agricultural residues of the area, on which they base their economy, and at the same time would contribute to a better management of the residues avoiding the increase of environmental pollution. To contribute to energy development and improve the paradigm of waste management in the Andean area of Guaranda (Ecuador), this Doctoral Thesis addresses the evaluation of the biochemical potential of methane (BPM) of agricultural organic waste in the region. A systematic quantification of biogas production is carried out through the biochemical transformation of agricultural organic waste that includes main substrates (vicuña, llama and guinea pig manure residues, and cattle slaughterhouse residues) and co-substrates (amaranth straw residues), quinoa and wheat). The general objective of this doctoral research has been carried out in four phases: (I) characterization of the raw material through elemental and proximal analysis through which the theoretical performance and biodegradability of substrates and co-substrates were estimated, (II) Performance of the co-digestion of agricultural organic waste with mixtures of sewage sludge in batch biodigesters, (III) Analysis of synergistic and antagonistic effects during monodigestion and co-digestion of raw materials and (IV) Evaluation of microbial kinetics of anaerobic digestion using modified Gompertz models, transfer, logistic equation, cone model and modified Richards. In the physicochemical characterization it was determined that the VS/TS ratios of the substrates and co-substrates ranged between 58 and 77% with a C/N ratio between 12 and 102, which indicated that these wastes are suitable raw materials to produce methane. In all the tests an increase in the amount of inoculum improved the biodegradability of the substrates and consequently the methane production; thus, in monodigestion there were increases of up to 90% and in co-digestion increases of 71%. All the mixtures produced synergistic effects, where the highest percentages of methane occurred when the mixtures of amaranth, quinoa and wheat residues were 50 and 75% volatile solids. Regardless of SIR1:1 and SIR 1:2, the production of methane from co-digestion was improved by increasing the percentage of co-substrate, especially amaranth and quinoa residues. The best results of all the tests carried out were obtained in the biodigesters composed of slaughterhouse waste and quinoa waste, where methane productions between 581 and 555 ml/g VS were obtained. Regarding the kinetic modelling of the anaerobic digestion process, it was found that all the models fit the experimental values quite well with the predicted ones. In the monodigestion, in all the logistic models, the calculated asymptotes were adjusted very precisely for the specific yield (Me
This work has been carried out within the framework of the project “Analysis of the implementation of biomass exploitation chains in rural communities in the province of Bolívar (Ecuador)” of the ADSIEO-COOPERATION program of the Universitat Politècnica de València (UPV). The Ecuadorian Energy Exploitation Research Network of Biomass (ECUMASA) and the IBEROMASA Network (719RT0586) of the IberoAmerican Program of Science and Technology for Development (CYTED) have participated in this program
Meneses Quelal, WO. (2021). Optimization of Anaerobic Codigestion Processes of Lignocellulosic Materials of Difficult Degradation with Residues from Andean Livestock [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171722
TESIS
Compendio

The aim of this experiment was to monitor the microbial communities in two biogas reactors and evaluate the efficiency of denaturing gradient gel electrophoresis (DGGE) as a technique for visualizing shifts in the microbial compositions. The reactors were followed from September 2011 to May 2012. The first reactor is a pilot scale upflow anaerobic sludge blanket (UASB) reactor situated at Foss farm outside of Porsgrunn, running on cow manure. The second reactor is lab scale and situated at Telemark University College, running on pig manure. Samples were taken from the reactors at regular intervals. DNA was extracted from the samples and amplified by polymerase chain reaction (PCR). The primers were 338f and 518r, targeting the 16S rDNA sequence. Changes in the microbial diversity were detected by DGGE in both reactors. Some bands appeared and other disappeared during the period. These changes could not be correlated to changes in operating conditions. This was probably because DGGE reflects cell amounts and not microbe activity levels. DGGE is a highly reproducible and consistently performing fingerprinting technique. It is capable of reflecting long term shifts in the microbial communities and several samples can be compared in one gel. This makes DGGE an effective method for monitoring reactors over time. Several DGGE bands were excised and sequenced, but the results were either negative, or of too poor quality, for further analysis. The probable cause was insufficient separation of bands leading to multiple sequences in the extracted DNA. This may be overcome by using a more specific primer set to reduce the amount of bands.

Textile is a global product used by all people in the world. These textiles after the use are thrown into the trash for incineration or land filling. However an efficient way that can be used to produce more energy, in an environmentally friendly process is anaerobic digestion. Waste textiles which contain cellulosic fibers (e.g. Cotton and viscose) can be converted to biogas. In this study, the performance of a two-stage anaerobic digestion process for biogas production from four different materials, including untreated jeans, treated jeans, cotton, and starch was studied. Starch was used as an easy-to-digest material to compare its digestion with that of cellulosic materials.The two-stage processes were composed of a CSTR (for hydrolysis) and a UASB (for methanogenisis) which were investigated in two different configurations, namely (closed and open systems). In the closed system, the outlet of UASB was completely returned back to the CSTR, while in the open system the UASB outlet was sent to sewage. In a stepwise progress, the OLR was aimed to increase from 2 to 20 g Vs per L per day along with reduction in hydraulic retention time from 10 days to 1 day.The results showed that the closed system was more stable when compared to the open system. The pre-treatment of jeans by NMMO helped to produce methane as that of cotton. The hydraulic retention time was decreased to less than 9 days for treated jeans and less than 5 days for starch. The overall methane yield at OLR of 4 gVS per L per day for starch and treated jeans was 98.5% and 97.4% in the closed system, whereas in the open system the yield was 77.0% and 35.5%, respectively.Another experiment was conducted to compare the performance of two-stage process with that of a single stage process of anaerobic digestion of textiles containing polyester and cotton or viscose. Viscose textiles produced more gas compared to the cotton textile; it may be due to the higher crystalline of cotton which makes it hard to be degraded by the microorganisms. Furthermore, two-stage process could able to produce more methane than the single stage process.The parameters like total solids, volatile solids, pH, gas production, gas composition, concentration of nutrients, and COD were also analyzed for both of the experiments.

This project investigates local industrial biomass streams as feedstocks for the generation of low-cost sustainable energy for The University of Iowa. Methane gas produced during anaerobic digestion would fuel an engine to generate electricity at the University of Iowa Research Park (Oakdale Campus). A current local industry identified for this project is West Liberty Foods (WLF), a turkey processing facility located in West Liberty, Iowa, USA. WLF generates about 6,000 gal/day of blood, 40,000 lb/day of offal (guts), 6,000 lb/day of sludge (process waste water) and 2-4 truckloads/day of feathers as waste streams. To investigate biochemical methane potential, mixed streams and individual streams of WLF were processed anaerobically and incubated at 35 °C. Mixed streams contained blood, offal, and sludge, and individual streams contained offal and sludge. Mixed streams and individual streams generated methane gas. The methane production from mixed streams was achieved on the 11th day of processing, and it was achieved on the 9th day from individual streams. Sludge was the only stream that did not require the addition of acetate for the production of methane gas. Methane production was analyzed using gas chromatography. Methane production was achieved without addition of microbial seed cultures. Cumulative methane and energy produced by the 36th day of processing 6 grams of offal with the addition of acetate are 110 ± 50 mmol/lb and 0.09 ± 0.04 kJ/lb respectively, and without the addition of acetate are 62 ± 2 mmol/lb and 0.054 ± 0.002 kJ/lb respectively. Cumulative methane and energy produced by the 36th day of processing 6 grams of sludge with the addition of acetate are 200 ± 20 mmol/lb and 0.18 ± 0.02 kJ/lb respectively, and without the addition of acetate are 220 ± 60 mmol/lb and 0.19 ± 0.04 kJ/lb respectively. Each average was calculated from three data points with their errors. Reported values are calculated at 95% confidence intervals. The Oakdale Campus is estimating to produce 5.5 MW energy from renewable sources of energy. The methane production capacity from processing turkey waste based on COD analysis was approximately 1% of the renewable energy target. However, the system is still producing methane gas and the process is not complete yet nor has it been optimized. Benchmarking methane productivity through improved quantitative measures should continue to establish the utility of the process.

In order to decrease the pollution of the marine environment from dumping fish waste and by-catch, alternative use for co-digestion with sludge in anaerobic condition was studied. The purpose of this project is to optimize the methane potential from adjustment of the proportion among mixed substrates. Ten groups of different proportions among fish waste, by-catch and sludge were conducted with AMPTS II instrument under mesophilic condition (37 ± 0.5 ºC), by means of the principle of BMP test. The ratio of inoculums and mixed substrate was set as 3:2. The optimal MP obtained after an experiment with 13 days digestion was 0.533 Nm3 CH4/kg VS from the composition of sludge, by-catch and fish waste as 33 %, 45 % and 22 %. It was improved by 6 % and 25.6 %, to compare with the previous studies by Almkvist (2012) and Tomczak-Wandzel (personal communication, February 2012) respectively.

Ever since 1976, livestock farmers in Fiji have been intrigued about biogas digesters as an animal waste management measure, but the concept has never evolved into one that is sustainable. Renewed interest came in 1997 after a better Chinese Modified Dome (CMD) design was established, with this came government funding, however by 2002, some failure was also observed. This study set out to investigate the reasons why biogas digesters have never been established as a sustainable concept, its effectiveness as an animal waste management tool and what changes if any, can be made to try and influence the further development of the concept in Fiji. In order to achieve the objectives, which were simply obtaining the answers to the questions presented above, several different approaches had to be followed. This study was the first on biogas digesters in Fiji and it was unique in the sense that the major component dealt with the social aspects of farmers in relation to their biogas digesters. Basically the study was carried out in two parts - desktop studies and field studies. Desktop studies were done to better understand the situation while the field studies included semi-structured interviews with the farmers as well as the collection of biophysical data. Twelve outcomes are presented in chapter 7 of this paper. Two in particular are the improvement of construction and maintenance, which can only come about through training. The research questions are also answered in chapter 7, with recommendations put forward on possible directions to take in terms of trying to influence the development of the concept in Fiji
Master of Science (Hons)

Thesis (M. Sc.) (Hons) -- University of Western Sydney, 2005.
" A thesis presented to the School of Environment and Agriculture, University of Western Sydney, in fulfilment of the requirements for the degree of Master of Science (Honours)." Includes bibliography : leaves 165 -175, and appendices.

