Dissertations / Theses on the topic 'Anaerobic baffed reactor'

O principal objeto desta pesquisa foi aprimorar a eficiência de remoção de DQO, DBO, SST e conversão de nitrogênio amoniacal de biofiltro aeróbio submerso (BF), aplicado no pós-tratamento do efluente de um reator anaeróbio compartimentado (RAC). O BF, em escala piloto, foi construído em tubos de PVC, com 0,40 m de diâmetro externo e volume útil de 190,6 L. Para a imobilização celular foram utilizadas, como material suporte, matrizes cúbicas de espuma de poliuretano, em um período total de operação de 180 dias e tempos de detenção hidráulica de 6, 4 e 12 horas, respectivamente. O trabalho de investigação foi dividido em duas fases: na fase I o BF operou por 55 dias com TDH de 6 horas, para a transferência de OD para o sistema foi utilizado uma câmara de saturação não pressurizada; na fase II, o BF operou por 28 dias com TDH de 6 horas; por 30 dias com TDH de 4 horas e no período restante por 67 dias com TDH de 12 horas. Nessa fase a câmara de saturação foi inicialmente removida por não atender à demanda de OD necessária para manter condições aeróbias no interior do BF; foi injetado ar comprimido diretamente no sistema. Foram alcançadas eficiências médias de remoção de DQOb, DBOb e SST; na fase I 32,4%, 39,2% e 62% com concentrações médias no efluente bruto de 143,7 mg DQOb/L, 101,2 mg DBOb/L e 25,1 mg SST/L, respectivamente. Nessa fase, não foi detectada eficiência de conversão de nitrogênio amoniacal. Na fase II, operando com TDH de 6 horas, o BF alcançou eficiências médias de remoção de DQOb, DBOb e SST de 74%, 85% e 85% com concentrações médias no efluente bruto de 63 mg DQOb/L, 15 mg DBOb/L e 13 mg SST/L, respectivamente. Nesse período também não foi detectado processo de nitrificação. Para TDH de 4 horas, as eficiências média de remoção de DQOb, DBOb e SST foram 77%, 70% e 71%, com concentrações médias no efluente bruto de 57 mg DQOb/L, 27 mg DBOb/L e 17 mg SST/L, respectivamente. Durante esse período também não ocorreu conversão de nitrogênio amoniacal. Na fase final, em que o BF operou com TDH de 12 horas, foram encontradas eficiências médias de remoção de DQOb, DBOb e SST de 83%, 73% e 86% com concentrações médias no efluente bruto de 42 mg DQOb/L, 36 mg DBOb/L e 9 mg SST/L, respectivamente. Nesse período a eficiência média de conversão de nitrogênio amoniacal foi de 57,8% com concentração média de 10 mg N-amoniacal/L no efluente bruto. A espuma de poliuretano foi adequada para imobilização da biomassa aeróbia, porém, a lavagem do leito foi dificultada pela mesma devido à sua alta capacidade de absorção. A injeção direta de ar no sistema resultou em considerável aumento da eficiência, produzindo efluente bastante clarificado.
The main object of this research was the removal efficiency improvement of COD, BOD, TSS and ammonia nitrogen conversion in a Submerged Aerated Biofilter (BF), used in the effluent post-treatment of an Anaerobic Baffed reactor (ABR). The BF, was built in pilot scale by PVC tubes with 0,40 m of external diameter and useful volume of 190,6 L. Cubic matrices of polyurethane foam with were used as support for cellular immobilization in an operation period of 180 days with HDT of 6, 4 and 12 hours, respectively. The investigations period was shared in two phases: BF in the phase I operated for 55 days with HDT of 6 hours and the oxygen transferring was done using a chamber not pressured; BF in the phase II operated for 28 days with HDT of 6 hours, 30 days with HDT of 4 hours and on the rest of the investigation period (67 days) with HDT of 12 hours. In this phase the chamber was initially removed due to not attending the DO demand necessary to keep aerobic condition into the BF and, compressed air was directly injected at the system. The removal averages efficiencies of CODr, BODr and SST in the phase I were 32,4%, 39,2% and 62% with average concentrations in the raw effluent of 146 mg CODr/L, 101,2 mg BODr/L and 25,1 mg TSS/L, respectively. Ammonia nitrogen conversion efficiency wasn\'t detected in this. In the phase II, operating with HDT of 6 hours, BF reached averages efficiencies of CODr, BODr and SST of 74%, 85% and 85% with averages concentrations in the raw effluent of 63 mg CODr/L, 15 mg BODr/L and 13 mg TSS/L, respectively. Nitrification process wasn\'t detected in this period too. For HDT of 4 hours, the removal averages efficiencies of CODr, BODr and SST were 77%, 70% and 71% with average concentrations in the raw effluent of 57 mg CODr/L, 27 mg BODr/L and 17 mg TSS/L, respectively. During this period ammonia nitrogen conversion also not occurred. In the ending phase, where BF operated with HDT of 12 hours, removal averages efficiencies found of CODr, BODr and TSS were 83%, 73% and 86% with averages concentrations in the raw effluent of 42 mg CODr/L, 36 mg BODr/L and 9 mg TSS/L, respectively. In this period the ammonia nitrogen conversion medium efficiency was 57,8% with medium concentration in the raw effluent of 10 mg N-ammonia/L. The polyurethane foam was appropriated for aerobic biomass immobilization however the bed washing was harmed by the same one due to its high absorption capacity. The direct air injection into the system resulted in a considerable efficiency increase producing a sufficiently clearly effluent.

Successful treatment of low strength aircraft deicing fluid (ADF) was achieved using the Anaerobic Baffled Reactor (ABR), under different hydrological retention times (HRT) and COD influent concentrations. A total of 17 experimental runs were conducted in continuous mode, achieving COD removal efficiencies of over 75% for most of the conditions tested. During this experiment different ADF concentrations (0.04%, 0.07%, and 0.13% v/v) were continuously fed at different HRTs (24, 12, 6 and 3 hrs) at organic loading rates (OLR) varying between 0.3 and 6 kg COD/m3/d. The performance of the reactor was determined by the COD removal efficiency at the different OLRs. The best COD removal was reached at high COD influent concentrations and HRTs, for the lowest HRTs essayed COD removal efficiency dropped to an average of 65% for the 3 COD influent concentrations tested. Methane production potential were close to the theoretical value of 0.39 L CH4/g COD removed at 35°C. The effect of biomass pre-acclimation was also evaluated and it was found to be effective in increasing specific acetoclastic activity for this type of wastewater in order to reduce the time needed for acclimation. (Abstract shortened by UMI.)

The feasibility of using a single vessel reactor for the biological treatment of recalcitrant compounds, namely reactive azo dyes discharged by the textile finishing industry was investigated. A synthetic effluent was derived from real processes to give reproducibility throughout the experimental period. The literature review found that a sequenced treatment of anaerobic then aerobic redox environments was required for the decolourisation and mineralisation of the dyes. Two biological reactor types were accordingly designed, built and tested, the sequencing batch reactor (SBR) and the hybrid anaerobic baffled reactor (HABR).

For decades, mainstream domestic wastewater treatment has relied on activated sludge processes to remove organic matter, and on biological nutrient removal systems like the A2/O process to remove nutrients. Recently, membrane filtration was also added to the realm of possible technologies for domestic wastewater treatment, with aerobic membrane bioreactors (MBRs) becoming increasingly popular, especially for decentralized, and small to medium scale applications. However, the aerobic activated sludge and MBR processes, which are often combined with biological nutrient removal processes, have high energy costs associated with supplying oxygen to the process, and end up converting the organic matter into CO2 and high amounts of microbial biomass, instead of more useful byproducts. In order to remedy the aforementioned shortcomings of the aerobic processes, anaerobic wastewater treatment has been a focus of research, with anaerobic baffled reactors (ABRs) and anaerobic membrane bioreactors (AnMBRs) having shown promise for achieving acceptable organic matter removal performance, along with potential to be energy neutral or positive through biogas production. In addition, phototrophic technologies, such as algal photobioreactors, have recently been shown to be able to remove nutrients from waste streams, while at the same time having the potential to be used as feedstock to produce biofuels. In this dissertation, a novel concentrically-baffled reactor (CBR) was designed that has the potential to reduce heat loss by transfering more of the heat between reactor zones than traditional baffled reactor designs, which will increase energy efficiency for heated systems. A prototype CBR was operated abiotically under varying hydraulic retention times (HRTs) from 4 h to 24 h, and achieved over 90% removal of total suspended solids (TSS) for all HRTs tested with feed particle sizes below 1.7 mm. In parallel with the baffled reactor research, phototrophic membrane bioreactors (PMBRs) were tested with low aeration conditions to decrease their energy demand, which resulted in nitrification-dominated systems. A phototrophic technology was developed for increasing the pH of waste streams to potentially aid pH-sensitive nutrient recovery processes. Phototrophic pH increase from 6.42±0.13 to 8.87±0.06 was achieved using batch reactors, and an increase of pH from 6.73 to 8.61 was recorded during a continuous reactor trial. Finally, the CBR was combined with a post-CBR membrane filtration process, and two PMBRs treating the effluent and permeate streams from the CBR in order to achieve complete organic matter and nutrient removal. The combined systems were tested both for high strength-high HRT and low strength-low HRT scenarios. Using the combined CBR-PMBR system, over 90% TN and TP removal were possible for 10 d HRT operation at high-strength feed conditions, with post-CBR membrane filtration. COD removal over 90% was possible for both high-strength and low-strength scenarios under all conditions tested.

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2019.
The biodiesel industry produces large volumes of biodiesel wastewater (BDWW) during the purification of crude biodiesel. This wastewater is characterised by high concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), and fats, oils and greases (FOG) which in turn defines BDWW as a highly polluted effluent. The low nitrogen and phosphorous content of BDWW creates an unfavourable environment for the growth of microorganisms, thereby making it difficult to degrade naturally. Biodiesel companies discharge untreated non-compliant wastewater directly to the municipal sewer system. Treatment prior to discharge is a necessity since the disposal of untreated BDWW may raise serious environmental concerns (i.e. disturbance of biological ecosystems) resulting in penalties liable by non-compliant companies due to the implementation of the waste discharge charge system (WDCS) which is regulated by the industrial waste discharge standard limits in South Africa (SA). This study aimed to combine the advantages of the conventional anaerobic baffled reactor (ABR) system with microbial fuel cell (MFC) technology resulting in an innovative technology used to treat high strength industrial BDWW at ambient conditions. Many studies have reported effective treatment of BDWW, however to date literature implementing an ABR equipped with MFC technology has not been reported. The main objectives of the study were to determine which parameters do not meet the industrial wastewater discharge standard limits, whether pH and carbon:nitrogen:phosphorous (C:N:P) ratio adjustments will suffice prior to treatment with the ABR-MFC, the maximum power density (PD) as well as to determine the treatment efficiency of the ABR-MFC.

