Dissertationen zum Thema „Leachate Analysis“

In this study, regularly measured long-term leachate data from Bursa Municipal Solid Waste Landfill (MSWL) were analyzed using conventional statistical, time series and factor analyses to investigate in detail the temporal variability of leachate quality and quantity, trend, randomness, seasonality and the auto- and cross- correlations of leachate pollutants. Evaluating the results of data analyses, leachate management recommendations, including sampling strategies in monitoring programs and treatment alternatives for old and fresh leachates, were developed. Statistically analyzed leachate parameters included BOD, COD, pH, SS, electrical conductivity, total CrO4, Cr6+, Fe, Cu, Zn, Pb, Cd, CN-, Cl, F, total P, NH4-N, total N, SO4, S2-, total alkalinity and leachate flow rate. Results indicated that the majority of pollutant concentrations varied in large ranges. Leachate parameters usually showed non-normal distributions and high variability in the closed T Valley compared to the open Main Valley. The majority of leachate parameters was autocorrelated and had statistically significant correlations amongst themselves. Factor analysis showed that different inter-relationships were present between leachate parameters for closed and open valleys. The sampling frequency and the number of leachate parameters need to be measured were determined to be higher for open landfills than for closed landfills. It was recommended that leachates, having high organic strength, in open landfill be treated using biological and physical/chemical processes. However, after the closure of the landfill, physical/chemical processes were recommended for leachate treatment, as it gradually completes transition from fresh to old leachate.

This study is conducted at the Trail Road Landfill, located in Nepean, Ontario, Canada. The objective is to investigate the leachate characteristics of changing spatial-temporal patterns in a landfill groundwater environment by comprehensive analyses of annual spatial data. Exploratory statistical data analysis identified the association of B (boron) with K, NH3 and TKN. Raster layers (maps) are created based on the concentrations of required variables in each time interval (year). In this study, it is notable that the raster data layers are used instead of discrete well data. Several change detection methods are applied to determine the spatial and temporal changes of B and its associated variables and to identify the well locations where the changes occurred. These included post-classification visualization, principal component analysis, standard deviation and unsupervised classification (clustering) methods. The suitability of these methods is also discussed. The results determined that during the 1993-95 time period the concentrations of B and its associates was initially increasing, and then decreased substantially. In summary, the study analysed characteristics of pollutants in landfill site groundwater environmental monitoring by using raster data in different change detection methods, and discussed the suitability of the applied methods. The same methodology and analysis techniques can be applied to other variables in similar environmental monitoring studies.

Colloidal material (0.001 - 1 um) in soil leachate and agricultural drainage waters is an important route for the transport of contaminants such as phosphorus from land to catchments. Excessive phosphorus concentrations can result in eutrophication of natural waters. To be able to characterise the colloidal material, in terms of size distribution, a mild and relatively new separation technique field-flow fractionation (FFF) can be used to fractionate complex colloidal samples. By combining FFF and flow injection analysis (FIA) more detailed physico-chemical information on phosphorus species in soil leachates and agricultural runoff waters can be obtained. Chapter 1 describes the methods used to determine phosphorus and also to characterise colloidal material, especially using FFF, and particularly focusing on the Flow FFF (FIFFF) sub-technique. Chapter 2 concentrates on the experimental considerations for FIFFF with recommended procedures for the setup and calibration of the system. In Chapter 3, SdFFF is used to compare the use of centrifugation and filtration for the fractionation of an Australian soil suspension, and demonstrates the uncertainties surrounding the use of conventional membrane filtration. FIFFF is used in Chapter 4 to optimise a sampling, treatment and preparation protocol for two contrasting soil types sampled in the UK. Centrifugation and filtration methods are also compared in a similar approach used in Chapter 3. In Chapter 5 a portable Fl monitor is optimised for the detection of reactive phosphorus. The linear range for the Fl monitor is determined as 0.8 - 8.0 uM PO4-P with a limit of detection o f 0.6 uM PO4-P. A digestion method is also optimised for the determination of total phosphorus using an acidic peroxydisulphate autoclaving method. In Chapter 6, FIFFF and FIA are combined in an experiment describing the fractionation of a soil suspension and the subsequent determination of phosphorus associated with different size fractions. The results from this combination show great potential and will help improve our understanding of the role of colloids in phosphorus transport from agricultural land to catchments.

Studies were conducted to evaluate the impact of landfill leachate discharge on the operation of waste water treatment plants (WWTPs). Two aspects of interferences were found: one is UV quenching substances, which are bio-refractory and able to penetrate the biological treatment processes, consequently interfere the UV disinfection in WWTPs. The other one is organic nitrogen, which can pass the nitrification-denitrification process and contribute to the effluent total nitrogen (TN). Also, treatability study was conducted for landfill gas (LFG) condensate. In a laboratory study, leachate samples were fractionated into humic acids (HA), fulvic acids (FA) and Hydrophilic (Hpi) fractions, the specific UV254 absorbance (SUVA254) of the three fractions follows: HA > FA > Hpi. However, the overall UV254 absorbance of the Hpi fraction was important because there was more hydrophilic organic matter than humic or fulvic acids. It was found that the size distribution of the three fractions follows: HA > FA > Hpi. This indicates that membrane separation following biological treatment is a promising technology for the removal of humic substances from landfill leachates. Leachate samples treated in this manner could usually meet the UV transmittance requirement of the POTWs. Also, nitrogen species in landfill leachates under various stabilization states were investigated. Although the effect of landfill stabilization state on the characteristics of organic matter and ammonia is well documented, there are few investigations into the landfill leachate organic nitrogen under different stabilization stages. Ammonia was found to leach out slower than organic matter and can maintain a constant level within the first a couple of years (< 10 years). The concentration and biodegradability of organic nitrogen were found to decrease with landfill age. A size distribution study showed that most of organic nitrogen in landfill leachates is < 1 kDa. The protein concentration was analyzed and showed a strong correlation with the organic nitrogen. Different slopes of regression curves of untreated and treated leachates indicate that protein is more biodegradable than the other organic nitrogen species in landfill leachates. XAD-8 resin was employed to isolate the hydrophilic fraction of leachate samples, hydrophilic organic nitrogen was found to be more biodegradable/bioavailable than the hydrophobic fractions. Furthermore, biological and physical-chemical treatment methods were applied to a landfill biogas (LFG) condensate to explore the feasible treatment alternatives for organic contaminant and arsenic removal efficiency. Sequencing batch reactor (SBR) showed effectiveness for the degradation of organic matter, even in an environment containing high levels of arsenic. This indicated a relatively low toxicity of organic arsenic as compared to inorganic arsenic. However, for arsenic removal, oxidation-coagulation, including biological oxidation, conventional oxidation and advanced oxidation followed by ferric salt coagulation, and carbon adsorption were not effective for what is believed to be tri-methyl arsenic. Among these, advanced oxidation-coagulation showed the best treatment efficiency (15.1% removal). Only reverse osmosis (RO) could reduce the arsenic concentration to an acceptable level to meet discharge limits. These results implied high stability and low toxicity of organic arsenic.
Ph. D.