The Brazilian city ofCuritiba produces 2 500 tons of MSW (municipal solid waste) per day that is landfilled.In an effort to find a more sustainable solution for waste management, the objective of this study was to investigate the potential for producing biogas from anaerobic digestion by analyzing the feasibility of small-scale decentralized biogas production as well as centralized production at commercialscale. A field study was carried out to map specific local circumstances and togather data by interviews and literature. Different methods of attaining the organic waste were reviewed and the options for biogas production were evaluated by comparing the highest investment cost admissible for a positive netpresent value of a prospective investment with estimations of investment costs from literature sources. Small-scale decentralized biogas production was found to be the most economically and socially viable option. For centralized production, the results were inconclusive but indicated the potential of profitable business cases. It is estimated that wet digestion in a floating-drum ortubular digester is most suitable for small scale applications while acontinuously dry digestion system is best suited for large scale biogasproduction in Curitiba. The sensitivity analysis showed that the amount oforganic waste available as well as the price of sold products had the biggest economic impact in the scenarios. It was found that any implementation of controlled anaerobic digestion would decrease the total global warming potential of the waste management system. It is recommended that the municipality proceed with and expand a pilot project at Mercado Regional, as well as exploring possibilities for more efficient waste collection, along with gathering more specific data on compositions and quantities for different waste flows. The study was carried out in the scope of a cooperation between KTH, the Swedish EnvironmentalProtection Agency, Municipality of Curitiba and local universities in Paraná,Brazil.
Den brasilianska staden Curitiba producerardagligen 2 500 ton MSW (municipal solid waste) som i dagsläget deponeras. Isyfte att hitta en mer hållbar lösning för avfallshantering ämnade denna studieundersöka potentialen för biogasproduktion via rötning genom att analyseragenomförbarheten av småskalig decentraliserad biogasproduktion samtcentraliserad produktion i kommersiell skala. En fältstudie genomfördes för attkartlägga specifika lokala omständigheter och samla in data genom intervjueroch litteratur. Olika metoder för insamling av organiskt avfall granskades ochalternativen för biogasproduktion utvärderades genom att jämföra de högstatillåtna investeringskostnaderna för ett positivt nettonuvärde av en framtidainvestering med uppskattade investeringskostnader från litteraturkällor.Småskalig decentraliserad biogasproduktion visade sig vara det bästaalternativet från ett ekonomiskt och socialt perspektiv. För centraliseradproduktion var resultaten tvetydiga men indikerade att en lönsam affärsmodellpotentiellt kunde utarbetas. Rötning av substrat med hög fuktighetshalt i en“floating-drum” reaktor eller en tub-formad reaktor bedöms vara bäst lämpat förbiogasproduktion i liten skala emedan ett kontinuerligt system för rötning avtorra substrat bedöms som det bästa alternativet för storskaligbiogasproduktion. Känslighetsanalysen visade att mängden insamlat organisktavfall samt priset på slutprodukterna hade störst påverkan på det ekonomiskautfallet. Studien påvisade även att en implementering av en rötningsanläggningskulle minska växthuspotentialen i avfallshanteringssystemet oavsett skala. Detrekommenderas att kommunen fortsätter med och utvecklar ett pilotprojekt iMercado Regional, samt undersöker möjligheterna för effektivare sophämtning ochsamlar mer specifika data om sammansättning och kvantitet för olika sopflöden. Arbetetutfördes som ett led i samarbetet mellan KTH, svenska Naturvårdsverket,Curitiba kommun och lokala universitet i Paraná, Brasilien.

The use of renewable waste for bioenergy production is in discussion because of the concurrence to the food or animal feed. The treatment of organic waste is necessary in order to keep clean the environment. The combination of those proposals, the waste utilization and the production of renewable energy can be combined with several techniques. In Vietnam the energy demand will increase rapidly in the next years, because a lot of people do not have access to electricity. The development of power sources is limited mainly to large central power plants using hydropower and traditional fossil fuels. So in the country there exists a considerable potential for sustainable energy sources like biomass and residues. The biogas potential is large due to the high livestock population. There are more than 30 million animals in farms, mostly pigs, cattle, and water buffalo. There is a high potential for biogas utilization. Biogas production is economic in small and in big plants, so household biogas digesters are one opportunity for production of renewable energy in small villages or cities with a high livestock population. The advantage of anaerobic treatment of organic waste is the work in closed loops. The treatment of organic waste and the utilization of digested sludge from wastewater treatment plants are samples for the circulation of materials after use. The remaining materials can be used in the natural circulation process, because the nutrients such as nitrogen, phosphorous and carbon, and also trace elements remain in the digested matter. In biogas plants a huge variety of substrates can be used. The adaption of biogas technology to the special conditions of the substrates, the increase of the prices for energy, the aim to replace fossil energies with renewable energies will be forced in the next years
Việc sử dụng chất thải có thể tái tạo được để sản xuất năng lượng sinh học là vấn đề còn đang được thảo luận vì sự cạnh tranh với thức ăn hoặc thức ăn cho động vật. Việc xử lý các chất thải hữu cơ là cần thiết để giữ sạch môi trường. Sự kết hợp của các đề xuất đó, tận dụng các chất thải và sản xuất năng lượng tái tạo có thể có thể được kết hợp với một số kỹ thuật. Ở Việt Nam, nhu cầu năng lượng sẽ tăng lên nhanh chóng trong những năm tiếp theo, bởi vì rất nhiều người vẫn chưa có điện sử dụng. Sự phát triển của các nguồn năng lượng chỉ giới hạn chủ yếu là các nhà máy điện lớn trung tâm sử dụng thủy điện và các nhiên liệu hóa thạch truyền thống. Vì vậy, trong nước tồn tại tiềm năng đáng kể cho các nguồn năng lượng bền vững như sinh khối và những nguồn khác. Tiềm năng khí sinh học lớn do quần thể động vật nuôi rất lớn. Có hơn 30 triệu động vật trong trang trại, chủ yếu là lợn, bò, trâu nước. Tiềm năng sử dụng khí sinh học rất cao. Sản xuất khí sinh học rất có hiệu quả kinh tế trong các nhà máy nhỏ và lớn, do đó, các thiết bị phản ứng tạo khí sinh học ở các hộ gia đình là một cơ hội để sản xuất năng lượng tái tạo trong các thành phố hay làng mạc nhỏ với số lượng lớn các gia súc được chăn nuôi. Ưu điểm của việc xử lý kỵ khí các chất thải hữu cơ là làm việc trong vòng khép kín. Việc xử lý các chất thải hữu cơ và sử dụng bùn phân hủy từ các nhà máy xử lý nước thải là các ví dụ cho việc tuần hoàn các vật chất sau khi sử dụng. Các vật chất còn lại có thể được sử dụng trong quá trình tuần hoàn tự nhiên, vì các chất dinh dưỡng như phốt pho, nitơ và carbon, và cả các nguyên tố vi lượng vẫn tồn tại trong nguyên liệu đã phân hủy. Trong các nhà máy khí sinh học, rất nhiều loại chất nền có thể được sử dụng. Sự cải tiến công nghệ sản xuất khí sinh học theo các điều kiện đặc biệt của các chất nền, sự gia tăng của giá năng lượng, mục đích thay thế nguồn năng lượng hóa thạch bằng năng lượng tái tạo sẽ là bắt buộc trong những năm tới

Global warming is the one of the most dangerous threats that the entire world is facing today. The emission of greenhouse gases is increasing the impact of global warming. In such a situation, reduction of GHG emissions and finding an alternative source of energy is more and more important. The production of biogas from food wastes is considered as a suitable way for the reduction of GHGs emission. The production of this type of renewable energy is very popular in Asian countries, especially in countries like India and China. Biogas production never creates any harmful effects to the environment but at the same time it also produces byproducts that are not harmful for the environment.  This study tries to investigate the possibility for the production of biogas from food wastes in restaurants under Swedish conditions. In order to do so, three different models of biogas plants in three different restaurants were used as a case study. The results showed that biogas production from food waste in restaurants are practically possible in Sweden and it can be used as an alternative source of cooking fuel with many benefits both economically and environmentally. Temperature problems in Sweden during winter season can be avoided by using pre-heating technique.

Orange cultivation is a huge industry which increasing for each year. By the year 2010 theorange production of the world is expected to reach 66.4 million tons per year. Most of theoranges are used for orange juice production. Consequently, a large amount of organic wastes,including seeds, segment membranes and peel, counting up to half of the weight of usedoranges, are generated As alternatives to land filling and incineration, source separation andcomposting together with biogas production are being considered as suitable methods fortreating this fraction of wastes, because it holds a high amount of organic materials in form ofvaluable carbohydrate polymers. However, the presence of peel oil, limonene, known to haveantimicrobial effects, has showed to be a strong inhibitor for the biogas producingmicroorganisms. Therefore the orange peel waste (OP) was mixed with the organic fraction ofmunicipal solid waste (MSW) in this study to keep the concentration of this inhibitorycompound at low level.Based on the results from previous batch experiments, this study was performed in order toconfirm and develop the possible use of orange peel waste in biogas production. Since thebatch experiments showed that the methane production was not affected, when a mixture of70% MSW and 30% OP (calculated on the basis of volatile solids (VS) content added) wasused as substrate, a continuous anaerobic digestion experiment was performed using the samemixture of MSW and OP as a substrate in this study. Furthermore, a reactor utilizing onlyMSW was used as a control. Both reactors were operated during 35 days at thermophilicconditions (55ºC), with an organic loading rate of 3gVS/L/day and a hydraulic retention timeof 21 days. The methane production was around 0,5 Nm3/kgVS/day in both reactors duringthe first period of operation. However, the production of methane started to decrease after 20days followed by a sharp decrease during the last 5 days in the orange peel-containing reactor.Furthermore, a steadily increase (from 4,85g/L to 6,51g/L) in the total content of volatile fattyacids (VFA) could be observed here, while the total content of VFA in the control reactorremained at low levels (0,84g/L). A second experimental set up using a decreased amount ofOP (20% OP and 80% MSW) in the substrate mixture and operating at the same conditions sthe previous experiment was also performed and showed similar trends in the results. Thefailure of the process can be explained by inhibition in the system, which led to theaccumulation of VFA’s resulting in a decreased and finally no methane production. Thisinhibition might be caused by the accumulation of the inhibitory compound, limonene,presented in the orange peel waste. Therefore some treatment of the OP is necessary prior todigestion to avoid this inhibition. Batch digestion of treated vs untreated OP showed that themethane production of treated OP could be increased to 0,628 Nm3/kgVS compared to that of0,408 Nm3/kgVS from the untreated sample. Further investigations utilizing this treated OPfraction in continuous biogas process are necessary in the future.