Decentralised Wastewater Treatment Systems (DEWATS) such as disseminated by the Bremen Overseas Research and Development Association (BORDA) are increasingly being recognized by decision makers across the world as an option for service delivery in densely populated low-income areas. However, little practical experience has been gathered methodologically on basic engineering and performance aspects surrounding these systems. This thesis investigates full-scale anaerobic reactors of communal DEWATS implemented in tropical regions in order to consolidate the basis of future design and support monitoring, operation and maintenance procedures. Special focus is laid on the operation of the Anaerobic Baffled Reactor (ABR) as the core technology of DEWATS. Field research has been conducted for over four years at numerous communal systems in Indonesia, India and South Africa in order to (i) verify the generally used parameter values for DEWATS design and operation, (ii) identify factors limiting the treatment efficiency of existing systems in the field and (iii) investigate the performance of DEWATS and DEWATS treatment steps (especially ABRs) under tropical field conditions in terms of effluent concentration, Chemical Oxygen Demand (COD) removal, sludge stabilisation and sludge activity. Field data on average per capita wastewater production in DEWATS implementation areas, long term fluctuations and peak-flow values are presented. General per capita organic load and per capita nutrient load, per capita biogas production in digesters and per capita sludge accumulation in ABRs are estimated. Based on available data and field observations, treatment limiting factors are hypothesised to be rain-water intrusion, general under-loading, organic under-loading and elevated raw-water salinity in coastal areas. Effluent measurements performed at one hundred nine systems in Indonesia indicated guaranteed maximum concentrations of 200 mg CODt l-1 for anaerobic DEWATS treatment effluent if the treated wastewater is non-saline. ABR COD reduction of four case studies was poor in three cases and fair in one case. Sludge accumulation rates indicated good sludge stabilisation and sludge activity in all four systems. Anaerobic Filters (AF) contributed in all three case studies, in which they were part of the plant design, significantly to COD reduction. Nutrient effluent concentrations were comparably high. Large fractions of effluent organics were found to be biodegradable. It is hypothesised that system treatment would improve significantly if maximum hydraulic load was lower, general organic load was higher and therefore both close to design estimation. It is thus proposed to control the amount of storm water intruding the systems, increase feed concentration through partial grey-water exclusion and reduce the nutrient load in system effluent through partial urine diversion. It is further proposed to reduce the HRT of the settler below 10 h in order to increase the organic load to the ABR. It is further hypothesised that systems could be operated at higher hydraulic dry weather load than currently assumed since active anaerobic digestion appears to be capable of establishing itself under extreme hydraulic pressure. This may lead to a considerable reduction of building costs. Anaerobic digestion modelling with the existing ADM-3P model confirmed that observed sludge accumulation rates indicate active hydrolytic systems. The model could however not be used to produce soluble COD effluent concentration benchmarks due to its sensitivity to methanogenic rate constants. The general view held for anaerobic reactors treating wastewater with high solid content is that hydrolysis is the rate-limiting degradation step. It is hypothesised that this does not apply for solid accumulating systems such as the ABR
Die durch die Bremen Overseas Research and Development Association (BORDA) verbreiteten Decentralised Wastewater Treatment Systems (DEWATS) werden international von Entscheidungsträgern zunehmend als Möglichkeit angesehen, kommunale Abwasserreinigung in dichtbesiedelten, einkommensschwachen Gegenden zu ermöglichen. Allerdings wurden bislang wenig praktische Erfahrungen methodisch über grundlegende Aspekte der Anlagendimensionierung und Anlagenleistungsfähigkeit aufgenommen. Im Rahmen dieser Dissertation wurden anaerobe Reaktoren kommunaler DEWATS unter tropischen Feldbedingungen untersucht, um eine Datengrundlage für zukünftige Dimensionierung, Wartung und Betrieb, als auch Monitoring der Anlagen zu schaffen. Schwerpunkt wurde dabei auf den Anaerobic Baffled Reactor (ABR) als Kerntechnologie von DEWATS gelegt. Felduntersuchungen wurden in der Zeit von mehr als vier Jahren an zahlreichen kommunalen DEWATS in Indonesien, Indien und Südafrika durchgeführt, um (i) die gängig gewählten Parameterwerte für Anlagen-Dimensionierung und -Betrieb zu überprüfen, (ii) leistungslimitierende Faktoren im Feldbetrieb zu identifizieren und um (iii) die Leistungsfähigkeit von DEWATS und DEWATS-Reinigungsstufen (insbesondere des ABRs) unter tropischen Feldbedingungen bezüglich Abflusskonzentrationen, Reduzierung des Chemischen Sauerstoffbedarfs (CSB), Schlammstabilisierung und Schlammaktivität zu untersuchen. Basierend auf den Untersuchungsergebnissen, wurden durchschnittliche Einwohnergleichwerte, Langzeitvariationen und Faktoren für Zuflussspitzen für kommunale Abwasserproduktion in DEWATS-Zielbevölkerungsgruppen präsentiert. Ferner werden allgemeine Pro-Kopf-CSB-Frachten, -Ammoniumfrachten und -Phosphorfrachten, die Pro-Kopf-Biogasproduktion in kommunalen Biogasanlagen sowie die Pro-Kopf-Schlammakkumulation in ABRs abgeschätzt. Auf Felduntersuchungen basierend, wurden Fremdwassereinfluss, generelle Unterbelastung, organische Unterbelastung und erhöhte Frischwassersalinität in Küstengebieten als leistungslimitierende Faktoren im Feldbetrieb identifiziert. An 109 indonesischen Anlagen durchgeführte Abflusskonzentrationsmessungen ließen auf eine garantierte Abflusskonzentration der anaeroben Reaktoren von 200 mg CSB l-1 schließen, wenn der negative Einfluss von erhöhter Frischwassersalinität ausgeschlossen werden kann. Der CSB-Abbau durch ABRs in vier detailliert untersuchten DEWATS war gering in drei Fällen und befriedigend in einem Fall. Anaerobe Filter (AF) trugen in den drei Fällen, in denen sie Teil der Anlagenkonfigurationen waren, signifikant zur CSB-Reduzierung bei. Ammonium- und Phoshorkonzentrationen in allen Reaktorabläufen waren vergleichsweise hoch. Ein großer Anteil des CSBs in Reaktorabläufen war biologisch abbaubar. Es wird die Hypothese aufgestellt, dass sich die Leistungsfähigkeiten der Anlagen signifikant verbessern würden, wären die Anlagenbelastungen den Auslegungswerten ähnlicher, d.h., wären die maximalen hydraulischen Belastungen geringer und die organischen Belastungen höher. Es wird deshalb geraten, den Fremdwasserzufluss zu minimieren, die Anlagenzulaufkonzentration durch partielle Grauwasserversickerung zu erhöhen und die Ammonium- und Phoshorkonzentration im Zulauf durch partiellen Urinabschlag zu verringern. Es wird außerdem vorgeschlagen, die hydraulische Aufenthaltszeit in Absetzbecken (settlers) auf zehn Stunden zu begrenzen, um so die organische Belastung der ABRs zu erhöhen. Ferner wird die Hypothese aufgestellt, dass Anlagen unter höherer Trockenwetterbelastung als bislang angenommen betrieben werden können, da aktiver anaerober Abbau auch unter extremen hydraulischen Belastungen möglich erscheint. Dies könnte zu einer signifikanten Senkung der Baukosten führen. Die Modellierung anaerober Abbauprozesse mit dem existierenden ADM-3P-Modell bestätigten, dass im Feld beobachtete Schlammakkumulationsraten auf eine aktive Hydrolyse schließen lassen. Das Modell konnte jedoch nicht genutzt werden, um Bezugswerte für den gelösten CSB im Ablauf der Anlagen zu erhalten, da es eine vergleichsweise hohe Sensitivität in Bezug auf die Raten für Methanogenese aufwies. Die allgemein anerkannte Sichtweise ist, dass die Hydrolyse den geschwindigkeitsbestimmenden Abbauschritt bei der anaeroben Behandlung feststoffreicher Abwässer darstellt. Es wird die Hypothese aufgestellt, dass dieses nicht für feststoffakkumulierende Systeme, wie den ABR, zutrifft

Deicing fluid, which is used to prevent ice formation and to remove ice from aircraft, is used in large quantities in Canada every winter. It has been reported that the application of aircraft deicing fluid (ADF) to planes can result in as much as 96% of the total glycol used being lost in the runoff. Since glycol has a very high chemical oxygen demand (COD), the resulting runoff will exert a high COD regardless of dilution. For this reason, it is desirable to treat the runoff before discharging it to a body of water. Successful treatment of ADF has already been achieved using Upflow Anaerobic Sludge Blanket (UASB) reactors, yet the treatment has been limited by the maximum flowrate attainable before substantial washout of biomass occurs. The particular flow characteristics within Anaerobic Baffled Reactor (ABR) which lead to long solids retention times (SRT) have been found, in the current study, to overcome the SRT limitations and have resulted in biomass accumulation which would require biomass wastage to maintain constant biomass concentration within ABR operated without recycle or with a 6:1 recycle ratio. (Abstract shortened by UMI.)

Orientador: Roberto Alves de Oliveira
Banca: Edson Aparecido Abdul Nour
Banca: Maria Bernadete Amâncio Varesche
Resumo: Neste trabalho avaliou-se o desempenho de processo anaeróbio em dois estágios composto por reator compartimentado (ABR) e reator de fluxo ascendente com manta de lodo (UASB), instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente), tratando águas residuárias de suinocultura com concentrações de sólidos suspensos totais de 4.591 a 13.001 mg L-1, submetidos a tempos de detenção hidráulica (TDH) de 60 a 24 h no primeiro reator e de 13,6 a 5,4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 69 a 88% no reator ABR e de 34 a 58% no reator UASB, resultando em valores médios de 87 a 95% para o sistema de tratamento anaeróbio em dois estágios (ABR+UASB) com carga orgânica volumétrica (COV) de 11,51 a 21,12 g DQOtotal (L d)-1 no reator ABR, e de 4,21 a 13,29 g DQOtotal (L d)-1 no reator UASB. As eficiências de remoção de SST e SSV variaram de 86 a 96% e 88 a 97% no sistema de tratamento (ABR+UASB). A produção volumétrica de metano máxima de 0,455 m3 CH4 (m3 reator d)-1 ocorreu no reator ABR, com COV de 13,42 g DQOtotal (L d)-1 e TDH de 48 h. Obtiveram-se eficiências médias de remoção de 62 a 95% para Cu, Fe, Mn e Zn e de 30 a 71% para NTK e P-total. Houve remoção de coliformes totais e fecais de 91,935 a 99,667% porém, foram observados nos efluentes número de coliformes fecais acima de 1,5 x 105 NMP/100 mL, o que restringe sua aplicação para a irrigação de plantas ...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In this work it was evaluated the performance of two stage anaerobic process constituted of anaerobic baffled reactor (ABR) and an upflow sludge blanket reactor (UASB) installed in series, in pilot scale testing (volumes of 530 and 120 L, respectively) treating swine wastewater with total suspended solid (TSS) concentration of 4591 a 13001 mg L-1 on and with hydraulic detention times (HDT) of 60 to 24 h in the first reactor and 13,6 to 5,4 h in the second reactor. The mean CODtotal removal efficiency varied from 69 to 88% in ABR and from 34 to 58% in UASB reactor, resulting in average values ranging from 87 to 95% for the two stage anaerobic treatment system (ABR+UASB) under organic volumetric load (OVL) of 11.51 to 21.12 g CODtotal (L d)-1 in ABR and 4.21 to 13.29 g CODtotal (L d)-1 in UASB reactor. The TSS and VSS removal efficiency varied from 86 to 96% and 88 to 97% in anaerobic treatment system (ABR+UASB). The maximum volumetric methane production of 0.455 m3 CH4 (m3 reactor d)-1 occurred in ABR reactor with OVL of 13.42 g CODtotal (L d)-1 and HDT of 48 h. The average mean removal efficiencies of 62 to 95% for Cu, Fe, Mn and Zn and of 30 to 71% for NTK and P-total. There was removal efficiency of total and fecal coliforms of 91,935 to 99,667% however, a number of fecal coliforms above 1,5 x 105 NMP/100 mL was observed on the effluents, which restricts its use for crop irrigation ...(Complete abstract, click electronic access below)
Mestre