Spatial and temporal variation in inorganic contaminant concentration and distribution in a landfill leachate plume is examined to determine the mechanisms responsible for the observed variation, and to provide an assessment of the implications of this variation with respect to the interpretation of monitoring data, specifically with regards to its application to geochemical modelling. An integrated approach to field investigation was utilised in this study, including sample collection from a network of standard and bundled piezometers, surface and borehole geophysical investigation techniques, and a manometer board for the measurement of hydraulic head in bundled piezometers. Nine groundwater sampling events were conducted over a 12 month period, with sample analyses comprising field measurement of water quality parameters and redox sensitive elements, and laboratory analysis for major and trace elements and stable isotopes (??18O, ??2H, ??13C-DIC, ??15N). The vertical position of the centre of mass of the leachate plume was observed to vary up to 2 metres between monitoring events, and concentrations of key indicator parameters were observed to fluctuate by as much as 160%. The electrical images created by surface resistivity transects along a groundwater flow path between the landfill and a groundwater-fed pond a short distance downgradient suggest a plume configuration characterised by discrete pulses of concentrated leachate migrating in a conservative manner between the landfill and the pond. It is hypothesized that these leachate slugs are flushed into the aquifer during sustained periods of rainfall, presumed to be a significant driver of leachate mobilisation into the underlying aquifer. The most significant hydrogeochemical processes affecting contaminant mobilisation, transport and attenuation in the leachate-impacted shallow aquifer included microbial degradation of organic waste, dissolution of inorganic waste, ion exchange, precipitation of sulfide and carbonate minerals, mixing with rainfall recharge along flow path, and redox transformations along the plume fringe. These processes are supported by hydrogeochemical data analysis, and generally agree with the results of inverse geochemical modelling. While analysis of detailed groundwater monitoring appears to provide a plausible description of the plume dynamics, the results of the electrical resistivity transects indicates a more varied and complex plume configuration than is suggested by the borehole data alone. This integration of investigation techniques underscores the inherent inadequacy of even a high-resolution monitoring well network to accurately describe the full extent of variation in time and space within a contaminant plume, even in a relatively simple aquifer environment, and accentuates the potentially significant limitations of site-scale hydrogeochemical interpretation based solely on borehole monitoring data.

The application of Ultrasound (US) irradiation to remove ammonia nitrogen from aqueous solutions, including synthetic solution and landfill leachate, at 20 kHz was investigated in this thesis. Batch experiments were carried out using two synthetic solutions with initial ammonia concentrations of 3000 and 5000 mg TAN/L in addition to two leachates from new and old landfills. The results of testing showed that US irradiation is an effective treatment technology for the removal of aqueous ammonia. More specifically, it was found that increasing sonication time and pH increased ammonia removal. The maximum observed removal of ammonia was 87.4% at a pH of 11 and sonication time of 25 minutes. Also, it was found that volatilization of ammonia to the atmosphere accounted for 0-7% of removal, the thermal effect of US accounted for 21.1-52.7%, and the non-thermal effect of US accounted for 44.5-78.8% (depending on pH and sonication time). Results of factorial design and response surface methodology showed that pH, energy output (kJ), and the interaction between the two were significant parameters. The predicted two factor interaction (2FI) model was in close agreement to the observed data (R2 = 0.94) and produced an optimum ammonia removal of 87% at a pH of 10.9 and energy output of 94.8 kJ. Analysis of variance tests showed that there were no significant differences in the percent removal of ammonia due to the non-thermal effects of US across all four solutions (synthetic and leachate) indicating that US irradiation is a non-selective treatment method for ammonia removal.

Calcite stalactites ranging in length from several inches to a foot long are found forming on the southeastern slag pile at the former Gadsden Steel Mill of the Gulf States Steel Corporation. Analyses of samples collected per EISOPQAM guidelines include the following: petrographic, conductivity, pH, XRD, XRF, TDS, and major cations and anions. Preliminary field pH and conductivity measurements indicate that waters near the slag pile have a pH ranging from 11-12 and a conductivity ranging from 1115-6300 μS/ cm. Titration data indicate that the maximum pH value is 12.5. These calcite stalactites and stream coatings result from the dissolution of the steelmaking slag by rainfall. These alkaline waters precipitate calcite when they are in contact with atmospheric CO2. Improper management of slag products can lead to aesthetically impacted environments and ecosystems. Several studies and this study show that steel slag could be used to sequester atmospheric CO2.