The focus of the current study was on the recovery of carbon from municipal bio-waste streams. Firstly, the relationship between methanogenic pathways and the properties of anaerobic granules was studied using two pilot-scale upflow anaerobic sludge blanket (UASB) reactors with different granule size distribution. UASB1 granules were larger (3-4 mm) with multi-layered internal structure and the archaeal community was dominated by acetoclastic methanogens, while the UASB2 granules were smaller (1-2 mm) without a layered internal structure and the archaeal community was predominated by hydrogenotrophic methanogens. The acetoclastic methanogenic activities of UASB1 (250-437 mL CH4/g VS·d) than UASB2 (150-260 mL CH4/g VS·d), confirming that acetoclastic methanogenesis was more dominant in UASB1. Temperature increase from 20oC to 28oC did not change the microbial community but resulted in increased and stable biogas production for both reactors. There was an increase in chemical oxygen demand (COD) with hydraulic retention time due to increased contact time. The second part of the study focused on anaerobic co-digestion to produce volatile fatty acid (VFA) due to its higher value. The impact of substrate ratio of primary sludge (PS) and external organic waste (OW) and the robustness of the VFA system in the long term were assessed. Lab-scale batch study with different proportions of PS and OW; 0%, 25%, 50%, 75%, 100% of OW in terms of COD and scaled up in a semi-continuous pilot reactor with substrate ratio of 50% OW based on the results of the lab-scale study were performed. There was an increase in VFA production with an increase in OW proportion due to the availability of biodegradable organics. Acetic acid was the most dominant VFA in the batch reactors while in the semi-continuous experiment, caproic acid was dominated (50%). As carbon sources, the VFA-rich liquid attained the highest specific denitrification rate when compared with acetate and methanol.
I kommunala avfallsströmmar finns det en stor potential för resursåtervinning på grund av det höga organiska innehållet vilket kan användas för biobaserade produkter. På grundval av detta så fokuserar denna studie på resursåtervinningen av kol från kommunala avfallsströmmar genom att undersöka nuvarande och nytillkomna tekniker för att få vattenreningssystem att också bli resursåtervinningssystem. Första delen av studien undersöker relationen mellan metanproduktion och karaktäriseringen av anaerobiska granuler med ändamålet att förbättra energiproduktionen genom direkt behandling av kommunalt avloppsvatten. För detta ändamål så användes två UASB (Upflow Anaerobic Sludge Blanket) pilotreaktorer. Reaktorerna kördes med olika stora granuler, olika temperaturinställningar och olika hydrauliska uppehållstider (HRTs). Storlek, mikrobiell struktur, intern mikrostruktur och specifik metanogenaktivitet av de anaerobiska granulerna analyserades. Granulerna i UASB1 var 3-4 mm stora med interna multilager av mikrostrukturer som bestod av acetoklastika-metanogen arkéer. Granulerna i UASB2 var 1- 2 mm stora utan interna multilager och bestod av hydrogenotrofa metanogener. Aktiviteten i granulerna i UASB1 var 250-437 mL CH4 /g VS·d och i UASB2 var det 150-260 mL CH4 /g VS·d, vilket bekräftar att de acetoklastisk-metanogesa var mer effektiva i UASB1 än de hydrogenotrofa i UASB2. Att öka temperaturen från 20 o C till 28 o C under försöket medförde ingen förändring av den mikrobiologiska strukturen, men gav en ökning i biogasproduktion i UASB1 och högre och stabilare biogasproduktionshastighet i UASB2. Ökningen av biogasproduktion berodde på en reduktion i metans löslighet i utflödet och stabilare metanogenes. Ökning i HRT resulterade i större reduktion av organiskt material mätt som kemisk syreförbrukning (COD) och större biogasproduktion på grund av längre kontakttid mellan substrat och mikroorganismer. Den andra delen av studien fokuserar på att utveckla ett tillvägagångssätt att få en anaerob rötning att producera flyktiga fettsyror (VFA) istället för biogas. Studien fokuserar på effekten som kvoten mellan substraten primärslam och externt matavfall (OW) har och hur robust VFA-systemet skulle vara i stor skala på lång sikt. Olika kvoter av primärslam och matavfall testades i labbskala i batchstudier med 0 %, 25 %, 50 %, 75 % och 100 % COD OW. Baserat på resultaten från labbskala så kördes 50% COD OW i ett semi-kontinuerligt pilotförsök. Batch-testerna i labbskala visade att högre % COD OW, gav högre VFA produktion på grund av högre koncentration av organiskt material. Ättiksyra var den mest förekommande VFAn i batch-testerna medan kapronsyra var högst förekommande (50%) i det semi-kontinuerliga försöket. Denitrifikationsförsök visade att VFA-rik vätska från pilotskalareaktorerna gav den högsta specifika denitrifikationshastigheten i jämförelse med acetat och metanol. Resultaten visar att värdefulla kolkällor kan återvinnas från kommunalt avfall genom anaerob behandling av kommunalt avloppsvatten och samfermentering av primärslam och matavfall.

QC 2020-06-15

Production of biogas through anaerobic digestion (AD) from the organic fraction of minucipal solid waste (OFMSW) was compared to incineration of the waste. At the moment, almost all of the OFMSW in Singapore is incinerated. Three different scales of biogas plants were compared to incineration: one large-scale biogas plant that can treat half of all OFMSW in Singapore; one medium- scale biogas plant about 15 times smaller than the large one; and one small-scale biogas plant that can treat waste from e.g. a shopping centre or food centre. Two alternatives for utilization of the biogas were also compared, generation of electricity and the use of the biogas in heavy vehicles. The combination of the different scales and the different utilization gives the six different scenarios. By using life cycle assessment (LCA) the different scenarios were compared in terms of global warming potential (GWP), acidification, eutrophication, energy use and land use. The results show that biogas production creates less environmental impact than incineration. The use of the gas as a vehicle fuel creates a bigger decrease of GWP, acidification and eutrophication than when using the gas for electricity generation. The prevention of leakage of biogas during production and upgrading is crucial for the environmental impact on GWP. A leakage of only a few percent of the produced gas will lead to a loss of all the gain in saved GHG-emissions.

Biogas is an environmentally friendly energy source with great importance for sustainable development. The purpose of this study is to determine the feasibility of setting up a biogas plant at the student housing area planned at Albano in Stockholm. The possibility of attaining self-sustainability in Albano is also investigated. After compiling the processes for converting household waste into biogas through a literature study, a quantitative feasibility study of setting up a biogas plant is carried out. The usable amount of household waste is determined through an empirical study. Investment costs of comparable biogas production facilities are obtained from companies working in the biogas field. The producible biogas amount and rates of conversion from biogas to heat/electricity are derived from existing data in similar studies. The energy demand is calculated based on existing data from housing companies and authorities. Four possible scenarios are created to study all the possible outcomes of establishing a biogas plant. The maximum producible biogas is determined to be 12.199 m3/year. The total energy demand in Albano is determined to be 2.931MWh/year, of which 2,4 TWh/year is heat and 531 MWh/year is electricity. This amount is not sufficient to meet the specific requirements. Recommendations for Albano were made accordingly.
Biogas betraktas som ett en miljövänlig energikälla med stor betydelse för det kommande arbetet mot en mer hållbar utveckling. Denna rapport avser behandla möjligheten till ett upprättande av en biogasanläggning vid ett planerat studentboende vid Albano, Stockholm. Vidare kommer även möjligheterna till ett mer självständigt hållbart arbete i området behandlas. Som en del i rapporten kommer en analys av omvandlingen från hushållsavfall till biogas utföras i form av en kvantitativ studie med fokus på en förstudie för upprättande av biogasanläggning. Mängden hushållsavfall fås genom en empirisk studie av författaren. Den andel energi som beräknas kunna produceras fås genom befintlig data från utförda studier på Albano. Utifrån detta fastställs energibehovet utifrån givna rekommendationer och uppskattningar utförda av företag och myndigheter. Fyra möjliga utfall är definierade i syfte att kartlägga de möjliga utfallen för biogasanläggningen. Den maximala andel producerad biogas uppgår till 12.199 m3/år. Den totala energibehov i Albano bestämdes till 2.931 MWh/år, varav värmebehovet är 2,4 TWh/år och elbehovet är 531 MWh/år. Den maximala andel producerad biogas kan användas för att tillverka 48,8 MWh/år värme och 24,4 MWh/år elektricitet. Denna mängd är inte tillräcklig för att tillgodose de bestämda kraven. Utifrån detta har olika förslag utformats.

Transport of fecal bacteria and nutrients from point and nonpoint sources to surface water bodies is of significant concern in Virginia and the United States. In Virginia, 4,320 river miles are impaired for one or more beneficial use and 72% of the streams are impaired due to pathogen indicators (VDEQ, 2002). Land applications of manure from confined animal systems and by direct deposit by grazing animals are both major sources of fecal bacteria and nutrients in runoff. Therefore, an understanding of the overland transport mechanisms for fecal bacteria and nutrients is very important for the development of best management practices to reduce loading of pathogens and nutrients to surface water bodies. The objectives of this study were to quantify the release and transport potential of three fecal bacterial indicators: E. coli, Enterococcus, and fecal coliforms; and nitrogen and phosphorus from land applied manure during runoff events. Another objective was to identify the Enterococcus species present in dairy manure and determine which species have the highest potential to be transported by runoff.

Release plots were established to study the in-field bacteria and nutrient release. The bacteria and nutrients released from the plots are available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, cowpies, and none or control) and three land type treatments: pasture with a history of poultry litter application (Turkey Farm), pasture with a history of liquid dairy manure application (Dairy Farm), and pasture with no prior manure application (Tech Research Farm) were studied. During a short but intense rainfall event, the highest bacterial release was measured under the cowpie treatment (E. coli concentrations ranging from 37,000 to >300,000 and FC concentrations ranging from 65,000 to >300,000). Pasturelands with a history of previous manure applications did not release higher bacteria concentrations compared with pasturelands which had never received manure applications. Pasturelands with a history of land application of liquid dairy manure and turkey litter had 143% and 94% higher TSS concentrations available to be transported off the field during overland flow events because of the build up of organic material on the soil surface. TP concentrations released from the cowpie, liquid dairy, and turkey litter treatments were 3.12 mg/L, 3.00 mg/L, and 1.76 mg/L, respectively.

Transport plots were developed to measure the concentrations of fecal bacteria and nutrients present in overland flow at the edge of the field. The bacteria flow-weighted concentrations were highest in runoff samples from the plots treated with cowpies (200,000 CFU/100 mL of E. coli and 234,000 CFU/100 mL of FC). The turkey litter had the highest concentration of dissolved phosphorus in runoff from pasturelands (1.22 mg/L), but the cowpie treatment had the highest concentrations of sediment bound phosphorus in runoff (0.73 mg/L). All three treatments investigated in this study contributed to phosphorus loading in surface waters and could potentially increase the risk of eutrophication. Total nitrogen concentrations from the transport plots exceeded the threshold for likely eutrophication problems for all treatments and the total nitrogen concentrations from plots treated with cowpies exceeded the threshold for severe eutrophication problems.

The Biolog System, a method of bacterial source tracking, was used to identify the different species of Enterococcus present both in the cowpie source manure and in the runoff collected from the transport plots treated with cowpies. The source manure is dominated by the Enterococcus mundtii (55%), Enterococcus gallinarum (20%), Enterococcus faecium (10%), and Enterococcus faecalis (10%). Enterococcus faecalis had the highest percentage of isolates present in runoff with a total of 37%, followed by Enterococcus mundtii which was present in 21% of the runoff events and Enterococcus gallinarum and Enterococcus faecium (11%).

Improvements in understanding the bacterial release and overland processes will enhance modeling of bacteria and nutrient transport, and provide a basis for a more realistic evaluation of the impacts of management practices implementation. The data from this study will serve as a baseline to model the release and transport of fecal bacteria and nutrients from agricultural watersheds to surface waters.

Master of Science

This master’s thesis has been performed in Bangkok, Thailand at the company Eco Design Consultant Co., Ltd. The aim is to investigate the possibilities to generate absorption cooling from municipal solid waste in the Bangkok area. The investigation includes a comparison between waste incineration and biogas production with combustion to see which alternative is preferable. During the investigation, a Swedish perspective has been used. The research for the report mainly consisted of published scientific articles from acknowledged sources as well as information from different Thai authorities. Also, experts within different areas were contacted and interviewed. In order to determine which of the two techniques (waste incineration or biogas production with combustion) that is best suited to generate absorption cooling, a model was designed. This model involved several parameters regarding e.g. plant efficiency, amount of treated waste and internal heat usage. As for the results of the model, three parameters were calculated: the generated cooling, the net electricity generation and the reduced greenhouse emissions. The overall Thai municipal solid waste generation in Thailand is estimated to approximately 15 million tons per year and the majority of the waste ends up at open dumps or landfills. There are only two to three waste incinerators in the country and a few projects with biogas generation from municipal solid waste. The main electricity is today generated from natural gas which makes the majority of the Thai electricity production fossil fuel based. As for absorption cooling, two applications of this technique has been found in Thailand during the research; one at the Naresuan University and one at the Suvarnabhumi airport in Bangkok. The model resulted in that the best alternative to power absorption cooling technique is waste incineration. This alternative has potential to generate 3200 GWh cooling per year and 1100 GWh electricity per year. Also, this alternative resulted in the largest decrease of greenhouse gas emissions, ‐500 000 tons per year. The model also showed that the same amounts of generated cooling and electricity can never be achieved from biogas production with combustion compared to waste incineration. Regardless, waste incineration has an important drawback: the citizens of Thailand seem to oppose further development of waste incineration in the country. The biogas technique seems more approved in Thailand, which benefits this alternative. Due to the high moisture and organic content in the municipal solid waste, a combination between the two waste handling alternatives is suggested. This way, the most energy can be withdrawn from the waste and the volume of disposed waste is minimized. Our overall conclusion is that the absorption cooling technique has great potential in Thailand. There is an increasing power‐ and cooling demand, absorption cooling generated from either or both of the alternatives can satisfy these demands while reducing greenhouse gas emissions. We also believes that the cost for using absorption cooling has to be lower than for the current compression cooling if the new technique is to be implemented further.