Vor dem Hintergrund saisonaler Einflussfaktoren stellen ländlich strukturierte Gebiete besondere Anforderungen an Bemessung und Betrieb von Kläranlagen. Tourismus bildet neben landwirtschaftlich bedingten Ernte- und Verarbeitungskampagnen den bedeutendsten Faktor für saisonale Belastungsschwankungen. Da der größte Teil der Fremdenverkehrseinrichtungen über weniger als 100 Übernachtungsplätze verfügt, besteht bei fehlendem Kanalanschluss ein entsprechender Bedarf an Klein- und Kleinen Kläranlagen zur Behandlung der anfallenden Abwässer. Die Bemessung von Kläranlagen der Größenklasse 1 wird bei fehlenden Messwerten auf Grundlage der im ATV-DVWK-A 198 (2003) als 85-%-Perzentil angegebenen einwohnerspezifischen Frachten durchgeführt. Abwasser aus einfachen Fremdenverkehrseinrichtungen wie Campingplätzen und Hütten weist im Vergleich zur üblichen kommunalen Abwasserzusammensetzung bezogen auf CSB und BSB5 höhere Anteile an Stickstoff- und Phosphorverbindungen auf. Die spezifischen Stickstofffrachten liegen i. M. bei 10 – 11 g/P/d, die spezifischen CSB-Frachten bei i. M. 52 – 68 g/P/d. Die tatsächlichen Frachten werden von der Ausstattung (Restaurant, Wäscherei, etc.) der jeweiligen Unterkunft beeinflusst und sind in der Bemessung gesondert zu berücksichtigen. Für die Behandlung saisonal anfallender Abwässer eignen sich Verfahren mit großem vorgeschaltetem Puffervolumen oder Anlagen mit großem internem Puffer, wie z. B. Bodenfilteranlagen. Anaerobe Vorbehandlungsanlagen wie Anaerobic Baffled Reactors (ABR) können bei entsprechenden Temperaturen zur Frachtentlastung nachgeschalteter aerober Stufen beitragen. Unter gemäßigten Klimabedingungen werden inklusive Sedimentationsprozessen in Vorklärbecken i. M. 50 % des zugeführten CSB eliminiert. Aufgrund der starken Temperaturabhängigkeit des CSB-Abbaus, der Dauer des Einfahrbetriebs, der Empfindlichkeit gegenüber zu hohem Schlammabzug und des nicht berechenbaren Feststoffabtriebs ist unter gemäßigten Klimabedingungen und ohne technische Weiterentwicklung des Verfahrens keine über den Wirkungsgrad von Absetzanlagen hinausgehende Eliminationsleistung bei der Bemessung kalkulierbar. Für saisonal belastete Bodenfilter stellt die Abminderung des Flächenbedarfs bzw. die Steigerung der CSB-Flächenbelastung analog zum nicht belasteten Zeitraum eine betriebssichere und wirtschaftliche Lösung dar, bei der die Einhaltung der Mindestanforderungen gewährleistet ist. Bei geforderter Nitrifikation ist aufgrund des hohen TKN-Konzentrationsniveaus im Abwasser aus Fremdenverkehrseinrichtungen ein Wirkungsgrad von > 95 % für die TKN-Elimination erforderlich. Im Abwasser enthaltene Hemmstoffe, insbesondere in Vorkläranlagen gebildetes Sulfid, können die Nitrifikation beeinträchtigen. Dabei werden Ammoniumoxidation und Nitritoxidation gehemmt. Charakteristisch sind hohe NH4-N- und NO2-N-Konzentrationen im Ablauf (Extremwerte bis zu 55 mg NO2-N/l). Während sich Nitritoxidierer über mehrere Jahre an dauerhaft hohe Sulfidkonzentrationen adaptieren können, wird die Ammoniumoxidation direkt über die Sulfidkonzentration beeinflusst
In rural communities seasonal factors complicate design and operation of wastewater treatment plants. Tourism as well as agricultural harvesting and processing campaigns are the major causes for seasonal load variations. Due to the fact that accommodation capacities in rural tourism industry rarely exceed 100 beds small sewage treatment plants are acquired if a connection to a sewer system is not feasible. Small wastewater treatment plants can be designed using the population equivalents (PE). According to the German Water Association spreadsheet ATV-DVWK-A 198, PEs are defined as the 85-%-percentile input load. Wastewater of basic accommodations like camping sites and lodges contains higher levels of nitrogen and phosphorous compounds than 'standard' domestic wastewater. The mean specific nitrogen loads reach 10 – 11 g/guest/d, the mean specific COD-load 52 – 68 g/guest/d. The special amenities of vacation homes (restaurant, laundry) affect the real loads and have to be considered in dimensioning. Regarding the treatment of seasonal wastewater, processes with large upstream buffer or large internal buffer, such as constructed wetlands, are suitable. Furthermore, at moderate temperatures anaerobic pretreatment devices, like anaerobic baffled reactors (ABR), can reduce the input load to aerobic post treatment stages. An approximate COD elimination of 50 % can be expected by anaerobic degradation and sedimentation in the ABR in combination with upstream primary clarifiers at around 20 °C. Due to the strong temperature dependence, the long start-up-period, the sensitivity towards fail-desludging, the generation of immediate oxygen demand at low temperatures as well as unpredictable sludge overflow events, it does not seem justified to calculate higher design elimination efficiencies for ABRs than for sedimentation tanks. The design of subsurface vertical flow constructed wetlands with seasonally induced high loading periods are approved for the elimination of organic substances. This accepted assumption was confirmed for the plant under investigation operated at a mean COD-load of 20 g/m²/d, not exceeding the effluent control values for COD in six years. In contrast, oxidation of ammonia and nitrite were inhibited by high sulfide levels (mean sulfide concentration: 48 ± 26 mg/L). Nitrite accumulation reached its peak value at 55 mg NO2-N/L and decreased within 4 years below 1 mg/L due to the adaption of nitrite-oxidizing microorganisms

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Neste trabalho avaliou-se o desempenho de processo anaeróbio em dois estágios composto por reator compartimentado (ABR) e reator de fluxo ascendente com manta de lodo (UASB), instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente), tratando águas residuárias de suinocultura com concentrações de sólidos suspensos totais de 4.591 a 13.001 mg L-1, submetidos a tempos de detenção hidráulica (TDH) de 60 a 24 h no primeiro reator e de 13,6 a 5,4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 69 a 88% no reator ABR e de 34 a 58% no reator UASB, resultando em valores médios de 87 a 95% para o sistema de tratamento anaeróbio em dois estágios (ABR+UASB) com carga orgânica volumétrica (COV) de 11,51 a 21,12 g DQOtotal (L d)-1 no reator ABR, e de 4,21 a 13,29 g DQOtotal (L d)-1 no reator UASB. As eficiências de remoção de SST e SSV variaram de 86 a 96% e 88 a 97% no sistema de tratamento (ABR+UASB). A produção volumétrica de metano máxima de 0,455 m3 CH4 (m3 reator d)-1 ocorreu no reator ABR, com COV de 13,42 g DQOtotal (L d)-1 e TDH de 48 h. Obtiveram-se eficiências médias de remoção de 62 a 95% para Cu, Fe, Mn e Zn e de 30 a 71% para NTK e P-total. Houve remoção de coliformes totais e fecais de 91,935 a 99,667% porém, foram observados nos efluentes número de coliformes fecais acima de 1,5 x 105 NMP/100 mL, o que restringe sua aplicação para a irrigação de plantas...
In this work it was evaluated the performance of two stage anaerobic process constituted of anaerobic baffled reactor (ABR) and an upflow sludge blanket reactor (UASB) installed in series, in pilot scale testing (volumes of 530 and 120 L, respectively) treating swine wastewater with total suspended solid (TSS) concentration of 4591 a 13001 mg L-1 on and with hydraulic detention times (HDT) of 60 to 24 h in the first reactor and 13,6 to 5,4 h in the second reactor. The mean CODtotal removal efficiency varied from 69 to 88% in ABR and from 34 to 58% in UASB reactor, resulting in average values ranging from 87 to 95% for the two stage anaerobic treatment system (ABR+UASB) under organic volumetric load (OVL) of 11.51 to 21.12 g CODtotal (L d)-1 in ABR and 4.21 to 13.29 g CODtotal (L d)-1 in UASB reactor. The TSS and VSS removal efficiency varied from 86 to 96% and 88 to 97% in anaerobic treatment system (ABR+UASB). The maximum volumetric methane production of 0.455 m3 CH4 (m3 reactor d)-1 occurred in ABR reactor with OVL of 13.42 g CODtotal (L d)-1 and HDT of 48 h. The average mean removal efficiencies of 62 to 95% for Cu, Fe, Mn and Zn and of 30 to 71% for NTK and P-total. There was removal efficiency of total and fecal coliforms of 91,935 to 99,667% however, a number of fecal coliforms above 1,5 x 105 NMP/100 mL was observed on the effluents, which restricts its use for crop irrigation ...(Complete abstract, click electronic access below)