The waste management and recycling company, Söderhalls Renhållningsverk (SÖRAB) have constructed a surface flow wetland in order to treat surface runoff from the waste management site, Löt. The contaminated water passes several treatment steps until it reaches the wetland and a subsequent soil infiltration step. It is suspected that the flow path of the water through the wetland is short-circuited which may result in a reduced treatment efficiency. The current discharge concentrations of the chemical compounds tested for do not exceed the allowed discharge limits. However, it is of interest to keep the discharge concentrations as low as possible to protect sensitive areas and water bodies downstream. The aim of the thesis was therefore to investigate the flow pattern of the wetland and suggest measures which potentially could improve the treatment efficiency. The flow pattern was modelled numerically in a Physio-Mathematical model developed by Wörman and Kjellin (2020). The current flow pattern was modelled, followed by several simulation runs where the controlling factors of the flow were changed one by one. The validity of the modelling result is uncertain and should therefore be confirmed or rejected by conducting a tracer test prior to implementing any changes in the wetland design. The modelling results indicate the presence of a main flow path passing through the narrower section of the permeable embankment (intersecting the northern and southern part of the wetland, see Fig. 3). The results further indicate that the permeable embankment, the bottom topography and the vegetation distribution were the three major factors controlling the flow pattern within the wetland. Recommended improvements would therefore be to first conduct a tracer test to make sure that any changes implemented are based on the true current flow pattern. The embankment and the vegetation distribution seem to be the main causes of non-idealities in the flow but at the same time probably also have positive effects on the treatment efficiency (since they provide filtration and surface areas where microorganisms can attach to perform their treatment). One solution to reduce the non- idealities in the flow could therefore be to adjust the embankment to be equally wide and deep across the wetland. Furthermore, the bottom topography around the embankment could be adjusted so that the shift in bottom elevation is equal around it. This would probably aid in hindering the development of preferential flow paths through the embankment. Finally, the vegetation distribution could be made uniform. (It should also be noted that a uniform vegetation distribution would require adjustment of the water depth to be below 1,5 m to allow an equal establishment of vegetation).
Avfallshanterings- och återvinningsföretaget Söderhalls Renhållningsverk AB (SÖRAB) har anlagt en våtmark vid Löts avfallsanläggning, ca 35 km norr om Stockholm. Våtmarken utgör det näst sista reningssteget i reningsprocessen av lak- och processvatten från avfallsanläggningen. Riktvärdena för utsläppshalterna överskrids inte men det är önskvärt för SÖRAB att åstadkomma så låga utsläppsvärden som möjligt för att minimera påverkan på känsliga områden och vattendrag nedströms. SÖRAB misstänker dock att preferentiella flödesvägar kan förekomma där vattnet passerar alltför fort genom våtmarken. Detta resulterar ofta i en lägre reningseffektivitet då föroreningarna som är lösta i vattnet får en kortare kontakttid med de naturliga reningsmekanismerna som förekommer i våtmarken. Syftet med det här arbetet var därför att undersöka strömningen i våtmarken och identifiera vattnets flödesvägar med hjälp av en numerisk modell utvecklad av Wörman och Kjellin (2020). Strömningen i våtmarker styrs av en energigradient där flödet går från en punkt i ett vattendrag med högt energiinnehåll till en punkt med lågt energiinnehåll. Enligt principen om energins bevarande omvandlas energin mellan kinetisk, potentiell, tryckenergi och värmeenergi. Ändringen i energiinnehåll beror i sin tur på verkan av externa krafter (gravitationskraften, hydrostatiska tryckkrafter, friktionskrafter, kontraktions- och expansionskrafter och skjuvkrafter från vind. Dessa krafter verkar vid förändringar i bottentopografin, vattendjupet, ytmotståndet (vid våtmarkens botten och väggar), våtmarkens geometri samt där vattenytan är exponerad för vind. Dessa faktorer orsakar utvecklandet av skjuvkrafter i flödet som i sin tur orsakar utvecklandet av hastighetsprofiler och omblandning. Bildandet av hastighetsprofiler och omblandning av vattnet gör att olika vätskeelement eller föroreningar stannar i våtmarken olika lång tid då de rör sig olika fort. För att åstadkomma en så hög reningsgrad som möjligt är det därför önskvärt att hela våtmarkens volym nyttjas till samma grad och att samtliga vätskeelement rör sig med samma hastighet genom våtmarken vilket även kallas för en ideal flödesregim (där ingen omblandning i flödesriktningen förekommer). Då utvecklandet av skjuvkrafter i flödet utgör den grundläggande orsaken till avvikelser från en ideal flödesregim är det önskvärt att minimera dessa. De styrande faktorerna som orsakade utvecklandet av skjuvkrafter i flödet var som nämndes ovan: variationer i våtmarkens bottentopografi och vattendjup, våtmarkens geometri (som kan orsaka isolerade vattenvolymer), ytmotståndet (som bl.a. beror på distributionen av vegetation), vind, samt in- och utflödeshastigeter. Våtmarken undersöktes genom inmätning och lodning som sedan låg till grund för en konceptuell modell av systemet. Den konceptuella modellen utgjorde sedan en grund för att modellera våtmarken numeriskt. I den konceptuella modellen ingick identifiering och definition av systemgränser samt randvillkor, att definiera bottentopografin samt att dela in våtmarken i delområden med homogent flödesmotstånd. Systemgränser och randvillkor identifierades baserat på en vattenbalans. Med hjälp av vattenbalansen kunde relevanta komponenter att inkludera som randvillkor identifieras. Randvillkorens värden bestämdes genom mätningar av den hydrauliska potentialen med hjälp av en GNSS-mottagare (där GNSS står för Global Navigation Satellite System och mottagaren nyttjar satelliter för att bestämma höjd och position i en geografisk punkt) samt från erhållna mätvärden från SÖRAB av in- och utflöden som pumpas in och ut ur våtmarken. Då bottentopografin var okänd bestämdes den genom att vattendjupet mättes, interpolerades och subtraherades från en referensnivå. Vattendjupet mättes genom lodning och mätpunkterna interpolerades sedan i det geografiska informationsverktyget ArcMap för att erhålla ett heltäckande lager av mätvärden över vattendjupet. Därefter kunde vattendjupet subtraheras från vattenytans medelhöjd över havet vilket var 38,1 m och ett heltäckande lager över bottentopografin kunde erhållas. Flödesmotståndet beräknades enligt ekvation 16 (se avsnitt 2.1.) och våtmarken delades in i homogena delområden baserat på förekomsten av vegetation och om strömningen skedde genom ett poröst medium eller öppet vatten. Den numeriska modelleringen genomfördes genom att först modellera den nuvarande strömningen med och utan ett rör som går genom den genomsläppliga vallen. Därefter ändrades de styrande faktorerna för flödet en i taget för att kunna utvärdera vilken effekt varje faktor hade på strömningen i våtmarken för att åstadkomma en ideal flödesregim. Följande simuleringar genomfördes: (1) Bottentopografin gjordes jämn med ett vattendjup på 0,5 respektive 1,0 m, (2) inloppszonen gjordes längre för att undvika skapandet av isolerade vattenvolymer längs ytterkanterna, (3) vegetationens distribution gjordes homogen, (4) den genomsläppliga vallen justerades. Pålitligheten i resultatet från den numeriska modelleringen är osäker. Därför skulle ett spårämnesförsök behöva genomföras för att undersöka huruvida resultatet från modelleringen är tillförlitligt eller inte. Enligt modelleringsresultatet förekom en tydlig flödesväg som passerade genom den smalare delen av vallen. Modelleringen indikerade vidare att de kontrollerande faktorerna som styrde flödet i våtmarken framförallt utgjordes av distributionen av vegetation samt den genomsläppliga vallen tillsammans med omgivande bottentopografi. Det rekommenderas därför att modelleringsresultatets validitet först undersöks med ett spårämnesförsök innan några åtgärder vidtas. Möjliga förbättringsåtgärder som skulle kunna införas därefter för att sträva mot ett idealt flöde skulle kunna vara att justera den genomsläppliga vallen till att ha en lika stor tjocklek och ett lika stort djup överallt samt att justera bottentopografin runt vallen så att den förändras lika mycket runt vallen. Detta för att skapa förutsättningar för att undvika preferentiella flödesvägar genom den. En jämn fördelning av vegetation (och justering av vattendjupet till att understiga 1,5 m som tillåter kolonisering av växter) att störningar i flödet minimeras.