Colombo City is the commercial capital of Sri Lanka with an estimated resident population of over 750,000 spread over 3741 hectares (ha) and has a population density over 1188 per ha. It is located in the western coast of Sri Lanka and is in wet zone. The topography is of flat terrain with a mix of land and water. Considering the population and the limited undeveloped land available, the disposal of Municipal Solid Waste (MSW) and Sewer is a major environmental problem in Colombo. The major object of this thesis is to identify and evaluate a productive waste management system that is not only environmental friendly but also sustainable and cost effective. In this context, as a sustainable technology, applicability of anaerobic digestion is investigated and methane generation potential of the waste is evaluated. In order to identify a sustainable waste management system, the quantity of waste generated within the city of Colombo is identified. The current practices of disposal of these wastes are then reviewed to identify any issues regarding its sustainability. The majority of the MSW is currently disposed as open landfill that is causing pollution of waterways, with its leachate, as well as the polluting the atmosphere around it with its bad odour. The sewer is discharged to sea or disposed via a self-contained soakage pit. Except for few small-scale anaerobic digestion plants that use solid waste for generation of biogas for localized use, there is no large-scale waste to energy projects in operation in Sri Lanka. The sewer is not used productively at all. Having identified the quantity of waste and the disposal methods practiced, the priority is to identify sustainable and productive methods of disposal of wastes that suits best the local conditions. With this in view research hitherto carried out are studied and available literature is reviewed. The objective is to ascertain the processes that productively harness the energy potential of MSW and Sewer, individually or in combination. There are many physical and chemical methods for treatment of wastes. However bioconversion of waste provides the best options for tapping the energy of the wastes. Of the two main bioconversion methods aanaerobic processes exhibit many advantages over aerobic digestion with its ability of handling high organic loading rates and low sludge production. However, the reason for the increase in applications of anaerobic processes, is, its potential for production of energy using the biogas generated. The methane so produced can replace fossil fuel and therefore has a direct positive effect on greenhouse gas reduction. Therefore, compared with other bioconversion technologies for treatment of MSW and sewer/wastewater, the energy and environment benefits make anaerobic digestion an attractive option. Anaerobic treatment of waste in an engineered landfill bioreactor is found to be the best option for treatment of MSW. Whilst providing a decrease in long term environmental risks and low operational and closure costs it provides with valuable energy source in generation of methane. As for sewer generation of methane in anaerobic processes can be enhanced with co-digestion of different types of waste suitably selected. In this regard co-digestion of sewer and wastewater with food waste is found to be productive and is applied in this study. Literature review is carried out to determine suitable models to predict the methane generation potential. The "First Order Decay Model" is identified as the appropriate model for prediction of methane from MSW in landfills. The "Anaerobic Digestion Model No.1" is applied for prediction of methane from sewer and waste water. Chemical composition of MSW is the primary parameter which affects the methane generation. The chemical composition is computed applying the ultimate analysis and using a stoichiometric based approach. For sewer and waste water the basic parameters of BOD and COD concentrations are available from data gathered. Apart from these two parameters the other parameters relevant to local conditions are not available. Therefore values that closely fit the local conditions are taken from the literature. The study determines the methane generation potential of MSW approximately 2.1 x 106 m3 per annum and anaerobic co-digestion of sewer and food substrates generate 9.1 x 106 m3 per annum. If parameters could be determined for the wastes generated locally the accuracy of the methane generation potential could be further enhanced. In this context, further studies, should be directed from the conventional landfills to "Anaerobic Bioreactor Controlled" landfill, where circulation of liquids including leachate is carried out to increase the biogas yield. For sewer the focus should be on the most economical foot print of parallel banks of number of continuous-flow stirred-tank reactors (CSTR) operating in series to accommodate the total flow rate of sewer.

This thesis presents the potential of biogas production using food waste collected from the region of Kartamantul in Yogyakarta, Indonesia. Biogas can be used for cooking and generating electricity. The study compares two different end uses or markets for utilizing the biogas in the region. The daily food waste collected in the region of Kartamantul is 120 tonnes. This corresponds to a daily biogas production of 13 087 m3. Electricity generated from biogas can replace fossil-based coal electricity while cooking biogas can substitute the common fossil fuel liquefied Petroleum Gas (LPG). The price for selling one kWh of electricity to the state owned enterprise PLN is 16.5 USD cents. The price for selling one m3 of biogas for cooking is 38.5 USD cents, which is equivalent to the available price of LPG. The study finds that the avoided emission due to the substitution of fossil-based coal electricity and cooking LPG-gas is around 64 GgCO2-eq per year. Considering the economical results for a life span of 20 years in the first utilization option Biogas for Electricity gives a net present value (NPV) of 2 MUSD while for the utilization option Biogas for Cooking gives a net present value (NPV) of 5.82 MUSD. The breakeven for Biogas for Electricity is 13.8 USD cents per kWhe while for Biogas for Cooking is 25.5 USD cents per m3-biogas. The study concludes that it is feasible to invest in AD plant in the region of Kartamantul where both markets are profitable and environmentally friendly.
Denna avhandling visar potentialen för biogasproduktion med hjälp av matavfall som samlats från regionen Kartamantul i Yogyakarta, Indonesien. Biogas kan användas för matlagning och elproduktion. Studien jämför två olika slutanvändningar eller marknader för att utnyttja biogasen i regionen. Det dagliga matavfallet som samlas i regionen Kartamantul är 120 ton. Detta motsvarar en daglig biogasproduktion på 13 087 m3. Elektricitet som genereras från biogas kan ersätta fossilbaserad koldioxid, medan tillagning av biogas kan ersätta det gemensamma fossila bränslet flytande petroleumgas (LPG). Priset för att sälja en kWh el till det statligt ägda företaget PLN är 16,5 USD cent. Priset för att sälja en m3 biogas för matlagning är 38,5 USD cent, vilket motsvarar det tillgängliga priset på LPG. Studien konstaterar att den undvikna utsläppet på grund av substitutionen av fossilbaserad kolkraft och matlagning av gasol är cirka 64 GgCO2-ekv per år. Med tanke på de ekonomiska resultaten för en livslängd på 20 år i det första utnyttjandegradet ger Biogas for Electricity ett nettopåverkande värde (NPV) på 2 MUSD medan för utnyttjandegraden Biogas for Cooking ger ett nettoförskott (NPV) på 5,82 MUSD. Breakeven för biogas för el är 13,8 USD cent per kWhe medan för Biogas for Cooking är 25,5 USD cent per m3-biogas. Studien drar slutsatsen att det är möjligt att investera i AD-anläggningar i regionen Kartamantul där båda marknaderna är lönsamma och miljövänliga.

Biodegradable wastes cause high emissions of greenhouse gases (GHG) if not properly treated. The emissions can be reduced by the development of an effective waste management strategy. Waste-to-energy technologies, such as anaerobic digestion (AD) can be utilised for this purpose. Biomass energy from wastes is of particular interest to Cyprus that has to meet legal commitments for reducing its GHG emissions by 5% compared to 2005 levels and increase the contribution of renewable energy sources to 13% by 2020. This research project is making a significant contribution to this effort. The research considered the quantities and distribution of biodegradable waste in Cyprus and developed the necessary methodologies and tools for their estimation and determination of the potential for energy production through AD. The study identified that the predominant biodegradable wastes in Cyprus are the biodegradable fraction of municipal solid waste (MSW), sewage sludge, solid and liquid agricultural residues and solid and liquid wastes from the food and drinks industries. According to the estimated amount of solid and liquid biomass from these waste streams, at least 4,200 TJ of energy can be produced through AD, which represents 4% of the national energy demand. Livestock production is a very important source of waste due to the high potential of biogas production with the aid of AD. The produced energy can satisfy the needs of a farm, reduce the consumption of fuel and provide renewable energy to the national grid. Simple methodologies were developed and implemented for the estimation of energy consumption of the farm and the respective GHG emissions. It was found that in Cyprus the annual energy consumption per animal is lower than most other countries, due to favourable weather conditions which reduce the energy needs for heating. The emissions from energy use in livestock production contribute 16% to the total agricultural energy emissions. Literature review on AD, confirmed the complexity of the process, due to the many microorganisms involved. To estimate the potential of biogas production from animal waste through AD, three methods were developed based on the accepted relations that exist between Chemical Oxygen Demand (COD), volatile solids (VS), waste digested and biogas production. The results show that livestock production could cover the complete agricultural energy demand and make a considerable contribution to the renewable energy targets of Cyprus. Due to the identified importance that AD could have for Cyprus and to overcome deficiencies of existing models, the software FARMS was developed. The tool can be used by any farmer, consultant or policy maker for the estimation of the potential of biogas production, associated costs, reduction in GHG emissions and comparison of scenarios for waste management. Furthermore, the validation of the tool is presented. This was done through comparison against data collected from existing AD plants and through testing by potential users.