Os efluentes com elevadas concentrações de lipídios, apesar de demonstrarem elevado potencial para produção de metano podem causar inibição da atividade do consórcio anaeróbio, impossibilitando a produção de biogás. O presente trabalho teve como objetivo o estudo de um reator anaeróbio compartimentado (ABR) com cinco compartimentos tratando efluente simulado de laticínio. Para tanto, a biomassa, foi adaptada por 51 dias e em seguida submetida a tempos de detenção de hidráulica (TDH) de 72h, 24h e 12h, tendo o monitoramento se estendido por 340 dias. Enquanto operando com TDH de 24, o sistema foi submetido a choques hidráulicos e de carga orgânica através da diminuição do TDH para 12 h. O reator absorveu bem a carga, e em 36 horas recuperou os valores prévios de eficiência. Quando operou permanentemente com 12 horas, todavia, problemas de flotação de biomassa e obstruções foram constantes. As eficiências de remoção de matéria orgânica alcançadas para cada condição aplicada foram de 92 ± 3,0; 91 ± 1,8 e 90 ± 2,4% para os TDH de 72h, 24h e 12h, respectivamente. Esses valores foram estatisticamente semelhantes (Anova e L-Fisher). A percentagem de metano no biogás aumentou com a redução de TDH, tendo sido 41 ± 23, 53 ± 27 e 62 ± 12% quando os TDH foram 72, 24 e 12 horas, respectivamente. A produção média de alcalinidade foi de 320±25 mg.CaCO3.L-1, sendo esta observada desde o início da operação. A relação média entre alcalinidade intermediária e parcial foi de 0.1±0.06 em amostras coletadas na saída do sistema. Embora apresentando problemas de obstrução com o menor TDH, o ABR foi eficiente, robusto e confiável ao tratar efluente de laticínios, tendo produzido um efluente líquido de alta qualidade e biogás rico em metano.
Effluents with high concentrations of lipids, although demonstrating high potential for methane production represents potential inhibition of the anaerobic consortium activity, depleting the production of biogas. This project was carried out monitoring an anaerobic hybrid baffled reactor with five compartments (ABR) treating simulated dairy wastewater. The biomass, was adapted for 51 days and then subjected to hydraulic retention times (HDT) of 72h, 24h and 12h, resulting in a monitoring period of 340 days. While operating with 24h of HRT, the system was subjected to three organic and hydraulic shock loads, when its HDT was decreased to 12 h. The reactor absorbed the shock within 36 hours, achieving similar efficiencies to the previous condition. Nevertheless, although presenting high organic matter efficiencies, when permanently operating with HDT of 12 h, clogging problems due to biomass flotation were constant. The organic matter removal efficiencies for each operational condition were 92 ± 3%, 91 ± 1.8%, 90 ± 2,4%. Those values were statistically similar. The methane percentage in the biogas increased with the HDT reduction, being 41 ± 23, 53 ± 27, and 62 ± 12% when the HDT were 72, 24 and 12 hours. Alkalinity production was observed since the beginning of operation. The mean relation between intermediate and partial alkalinity was 0.1±0.006 in samples collected in the system output. Although presenting clogging problems with the smallest HDT, the ABR was efficient, robust and reliable when treating dairy effluents, producing a high quality liquid effluent and a methane rich biogas.

Orientador: Vanildo Luiz Del Bianchi
Banca: Tânia Maria Alberte
Banca: Crispin Humberto Garcia Cruz
Resumo: Este trabalho teve por objetivo avaliar o desempenho de um reator anaeróbio compartimentado no tratamento de soro de queijo. Para tanto, foi utilizado um reator de 4,9 L com cinco compartimentos, inoculados com lodo biológico granulado obtido de uma indústria da região. O reator foi operado com variados tempos de residência hidráulicos (1 a 4 dias) e concentrações de soro de queijo que variaram de 2500 a 11000 DQO mg L-1. Foram efetuadas as análises de Acidez e Alcalinidade, Turbidez, pH, Demanda Química de Oxigênio (DQO), Sólidos Voláteis (SV) e Sólidos Totais (ST). A partir dos resultados obtidos, e devido às características do reator, foi possível compreender a dinâmica do processo anaeróbio, nas fases acidogênica e metanogênica, tanto na geração / desaparecimento da alcalinidade / acidez, como na redução da carga orgânica. Na primeira etapa da pesquisa, o soro de queijo da alimentação do reator foi diluído a uma DQO de 2500 mg L-1, e o reator mantido em quatro tempos de residência hidráulicos (TRH), 4, 3, 2 e 1 dia. Com TRH 4 dias, a redução da DQO foi de 96,3%. Com TRH 3 dias, o reator apresentou um problema de queda no pH e, devido a isso, foi dividido em duas partes: a primeira na qual o reator apresentou uma redução de 97,3% e a outra na qual a redução foi de 89,4%. Com TRH 2 dias, a redução de DQO foi de 89,5%; e com TRH 1 dia a redução foi de 50,5%. A segunda etapa da pesquisa contou com um aumento da concentração de soro de queijo na alimentação do reator, DQO 6000 mg L-1, e TRHs de 3, 2 e 1 dia. Com TRH 3 dias, a redução de DQO foi 80,7%, com TRH 2 dias 74,0% e com TRH 1 dia, a redução foi 33,5%. Na terceira etapa da pesquisa, a concentração do soro foi elevada para uma DQO de 11000 mg L-1, sendo testado o TRH 3 dias e como a eficiência do reator na redução da DQO apresentou um baixo valor, 47,1%, nenhum outro TRH foi testado.
Abstract: This study aimed to evaluate the efficiency of an anaerobic baffled reactor treating cheese whey. For this, it was used a five-compartment reactor, 4.9 L, inoculated with granular sludge obtained from a biological industry in the region. The reactor was operated at different hydraulic residence times (HRT) from 1 to 4 days and the concentration of cheese whey was of 2500 to 11000 mg COD L-1. The procedures included analyses of acidity and alkalinity, turbidity, pH, chemical oxygen demand (COD), volatile solids (VS) and total solids (TS).From the results shown and due to the characteristics of the reactor, it was possible to understand the dynamics of the anaerobic process at the acidogenic and methanogenic stages both in the generation / disappearance of alkalinity / acidity and in reducing the organic load. In the first stage of research, the cheese whey used for feeding the reactor was diluted to a 2500 mg L-1 COD. The reactor was maintained at four hydraulic residence times (HRT) of 4, 3, 2 and 1 days. At a HRT of 4 days, the reduction in the COD was 96.3%. At a HRT of 3 days, the reactor had a problem - a decrease in pH and because of that, it was divided into two parts: in the first part the reactor showed a reduction of 97.3% and in the second one, the reduction was of 89.4%. At a HRT of 2 days, the reduction in the COD was of 89.5%; and at a HRT of 1 day, the reduction was of 50.5%. During the second stage of the survey, there was an increase of the concentration of cheese whey while feeding the reactor, COD 6000 mg L-1, and at a HRT of 3, 2 and 1 day. At a HRT of 3 days, the reduction in the COD was of 80.7%; at a HRT of 2 days, it was 74.0% and at a HRT of 1 day, the reduction was of 33.5%. In the third stage of the study, the concentration of whey was increased to a COD of 11000 mg L-1, being tested at a HRT of 3 days and since the efficiency of the reactor in the COD reduction showed a low value, 47.1%, no other HRT was tested.
Mestre

A digestão anaeróbia é uma potencial solução para a destinação dos grandes volumes de vinhaça gerada em biorrefinarias de cana-de-açúcar. A alta concentração de matéria orgânica presente na vinhaça é uma questão importante a ser considerada, uma vez que as populações microbianas anaeróbias, principalmente metanogênicas, são sensíveis a sobrecargas orgânicas. Uma série de configurações de reatores, bem como diferentes estratégias de partida e operação tem sido aplicadas ao tratamento de vinhaça, como a recirculação do efluente tratado, a qual é usualmente empregada para prevenir eventos de sobrecarga orgânica. O objetivo deste estudo foi determinar a influência da recirculação de efluentes em reatores anaeróbios compartimentados (RAC) tratando águas residuárias concentradas, uma vez que a literatura não é conclusiva sobre os efeitos da recirculação neste tipo de reator. Para atingir esse objetivo, foi utilizada uma abordagem dupla: experimental e modelagem matemática. Um RAC com 4 compartimentos em série em escala de bancada foi alimentado com vinhaça de cana-de-açúcar (DQO = 18,0 g/L) e monitorado durante 273 dias. Os parâmetros cinéticos e de transferência de massa do reator foram obtidos e utilizados para criar um modelo matemático para a conversão da matéria orgânica no software Matlab®. Tanto os dados operacionais como os parâmetros cinéticos mostraram que a elevada concentração de DQO fez com que o RAC não se comportasse como um sistema de duas fases, bem como a recirculação não resultasse em melhorias relevantes de desempenho. O modelo matemático concordou com os dados operacionais e mostrou que, em termos de capacidade de conversão, o uso de elevadas taxas de recirculação não é necessário para um adequado desempenho do RAC, uma vez que a cinética bioquímica observada não foi expressivamente limitada pela concentração de substrato.
Anaerobic digestion is a potential approach to handle the large volume of vinasse generated in sugarcane biorefineries. The high concentration of organic matter present in vinasse is an important issue to be considered, since anaerobic microbial populations, mainly methanogens, are sensitive to organic overloads. A serie of reactors configurations, as well as different startup and operating strategies, have been applied to the treatment of vinasse, so that the recirculation of the treated effluent is usually used to prevent organic overloading events. The aim of this study was to determine the influence of effluent recirculation in anaerobic baffled reactors (ABR) treating high concentrated wastewater, since literature is not conclusive about its effects. To achieve this aim an experimental and mathematical modeling dual approach was employed. A bench-scale ABR with four serial baffleds was fed with sugarcane vinasse (COD = 18,0 g/L) and monitored for 273 days. Kinetic and mass transfer parameters were obtained and used to create a mathematical model for the organic matter conversion in Matlab®. Both the operating data and the kinetic parameters showed that at high COD concentrations the ABR does not behave as a two-stage system, as well as recirculation did not result in relevant performance improvements. The mathematical model agreed with the operational data and showed that, in terms of conversion capacity, the use of high recirculation ratios is not necessary for suitable ABR performance, since the observed biochemical kinetics were not high limited by the concentration of substrate.