The Amadeus Basin is one of several sedimentary basins where evaporite minerals are located in Australia. The Karinga Creek Drainage System, Northern Territory, which is situated in the eastern zone of the Amadeus Basin was the study area for this project. Sample cores of the evaporitic sediments from several playa lakes in the study area were collected for chemical analysis. The two main aims of the project were: (1) to chemically characterize these evaporitic sediments in an unleached and leached state; and (2) to assess the leachability of evaporite minerals such as gypsum, glauberite, halite and thenardite under variable leaching conditions. Other objectives of the work in this thesis covered: (i) the development of new methodology for the determination of trace elements in the sediments using microwave heating, (ii) the determination of the major evaporite minerals present and their location in the sediments of selected playa lakes, (iii) the presentation of selected major, minor and trace elements as depth profiles for each core from the playa lakes under study, (iv) the application of chemometrics to the collected data. The chemical analysis strategy developed to achieve these aims and objectives involved the use of many instrumental techniques such as x-ray fluorescence spectrometry (XRF), atomic absorption spectroscopy (AAS), inductively coupled plasma spectroscopy (ICP), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and ion chromatography (IC). XRF analysis of the core samples showed a wide variation in the major and minor components along the core profiles reflecting the depth of deposition of different evaporite minerals. The predominant minerals found by DRIFT analysis were gypsum, glauberite, halite and calcite. The results of trace element analysis showed that generally there were very low levels of heavy metals in the sediments.

O trabalho tem como finalidade a realização de um estudo a respeito da análise de parâmetros analíticos, determinados em líquidos percolados provenientes de disposição final de lixo urbano gerados por diferentes sistemas de aterramento. O estudo foi realizado no município de Ribeirão Preto, analisando-se 45 parâmetros em amostras de líquidos percolados de aterros sanitários, distintos entre si nos seguintes aspectos: geológico, cronológico e operacional. A partir dos resultados obtidos, pretende-se verificar os parâmetros analisados nos diferentes líquidos percolados, procurando-se compará-los entre si, para verificação de possível influência do tipo de aterramento em relação a essas variáveis. O trabalho objetiva ainda, o desenvolvimento e adaptações de técnicas referentes às metodologias para a determinação dos parâmetros, visando a eliminação de interferentes das amostras complexas, como é o caso dos líquidos percolados e chorume. Os resultados foram obtidos através de ensaios realizados no Laboratório de Recursos Hídricos da Universidade de Ribeirão Preto - UNAERP.
This work is aimed on a study about the analysis of a analytical parameters determinate on leachate from final disposition of municipal landfill produced by different systems of disposal. The study took place in the town of Ribeirão Preto, analyzing forty five parameters in samples of leachate from landfill area, distinct among themselves in aspects such as geological, chronological and operational. From given results it is intended to check the parameters analyzed in different leachate comparing themselves, for checking possible influence from the kind of landfill area according to the aspect above. It techniques referent the methodology to determinate the parameters, trying to put interference of matrix samples such is the leachates. The results were achieved through studies do realizable the hydric sources laboratory at the University of Ribeirão Preto - UNAERP.

Degradation of the several million tons of solid waste produced in the U.S. annually is microbially mediated, yet little is known about the structure of prokaryotic communities actively involved in the waste degradation process. In the first study, leachates generated during degradation of municipal solid waste (MSW) in the presence (co-disposal) or absence of biosolids were analyzed using laboratory-scale bioreactors over an eight-month period. Archaeal and bacterial community structures were investigated by denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes. Regardless of waste composition, microbial communities in bioreactor leachates exhibited high diversity and temporal trends. Methanogen sequences from a co-disposal bioreactor were predominantly affiliated with the orders Methanosarcinales and Methanomicrobiales. Effect of moisture content on indicator organism (IO) survival during waste degradation was studied using culture-based methods. Fecal coliform and Enterococcus concentrations in leachate decreased below detection limits within fifty days of bioreactor operation during the hydrated phase. IOs could be recovered from the bioreactor leachate even after a prolonged dry period. This study advances the basic understanding of changes in the microbial community during solid waste decomposition. The purpose of the second study was to compare the ability of BOX-PCR to determine genetic relatedness with that of the "gold standard" method, 16S rRNA gene sequencing. BOX-PCR typing could clearly differentiate the strains within different Enterococcus species but closely related genera were not as distinguishable. In contrast, 16S rRNA gene sequencing clearly differentiates between closely related genera but cannot distinguish between different strains of Enterococcus species. This study adds to our knowledge of genetic relationships of enterococci portrayed by two separate molecular methods. The incidence of vancomycin resistant enterococci (VRE) in environmental matrices, residential and hospital wastewater was also investigated. Low-level VRE ( vanC genotype) were isolated from environmental matrices and residential wastewater. VRE isolates from hospital wastewater were identified as E. faecium and demonstrated resistance to ampicillin, ciprofloxacin and vancomycin (vanA genotype), but sensitivity to chloramphenicol and rifampin. Although no high-level VRE were isolated from surface waters, the high proportion of low-level VRE in environmental matrices is a cause for concern from the public health perspective.

Subtitle D of the Resource Conservation and Recovery Act (RCRA) requires a post closure period of 30 years for non hazardous wastes in landfills. Post closure care (PCC) activities under Subtitle D include leachate collection and treatment, groundwater monitoring, inspection and maintenance of the final cover, and monitoring to ensure that landfill gas does not migrate off site or into on site buildings. The decision to reduce PCC duration requires exploration of a performance based methodology to Florida landfills. PCC should be based on whether the landfill is a threat to human health or the environment. Historically no risk based procedure has been available to establish an early end to PCC. Landfill stability depends on a number of factors that include variables that relate to operations both before and after the closure of a landfill cell. Therefore, PCC decisions should be based on location specific factors, operational factors, design factors, post closure performance, end use, and risk analysis. The question of appropriate PCC period for Florida’s landfills requires in depth case studies focusing on the analysis of the performance data from closed landfills in Florida. Based on data availability, Davie Landfill was identified as case study site for a case by case analysis of landfill stability. The performance based PCC decision system developed by Geosyntec Consultants was used for the assessment of site conditions to project PCC needs. The available data for leachate and gas quantity and quality, ground water quality, and cap conditions were evaluated. The quality and quantity data for leachate and gas were analyzed to project the levels of pollutants in leachate and groundwater in reference to maximum contaminant level (MCL). In addition, the projected amount of gas quantity was estimated. A set of contaminants (including metals and organics) were identified as contaminants detected in groundwater for health risk assessment. These contaminants were selected based on their detection frequency and levels in leachate and ground water; and their historical and projected trends. During the evaluations a range of discrepancies and problems that related to the collection and documentation were encountered and possible solutions made. Based on the results of PCC performance integrated with risk assessment, projection of future PCC monitoring needs and sustainable waste management options were identified. According to these results, landfill gas monitoring can be terminated, leachate and groundwater monitoring for parameters above MCL and surveying of the cap integrity should be continued. The parameters which cause longer monitoring periods can be eliminated for the future sustainable landfills. As a conclusion, 30 year PCC period can be reduced for some of the landfill components based on their potential impacts to human health and environment (HH&E).