Increased access to energy is a key factor to reduce poverty and to gain increased development and prosperity. Access to energy is not equally distributed globally. On average a Swedish person consumes more energy than 12 individuals in Tanzania. The Msambara village arose in the 1930s. 80% of the inhabitants are children and the families are large. Life expectancy is 52 years for women and 54 for men. The entire region is very poor and the standard of living in Msambara is low, even compared to other parts of the country. In rural Msambara in Tanzania the cooking method is very primitive and is usually carried out indoors on three stones. Indoor pollution is contributing to eye infections. Incomplete combustion not only emits greenhouse gases increasing global warming, but also more directly emits particles effecting human health. Women and girls are particularly vulnerable to burning caused by air pollution, especially since they are responsible for cooking. The women pull a heavy load in the household work. They are responsible for raising and caring for children, managing farms, collecting firewood, fetching water, visiting the market and cooking for the family. The adoption of biogas technology reduces the need for traditional energy and thereby reduces environmental degradation. In addition, the residue is an improved agricultural fertiliser. Biogas technology has social considerations; burning of biomass for cooking reduces indoor air pollution and reduces workload to collect firewood, often performed by women. Moreover, biogas is desirable from an economic point of view. The method in this work can conveniently be divided into three different parts. These are the designing and construction process as well as the socio-economic study. The socio-economic component is split into two different sections, which are field study and data modelling. The study shows that the social negative impact may or may not be reduced by the introduction of the biogas facility, but the biogas facility in the way it is made will potentially contribute to sustainable economic growth for the household. It also shows that the household’s organic waste produced from human, animal, kitchen and garden waste is enough to provide the necessary gas needed for cooking and no additional firewood will be needed. Two diary cows, in addition to the household’s waste, will provide enough gas needed to introduce cooling capacity for food storage. By adding cooling capacity in the household, time will be saved from the food preparation process but the introduction of biogas itself will not reduce the individual work burden when no cooling capacity is installed. The study also shows that placing the digester in the ground makes a stable environment for the mesophilic and methanogenic microbes. The Socio-economic study indicates that by introducing an alternative method to cooking, positive health effects will arise and the household benefits economically. It is not possible from this thesis to conclude that by adding and treating human toilets as a substrate that possible health benefits will take place.
Sammanfattning Ökad tillgång till energi är en nyckelfaktor för att minska fattigdom och för att få ökad utveckling och välstånd. Tillgången till energi är inte jämnt fördelad globalt. En svensk person konsumerar i genomsnitt mer energi än 12 individer i Tanzania. Byn Msambara uppstod på 1930-talet, 80 % av invånarna utgörs av barn, familjerna är stora. Medellivslängden är 52 år för kvinnor och 54 år för män. Hela regionen präglas av fattigdom och levnadsstandarden i Msambara är låg, även jämfört med andra delar av landet. I Msambara som ligger på Tanzanias landsbygd är tillagningsmetoden mycket primitiv och utförs vanligen inomhus på tre stenar. Den rökiga inomhusmiljön leder ofta till ögoninfektioner. Den ofullständiga förbränningen frigör inte bara växthusgaser och bidrar till den globala uppvärmningen, utan mer direkt avges partiklar som påverkar människors hälsa. Kvinnor och flickor är särskilt utsatta för luftföroreningar eftersom de är ansvariga för matlagning. Kvinnorna drar ett tungt lass i hushållsarbetet. De är ansvarig för uppfostran och vårdnaden utav barnen, hushållsarbetet, sköta jordbruket, samla ved, hämta vatten, besöka marknaden och att laga familjens mat. Introduktion av biogasteknik minskar behovet av traditionell energi och miljöbelastningen. Rötresten är dessutom ett förädlat gödningsmedel. Biogas introduktionen ger positiva sociala konsekvenser då det leder till reducerade luftföroreningar inomhus och minskar behovet av att införskaffa ved, vilket nästan undantagslöst utförs av kvinnor. Dessutom är biogas positivt ur ekonomisk synvinkel. Arbetsmetoden är tydlighetens uppdelat i tre delar. Nämligen dimensionering av rötkammaren, uppförandet av densamma och en okonstlad socioekonomisk studie som i sin tur är uppdelad i en fältstudie och simulering. Studien kan inte visa på att summan av de sociala negativa effekterna minskar med införandet av biogasanläggningen men däremot att den potentiellt bidrar till stärkt ekonomi för hushållet. Den visar också att hushållens organiska avfall som produceras i form av avfall från människor, djur, kök och trädgård är fullt tillräckligt för att producera den nödvändiga gasen som behövs för matlagning. Ingen ytterligare ved kommer att behövas. Två kor förutom hushållets avfall ger den biogas som krävs för att driva ett kylskåp vilket ökar hållbarheten vid matförvaring. Genom tillförandet av kyleffekt till hushållet frigörs tid vilket innebär en tidsbesparing. Införandet av biogas i sig minskar inte den individuella arbetetsbördan. Studien visar också att placeringen av rötkammaren i marken utgör en stabil miljö för de mesofila metanogena. Den socioekonomiska studien visar att införandet av den alternativ matlagningsmetoden medför positiva hälsoeffekter och är ekonomiskt gynnsamt för hushållet. Från denna studie är det inte möjligt att dra slutsatsen att tillförandet och behandlingen av den mänskliga toaletten i rötprocessen ger hälsofördelar.

In the waste management system of Peru, there is a lot to fix, change and improve from households areas. In this report is presented why and how necessary is the construction of landfills to have an appropriate place to dispose the waste of the collection .At the same time, the report shows how profitable can be from social, economic and ecologic way, with the investment of treatment plants that use biogas from the landfills to produce energy. Differents solutions – vehicle fuel production, electricity generation etc – are discussed in light of the different economy, geography and social situation in three selected cases.

Content: The understanding of how chemical, physical and environmental parameters work during anaerobic digestion production and waste treatment is an important step in improving the efficiency and process stability. This study provides the evolution of the biogas production and the efficiency of the treatment of the anaerobic digestion of solid wastes of tanneries at-line monitored in batch laboratory-scale bioreactors. Leather shavings and sludge from wastewater treatment plants substrates were considered in the study. The findings suggest that AD of the tannery solid waste can be separated into three phases: a long lag phase, a log phase with a low metabolic rate and the final phase where all the shavings were metabolized. Take-Away: The AD of the tannery solid waste can be separated into three phases: a long lag phase, a log phase with a low metabolic rate and the final phase where all the shavings were metabolized

The controlled anaerobic digestion of organic waste in a biogas facility aggregates advantages of waste treatment, energy recovery and nutrient recycling and is a promising technology to deal with contemporary issues of waste management and energy recovery. Small-scale biogas production units can be simply designed and successfully operated even in settings where means for advanced technology equipment are low and institutional capacities limited. In the country of Lebanon, landfilling and open dumping of solid waste is common practice and anaerobic treatment of waste is applied only sporadically and hence, not well-established. The aim of this study was to assess the feasibility of small-scale biogas production using organic waste, explore options for its application and propose a business model on how feedstock sourcing, facility operation and end product utilization could be realized in the research area. Research area was Ghazir village, a community within the urbanized coastal area in Lebanon. Methods were of both quantitative and qualitative nature.A techno-economic assessment served to quantify biogas and liquid digestate production rates, based on available resources of organic waste in the research area. Costs associated with installation, operation and maintenance of the proposed facility have been projected based on present examples of similar facilities in the country. Interviews with local stakeholders and a questionnaire survey among residents in the area of research allowed to identify suitable end use options for the produced biogas and served to explore communal acceptance of local biogas production. Results show that the produced biogas can be used for thermal feedstock treatment to supply local farmers with a fertilizer alternative, i.e. the liquid digestate. Organic waste that is subject to the anaerobic treatment in a digester can be provided by multiple point sources, i.e. households and a local food market in the form of source-sorted kitchen waste and unsold fruits and vegetables, respectively. Due to the current unfamiliarity with anaerobic treatment of organic waste in the research area, tests on the effects on crop yields are advised to take place before implementation of the proposed business model, as its communal benefits hinge on the suitability of the liquid digestate as a fertilizer. Economic calculations show low investment costs for the proposed facility as well as acceptable annual revenues in case the liquid digestate proves to be of interest for commercial acquisition by local farmers. The used methods and strategies in this feasibility assessment, i.e. waste quantification, yield and cost calculations, stakeholder interviews and questionnaire survey allow for replication of the taken investigation to eventually initiate small-scale biogas production using organic waste in other settings with similar conditions.

At present time, climate and energy issues are important subjects in the international market and environmental technology is a rapidly growing concept. Many companies in Sweden have developed much in-house knowledge in environmental technology. Therefore, they have great opportunity to export. In the sustainability perspective, export has not only benefits in the economic aspect, but also advantages for the environment. Development of appropriate business models is necessary for supporting environmental technology export.In this research an attempt was made to explore business model elements and offerings for export of environmental technology. The relevant theories in environmental technology characteristics, customization, product service systems and business models were used.The case studies included a Swedish municipality-owned company, its subsidiaries and a Swedish private company which was active in export. Empirical data were collected by conducting of interviews. The results reflect the business models and offerings of the studied cases. The analysis of cases provided findings for environmental technologies characteristics which have effect on export business models.Furthermore, six categories for making distinction among different elements of business models in literature were defined in this study. By analysis of the cases a new category which entailed new elements was added as the seventh category. The mentioned categories are useful in business model formulating for export of environmental technology.

A big challenge within pulp and paper mills is the large quantities of waste activated sludge (WAS) that is produced during the wastewater treatment. The WAS is made up of biological cells and extra polymeric substances (EPS) and can bind a large amount of water causing difficulties to dewater the WAS. This study aimed to determine how to improve the dewatering properties of the WAS by using hydrolysis. Hydrolysis will cause the cells to disrupt and the bound water in the cells and the water trapped by the EPS can be released. Specifically, this study investigated what impact hydrolysis with heat, alkalis, and acids had on the WAS dewatering properties. In addition to the impact on the dewatering properties, the release of organic material and nutrients from the cells has also been important for biomethane production. In this study, it was specifically NH4-N, PO43- and COD that have been studied. WAS from paper mills have in general poor methane potential so it was of interest to see how the WAS was affected by hydrolysis and how hydrolysis could improve the methane production. To test the hypothesis of whether hydrolysis could affect the WAS and improve the dewatering properties, several experiments were performed. The experiments included thermal hydrolysis at temperatures of 70-90 °C, acidic hydrolysis with acids such as spent acid and acid water, and alkalis such as green liquor sludge and EOP. All acids and alkalis used in the study were chemicals that exist at the paper mills included in this study. To test the dewatering properties, methods such as TS analysis on the accept, CST-analysis, and a belt press were used. Analyses were also performed on the reject to measure the suspended solids and the nutrients NH4 – N, PO43– and COD in the WAS. This study did also determine what effect hydrolysed WAS had on the biomethane potential. In this study were the paper mills BillerudKorsnäs in Skärblacka and SCA in Östrand included. Hence was sludge from the two mills of interest to analyse. This study has shown better dewatering properties with an increase in the total solids (in the accept) after the thermal hydrolysis, the acidic hydrolysis with spent acid, and the alkali hydrolysis with green liquor sludge. Specifically did the acidic hydrolysis with spent acid improve the dewatering properties in terms of an increase in TS in %. The biggest increase in TS in % could be seen after using 10% spent acid ratio. The TS for the WAS from SCA Östrand increased in this experiment by 107 %. The thermal hydrolysis also showed promising results both in terms of dewatering properties and in the release of organic material. The biochemical methane potential test results showed a better and more rapid stabilized production of biomethane after hydrolysis of WAS compared to untreated WAS. The thermal hydrolysis both increased the rate of production and the total amount of methane produced. The thermally hydrolysed WAS from SCA Östrand improved the methane production from 77 Nml methane/g VS to 95 Nml methane/ g VS. The WAS from BillerudKorsnäs improved the methane production from 40 Nml methane/ g VS to 55 Nml methane/ g VS. These results, both from the methane potential tests and the results of the increased dewatering properties, show that the concept with hydrolysing should be evaluated further for improving the dewatering of the WAS.

Energy is considered as the foremost significant factor towards socio-economic growth. Due to the rapid growth of industrialization in Bangladesh, the need of energy is increasing day by day. Considering the environmental issues, sustainable solutions are needed to address the energy crisis. Energy generation from waste through biogas can be a good solution that can address both the energy demand as well as the waste management issue.    The overall aim of this master thesis is to analyze Hazaribagh’s biogas potential from municipal waste and agricultural residues and estimate how much electricity that can be generated from the produced biogas. The feasible sources of Hazaribagh were considered in order to get the information that would be later on analyzed to estimate possible biogas production. The potential sources include wastes from two markets, six slaughterhouses, domestic wastes, three large-scale tanneries and two small scale tanneries, one poultry farm and three crop lands. The calculations made in this thesis to roughly estimate the amount of biogas and electricity from the described sources are done in a simple way, just to illustrate the potential. The result shows that the tannery waste has the highest potential followed by slaughterhouse waste. Furthermore, the calculations show that the tannery waste contributes most for electricity generation also followed by slaughterhouse waste. In order to implement biogas solutions, several actors should be involved like government, future owners, local people etc. Different tools like legislation, financial support etc. are also important for implementing the biogas solutions.   In summary, there is a good potentiality of biogas production and electricity generation from municipal wastes and agricultural residues of Hazaribagh. Biogas solutions from waste and agricultural residues can be beneficial from both the energy and the waste management perspective.