Um sistema de tratamento constituído de um reator anaeróbio de mistura completa e um reator anaeróbio compartimentado (ABR) foi operado durante 140 dias para estudar os efeitos do pré-tratamento das águas residuárias de uma indústria química, por carvão ativado em pó (CAP), e suas implicações nos processos de nitrificação e desnitrificação. Utilizou-se, no pré-tratamento do resíduo, duas concentrações de carvão ativado em pó. Para aplicação de 10 mg/l de CAP a remoção de DQO foi de 60% e a de NTK foi de 50%. Nesta fase, os processos de remoção de nitrogênio foram plenamente viabilizados. Para 5 mg/l de CAP a remoção de DQO foi de 44% e a remoção de NTK 46%, neste período se observou inibição por metais pesados e acúmulo de nitrito no sistema.
A treatment system composed of both an aerobic complete-mix reactor and a anaerobic baftled reactor (ABR) was operated for 140 days to study the effects of the treatment of wastewater chemical industry by powdered activate carbon (PAC) and its implications in nitrification - denitrification processes. In the residue preliminary treatment, two concentrations of PAC were used. For the application of 10 mg/l of CAP the removal of COD was 60% and the removal of TKN was 50%. In this phase, the processes of nitrogen removal were possible to be completely carried out. For 5 mg/l of CAP, the removal of COD was 44% and the removal of TKN 46%. In this period, the inhibition by heavy metaIs and nitrite accumulation in the system was observed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Este trabalho teve por objetivo avaliar o desempenho de um reator anaeróbio compartimentado no tratamento de soro de queijo. Para tanto, foi utilizado um reator de 4,9 L com cinco compartimentos, inoculados com lodo biológico granulado obtido de uma indústria da região. O reator foi operado com variados tempos de residência hidráulicos (1 a 4 dias) e concentrações de soro de queijo que variaram de 2500 a 11000 DQO mg L-1. Foram efetuadas as análises de Acidez e Alcalinidade, Turbidez, pH, Demanda Química de Oxigênio (DQO), Sólidos Voláteis (SV) e Sólidos Totais (ST). A partir dos resultados obtidos, e devido às características do reator, foi possível compreender a dinâmica do processo anaeróbio, nas fases acidogênica e metanogênica, tanto na geração / desaparecimento da alcalinidade / acidez, como na redução da carga orgânica. Na primeira etapa da pesquisa, o soro de queijo da alimentação do reator foi diluído a uma DQO de 2500 mg L-1, e o reator mantido em quatro tempos de residência hidráulicos (TRH), 4, 3, 2 e 1 dia. Com TRH 4 dias, a redução da DQO foi de 96,3%. Com TRH 3 dias, o reator apresentou um problema de queda no pH e, devido a isso, foi dividido em duas partes: a primeira na qual o reator apresentou uma redução de 97,3% e a outra na qual a redução foi de 89,4%. Com TRH 2 dias, a redução de DQO foi de 89,5%; e com TRH 1 dia a redução foi de 50,5%. A segunda etapa da pesquisa contou com um aumento da concentração de soro de queijo na alimentação do reator, DQO 6000 mg L-1, e TRHs de 3, 2 e 1 dia. Com TRH 3 dias, a redução de DQO foi 80,7%, com TRH 2 dias 74,0% e com TRH 1 dia, a redução foi 33,5%. Na terceira etapa da pesquisa, a concentração do soro foi elevada para uma DQO de 11000 mg L-1, sendo testado o TRH 3 dias e como a eficiência do reator na redução da DQO apresentou um baixo valor, 47,1%, nenhum outro TRH foi testado.
This study aimed to evaluate the efficiency of an anaerobic baffled reactor treating cheese whey. For this, it was used a five-compartment reactor, 4.9 L, inoculated with granular sludge obtained from a biological industry in the region. The reactor was operated at different hydraulic residence times (HRT) from 1 to 4 days and the concentration of cheese whey was of 2500 to 11000 mg COD L-1. The procedures included analyses of acidity and alkalinity, turbidity, pH, chemical oxygen demand (COD), volatile solids (VS) and total solids (TS).From the results shown and due to the characteristics of the reactor, it was possible to understand the dynamics of the anaerobic process at the acidogenic and methanogenic stages both in the generation / disappearance of alkalinity / acidity and in reducing the organic load. In the first stage of research, the cheese whey used for feeding the reactor was diluted to a 2500 mg L-1 COD. The reactor was maintained at four hydraulic residence times (HRT) of 4, 3, 2 and 1 days. At a HRT of 4 days, the reduction in the COD was 96.3%. At a HRT of 3 days, the reactor had a problem - a decrease in pH and because of that, it was divided into two parts: in the first part the reactor showed a reduction of 97.3% and in the second one, the reduction was of 89.4%. At a HRT of 2 days, the reduction in the COD was of 89.5%; and at a HRT of 1 day, the reduction was of 50.5%. During the second stage of the survey, there was an increase of the concentration of cheese whey while feeding the reactor, COD 6000 mg L-1, and at a HRT of 3, 2 and 1 day. At a HRT of 3 days, the reduction in the COD was of 80.7%; at a HRT of 2 days, it was 74.0% and at a HRT of 1 day, the reduction was of 33.5%. In the third stage of the study, the concentration of whey was increased to a COD of 11000 mg L-1, being tested at a HRT of 3 days and since the efficiency of the reactor in the COD reduction showed a low value, 47.1%, no other HRT was tested.

Um dos principais resíduos gerados nos aterros é o lixiviado, que possui elevada concentração de matéria orgânica biodegradável e refratária e de matéria inorgânica, como nitrogênio amoniacal e metais pesados. O tratamento combinado de lixiviado com esgoto sanitário tem sido utilizado em algumas estações de tratamento de esgoto (ETE) brasileiras. No entanto, o processo ainda sofre vários questionamentos e incertezas, especialmente sobre os efeitos da adição do lixiviado sobre o sistema de tratamento. Nesse contexto, o presente trabalho visou avaliar a eficiência do tratamento combinado de lixiviado/esgoto em sistema de lodos ativados, em diferentes condições. Na primeira etapa desta pesquisa, foram realizados experimentos de tratabilidade em escala de bancada (regime de batelada) utilizando as proporções volumétricas de 0% (controle), 0,2%, 2% e 5% de lixiviado em diferentes condições experimentais. Dentre eles, o Experimento 2 (lixiviado pré-tratado por alcalinização e air stripping) se mostrou mais viável tecnicamente, alcançando eficiências de remoção da DBO, da DQO e do COD acima de 97, 82, 60%, respectivamente, até a proporção de 2% de lixiviado pré-tratado. Na segunda etapa da pesquisa, foi avaliada a tratabilidade utilizando reatores em escala piloto (regime contínuo) tratando esgoto sanitário com 2% (P1) e 0% (P2-controle) de lixiviado pré-tratado, com relação microrganismo-alimento de 0,22 kgDBO/kgSSV.dia, tempo de detenção hidráulica de 24 horas e idade do lodo de 20 dias. Os resultados indicaram viabilidade do tratamento nas condições estudadas com 2% de lixiviado pré-tratado, cujas eficiências médias de remoção da DBO, da DQO, do COD foram de 93, 84 e 60%, respectivamente. Esta pesquisa foi desenvolvida com apoio financeiro (Processo N° 2010/51955-2) da Fundação de Amparo à Pesquisa de São Paulo (FAPESP).
The leachate is one of the main wastes generated in landfills, it has a high concentration of biodegradable and refractory organic matter and inorganic matter, such as ammonia and heavy metals. The combined treatment of leachate with sewage has been used in various sewage treatment plants in Brazil. However, there are still many questions and uncertainties about the process, especially the effects of adding leachate on the treatment system. In this context, this study aimed at evaluating the efficiency of combined treatment of leachate/sewage in activated sludge under different conditions. In the first stage of this research, treatability experiments were carried out in a bench scale (SBR) using the volumetric proportions of 0% (control), 0.2%, 2% and 5% leachate under different experimental conditions. The Experiment 2 (leachate pretreated by alkalinization and air stripping) was more technically feasible, achieving efficiencies of removal of BOD, COD and DOC above 97, 82, 60%, respectively, until the proportion of 2% pre-treated leachate. In the second stage of the research was evaluated the treatability using pilot-scale reactors (continuous flow) for sewage treatment with 2% (P1) and 0% (P2-control) leachate pretreated. The operational parameters adopted were food-microorganism rate of 0.22 kgDBO/ kgSSV.d, hydraulic retention time of 24 hours and the sludge retention time of 20 days. The results indicated the viability of the combined treatment with 2% leached pretreated, whose average efficiency of removing BOD, COD, DOC were 93, 84 and 60% respectively. This research was developed with financial support (case No. 2010/2-51955) of Fundação de Amparo à Pesquisa de São Paulo (FAPESP).

碩士
國立成功大學
環境工程學系碩博士班
91
Treatment of Piggery Wastewater Using Anaerobic Baffled Reactors/ Upflow Anaerobic Sludge Bed Reactor ABSTRACT Four anaerobic reactors including anaerobic non-baffled reactor (ANBR), anaerobic baffled reactor (ABR), ABR with effluent recycle (ABRr), and upflow anaerobic sludge bed reactor (UASBR) were used to treat piggery wastewater (i.e., pretreated by a solids-liquid separator followed by a facultative lagoon with an HRT of 2 days; chemical oxygen demand (COD) = 2,050 — 2,820 mg/L). At the reactor volume of 5.15 L, volumetric loading rates (VLRs) of 0.78 — 5.48 kg COD/m3-d, and hydraulic retention times of 2.6 — 0.52 d, the biomass of the ANBR, ABR, ABRr, and UASBR were 12.4 — 53.4, 14.4 — 73.5, 14.3 — 72.0, and 14.5 — 73.3 g VSS, respectively; the average diameter of granules (dp,avg, weighted mean) were 0.81 — 1.31, 0.92 — 1.46, 1.05 — 1.61, and 1.05 — 1.75 mm, respectively and; the COD removal efficiencies were 84 — 75%, 91 — 92%, 90 — 87%, and 91 — 93%, respectively. In other words, the performance of anaerobic baffled reactors (ABR and ABRr) and UASBR are superior to that of ANBR; the formal can retain more biomass, maintain higher COD removal efficiencies, and grow larger granules, compared with the latter. Percentage (by volume) of large sizes of granules in the ABRr and UASBR with a higher superficial velocity (us = 2 m/h) was higher than that of large sizes of granules in the ANBR and ABR with a lower us (= 0.017∼0.085 m/h). In the four anaerobic reactors, the dp,avg increased with an increase in VLR; the granule diameter (dp) in the lower-part of the sludge bed was the biggest, the dp in the middle-up of the sludge bed was the next and, the dp in the upper-part of the sludge bed was the smallest. From independent batch experiments (30 ± 1℃) using sludge granules removed from the four anaerobic reactors (VLRs = 0.78∼5.48 kg COD/m3-d), the estimated mass fractions of methanogens ranged from 0.27 to 0.70; the f value decreased with an increase in VLR. According to tracer tests and the calculated dispersion number, the flow regimes of the ANBR, ABRr, and UASBR were close to complete-mix, while the flow regime of the ABR was close to plug flow; dead spaces of the ANBR, ABR, ABRr, and UASBR were 32.7 — 56.2%, 8.5 — 37.4%, 14.3 — 37.4%, and 9.2 — (~0)%, respectively. From independent batch experiments (30 ± 1℃) together with Levenberg- Marquardt algorithm (i.e., nonlinear regression), the anaerobic degradation of piggery wastewater (mixed culture) followed Monod-type kinetics with the maximum specific substrate utilization rate constant (k) of 0.41 — 1.29 mg COD/mg VSS-d and the half-saturation constant (Ks) of 48 — 131 mg COD/L. Acetate methanogenesis (enrichment culture) also followed Monod-type kinetics with the k2 of 3.9 mg acetate/mg VSS-d and the Ks of 370 mg acetate/L. By using the proposed two kinetic models (i.e., Model 1 incorporating only liquid-phase model and f; Model 2 incorporating solid-phase and liquid-phase model and f), the simulated COD (VFAs) concentrations and COD (VFAs) removal efficiencies in the ANBR, ABR, ABRr, and UASBR were in good agreement with the experimental results. Accordingly, Model 1 (i.e., rather simple calculations) should be acceptable for function design and operation and management of the four anaerobic reactors. Keywords:Anaerobic baffled/non-baffled reactors; Upflow anaerobic sludge bed reactor; Piggery wastewater; Performance evaluation; Mass fraction of methanogens; Kinetic model; Model verification.