Expansive clays undergo a large swell when they are subjected to water. Thus, expansive clay is one of the most abundant problems faced in geotechnical engineering applications. It causes heavy damages in structures, especially in water conveyance canals, lined reservoirs, highways, airport runways etc., unless appropriate measures are taken. In this thesis, Granulated Blast Furnace Slag (GBFS), GBFS - Lime combinations and GBFS Cement (GBFSC) were utilized to overcome or to limit the expansion of an artificially prepared expansive soil sample (Sample A). GBFS and GBFSC were added to Sample A in proportions of 5 to 25 percent. Different GBFS-Lime combinations were added to Sample A by keeping the total addition at 15 percent. Effect of stabilizers on grain size distribution, Atterberg limits, swelling percentage and rate of swell of soil samples were determined. Effect of curing on swelling percentage and rate of swell of soil samples were also determined. Leachate analysis of GBFS, GBFSC and samples stabilized by 25 percent GBFS and GBFSC was performed. Use of stabilizers successfully decreased the amount of swell while increasing the rate of swell. Curing samples for 7 and 28 days resulted in less swell percentages and higher rate of swell.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
Mediante avaliação experimental comparativa, foi estabelecido que os processos de tratamento eletrolítico e de precipitação química são adequados para o tratamento primário de chorume gerado em aterro de resíduo sólido urbano. Foi também comprovado experimentalmente ser o stripping uma operação indicada para a remoção da amônia presente no chorume. O trabalho teve início com a caracterização do chorume através de parâmetros sanitários convencionais e também de análise instrumental visando a determinação das substâncias orgânicas presentes. Nesta caracterização foi dada ênfase ao chorume do aterro metropolitano do Rio de Janeiro (Gramacho). A caracterização do chorume indicou altas concentrações de sais dissolvidos, amônia e matéria orgânica, características de chorume velho. Os resultados são compatíveis com os obtidos com amostras de chorume oriundas de aterros de mesmo porte de outros países. No chorume bruto a concentração de amônia ficou normalmente cerca de 500 vezes acima do limite de lançamento. A amônia apresenta alta toxidade aos peixes, o que torna a sua remoção justificada e necessária. Por outro lado, as análises instrumentais utilizando a técnica de cromatografia gasosa com espectrometria de massa (GC/MS), permitiram a identificação, ainda inédita, de substâncias orgânicas oriundas da biodegradação e/ou decomposição dos resíduos sólidos urbanos, bem como de produtos químicos dispostos no aterro ou contidos em embalagens. Foi também conduzido um programa experimental, em escala de bancada, para avaliar a aplicação dos processos eletrolíticos e de precipitação química ao tratamento do chorume. Foram investigados diversos parâmetros, tais como:adição de produtos químicos, consumo de energia, quantidade e características do lodo gerado e qualidade do chorume tratado em relação a diversos parâmetros sanitários. O chorume tratado também foi submetido a análise cromatográfica, de modo a determinar alterações qualitativas na sua composição química durante o tratamento. O processo eletrolítico mostrou-se bastante indicado para a remoção de compostos orgânicos do chorume, porém não adequado para a remoção de amônia. A precipitação química mostrou-se boa para a remoção de orgânicos e propiciadora da remoção de amônia, sem ser, no entanto, a melhor opção do ponto de vista de otimização de custos. A melhor solução encontrada, sob todos os aspectos, consiste na combinação desses dois processos. Foi então conduzida uma série de experimentos voltados para a remoção da amônia por stripping, após a etapa de precipitação química com hidróxido de cálcio (cal). Investigou -se a influência de parâmetros tais como pH e temperatura na eficiência de remoção de amônia, tendo sido obtidas eficiências de remoção da ordem de 90 % nas condições de pH na faixa de 10 a 12,5 na temperatura ambiente. Estes resultados experimentais indicaram que os processos físicoquímicos estudados são a alternativa mais vantajosa para a remoção das altas concentrações de nitrogênio amoniacal encontradas no chorume. A remoção dessas grandes quantidades de N-NH3 também foi vantajosa, tanto operacional como economicamente, considerando-se a etapa subseqüente de tratamento biológico. Verificou-se também que a quantidade de amônia removida do chorume de Gramacho através do stripping aponta para a possibilidade de sua recuperação para fins econômicos, sob a forma de sulfato de amônio.
Following an experimental examination of available techniques, it was established that electrolytic treatment and chemical precipitation are most adequate for the primary treatment of leachates generated in municipal solid waste landfills. It was also determined experimentally that an air stripping operation is indicated for removal of ammonia present in the leachate. The initial stages of this present work concerned the characterization of leachate in accordance with conventional sanitary parameters, together with analytically determined organics contents. In making such characterizations, use was made of the leachate emanating from the metropolitan landfill of Rio de Janeiro (Gramacho). This leachate exhibited high concentrations of dissolved salts, ammonia and organic material - typical of old established landfills. Such results are comparable with those obtained from similar landfills in other countries. The concentration of ammonia in the raw leachate was frequently at least 500 times the permissible limit. Ammonia is highly toxic towards fish and its removal is accordingly justified on these grounds alone. Furthermore, the analyses were carried out using the techniques of gas chromatography with mass spectrometry (GC/MC), which permitted the identification, previously unreported, of organic substances, originated from the biodegradation and/or decomposition of municipal solid wastes, and of the chemical products found in the landfill itself or in deposited containers. An experimental programme was, at the same time, conducted in the laboratory to evaluate the application of the electrolytic and chemical precipitation processes for the treatment of leachate. A number of diverse parameters were investigated, such as: usage of chemicals, energy consumptions, quantity and characteristics of sludge generated, and the quality of treated leachate, in terms of diverse sanitary parameters. The treated leachate was also submitted to chromatographic analysis in order to determine changes in its chemical composition during treatment. The electrolytic process was shown to be well suited to the removal of organic materials from the leachate but was not effective in the removal of ammonia. Chemical precipitation was found to be a suitable means of removal of both organics and ammonia, although it does not feature highly in terms of its cost effectiveness. A better solution, in the overall sense, is considered to be that which comprises a combination of these two processes. A series of experiments was also undertaken designed to investigate the removal of ammonia by air stripping, after the chemical precipitation stage with calcium hydroxide. During these experiments, the influence on the efficiency of removal of ammonia of parameters such as pH and temperature was determined. Removal efficiencies of the order of 90% were obtained at pH levels between 10 and 12.5, at ambient temperature. These experimental results indicate that the physico-chemical processes studied represent the optimum alternative for removal of high concentrations of ammoniacal nitrogen encountered in leachate. The removal of large quantities of N - NH3 is furthermore considered to be economically attractive when followed by biological treatment. It was also established that the quantity of ammonia, which could be removed from the Gramacho leachate, utilizing the stripping process, is such as to present economic possibilities for its recovery as ammonium sulphate.