The National Solid Waste Policy recommends that, in adequate final disposal, only unserviceable waste should be released, which it is not the case of organic waste that accounts more than half of the municipal solid waste generation in the country. In this context, this research aimed to develop a proposal for a selective collection of the organic fraction of household solid waste (OFHSW) in Pici neighborhood, Fortaleza-CE, aiming its use for the generation of biogas from the anaerobic digestion. This research occurred in 05 (five) steps, namely: the development of the environmental education (EE) program; physical characterization of household solid waste (HSW); the implementation of a selective collection program of OFHSW; the physical and chemical characterization of OFHSW; and the anaerobic biodegradability tests. Initially, a socio-environmental questionnaire was applied to a total of 175 residences, in which most of its residents presented favorable socioeconomic characteristics for the development of this project. The HSW sampled showed a high average of per capita generation (0.93 Kg/hab.dia), low apparent specific weight (average of 156 Kg/mÂ) and high percentage of organic matter (average of 55.9%). In regard to the participation in the selective collection program, there was a potential participation of 61% of the residences, from which 33% effectively donated a clean OFHSW. The OFHSW showed slightly acidic characteristics, consisting of 74% moisture and 26% of TS, being basically composed of putrescible organic matter (VS = 92.15% TS on average) and rich in nutrients (average of TP= 0.68% and TKN = 1.43%). In biodegradability tests to analyze the effect of operating conditions, better results were found of SMA, biogas production and composition and COD removal in the flasks incubated at a speed of 150 rpm and with addition of 1 g/L of alkalizing. The pretreatment type that provided a higher biodegradability of OFHSW was the thermal one, in which the matter was exposed to a 30 minutes process of autoclaving, where were identified the largest removals of VS (41% removed), COD (56% removed) and value of SMA (1.0777 gCOD-CH4/gVS.d). It is also emphasized that in all the biodegradability tests, about 60% or more of the biogas composition was methane. It was observed that EE actions were able to provide a representative participation of the population in the OFHSW segregation
A PolÃtica Nacional de ResÃduos SÃlidos preconiza que na disposiÃÃo final adequada somente os rejeitos devem ser lanÃados, nÃo sendo o caso dos resÃduos orgÃnicos, que constituem mais da metade dos resÃduos sÃlidos urbanos gerados no paÃs. Diante desse contexto, esta pesquisa teve como principal objetivo desenvolver uma proposta de coleta seletiva da fraÃÃo orgÃnica dos resÃduos sÃlidos domiciliares (FORSD) no bairro Pici, Fortaleza-CE, visando sua utilizaÃÃo para a geraÃÃo de biogÃs a partir da biodigestÃo anaerÃbia. Esta pesquisa ocorreu em 05 (cinco) etapas, sendo elas: o desenvolvimento do programa de educaÃÃo ambiental (EA); a caracterizaÃÃo fÃsica dos resÃduos sÃlidos domiciliares (RSD); a implantaÃÃo do programa de coleta seletiva da FORSD; a caracterizaÃÃo fÃsica e quÃmica da FORSD; e, os ensaios de biodegradabilidade anaerÃbia. Inicialmente, aplicou-se questionÃrio socioambiental, abordando-se um total de 175 residÃncias, com um pÃblico que possuiu, em sua maioria, caracterÃsticas socioeconÃmicas favorÃveis ao desenvolvimento deste projeto. O RSD amostrado apresentou uma geraÃÃo per capita mÃdia elevada (0,93 Kg/hab.dia), baixo peso especÃfico aparente (156 Kg/mÂ, em mÃdia) e percentual de matÃria orgÃnica elevada (mÃdia de 55,9%). Quanto à participaÃÃo no programa de coleta seletiva, registrou-se uma participaÃÃo em potencial de 61% das residÃncias e com 33% doando efetivamente a FORSD limpa. A FORSD apresentou caracterÃsticas ligeiramente Ãcidas, constituÃda de 74% de umidade e 26% de ST, sendo basicamente composta por matÃria orgÃnica putrescÃvel (STV = 92,15% dos ST, em mÃdia) e rica em nutrientes (mÃdia de PT = 0,68% e de NTK = 1,43%). Nos ensaios de biodegradabilidade, para anÃlise da influÃncia das condiÃÃes operacionais, foram encontrados melhores resultados de AME, produÃÃo e composiÃÃo de biogÃs e remoÃÃo de DQO nos frascos incubados a uma rotaÃÃo de 150 rpm e com adiÃÃo de 1g/L de alcalinizante. O tipo de prÃ-tratamento que proporcionou maior biodegradabilidade da FORSD foi o tÃrmico submetido a 30 minutos no processo de autoclavagem, em que foram registrados as maiores remoÃÃes de STV (41% removido), DQO (56% removida) e valor de AME (1,0777 gDQO-CH4/gSTV.d). Ressalta-se tambÃm que nos ensaios de biodegradabilidade cerca de 60% ou mais da composiÃÃo do biogÃs era gÃs metano. Observou-se que as aÃÃes de EA proporcionaram uma participaÃÃo representativa da populaÃÃo na segregaÃÃo da FORSD.

This paper investigates, in the context of Cape Town the emission reduction potential (ERP) of energy from biogas and related cost. Two project-scale models and a city-scale model were developed. Substrates for project model 1 were organic fraction of municipal solid waste (OFMSW) and primary sludge (PS) from sewage works. Project model 2 considered waste paper sludge (WPS) and PS. For the city-scale model, substrates for project model 1 were extended to include total amounts of OFMSW and PS generated in Cape Town. Financial results show that at the REFIT tariff model 1 would have a higher internal rate of return (20.5%) than model 2 (5.6%). The landfill ERP of the project-scale models is 98 600 CO2 equivalent tons per year, corresponding to a weighted average capital investment of R372 per CO2 equivalent ton saved in year 1. The results for the city-scale model indicate that a landfill ERP of 458 000 CO2 equivalent tons per year can be expected at an investment cost of R287 per CO2 equivalent ton saved in year 1. Energy emissions from fossil fuels at city-scale are most effectively mitigated if coal rather than other fossil fuel based power and heat generation are replaced.

The main objective of this master’s thesis is to develop design equipment for thermomechanical pre-treatment of biodegradable waste. An important aspect of the design is taking into account current legislation, sanitary conditions for determining the pre-treated biodegradable material, which also serves as a raw material for biogas production. So the device will be used to monitor the impact of thermomechanical pre-treatment of biodegradable waste for biogas recovery. The following describes the processes of anaerobic decomposition of biodegradable materials and technology, whose main task is intensification of anaerobic decomposition of organic materials. The theoretical work are given various methods of processing and utilization of biodegradable wastes, focusing on kitchen waste and sludge from sewage plants. The next section describes the various factors that may affect the stability of the process of biogas generation. This also results in yield and chemical composition of biogas. A key part of this master’s thesis is to develop technical documentation and an approximate calculation of the hot slurry.

This paper introduces the results of a project initiated by Cantho University (CTU) on the introduction of micro-credits for addressing the environmental pollution in Vietnam’s craft villages. At Tan Phu Dong, a traditional rice powder production village in Sa Dec, Dong Thap, all wastes from domestic and production activities and animal husbandry were freely disposed into open water sources. This practice led to a negative impact on the local environment. With the financial support provided by the Bread for the World (BfdW), a micro-credit program was initiated in which farmers could borrow money to construct a biogas plant to treat animal husbandry and domestic wastes. In addition, the staff transferred biogas plant construction technology to the local masons and organized training courses on biogas plant operation and maintenance and biogas usage for the farmers and the local officials. 61 farmers borrowed money from the program to construct their biogas plants, followed by more than 250 farmers that constructed their biogas plants by their own finance after realizing the positive benefits of biogas plants. As result, the environmental pollution issue was solved step-by-step, thereby helping enhance the living conditions of the local community
Bài báo này trình bày biện pháp sử dụng nguồn quỹ tín dụng nhỏ để các hộ dân cải thiện tình trạng ô nhiễm môi trường ở các làng nghề Việt Nam. Tại làng nghề làm bột Tân Phú Đông - Sa Đéc - Đồng Tháp, các loại chất thải sinh hoạt, chất thải sản xuất và chăn nuôi xả thải bừa bãi đã gây ô nhiễm môi trường nghiêm trọng. Với kinh phí tài trợ từ tổ chức Bánh mỳ cho thế giới (BfdW), các cán bộ trường Đại học Cần Thơ đã tổ chức cho người dân luân phiên vay vốn để xây dựng hầm ủ khí sinh học xử lý chất thải chăn nuôi và chất thải sinh hoạt. Bên cạnh đó còn tổ chức các lớp tập huấn chuyển giao công nghệ xây hầm ủ khí sinh học cho thợ xây địa phương, hướng dẫn vận hành và bảo dưỡng hầm ủ cho người dân và cán bộ địa phương. Thông qua nguồn vốn vay của dự án, có 61 hộ dân đã xây dựng hầm ủ khí sinh học và trên 250 hộ dân khác đã tự đầu tư xây dựng khi thấy được lợi ích của hầm ủ. Nhờ đó tình trạng ô nhiễm môi trường từng bước được giải quyết góp phần cải thiện điều kiện sống của người dân tại địa phương

The key objective of this multi-disciplinary research was to seek for feasible solutions to avoid effluent from livestock trucks spilling onto roads. Stock effluent spillage mainly poses road safety hazards and environmental damage, and also causes offence to road users and tourists. This task required reviewing previous institutional actions, assessing the power of the existing legislation, and evaluating the interests and attitudes of the stakeholder groups involved in the overall livestock supply chain. It was also necessary to consider politics, administration, public policy and economics, gaining the willing cooperation and confidence of the stakeholder groups through application of 'Soft Systems Methodology' (SSM). A key component was the creation of a 13 minute video and its associated brochure as a primary tool for a stakeholder educational awareness programme. It was necessary to analyse the complex relationships between livestock preparation prior to transport; effluent produced in-transit; and end product quality factors. Detailed information pertaining to the nature of livestock shipments by truck in the South Island of New Zealand had to be collected and verified. All the above information were fed into the calculation of an ideal network of in-transit effluent discharge sites on State Highways in the South Island of New Zealand. Assuming the adoption of best practice throughout the supply chain, it was possible to recommend sustainable solutions. The problem is amenable to solution. Adoption of a strong Industry Code of Practice, coupled with the construction of a strategic network of dump sites will enable the industry to avoid the heavy-handed legal consequences of allowing the status quo to continue.

AD is regarded as a sustainable technology that could assist the UK Government meet internationally agreed GHG emission targets by 2050. However, the mature status of the technology is based on expensive systems that rely on high energy feedstock to be profitable. Meanwhile, the natural biodegradation of cow slurry is a recognised contributor to climate change despite having a relatively low CH4 potential because of the large volumes produced. Economic mixing is essential to the cost-effectiveness of farm AD but techniques applied are not always appropriate as slurry is a shear thinning thixotropic Herschel-Bulkley fluid and therefore challenging to mix. The apparent viscosity of slurry and the shear stress induced was most influenced by solids content (exponential change) followed by temperature (linear). Most shear thinning occurred before a rising shear rate of 20s-1 was achieved with the fluid acting near-Newtonian above. Thixotropic recovery occurred within 1 hour of resting. Rheological values were also much higher than previously reported. Highest CH4 production occurred in the first 10 days of the batch process using a range of mixing regimes with different shear rates and rest periods. During fed-batch operations, changing shear rate had a minimal effect on CH4 production using a 30-day HRT whereas shorter rest periods increased production. Specific CH4 production rate was highest when feeding and mixing coincided. However, when HRT was reduced (OLR increased) the CH4 produced by all mixed regimes significantly increased with highest values being achieved using high intensity mixing rested for short periods. Lower HRTs also requires smaller digesters. Parasitic mixing energy invariably had the most influence on net energy production. Signs of instability were evident after 20 days using the low HRT. Significant microbial adaptation was also observed as the experiments progressed. The research outcomes demonstrate that mixing regime and HRT can be managed to maximise net energy production whilst reducing capital expenditure.