碩士
國立成功大學
環境工程學系碩博士班
92
A combined anaerobic baffled reactor (ABR)–activated sludge reactor (ASR) system was used to treat piggery wastewater (pretreated by a solids-liquid separator followed by a facultative lagoon with an HRT of 2 days; COD = 1930 – 2050 mg/L, TKN = 392 – 410 mg/L). To operate the combined reactor system, the effluent from the rear ASR was recycled to the front ABR. Thus, the ABR could proceed with denitrification and methanogenesis (with the utilization of inflow organics). Meanwhile, the ASR could proceed with aerobic degradation of the remaining organics and ammonia nitrification. Under proper operating conditions of HRT, �塶, and Re, the combined reactor system could remove 96.1% – 97.3% of COD, ~100% of TKN and 53.2% –80.1% of TN. 　　Neglecting the effect of mass transfer resistance on the overall reaction process (this assumption was also proven by independent batch experiments with the use of dispersed sludge and granular sludge), a kinetic model of substrate (COD) degradation and nitrification/denitrification in the combined reactor system is proposed. Independent batch experiments were carried out to determine most of the biological parameter values used in model simulation. In addition, all the experimental data obtained from the steady-state combined reactor system were used to validate the kinetic model. 　　According to pulse perturbation tests, the calculated tank numbers (N) and dead space of the ABRs (Runs 1 and 2) were 1.14, 1.04 and 8.2%, 13.5%, respectively. Although the ABR used in this work was divided into three compartments, the tank numbers of 1.04 – 1.14 implied that the flow regime in the liquid phase of the ABR approached complete-mix. 　　Sludge granulation occurred in the ABRs; the average granule diameter (volume fraction basis) ranged from 0.84 to 1.71 mm, and the granule diameter, biomass concentration and sp. gr. of the granule in the lower-part of the sludge-bed zone was the largest, the middle-part of the sludge-bed zone was the next and, the upper-part of the sludge-bed zone was the smallest; the three parameter values measured in the first compartment were significantly larger than those measured in the last compartment. From independent batch experiments, nitrification and substrate utilization in the ASR, denitrification and substrate utilization in the ABR, and nitrification and denitrification with enrichment culture followed Monod-type kinetics. From independent batch experiments, the estimated mass fractions of denitrifiers in the ABRs (fd) and the mass fractions of nitrifiers in the ASRs (fn) were 0.65 – 0.93 and 0.42 - 0.71, respectively. 　　According to mass-balance calculations, the specific nitrification rate and the specific substrate utilization rate in the ASRs are 0.15 – 0.47 mg TKN/mg VSS-d and 0.32 – 0.43 mg COD/mg VSS-d, respectively; while the specific denitrification rate and the specific substrate utilization rate in the ABRs are 0.041 – 0.052 mg NOx--N /mg VSS-d and 0.24 – 0.30 mg COD/mg VSS-d, respectively. The biogas contents N2 and CH4 monitored in the ABRs were 52.0% – 97.2% and 2.6% – 44.1%, respectively. 　　From the simulated results of the proposed model, the calculated residual concentrations of COD, TKN, and TN in the ABRs and ASRs were in good agreement with the experimental results; the calculated COD, TKN, and TN removal efficiencies of the combined reactor system were in good agreement with the experimental results. Accordingly, the proposed kinetic model can be appropriately used to predict treatment performance of the combined reactor system.

Human consumption of water contaminated with faecal polIutants is the source of most sanitation related diseases. Excreta related diseases can be controlIed by improvements in excreta disposal. The primary consideration is to remove contact between the people and the faecal matter. The conventional waterborne sewage system is not an achievable minimum standard in dense peri-urban areas in the short term, due to its high cost. A need for a cost effective system that is easily maintained and does not require electricity or highly skilled labour for developing communities in South Africa was identified. The objective of this investigation was to assess the suitability of the Anaerobic Baffled reactor (ABR) as a primary onsite treatment system for low-income communities. The ABR is a high-rate compartmentalised anaerobic bioreactor, the design of which promotes the spatial separation of microorganisms. The trials were conducted on a 3200 L pilot-scale reactor placed at Kingsburgh wastewater treatment works, which receives only domestic wastewater. The ABR proved to be stable and consistent in its performance. Operating at a hydraulic retention time of 22.5 h, the reactor effiuent was ca. 200 mgCODIL. The 0,45flm filtered (soluble) COD was 100 mgIL, indicating there was approximately 100 mgIL of COD in the effluent that was in particulate form. The ABR achieved 60%VSS and 50%TSS removal with effiuent TSS content of about 225 mgIL. The system was hydraulicalIy overloaded and organicalIy under loaded. The Biochemical Methane Potential tests showed that 60% of the COD in the effiuent was biodegradable, and the effluent COD could be reduced to less than 100 mgCODIL if the HRT is increased giving a possible removal of 80%. The analytical campaign revealed that we were sampling at peak flow, when COD was high. The average COD fed to the reactor was much lower than that showed by routine analysis and the ABR had a "true" COD removal of 42%. The reactor was able to handle the daily variation ofthe wastewater. Settling tests were done to measure how much of the suspended solids in the ABR are retained at the operating upflow velocity. The method selected was shown to have an error that ranged from 5 to 42%, and the ABR was retaining between 60 and 90% ofsolids in the reactor at an upflow velocity of O.5m/h. The preliminary work with the fabric membrane showed great potential benefits that can be gained if it had to be included. It showed good ability to remove indicator organism and solids that contributed a lot to the effiuent COD. The membrane had 5 log removal of indicator organism and 80% reduction of COD. The membrane was operated for a short time before clogging; its operational lifespan needs to be greatly extended before it can be used with the reactor in a community. Since there is no nutrient removal in the AER, the effiuent can be used for food production provided sufficient pathogens removal is achieved. Provided that the first compartment can be modified and the concentration of pathogens in the effluent is sufficiently reduced, the ABR can be considered for use in a community.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.

Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Biotechnology, Technikon Natal, 2001.
The vegetable oil industry produces effluent containing quantities of fat, oil, sodium, phosphates as well as other pollutants. Oils and greases tend to clog sewers and pumps, thus creating difficulties within the municipal wastewater treatment works. Physico-chemical treatment methods, such as (Dissolved Air Flotation) OAF, gravity separation and the use of coagulants have been attempted providing a considerable reduction in organic loading; however, discharge standards are still not met. Thus, biological treatment methods are being sought after. Aerobic treatment has been attempted however, shock loads cause problems while running such a process. The objective of this study was to assess the efficiency of anaerobic digestion to degrade Vegetable Oil Effluent (VOE) as well as the efficiency of the Anaerobic Baffled Reactor (ABR). Anaerobic digestion involves the breakdown of organic matter by the action of microorganisms in the absence of oxygen, producing methane-rich biogas. The VOE was characterized, providing significant information on its chemical composition. It was found that the effluent had high sulphate content as well as a high COD content. High sulpahte content of wastewaters have known to promote growth of Sulphate Reducing Bacteria (SRB), which utilize the same energy source as Methane Producing Bacteria (MPB) and therefore compete for the same energy source. Sulphate and lipid reduction pretreatment experiments were carried out, using barium chloride and gravitational separation respectively. The results obtained, showed that the use of barium chloride to reduce sulphate content in VOE was successful, with significant sulphate reduction. The lipid reduction experiments however, did not show any significant lipid reduction. Batch tests were conducted in serum bottles to assess the extent of biodegradation of the VOE in its raw state as well as with reduced sulpahte content. Methanogenic toxicity tests on the raw and pretreated VOE provided a range of toxicity results. These assays are relatively simple and inexpensive. Gas production was monitored to determine the rate and extent of biodegradation. The efficiency of digestion was assessed by COD reduction. Results indicated potential inhibition of the methanogenic bacteria responsible for methane production by the
M

The aim of the investigation was to compare the performance of an anaerobic baffled reactor (ABR) with a completely mixed anaerobic reactor (CMAR). The ABR was operated with a hydraulic retention time (HRT) of 20 h while the CMAR was operated at 20 d. A control experiment was conducted with a CMAR operated at a constant hydraulic retention time and substrate feed concentration. During the first phase, the start-up performance of the ABR and CMAR were compared. In the second phase of the study the steady state COD removals were compared. The laboratory completely mixed anaerobic reactor was a 20L glass vessel with a stirrer coming in through the neck. A second type of reactor, anaerobic baffled reactor (ABR) was also operated. The ABR was a rectangular perspex box with internal vertical baffles alternately hanging and standing. The baffles divide the reactor into eight compartments with a total working volume of 7.5 L. Each baffle is angled at about 45Q to distribute the flow towards the centre of the upcomer. The reactors were seeded with raw sewage and allowed to stand for 3 days after which a continous feed of sucrose and basal salts was commenced. The initial HRT for the ABR and the CMAR were 60 h and 30 days respectively. When the reactors reached steady state (pH, gas production, gas composition and alkalinity), the HRT was reduced in a stepwise fashion (ABR 60 h to 35 h to 20 h and CMAR 35 d to 30 d to 20 d). At the final HRT the COD removals were similar (67 %). The ABR took 120 d to attain final steady state while the CMAR took 200 d. The organic loading tests were undertaken with a stepwise increase (doubling) in the influent substrate concentration. The feeding commenced at an organic loading rate (OLR) of 4.8 kg/m(3).d for the ABR. The flow rate (HRT) into both reactors and other parameters were kept constant (HRT of 20 h and 20 d for ABR and CMAR respectively). The substrate concentration was increased from 4 gCOD/L (4.8 kg/m(3).d) to 64 gCOD/L (76.8 kg/m(3).d) for the ABR. For the CMAR it was increased from 4 gCOD/L (0.25 kg/m(3).d) to 32 gCOD/L (2 kg/m(3).d). The method used was to increase the organic loading rate until the reactors failed. Since the two reactors had different operating HRTs, the tests began when both had the same COD removal rate of about 60 % COD reduction. The same parameters as in the start-up period were monitored for both reactors. The CMAR had a COD removal efficiency ca. 70 %, which did not fluctuate when OLR was increased. The ABR reached a maximum COD removal of 80 %. An increase in the OLR led to an initial decrease in the COD removal until the biomass recovered and the high COD (80 %) removal rates resumed. The ABR reached a maximum OLR of 76.8 kg/m(3).d whilst the CMAR reached a maximum OLR of 2.0 kg/m(3).d. The investigations showed that the ABR could be operated at higher organic loads than the CMAR and give the same organic removal rate. This verified the importance of increasing the SRT/HRT ratio in anaerobic reactors. The CMAR, however, proved to be stable to changes in the influent feed strength, as there was no immediate noticeable changes in the gas production.
Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban Institute Of Technology, 2005 xxiii, 172 p. : ill. ; 30 cm
The provision of safe and sanitary water is a constitutional right and above all, a necessity of life. As a result of the rapid urbanisation and the past policies of apartheid, a large population of South Africa dwell in informal settlements, where there is very little hope of development, as the government does not possess the resources that are necessary for a full-scale sanitation programme. Therefore, on-site treatments have been considered to provide sanitation in these dense peri-urban areas. The anaerobic baffled reactor (ABR) is one such sanitation system. This reactor utilises the phenomenon of anaerobic digestion to degrade substrates. One of the major disadvantages of any anaerobic treatment processes is the extreme sensitivity of the bacterial communities, thus inducing slow recovery rates following toxic shocks. Therefore, an understanding of these microbial consortia is essential to effectively control, operate and optimise the anaerobic reactor. Fluorescence in situ hybridization, 4’,6-diamidino-2-phenylindole (DAPI) staining and DNA sequencing techniques were applied to determine the microbial consortium, as well as their reactions to daily operating conditions. With an understanding of these populations and their responses to perturbations within the system, it is possible to construct an anaerobic system that is successful in its treatment of domestic wastewater. In situ hybridizations were conducted for three operating periods, each characterised by specific flow rates. Results showed Eubacterial population dominance over the Archaeal population throughout both of the operating periods investigated. However, these cells cumulatively consisted of 50% of the total biomass fraction, as determined by DAPI staining. Group-probes utilised revealed a high concentration of fermentative acidogenic bacteria, which lead to a decrease in the pH values. It was noted that the ABR did not separate the acidogenic and methanogenic phases, as expected. Therefore, the decrease in pH further inhibited the proliferation of Archaeal acetoclastic methanogens, which were not present in the second operating period. DNA sequencing results revealed the occurrence of the hydrogenotrophic Methanobacterium and Methanococcus genera and confirmed the presence of Methanosarcina. Sequencing of the bacterial DNA confirmed the presence of the low G+ C Gram Positives (Streptococcus), the high G+C Gram Positives (Propionibacterium) and the sulfate reducing bacteria (Desulfovibrio vulgaris). However, justifications were highly subjective due to a lack of supportive analytical data, such as acetate, volatile fatty acids and methane concentrations. Despite this, findings served to add valuable information, providing details on the specific microbial groups associated with ABR treatment processes.