Landfilling is the most widely used method for the disposal of municipal solid wastes (MSW) in the United States due to its simplicity and low cost. According to the 2014 report on Advancing Sustainable Materials Management by the USEPA, only 34% of the total MSW generated in the US was recycled, while 13% was combusted for energy recovery. In 2014, 53% of the MSW generated, (i.e. 136 million tons) in the US was landfilled. The treatment of landfill leachates, generated by percolation of water through the landfill, primarily due to precipitation, has been found to be one of the major challenges associated with landfill operation and management. Currently, leachates from most landfills are discharged into wastewater treatment plants, where they get treated along with domestic sewage. Issues associated with treatment of landfill leachates due to their high nitrogen and heavy metal content have been widely studied. Recently, it has been observed that the organic carbon in landfill leachates, specifically humic and fulvic acids (together referred to as "humic substances") contain aromatic groups that can absorb large amounts of ultraviolet (UV) light, greatly reducing the UV transmissivity in wastewater plants using UV disinfection as the final treatment step. This interference with UV disinfection is observed even when landfill leachates constitute a very small fraction (of the order of 1%) of the total volumetric flow into wastewater treatment plants. Humic substances are present as dissolved organic matter (DOM) and typically show very low biodegradability. Removing these substances using chemical treatment or membrane processes is an expensive proposition. However, the concentrations of humic substances are found to be reduced in leachates from landfill cells that have aged for several years, suggesting that these substances may be degraded under the conditions of long-term landfilling. The primary objective of this research was to use a two-stage process employing thermophilic pretreatment followed by a mesophilic anaerobic membrane bioreactor (AnMBR) to mimic the conditions of long-term landfilling. The AnMBR was designed to keep biomass inside the reactor and accelerate degradation of biologically recalcitrant organic carbon such as humic substances. The treatment goal was to reduce UV absorbance in raw landfill leachates, potentially providing landfills with an innovative on-site biological treatment option prior to discharging leachates into wastewater treatment plants. The system was operated over 14 months, during which time over 50% of UV-quenching organic carbon and 45% of UV absorbance was consistently removed. To the best of our knowledge, these removal values are higher than any reported using biological treatment in the literature. Comparative studies were also performed to evaluate the performance of this system in treating young leachates versus aged leachates. Next-generation DNA sequencing and quantitative PCR (qPCR) were used to characterize the microbial community in raw landfill leachates and the bioreactors treating landfill leachate. Analysis of microbial community structure and function revealed the presence of known degraders of humic substances in raw as well as treated landfill leachates. The total number of organisms in the bioreactors were found to be higher than in raw leachate. Gene markers corresponding to pathogenic bacteria and a variety of antibiotic resistance genes (ARGs) were detected in raw landfill leachates and the also in the reactors treating leachate, which makes it necessary to compare these ARG levels with wastewater treatment in order to determine if leachates can act as sources of ARG addition into wastewater treatment plants. In addition, the high UV absorbance of leachates could hinder the removal of ARBs and ARGs by UV disinfection, allowing their release into surface water bodies and aiding their proliferation in natural and engineered systems.
Ph. D.

Masters Research - Master of Philosophy (MPhil)
More than 90% of municipal solid waste (MSW) in developing countries is disposed of in landfills. In Bhutan, about 90% of solid waste is disposed of in landfills. One of the significant problems associated with landfills is the generation of leachate. Landfill leachates are highly contaminated waste waters containing high concentrations of organic matter (OM) measured as biochemical oxygen demand (BOD) and chemical oxygen demand (COD), ammonia, halogenated hydrocarbons and trace elements. The direct release of leachate into the environment may pose potential risks and hazards to public health and ecosystems. As a result, cost effective and environmentally acceptable treatments of leachate are sought. This research aims to examine leachate characteristics and two low cost passive treatment options. The characteristics of a typical leachate generated at a modern sanitary landfill were investigated by analysis of long-term monitoring data collected at Summerhill Waste Management Centre (SWMC), Newcastle, NSW. Leachate production from the SWMC landfill was clearly related to rainfall events at the landfill site. Rainfall has a direct impact on the volume of leachate produced and consequently on its chemical characteristics. Thus, leachate treatment systems must have provisions for the variation in concentrations. The primary goal of this study was to investigate the suitability of two low cost passive leachate treatment options, which are viable and suitable for adoption in Bhutan. Two laboratory bench scale experiments were undertaken. The first experiment involved surface aeration of raw leachate over a period of 20 days, while the second investigated the treatment performance of three low cost filter media (Granular Activated Carbon (GAC), Blast Furnace Slag (BFS) and sand) by examining their sorption efficiencies in a series of column experiments. Leachate samples were collected from the landfill at SWMC. The results of the research showed that a medium strength landfill leachate can be treated by both methods to reduce the concentrations of certain parameters. Aerobic treatment enhanced the leachate quality mainly through removal of ammonia and OM (>95%). It resulted in significant pollutant reductions as opposed to no aeration, which resulted in anoxic conditions. Column experiments provided leachate treatment essentially by lowering soluble reactive phosphorus (SRP) concentration. BFS and GAC have performed comparatively better with P-removal efficiencies of 92% and 67%, respectively, than sand (40%) in the laboratory work undertaken. Finally, the research results also suggested landfills in Bhutan do not have appropriate leachate and gas collection facilities. Due to a lack of proper waste segregation, the leachates produced in landfills could be chemically complex. Composting is suggested as a sustainable alternative for SWM in Bhutan to reduce the 50-60% of organic waste disposed of in the landfills if leachate collection and treatment cannot be afforded.

碩士
朝陽科技大學
環境工程與管理系碩士班
91
Landfills in Taiwan are still unavoidable now, although incinerators are widely used for treatments of municipal solid wastes. However, It is believed that the original protection facilities of landfill sites may have been damaged after a long term operating period or closed. According to the collected data, many landfills in Taiwan have polluted the groundwater quality and probably increase the health risk of the residents. Hereby, it is important to simulate theleachate of a landfill. In this research, we collect the relative data of the landfill,and inquire the affections of leachate of the uncertainty of precipitation and linerparameters to estimate the probable pollution of the landfill. In this research, weuse Crystal BallR2000.2 to analyze the uncertainty of precipitation, HELP model to simulate the leachate of the landfill, inquire the affections of leachate of the uncertainty of precipitation and parameters of defects and replacement quality of the liner. According to the above results of leachate, use MOC model to simulate the probable pollution of leachate. The results of this research show affections ofleachate of precipitation are smaller than the relative parameters of the liner. Wealso use an unreal case to prove the suitability and feasibility of this method.