碩士
國立中興大學
獸醫學系
86
If the 12.9 million metric ton of livestock waste that were productedannually in Taiwan were not properly disposed of or processed, they mayresult in the pollution of the rural environment and water resources,andmay also be detrimental to the prophylaxis and control of livestock andhuman diseases. Under highly aerobic condition, livestock waste, which contain a high degree of organic content and thermophilic bacteria, canstart the composting process and the temperature may reach to 70-80 ℃Such high temperature can destroy the pathogenic bacteria. There aremany factors which influence the composting of livestock waste to manure.One of there factors is to adjust the optimum composition of the livestockwaste itself for composting. Under high humidity and with a highconcentration of nitrogenous compound, and by adding wood chips whichhad been used for culturing mushroom, and optimum condition for thecomposting process can be worked out, By properly adjusting the aerobiccondition of the compost, and attaining a high compost temperature, it isthought that the pathogenic microorganisms which might be present in the livestock waste will be destroyed. The objective of this study is to modifythe composting process of poultry waste by varying the ratio of the carbonto nitrogen content and also to evaluate if the maximum temperatureattained can destroy the pathogenic microoganisms or not.Poultry waste were mixed with the wood chips at different ratios of(v/v)2:1,1:1,and 1:2at a humidity of 65% and were then separatelyaerated at 0,50,100,200,300,400 and 500 L/min/m^3 .Th temeprtures ofthe compost were then continuously monitored for any changes. It wasobserved that the 4 groups of compost which were aerated at 50,100,200and 300 L/min/m^3 ,attained and then maintained a temperature of over 72℃ for 1-48 hours. The samples aerated at 400 L/min/m^3 . and 500L/min/m^3 . attained a maximum temperature of only 68 and 71 ℃,respectively. In the three groups with different composition, it was found that the higher the degree og aeration, the shorter the time was needed to attain the maximum temperature. However, under sch condition of highdegree of aeration, the maximum temperature attained was much lowerthan those aerated at the lower level. Not much difference in maximumtemperature attained was observed for the different composition group ofthe compost treated with the same degree of aeration. Optimum condotionfor the compost to attain the maximum temperature at the shortest possibletime and also maintaining the high temperature of over 72℃ for the longest period of time could be achieved under following condition;ratio of poultry waste to wood chips at 2:1 (C/N, average 15)with aerationof 200 L/min/m^3, or 1:1 (C/N,average 17) with aeration of 100 L/min/m^3 or 1:2 (C/N,average 20) with aeration of 50 L/ min/m^3. No Salmonella spp. nor Mark''s disease virus could be isolated or detected from the compostedlivestock waste. It is implicated that the high termperature might have thesterilizing effect on the manure to destroy the pathogenic microorganisms.

碩士
國立屏東科技大學
環境工程技術研究所
86
The objectives of this research are to investigate the emission metallic chara cteristics of three animal corpse incinerators in Pingtung County and to understand the metallic distribution in the incinerators and the parameters that in fluenced the metal emission. The stack flue-gas samples(part偞ate and heavy metals) were collected by an isokinetic sampling system. Heavy metal samples were digested by an autoclave digestor and w愉e analyzed primarily by an inductively coupled plasma emission sepectrometry CP-AES). The concentration and particle-bound composition of heavy metals were determinded and evaluated. The shapes and components of sampled particles were also studied by a SEM-EDX. The average particulate concentration in the stack flue-gas was 213、118 and 28.3 μg/Nm3 for incinerators A、B and C. Metallic emission for incinerator A was mainly caused by the incineration of animal corpse. For incinerator C ,over 70﹪of Ni was contributed by the combustion of dissel oil. The Cu compositi on in partulate averaged 1.08mg/g、5.03mg/g for incinerators A and B, respectively. For C incinerator, the Cu composition in particular was 0.05 mg/g which was much lower than those for incinerators A and B. In the bottom ash of incin erator A, Zn was the highest composition(1.26 mg/g) compared to other elements. For incincerator B, Pb and Zn (2.85mg/g and 7.13mg/g) were higher than other toxic elements. In incinerator C, Pb and Zn (2.23mg/g and 8.12mg/g) were higher than other toxic elmenets in the bottom ash. The high volatile elemen ts (Cd and Pb) were mainly in the particulate of stack flue-gas(82.17﹪and 58.23﹪) and the other elements were mainly in the bottom ash for incinerator A. For incinerator B, Cd、Pb and Zn (71.01﹪、69.52﹪ and 5.68﹪) were mainly in the particulate of stack flue-gas while the low volatile elements (Cu、Fe and Mn) were primarily in the bottom ash. For incinerator C, Cd、Cr、Ni and Pb were mainly in the particulate of stack flue-gas. From the SEM-EDX analysis, the particle sizes of iinerator A ranged from 10 to 15μm with irregular rectangular shape and fragile rough surface. Particle sizes of incinerators B and C ranged from 5 to 10 μm with elliptic shape and rough surface. The elements of C a、K、Na and Cu in A incinerator were existed in the animal corpse. Incinerator C was used to incinerate the medical waste utilizing the diesel oil as auxiliary fuel. The particle characteristics of incinerator B was similar to those of incinerators A and C.

碩士
國立臺灣大學
動物科學技術學研究所
103
The cost of treating excess or waste sludge is about 20~50% of total wastewater treatment. Sewage sludge can be the feedstock of producing biodiesel, and it is fatty acid methyl ester (FAME) and a kind of renewable energy. The target of study is try to solve problem of excess livestock sludge by producing biodiesel and evaluates its feasibility by using waste livestock sludge including swine farm, dairy cattle farm and slaughterhouse sludge. These waste livestock sludge were used and produced FAME by acid-catalyst transesterification in this study. The waste sludge was de-watered by freeze-dried way and reacted with methanol to produce FAME. The test conditions were divided into four kinds of reaction time (4, 8, 16, and 24 h) with different ratios of methanol addition (10:1, 15:1, 25:1, and 40:1). All FAME yield and species were analyzed by gas chromatography. The FAME yield of slaughterhouse sludge, swine farm sludge, and cattle farm sludge was about 0.78~2.24, 0.14~0.35, and 1.41~2.18% (w/w), respectively. The oven-dried way (105℃, 12 h) was used and compared the yield with freeze-dried way under different reaction time (4 and 24 h) but other conditions were the same. The result showed there was significant difference in 4-h sets but no significant in 24-h sets. Compared with 10-min treatment by ultrasonic and non-treatment under different reaction time (2 and 4 h) but other conditions were the same. The result showed there was significant difference in 2-h or 4-h sets. The results showed reaction time, methanol addition, de-watering way, and treatment by ultrasonic had no effect on FAME composition but species of sludge would do. The dominant FAME species from livestock sludge is C15/C17/C18. Biodiesel production can be an alternative way to treat livestock waste sludge and recover resource from it.

碩士
國立屏東科技大學
環境工程技術研究所
86
The objective of this research is to investigate the emission characteristics of PAHs from two livestock waste incinerators and one batch-type medical waste incinerator in Pingtung County. The results of this study can be used to estimate the emissions, and establish the regulation and emission reduction strategy. The flue gas samples were taken by a gas-particle phase PAHs sampling instrument with a condensing system. Twenty-one constituents of PAHs were analyzed by the GC/MS. The primary results of This study were summarized as follows: (1).Since incomplete combustion resulted from the lower temperature, a great amount of PAHs was observed in the emissions of hog farm incinerator. The total-PAHs concentrations ranged from 339 to 1262 (g/Nm3 and averaged 636 (g/Nm3 in the stack flue gas. The mean value of the hog farm incinerator was approximately 1.1 and 1.6 times of magnitude higher than those of the livestock disease control center and medica medical waste incinerator, respectively. (2).The stack fluesample was divided into four parts: gas phase, particle phase, water from cooling device and rinse sol solution of pipe. The results show that the gaseous PAHs were more abundant than the particulate PAHs for three incinerators. Few PAHs were resided in the sa sampling duct or condensed liquid. The fraction of Nap in gas phase were 75.9 % , 56.1 % and 84.4 % for the hog farm, livestock disease control center and the medical waste incinerator, respectively. (3).The mean values of the total-PAHs emission factor were 285, 2.86 and 4.96 mg/Kg-waste in the stack flue gas of hog farm, livestock disease control center and the medical waste incinerato incinerator, respectively. Comparison of the individual PAHs distribution, Nap displayed the highest mean values for three incinerators. (4).The total-PAHs emission rates were averaged 26.2 mg/min, 8.94 mg/min and 8.48 mg/min for the hog farm , livestock disease control center and the medical waste incinerator, respecti respectively. In the stack flue gas samples of the livestock disease cocenter and the hospital, the emission rates of twenty-one individual PAHs, except Nap, were below 1 mg/min. (5).The mass concentrations of PAHs in the bottom ashes from a medical waste incinerator were ranged between 310 and 562 ng/g. The mean value was approximately 0.58 and 0.89 times of those for the livestock disease control center and the hospital, respectively. (6).The mass percentage of liquid phase PAHs mass emitted from the hog farm incinerator were ranged between 37.9 and 83.4 % and averaged 55.2 % by effluent from wet scrubber. The mass percentage of solid phase PAHs emitted from the same incinerator were ranged from 16.7 to 62.1 % and averaged 44.8 % by effluent from wet scrubber. Lower molecular weight (LMW) PAHs has a higher fraction in liquid phase than that in the solid phase. There were no decidedly difference from the liquid and solid phase PAHs for the effluent from wet scrubber of medical waste incinerator. (7).The predominant PAHs were the LMW PAHs from the stack gas for two livestock waste incinerators. The amount of PAHs in bottom ashes tends to increase with the increase of the ring number of PAHs.From the results obtained in this investigation, a group of 2, 3, 6 and 7-ring PAHs were observed in the flue gas from a medical waste incinerator. In the bottom ashes, the 4 and 5-ring PAHs were present as a major product in the PAHs group.