Providing water and proper sanitation to poor communities by 2015 is one of the United Nations targets for this millennium. In South Africa many communities aspire to waterborne sanitation. However, there is a technology gap for decentralized and sustainable waterborne sanitation systems capable of treating domestic wastewater (Foxon et al., 2006). Although domestic wastewater is more commonly treated using aerobic processes, anaerobic processes may be more appropriate for decentralized applications since they do not require aeration. Research is currently being undertaken to understand the behavior of a combined ABR-MBR unit for treating domestic wastewater. In this study, the anaerobic baffled reactor (ABR) was investigated by analyzing physico-chemical and biochemical data from experiments on a laboratory-scale ABR. This anaerobic reactor was treating complex particulate wastewater made up of sludge from the ventilated improved pit latrine toilets (known as VIP sludge). The main focus of this study was to establish the relationship between the increasing organic loading rates and the effluent characteristics (such as chemical oxygen demand: COD and extrapolymeric substances: EPS). The present work was structured in two parts; in the first part the reactor was operated at constant hydraulic retention time (HRT) without controlling feed characteristics. In the second part, the ABR was operated with step increases in organic loading rates. It was logistically not possible to provide a feed of real domestic wastewater to the laboratory-scale equipment. Consequently, a pit latrine sludge diluted with tap water was used to feed the ABR. This feed was found to have different biodegradability characteristics compared to domestic wastewater. However, the results still give insight into the performance of the ABR and into the treatability of VIP sludge. COD removal ranged from 52 to 80 % depending on the inlet COD. Some COD removal was due to solids retention in compartments, while it was estimated that only 28% of COD removal was due to biological degradation. Soluble extrapolymeric substances (proteins and carbohydrates) which are usually a by -product of anaerobic degradation were higher in the feed than in the effluent despite the increasing organic loading rates. However, more than 50 % of soluble extrapolymeric substances from the influent remained in the effluent and were found (in a parallel project) to influence membrane fouling in the membrane section of the experimental set-up (ABR-MBR unit). Parameters such as pH, conductivity, alkalinity, total and volatile solids were also investigated in this study. The pH decreased slightly from the inlet to the outlet during all runs even though the loading rates were increased. Conductivity increased significantly from influent to effluent with the increasing organic loading rates. Large amounts of total solids were retained in the reactor during the treatment process. Low alkalinity production was recorded during the operation of the reactor. In most cases, the data recorded in this study showed a low biological activity taking place while the reactor was working at room temperatures. Overall, up to 80% of removal efficiencies in terms of total COD and solids were recorded with increasing organic loading rates at constant hydraulic retention time. While these results do not allow the prediction of ABR-MBR performance during the treatment of real wastewater, it was concluded that: Most solids retention occurred in the feed tank. Most COD removal occurred as a result of solids retention and digestion. Loading characteristics did not strongly influence effluent EPS, pH or alkalinity, but did influence COD and conductivity. The relatively low biodegradability of the feedstock indicates that anaerobic digestion is not the most appropriate treatment for VIP sludge.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

There is potential for the anaerobic baffled reactor (ABR) to be implemented on-site for pre-treatment of coloured wastewaters. The implementation of waste minimisation and cleaner production strategies in industry will result in the production of smaller volumes of concentrated wastewaters. With implementation of the ABR, the concentrated waste stream could be pre-treated, with an acclimated biomass, which should facilitate sufficient degradation such that the effluent could be discharged to sewer for further treatment. The ABR is a high-rate compartmentalised anaerobic bioreactor, the design of which promotes the spatial separation of microorganisms. The use of molecular teclmiques to characterise the microbial populations and the dynamics of these populations with time and/or changing operating conditions will add to the current understanding of the process, which is based on the biochemical pathways and chemical analyses. This knowledge will allow for optimisation of the design of the ABR. The hypothesis of the horizontal separation of acidogenesis and methanogenesis through the ABR was proven. Changes in the HRT affected the operation of the reactor, however, recovery from these upsets was almost immediate and operation of the reactor was stable. Two synthetic dye waste streams, one food dye (tartrazine) and one textile dye (Cl Reactive Red 141), and a real industrial dye wastewater, were treated in separate laboratory-scale ABRs. These investigations showed that successful treatment of a highly coloured wastewater is possible in the ABR. The design of the ABR facilitates efficient treatment of concentrated dye wastewaters by protecting the sensitive methanogens from the inhibitory dye molecules and promoting efficient colour and COD reduction. The molecular-based method, fluorescent in situ hybridisation, allowed the direct identification and enumeration of microbial populations active in the ABR. In all of the reported investigations, there was a definite shift in the microbial populations through the ABR, with a predominance of eubacteria in the first compartments (acidogenesis) and archaea (methanogenesis) in the later compartments. The number of compartments involved in each depended on the strength of the substrate (organic loading rate - OLR). A combination of FISH probing, and the analysis of 98 archaeal l6S rDNA clone inserts provided useful descriptions of the methanogens actively involved within each compartment. These showed a predominance of the Methanosaeta spp., particularly in the last compartments of the reactor. Methanogens present in the first four compartments consisted of species of Methanobacterium and Methanospirillum, a relatively unstudied methanogen Methanomethylovorans hollandica, and an unidentified short filamentous species.
Thesis (Ph.D.)-University of Natal, Durban, 2002.

Decentralised Wastewater Treatment Systems (DEWATS) such as disseminated by the Bremen Overseas Research and Development Association (BORDA) are increasingly being recognized by decision makers across the world as an option for service delivery in densely populated low-income areas. However, little practical experience has been gathered methodologically on basic engineering and performance aspects surrounding these systems. This thesis investigates full-scale anaerobic reactors of communal DEWATS implemented in tropical regions in order to consolidate the basis of future design and support monitoring, operation and maintenance procedures. Special focus is laid on the operation of the Anaerobic Baffled Reactor (ABR) as the core technology of DEWATS. Field research has been conducted for over four years at numerous communal systems in Indonesia, India and South Africa in order to (i) verify the generally used parameter values for DEWATS design and operation, (ii) identify factors limiting the treatment efficiency of existing systems in the field and (iii) investigate the performance of DEWATS and DEWATS treatment steps (especially ABRs) under tropical field conditions in terms of effluent concentration, Chemical Oxygen Demand (COD) removal, sludge stabilisation and sludge activity. Field data on average per capita wastewater production in DEWATS implementation areas, long term fluctuations and peak-flow values are presented. General per capita organic load and per capita nutrient load, per capita biogas production in digesters and per capita sludge accumulation in ABRs are estimated. Based on available data and field observations, treatment limiting factors are hypothesised to be rain-water intrusion, general under-loading, organic under-loading and elevated raw-water salinity in coastal areas. Effluent measurements performed at one hundred nine systems in Indonesia indicated guaranteed maximum concentrations of 200 mg CODt l-1 for anaerobic DEWATS treatment effluent if the treated wastewater is non-saline. ABR COD reduction of four case studies was poor in three cases and fair in one case. Sludge accumulation rates indicated good sludge stabilisation and sludge activity in all four systems. Anaerobic Filters (AF) contributed in all three case studies, in which they were part of the plant design, significantly to COD reduction. Nutrient effluent concentrations were comparably high. Large fractions of effluent organics were found to be biodegradable. It is hypothesised that system treatment would improve significantly if maximum hydraulic load was lower, general organic load was higher and therefore both close to design estimation. It is thus proposed to control the amount of storm water intruding the systems, increase feed concentration through partial grey-water exclusion and reduce the nutrient load in system effluent through partial urine diversion. It is further proposed to reduce the HRT of the settler below 10 h in order to increase the organic load to the ABR. It is further hypothesised that systems could be operated at higher hydraulic dry weather load than currently assumed since active anaerobic digestion appears to be capable of establishing itself under extreme hydraulic pressure. This may lead to a considerable reduction of building costs. Anaerobic digestion modelling with the existing ADM-3P model confirmed that observed sludge accumulation rates indicate active hydrolytic systems. The model could however not be used to produce soluble COD effluent concentration benchmarks due to its sensitivity to methanogenic rate constants. The general view held for anaerobic reactors treating wastewater with high solid content is that hydrolysis is the rate-limiting degradation step. It is hypothesised that this does not apply for solid accumulating systems such as the ABR.
Die durch die Bremen Overseas Research and Development Association (BORDA) verbreiteten Decentralised Wastewater Treatment Systems (DEWATS) werden international von Entscheidungsträgern zunehmend als Möglichkeit angesehen, kommunale Abwasserreinigung in dichtbesiedelten, einkommensschwachen Gegenden zu ermöglichen. Allerdings wurden bislang wenig praktische Erfahrungen methodisch über grundlegende Aspekte der Anlagendimensionierung und Anlagenleistungsfähigkeit aufgenommen. Im Rahmen dieser Dissertation wurden anaerobe Reaktoren kommunaler DEWATS unter tropischen Feldbedingungen untersucht, um eine Datengrundlage für zukünftige Dimensionierung, Wartung und Betrieb, als auch Monitoring der Anlagen zu schaffen. Schwerpunkt wurde dabei auf den Anaerobic Baffled Reactor (ABR) als Kerntechnologie von DEWATS gelegt. Felduntersuchungen wurden in der Zeit von mehr als vier Jahren an zahlreichen kommunalen DEWATS in Indonesien, Indien und Südafrika durchgeführt, um (i) die gängig gewählten Parameterwerte für Anlagen-Dimensionierung und -Betrieb zu überprüfen, (ii) leistungslimitierende Faktoren im Feldbetrieb zu identifizieren und um (iii) die Leistungsfähigkeit von DEWATS und DEWATS-Reinigungsstufen (insbesondere des ABRs) unter tropischen Feldbedingungen bezüglich Abflusskonzentrationen, Reduzierung des Chemischen Sauerstoffbedarfs (CSB), Schlammstabilisierung und Schlammaktivität zu untersuchen. Basierend auf den Untersuchungsergebnissen, wurden durchschnittliche Einwohnergleichwerte, Langzeitvariationen und Faktoren für Zuflussspitzen für kommunale Abwasserproduktion in DEWATS-Zielbevölkerungsgruppen präsentiert. Ferner werden allgemeine Pro-Kopf-CSB-Frachten, -Ammoniumfrachten und -Phosphorfrachten, die Pro-Kopf-Biogasproduktion in kommunalen Biogasanlagen sowie die Pro-Kopf-Schlammakkumulation in ABRs abgeschätzt. Auf Felduntersuchungen basierend, wurden Fremdwassereinfluss, generelle Unterbelastung, organische Unterbelastung und erhöhte Frischwassersalinität in Küstengebieten als leistungslimitierende Faktoren im Feldbetrieb identifiziert. An 109 indonesischen Anlagen durchgeführte Abflusskonzentrationsmessungen ließen auf eine garantierte Abflusskonzentration der anaeroben Reaktoren von 200 mg CSB l-1 schließen, wenn der negative Einfluss von erhöhter Frischwassersalinität ausgeschlossen werden kann. Der CSB-Abbau durch ABRs in vier detailliert untersuchten DEWATS war gering in drei Fällen und befriedigend in einem Fall. Anaerobe Filter (AF) trugen in den drei Fällen, in denen sie Teil der Anlagenkonfigurationen waren, signifikant zur CSB-Reduzierung bei. Ammonium- und Phoshorkonzentrationen in allen Reaktorabläufen waren vergleichsweise hoch. Ein großer Anteil des CSBs in Reaktorabläufen war biologisch abbaubar. Es wird die Hypothese aufgestellt, dass sich die Leistungsfähigkeiten der Anlagen signifikant verbessern würden, wären die Anlagenbelastungen den Auslegungswerten ähnlicher, d.h., wären die maximalen hydraulischen Belastungen geringer und die organischen Belastungen höher. Es wird deshalb geraten, den Fremdwasserzufluss zu minimieren, die Anlagenzulaufkonzentration durch partielle Grauwasserversickerung zu erhöhen und die Ammonium- und Phoshorkonzentration im Zulauf durch partiellen Urinabschlag zu verringern. Es wird außerdem vorgeschlagen, die hydraulische Aufenthaltszeit in Absetzbecken (settlers) auf zehn Stunden zu begrenzen, um so die organische Belastung der ABRs zu erhöhen. Ferner wird die Hypothese aufgestellt, dass Anlagen unter höherer Trockenwetterbelastung als bislang angenommen betrieben werden können, da aktiver anaerober Abbau auch unter extremen hydraulischen Belastungen möglich erscheint. Dies könnte zu einer signifikanten Senkung der Baukosten führen. Die Modellierung anaerober Abbauprozesse mit dem existierenden ADM-3P-Modell bestätigten, dass im Feld beobachtete Schlammakkumulationsraten auf eine aktive Hydrolyse schließen lassen. Das Modell konnte jedoch nicht genutzt werden, um Bezugswerte für den gelösten CSB im Ablauf der Anlagen zu erhalten, da es eine vergleichsweise hohe Sensitivität in Bezug auf die Raten für Methanogenese aufwies. Die allgemein anerkannte Sichtweise ist, dass die Hydrolyse den geschwindigkeitsbestimmenden Abbauschritt bei der anaeroben Behandlung feststoffreicher Abwässer darstellt. Es wird die Hypothese aufgestellt, dass dieses nicht für feststoffakkumulierende Systeme, wie den ABR, zutrifft.