碩士
國立中興大學
水土保持學系所
107
Abstract Groundwater contamination is of great concern. Research to predict the pollutant concentration with good accuracy will be interest. In this study, the we used generalized integral transformation technique applied solve the one dimensional Advection Dispersion Equation (ADE), and the results were compared with previous research. Impact of physical parameters on the contamination transportation was explored, and it was found that the retardation factor is the most important factor to reduce the concentration of contamination, followed by, groundwater flow velocity and then the first order decay constant. In this study, two landfill sites in Taipei and Taichung were employed as the studied cases. The governing equation with or without the natural degradation effect were assumed to analyze the heavy metals concentration in the leachate. Heavy metals exposure for human health risks was also discussed, and a risk assessment model for the leachate contaminant plume was employed to examine the pollution. The results show that the leachate is not a suitable water sources for drinking or daily use purpose because it will be harmful to the human body.

This thesis consists of work conducted in two separate studies, evaluating the performance of passive systems for treating wastewater effluents. The first study involved the characterization of three wastewater stabilization ponds (WSPs) providing secondary and tertiary treatment for municipal wastewater at a facility in Amherstview, Ontario, Canada. Since 2003, the WSPs have experienced excessive algae growth and high pH levels during the summer months. A full range of parameters consisting of: pH, chlorophyll-a (chl-a), dissolved oxygen (DO), temperature, alkalinity, oxidation-reduction potential (ORP), conductivity, nutrient species, and organic matter measures; were monitored for the system and the chemical dynamics in the three WSPs were assessed through multivariate statistical analysis. Supplementary continuous monitoring of pH, chl-a, and DO was performed to identify time-series dependencies. The analyses showed strong correlations between chl-a and sunlight, temperature, organic matter, and nutrients, and strong time dependent correlations between chl-a and DO and between chl-a and pH. Additionally, algae samples were collected and analyzed using metagenomics methods to determine the distribution and speciation of algae growth in the WSPs. A strong shift from the dominance of a major class of green algae, chlorophyceae, in the first WSP, to the dominance of land plants, embryophyta – including aquatic macrophytes – in the third WSP, was observed and corresponded to field observations during the study period. The second study involved the evaluation of the performance and chemical dynamics of a hybrid-passive system treating leachate from a municipal solid waste (MSW) landfill in North Bay, Ontario, Canada. Over a three year period, monitoring of a full range of parameters consisting of: pH, DO, temperature, alkalinity, ORP, conductivity, sulfate, chloride, phenols, solids fractions, nutrient species, organic matter measures, and metals; was conducted bi-weekly and the dataset was analyzed with time series and multivariate statistical techniques. Regression analyses identified 8 parameters that were most frequently retained for modelling the five criteria parameters (alkalinity, ammonia, chemical oxygen demand, iron, and heavy metals), on a statistically significant level (p < 0.05): conductivity, DO, nitrite, organic nitrogen, ORP, pH, sulfate, and total volatile solids.
Thesis (Master, Civil Engineering) -- Queen's University, 2013-10-27 05:29:20.564

abstract: Zero-Valent Metals (ZVM) are highly reactive materials and have been proved to be effective in contaminant reduction in soils and groundwater remediation. In fact, zero-Valent Iron (ZVI) has proven to be very effective in removing, particularly chlorinated organics, heavy metals, and odorous sulfides. Addition of ZVI has also been proved in enhancing the methane gas generation in anaerobic digestion of activated sludge. However, no studies have been conducted regarding the effect of ZVM stimulation to Municipal Solid Waste (MSW) degradation. Therefore, a collaborative study was developed to manipulate microbial activity in the landfill bioreactors to favor methane production by adding ZVMs. This study focuses on evaluating the effects of added ZVM on the leachate generated from replicated lab scale landfill bioreactors. The specific objective was to investigate the effects of ZVMs addition on the organic and inorganic pollutants in leachate. The hypothesis here evaluated was that adding ZVM including ZVI and Zero Valent Manganese (ZVMn) will enhance the removal rates of the organic pollutants present in the leachate, likely by a putative higher rate of microbial metabolism. Test with six (4.23 gallons) bioreactors assembled with MSW collected from the Salt River Landfill and Southwest Regional Landfill showed that under 5 grams /liter of ZVI and 0.625 grams/liter of ZVMn additions, no significant difference was observed in the pH and temperature data of the leachate generated from these reactors. The conductivity data suggested the steady rise across all reactors over the period of time. The removal efficiency of sCOD was highest (27.112 mg/lit/day) for the reactors added with ZVMn at the end of 150 days for bottom layer, however the removal rate was highest (16.955 mg/lit/day) for ZVI after the end of 150 days of the middle layer. Similar trends in the results was observed in TC analysis. HPLC study indicated the dominance of the concentration of heptanoate and isovalerate were leachate generated from the bottom layer across all reactors. Heptanoate continued to dominate in the ZVMn added leachate even after middle layer injection. IC analysis concluded the chloride was dominant in the leachate generated from all the reactors and there was a steady increase in the chloride content over the period of time. Along with chloride, fluoride, bromide, nitrate, nitrite, phosphate and sulfate were also detected in considerable concentrations. In the summary, the addition of the zero valent metals has proved to be efficient in removal of the organics present in the leachate.
Dissertation/Thesis
Masters Thesis Environmental and Resource Management 2019

Landfill gas represents either a significant contributor to the build-up of greenhouse gases in the troposphere when released, or a potential energy source when recovered. An analysis of variation in landfill gas production and composition (%CH₄, %C0₂) in response to variations in ambient temperature, precipitation, barometric pressure and refuse age was carried out at the Vancouver Landfill Site at Burns Bog, located in Delta, B.C.. Results indicate that precipitation is a predominant factor, as illustrated in the relationship between cumulative precipitation 14 days prior to sampling and CH₄ generation (mean r2=0.88). This finding suggests that a time lag is in effect wherein the moisture acts to enhance the anaerobic nature of the niche, increase the mixing and availability of carbon rich organic matter and nutrients, directly stimulate bacterial growth and dilute metabolic inhibitors, leading to increased CH₄ production. Ambient temperature displayed only a moderate correlation with CH₄ production (mean r2=0.41), likely due to the establishment of a relatively consistent microclimate within the waste matrix. High gas temperatures were observed to correspond with periods of peak CH₄ production. Fluctuations in barometric pressure were not seen to have an effect on landfill gas production at the p=0.05 level of significance. Refuse age showed some relationship to CH₄ production, but results of this were inconclusive. Regression equations were calculated to predict CH₄ production from the sample gas ports and gas collection lines. Total annual CH₄ production from this site was calculated to be 44.76 kT, which equates to approximately 3% of the total CH₄ produced by landfills in Canada. Results suggest that the potential does exist for the optimization of waste degradation within the matrix. The production ratio of CH₄:C0₂ showed a strong relationship to cumulative precipitation 7-days prior to sampling (r2=0.85), with the relatively high ratio following periods of heavy rainfall. It is likely that conditions of low hydraulic retention time cause the CO₂ to be dissolved from the matrix and flushed downward with the movement of the leachate. It is also possible that the CO₂ acts as an end-product inhibitor during acetate and propionate degradation; its decreased partial pressures after periods of heavy rainfall would thus favour enhanced CH₄ production. Leachate parameters displayed high variability. COD concentrations were observed to decrease following heavy rainfall. Loadings of both NH4 + -N and acetic acid were observed to increase with higher precipitation inputs, most likely due to the increased mobilization of the substances. Both NH4 + -N and acetic acid loadings were found to increase significantly with increasing CH₄ production. Once again, it is likely that the "washing" of the matrix following periods of heavy rainfall (and increased CH₄ production) is responsible for this observation.