碩士
國立交通大學
分子醫學與生物工程研究所
106
Petrochemical fuel damage environment and produce green-house gas emission. The researches for alternative energy can meet the environment protection. Biogas is one of good choose for alternative energy because it turns waste into energy and produces a similar heat value as natural gas. According to UN statistical data, the agricultural biomass is generated more and more for every year. The energy efficiency is equivalent to 25 percent of global oil production. The agricultural waste is composed of cellulosic compounds that are aggregated by pentose or hexose. They will be excellent biogas materials after destructed structure pretreatment. The agricultural cellulosic waste is generated about 2.12 million tons every year in Taiwan. The kinds of agricultural waste are rice straw, sugarcane bagasse and wood dust. This study utilizes INRI cellulosic de-aggregation technology which uses steam explosion or acid-catalyzed steam explosion to destruct cellulosic structure. The de-aggregation cellulosic materials would enhance biodegradability and biogas production by anaerobic digestion. In this study, we examined biogas potential of different agricultural wastes and adjust the parameters (e.g pH value or C/N ratio) of anaerobic digestion. Since the pig farms produce lots of wastewater in Taiwan which water are nitrogen-rich and it can adjust high carbon materials to appropriate C/N ratio. Furthermore, we set up a lab-scale continuously anaerobic digestion to simulate the actual fermentation conditions. The results demonstrated that adjust the conditions of de-aggregation cellulosic material and anaerobic digestion enhancement of biogas production. The de-aggregation of rice straw, sugarcane bagasse and wood dust were the best performance for biogas production at pH= 6-7. They produced 313, 213 and 282 ml/gTS, respectively. In C/N ratio treatment group, the best conditions were C/N= 20, which produced 256, 250 and 251 ml/gTS, respectively. The co-digestion was de-aggregation rice straw and pig wastewater. In the continues anaerobic digestion, addition 1% dry weight of wastewater volume could produce 315 ml/gTS.

M. Tech. Civil Engineering
Rural communities in South Africa and Africa as a whole are faced with a problem of the lack of reliable, efficient, sustainable and affordable energy sources. This problem serves as a catalyst to the slow economic development of the rural communities. In order to eradicate the problem and expedite economic development, a need exists to expand energy supply from the national grid or introduce alternative clean, sustainable, environmentally friendly and affordable energy sources to rural areas. However, expanding the national grid would not be sustainable in the long term because 80% of the national grid energy in South Africa is generated from burning fossil fuels, which is neither environmentally friendly nor renewable. The aim of this study was to address the above challenge through scientific investigation of the feasibility of introducing biogas as an alternative source of energy in rural areas. The investigation was to establish a mix ratio of the three types of domestic animal waste namely cow dung, pig dung and chicken droppings, which would optimise biogas production. Biogas, which is a mixture of mainly methane and carbon dioxide gases would in turn be used for cooking. Therefore, the broad objective of the study was to optimise methane gas production through the anaerobic digestion of domestic animal waste.

Anaerobic digestion can be used to sustainably treat the organic byproducts of the biodiesel process (crude glycerol and biodiesel wastewater) while generating a renewable natural gas to be used for heating or electricity generation. The purpose of this thesis was to (1) investigate the possibility of co-digestion of biodiesel byproducts without use of external substrates or pretreatment and (2) assess the impact of various acclimatization rates on the stability and efficiency of such a system. Two inocula (effluent from a wastewater treatment plant digester and from an agro-industrial waste digester) and two acclimatization rates were studied. The results showed that co-digestion of crude glycerol and biodiesel wastewater at high organic loading rates(up to 6.8 g COD L-1day-1)is possible without addition of other substrates or pretreatment.Thecumulative biogas production of the digesters using inoculum from the agro-industrial waste digester was statistically greater than the digesters using the wastewater treatment plant digester, indicating that similar inoculum could be useful for additional experiments.In addition,maximum efficiency due to a slower rate of acclimatization was higher for both inocula, up to a maximum average daily biogas yield of 621 mL biogas g-1COD added.Finally, comparison of two methods for measuring gas production (mass difference and volumetrically using a syringe) revealed a reasonable correlation(R2= 0.97)between the methods. Additional validation could lead to use of the mass difference method as a validation method or an alternative gas production measurement method.

Dissertação de Mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
A utilização das energias renováveis tem vindo a aumentar nos últimos anos devido à diminuição do crude e dos seus efeitos negativos para o planeta (efeito estufa). Alternativas a esta fonte de energia são necessárias. Existem várias alternativas designadas verdes aos combustíveis fósseis, nomeadamente, energia do vento, energia solar e energia proveniente de biomassa. O biogás (maioritariamente composto por metano e dióxido de carbono) apresenta ser uma alternativa viável por dois motivos: a sua combustão não contribui para o aumento do efeito estufa (ciclo de carbono é completo) e os resíduos sólidos da biomassa digerida durante a digestão anaeróbia podem ser utilizados como fertilizantes para agricultura. Apesar da produção de biogás em digestores anaeróbios ser um processo bastante conhecido, existe espaço para novos avanços pois embora os reatores estejam bem descritos em termos de população microbiana o estabelecimento dessa população permanece pouco conhecido. Neste sentido interessa compreender a complexidade do sistema anaeróbio de forma a obter um maior rendimento de biogás. Isto passará por determinar quais as populações microbianas envolvidas em diferentes condições de digestão. Prevendo-se que principalmente a temperatura, o substrato e o inóculo terão maior influência nas espécies e o número de indivíduos presentes no digestor. Neste estudo tentou-se cultivar microrganismos responsáveis pela digestão anaeróbia em culturas puras e desconhecidas para a produção de biogás. Os Archaea que foram utilizados nas culturas puras foram Methanosarcina mazei, Methanococcus maripaludis and Methanospirillum hunatei. As culturas com microrganismos não conhecidos partiram duas lamas de estações de tratamento de águas residuais em regime mesófilico Garmerwolde e Lelystad, ambas no norte da Holanda. Os meios de cultura e as culturas puras utilizadas foram da Deutsche Sammlung von mikroorganismen und Zelkulturen (DSMZ). O crescimento das culturas metanogénicas foi monitorizado através da turbidez medindo a absorvância da amostra ao comprimento de onda de 600nm no espectrofotómetro. Para a determinação do consumo de substrato e produção do produto foram analisadas amostras usando cromatografia líquida de alta pressão (HPLC) e cromatografia gasosa (GC), respetivamente. A verificação da presença de organismos produtores de metano foi feita recorrendo à microscopia de fluorescência com excitação a 350 nm e filtro de emissão a 460 nm. Os resultados obtidos mostraram que não foi possível crescer os microrganismos em culturas puras com os equipamentos usados, contudo o crescimento em câmara anaeróbia e mistura de gases apropriada poderá solucionar o problema. Por outro lado, o cultivo de uma população desconhecida foi possível e produziu-se metano. O fato de existirem microrganismos na população desconhecida que sejam anaeróbios facultativos permite a eliminação do oxigénio na cultura, permitindo, em condições menos favoráveis o crescimento de microrganismos anaeróbios. A presença de microrganismos anaeróbios responsáveis pela produção de metano foi confirmada pelas observações ao microscópio de fluorescência- fluorescência azul. A deteção de metano foi possível através de cromatografia gasosa, contudo a correta e replicável quantificação de metano não foi possível por motivos técnicos. A resolução destes problemas técnicos vai para além do objetivo deste trabalho. Para solucionar os problemas encontrados para a produção de biogás nas condições laboratoriais existentes sugere-se um sistema contínuo ao invés de um sistema descontínuo.

Anaerobic digestion (AD) is becoming a widely adopted technology for conversion of organic waste and nutrient-rich fertiliser production due to its cost-effectiveness and sustainability. In this study, a batch experiment was conducted using five different types of food waste and cow dung (CD). No significant difference was observed among the four substrates that produced the highest methane (P<0.05). Based on the batch experiment results, two substrates were selected for semi-continuous digestion and the highest methane yield (67%) was obtained from co-digestion (CO). PCR-DGGE results revealed higher bacterial and archaeal diversity indices in CO as compared to mono-digestion of CD and mixed food waste. The high-throughput sequence analyses revealed that the Operational Taxonomic Units (OTUs) belonging to the phyla Bacteroidetes, followed by Firmicutes, Actinobacteria and Proteobacteria, were dominant in all treatments. The enhanced methane production in CO could be attributed to the neutral pH and partial shift of archaea from Methanosaeta to Methanosarcina. The digestate and fresh CD were screened for plant growth promoting bacteria (PGPB), nutrient and heavy metal content. The dung contained higher concentrations of heavy metals (P<0.05) and potential pathogens in comparison to the digestate. The use of digestate may, therefore, enhance soil fertility with minimal negative environmental effects.
School of Agriculture and Life Sciences
M. Sc. (Life Sciences)

The scarcity of feed resources often imposes a major challenge to the development of animal production in the tropics and subtropics. However, by-products have long been recognised in providing cheaper alternative feed ingredients relative to conventional feed ingredients, thus alleviating the challenge. The aim of the present study was to investigate the potential of three waste products from the subtropical fruit processing industry in animal feeding. The products include avocado meal (AM), macadamia oil cake (MOC) and macadamia chips (MCH). The samples were obtained from the processing plants in Nelspruit of Mpumalanga Province, Makhado (Louis Trichardt) and Tzaneen of Limpompo Province. Eight samples of each waste product were collected, prepared and their chemical composition, in vitro dry matter digestibility and, in situ ruminal dry matter and crude protein (CP) degradability were determined. A broiler growth trial was conducted as well to determine the effect of replacing maize with AM on performance of broilers under commercial production thus establishing the replacement value of avocado meal in broiler feeds. As the products under study were from the oil extraction process of the two fruits, there were high remnants of oil in all three waste products. As a result the ether extract (EE) content of the three waste products was higher compared to any of the commonly used oilseed meals. The MCH had the highest EE concentration, followed by the MOC and the AM had the lowest. However, after defatting the AM had the highest (P<0.05) EE concentration compared to either the MOC or MCH. The CP concentration of the MOC was significantly higher than that of the AM and MCH. There was no significant difference observed between the AM and MCH in CP concentration. A better amino acid profile was observed with the MOC compared to the AM and MCH. None of the products can be regarded as a protein source. The fibre fractions of the MCH were significantly higher than that of AM and MOC, with the exception of the acid detergent lignin (ADL) concentration. The ADL concentration of the AM and MCH did not differ significantly although the MCH concentration was higher. The MOC had the lowest (P<0.05) ADL concentration compared among these waste products. Generally, the fibre concentration in the MOC was lower compared to other waste products but higher compared to the SBM and POCM. The acid detergent insoluble nitrogen (ADIN) concentration of the AM was significantly higher than that of MOC and MCH. There was no significant difference observed between MOC and MCH. The condensed tannin (CT) concentration of the waste products differed significantly with the AM being the highest and the MOC the lowest. The ADIN concentration of the MOC could be compared to that of the SBM and lower than that of the POCM. There were some significant differences observed in the mineral composition between the waste products under study. The mineral concentrations were below the maximum tolerable levels of animals except for iron (Fe) in AM which can be toxic to sheep as it was above the maximum tolerable level of 500mg/kg. The in vitro dry matter digestibility of the three waste products differed significantly, with the MOC being the highest and the MCH the lowest. Huge variation within waste products was observed and it could be due to the contamination levels of the products with the indigestible portions of the parent fruits. The in situ degradability of dry matter and CP of the AM and MOC differed significantly, with the MOC surpassing the AM in most of the degradability characteristics. The potential degradable fraction (“b”) and the degradation rate of the b fraction (“c”) fractions of the AM and MOC did not differ significantly. The MCH had more indigestible particles of the kernel and as a result it could not be analysed statistically and was therefore omitted. The effect of replacing maize with AM at different inclusion rates led to decreased feed intake and the final mass of the broilers during the trial period. The feed intake of the broilers on commercial diet was significantly higher than that of the broilers on commercial diets with avocado meal, except for the inclusion rate of 10% AM. The final mass, the ADG and the FCE of the broilers on commercial diet were significantly higher compared to the broilers on diet with AM irrespective of the inclusion rate. No mortalities observed during the experimental period. Copyright
Dissertation (MSc(Agric))--University of Pretoria, 2012.
Animal and Wildlife Sciences
unrestricted