Scarcity of water for irrigation is a serious hindrance for small-scale farmers in sub-Saharan Africa. The use of good quality water for irrigation has resulted in increasing pressure on such water which has prompted sourcing of wastewater as an alternative. One possibility, being investigated by eThekwini Water and Sanitation (Durban, South Africa), is to install anaerobic baffled reactors within local communities to treat wastewater to allow its use for agriculture. The success of wastewater irrigation depends on the ability of the soil to assimilate the water, nutrients and any other contaminants that are applied to it. The aim of this project was to investigate the potential of an anaerobic baffled reactor (ABR) effluent as both an irrigation and nutrient source for use in peri-urban agriculture. The effluent was slightly alkaline (pH 7.40–7.60) and in class C2S1 (medium-salinity/low sodicity water) according to the United States Soil Salinity Laboratory classification for irrigation waters. It was very low in heavy metals, values being below permissible levels according to the Food and Agricultural Organisation (FAO) of the United Nations and the South African Department of Water Affairs and Forestry (DWAF) guidelines for water use in agriculture. The total solids were low thus particulate matter was minimal with a greater concentration of the major elements found in solution. An investigation was carried out to ascertain the behaviour of the effluent when applied to soil and how the soil was able to adsorb plant nutrients from it. A soil column study was undertaken in the laboratory with three contrasting soil types namely a sandy soil (Longlands, E horizon), an organic soil (Inanda, A horizon) and a clayey soil (Sepane, A horizon). The effluent was leached through the soil while distilled water was concurrently used as a control. Results indicated that after application of 16 pore volumes, leachates from the columns contained concentrations of Na, equal to that in the incoming effluent for all soils. The concentrations of Ca and Mg were lower in the leachates than in the original effluent indicating adsorption in the soils. Phosphorus was the element that was most strongly adsorbed in all soils. While its adsorption in the Ia could be attributed to organic matter and the presence of iron oxides and oxyhydroxides, the clay type and amount in the Sepane was likely to have been responsible for P adsorption. The NO₃-N, which was initially low in the effluent, increased as leaching progressed, while the NH₄-N decreased. In the water-leached columns, elements were leached out of soil because none were added with the water. At the end of leaching, columns were allowed to drain and then sectioned into 2 cm segments. The 0-2 cm, 8-10 cm and 14-16 cm segments representing the top, middle and bottom parts of the column were analysed for inorganic-N, phosphorus and potassium. The elemental content of the 0-2 cm segment was significantly higher (p<0.05) than the lower segments in all columns for soluble P in all soils. This reflects the immobile nature of P in soils and confirmed the high amounts of P retained by the soils. There were significant differences between the effluent and the water-leached soils in terms of P retention. The amount of inorganic-N and K in the top layer was not significantly different from the other layers. In the Ia 0–2 cm segment, a pH increase of about 1.3 pH units was recorded in the effluent-leached columns when compared to the equivalent segment in the water-leached columns. A glasshouse study was undertaken to assess the availability to maize of nutrients from the effluent. Maize was grown for 6 weeks in pots filled with the same soil types used in the columns study except that a similar sandy soil, Cartref (Cf, E horizon), replaced the Lo due to inadequate availability of the latter. Fertilizer (N, P and K) was applied at the full recommended rate, half the recommended rate and zero fertilizer for each of the three soils used. This corresponded to 0, 100, 200 kg N ha⁻¹ for all soils; 0, 40, 80 kg P ha⁻¹ and 0, 50, 100 kg K ha⁻¹ for the Cf; 0, 10, 20 kg P ha⁻¹ and 0, 102.5, 205 kg K ha⁻¹ for Ia; and 0, 30, 60 kg P ha⁻¹ and 0, 5, 10 kg K ha⁻¹ for Se. Lime was applied to the Ia soil at the rate of 10 t ha⁻¹. Plants were watered with either effluent or tap water. Dry matter yield and nutrient concentrations for effluent-irrigated maize were significantly higher (p<0.05) than for all equivalent fertilizer applications in the water-irrigated plants. The unfertilized effluent-irrigated plants were not significantly different from the fertilized water-irrigated plants, but performed as well as the water-irrigated plants at half fertilization irrespective of soil type. Phosphorus deficiency was observed in the Ia and Se soils but not in the Cf soil, irrespective of fertilizer treatment. Plants grown on the Cf soil irrigated with effluent and fully fertilized had the highest above-ground dry matter yield (4.9 g pot⁻¹) and accumulated the most nutrients namely N, P, K, Ca and Mg than all other treatments. After harvest the most marked changes had occurred in the Cf soil for P as the effluent-irrigated soils were significantly higher (p<0.05) than the water-irrigated soils reflecting the P input from the effluent. The effect of effluent on soil and plants was further investigated by planting maize on the Ia soil without lime application. Plants that received effluent irrigation and no lime had significantly higher (p<0.05) dry matter yields and accumulated more N, P and K than the water-irrigated with no lime as well as the equivalent limed treatments. This suggests an interaction effect between the lime and the effluent with its effects obvious on above-ground dry matter yield and plant N, P and Mg. A soil column experiment using the Cf, Ia and Se soils and planted with maize was conducted to assess the ability of plants to take up nutrients with concurrent leaching. Plants from the Cf soil recorded the lowest above-ground dry matter yield which was observed from the less vigorous growth as compared to plants in the Ia and Se soils. This growth pattern could also be explained by the low N accumulation in the plants from the Cf soil. Unlike N, P in plants grown on the Cf soil was significantly higher (p<0.05) than in the plants on the Ia and Se soils, despite having the least P gain from the effluent. The readily available P triggered both more uptake and also greater losses through leaching. The rate at which P was being supplied from the effluent was greater than its uptake by the plants and with limited capacity to hold onto P in this sandy soil there was inevitably loss though leaching. A pot experiment was conducted to investigate the interaction effects between lime and effluent. Lime type (calcium hydroxide or dolomite) was applied to two acidic top soils namely Inanda and Avalon at 0%, 25%, 50%, 75% and 100% of the recommended rates for these soils. Maize was planted and after 6 weeks it was harvested and evaluated for above-ground dry matter yields and plant nutrient concentrations. Non-significant effects were recorded for above-ground dry matter, N, P and K as a result of altering the liming rate and type within each soil. The effects of lime application were apparent in the soils after harvest as increasing the lime rate caused an increase in pH and an inverse relationship with the exchangeable acidity and acid saturation in soils, as expected. Although the unlimed treatments did not impact on the acidity as much as the limed treatments, effluent irrigation was shown to reduce soil acidity after harvest when compared to the soils at the beginning of the experiment. Phosphorus accumulation in plants was also unaffected by either lime rate or type which showed that effluent irrigation could influence P availability and further liming would not accrue benefits to the soil so as to influence plant P uptake. Based on these data, ABR effluent could be perceived as a resource rather than a waste product. It could conveniently be used for irrigation provided there is soil and plant monitoring to assess build-up of elements especially in the long term. Further investigations have to be carried out on other crop types both in the field and glasshouse to ascertain nutrient uptake and effect on different soil types.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.