Co-disposal with refuse in a controlled landfill is the cheapest option for the disposal of hazardous waste and, if carefully controlled, can be an effective treatment option. In this present study a high-strength phenolic wastewater and activated sewage sludge were co-disposed with refuse. The effectiveness of phenol catabolism at two organic loading rates (500mgt1 and 1000mgtl) was assessed in the presence of various co-disposal strategies. Leachate recycle at the lower phenol organic loading rate was found to facilitate the greatest rate of phenol catabolism. Despite the effective removal of phenol, however, leachate recycle promoted the production of high concentrations of ammoniacal-N and hydrogen sulphide. At the higher phenol organic loading rate, recirculation was ineffective in reducing the residual phenol concentration due to inhibition of the phenol-catabolisers. Microcosms operated with single elution and batch co-disposal strategies at both phenol organic loading rates resulted in serious detrimental effects on the refuse fermentation and subsequent leachate quality. A high-strength leachate obtained from a closed co-disposal site was characterised to determine its chemical composition and was assessed for its susceptibility to biological treatment. If carefully controlled, co-disposal sites should produce leachates which differ little in quality to those produced by municipal waste sites. The exceptionally high specific conductivity of the leachate used in this present study was, however, uncharacteristic of a leachate from a municipal waste site. The leachate required dilution to 25 % (v/v) before responding to aerobic biological treatment due to the presence of bactericidal/bacteriostatic components. Anaerobic treatment was ineffective even at a final dilution of 10% (v/v) of the original due to the inhibition of methanogenesis caused indirectly by the high concentration of sulphate in the leachate. Following phosphate addition, aerobic biological treatment effected a significant reduction in the chemical oxygen demand (COD) but did not reduce the ammoniacal-N concentration. Scaling and precipitation occurred following addition of the phosphate, and although these did not affect the biological process they can cause operational problems in full-scale leachate treatment plants. Ion exchange, with soil, and lime treatment, were, therefore, considered for their ability to reduce the inorganic content of the leachate prior to biological treatment. However, these particular pretreatments were unsuitable due to their ineffectiveness to reduce calcium, the main inorganic element involved in scaling, to an acceptable concentration.
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.

Dumping of municipal solid waste (MSW) generated due to anthropogenic activities in any barren land or out fields causes severe hazards to human populations, ecosystems and the environment. In order to avoid this, it is required to design landfills in an engineered and scientific manner. Therefore, it is necessary to understand the behaviour of landfills over a period of time, to design landfills for site specific conditions. In this thesis such an attempt is made to evaluate performance of conventional landfill system using a large scale anaerobic reactor in the laboratory. The performance of the containment (bottom liner and final cover) systems is evaluated through numerical modelling and reliability based analysis. Response Surface Methodology (RSM) is used to develop linear regression models. Influence of various parameters and their uncertainty on the reliability of the containment systems are studied for various scenarios and conditions. Reliability assessment of containment systems play a decisive role in taking remedial measures in order to reduce its adverse affects on the environment and human health in the vicinity of landfill sites. On the other hand, pre-assessment of risk guides the engineers, planners and decision makers in achieving the goal of sustainable solid waste management as well as safe landfills. The thesis also includes assessment of vulnerability of groundwater to contamination, identification and ranking of suitable sites for municipal solid waste (MSW) disposal in the Bengaluru district, using remote sensing and Geographic information system (GIS) integrated with analytical hierarchy process (AHP), a multi criteria decision making tool. The study considers various land use, geological, hydrogeological and environmental factors as criteria. As a result, two most suitable locations are identified around the Bengaluru city and their descriptions are provided. Further, reliability analysis of the suitability of sites is evaluated considering criteria as random variables. The proposed reliability based approach helps the decision makers and planners to choose site locations having low probability of environmental pollution. The provided methods in the thesis can be effectively used for engineered design of landfills.

This research project aimed at evaluating four internationally accepted leachate extraction tests to determine their applicability on sewage sludge samples. Furthermore, the present analytical method to determine the leachable fraction of sludge for compliance to South African sludge legislation was evaluated. Leaching tests are done on sludge samples to determine element mobility. This is important since land application of sewage sludge is an accepted and regulated sludge management practice. A literature survey was done to evaluate the mobility over time of metals originating from sludge-amended soils. Mobility is initially due to the organic content of the soil and after organic matter decomposition, it is dependant on the inorganic content. Mobile metals in sludge-amended soil can cause potential environmental risks like groundwater contamination and metal accumulation in soil. Metal accumulation can further lead to increased plant uptake of metals. To determine the partitioning or fractionation of metals found in sludge-amended soil, selective sequential extractions and single extractions can be used. Since South African sludge legislation specifies a single extraction procedure, four were selected for comparative studies. The selected procedures were the USA Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure (TCLP) the Australian Standard Bottle leaching Test (AS 4439.3) the Nederlands Normalisatie-Insitiuut availability test (NEN 7341) and the Deutches Institut für Normung water leachability test (DIN 38 414-S4). A variation of the TCLP is specified for use in South Africa. Three sewage sludge sample lots were collected. The first consisted of 24 sub-samples that were collected from 24 different wastewater treatment works on the East Rand. Both leachable (TCLP) and total (aqua regia) extraction was done on these samples for Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Zn, Se, B and Fe. A relationship between the leachable and total extractions was found for Co and Pb but could not be tested by literature values due to a variation in the sample preparation. The TCLP leachates were also analysed by Atomic Absorption and Inductively Coupled Plasma techniques to compare the applicability of the two. It was found that both techniques are acceptable for leachate analysis. The second sample lot collected from a single wastewater treatment plant was used to determine the leachable effect of the difference between the South African adapted TCLP and the USA EPA procedure as well as the NEN procedure. The EPA specifies all samples be extracted on an “as is” basis while the South African adaptation specifies dry samples. It was found that no element was comparative between dry and wet sample for both extraction procedures. It was observed that wet extractions yield generally higher values than dry extractions. A third sample lot was collected two months after the second sample lot at the same wastewater treatment works. It was used to compare the four extraction procedures. From this it was found that the DIN yielded the highest results for the specified elements. This procedure could not be recommended since the experimental difficulties and the duration of the test make it an unsuitable regulatory compliance tests protocol.
Dissertation (MSc (Environmental Technology))--University of Pretoria, 2006.
Chemical Engineering
unrestricted