Application of an innovative methodology to improve the starting-up of UASB reactors treating domestic sewage

2001 ◽  
Vol 44 (4) ◽  
pp. 295-303 ◽  
Author(s):  
J. A. Rodríguez ◽  
M. R. Peña ◽  
V. Manzi
Keyword(s):  
Sewage Treatment ◽  
Quality Parameters ◽  
Domestic Sewage ◽  
Design Flow ◽  
Uasb Reactor ◽  
Removal Mechanisms ◽  
Start Up ◽  
Innovative Methodology ◽  
Valle Del Cauca ◽  
Positive Evolution

This study shows the results obtained during the starting-up evaluation of an UASB reactor treating domestic sewage. It is located in the municipality of Ginebra, Valle del Cauca region in Colombia. Its design flow is 7.5 l/s with a maximum capacity of 10 l/s. The reactor was seeded with a deficient quality inoculum which accounted for 20% of the total reactor volume. The starting-up methodology comprised the sequential washing of the sludge (inoculum) by applying three different upflow velocities. This procedure resembles what other authors term the “selective pressure method”. Once the sludge was washed, the reactor was started-up with an initial hydraulic retention time (HRT) of 24.9 hours, which was steadily reduced down to 6.7 hours in the final stage. Along the starting-up phase, there was a positive evolution in terms of quantity, quality and spatial distribution of the sludge. Consequently, there was a positive evolution in organic matter removal mechanisms. For HRT above 14 hours, the removal mechanisms were mainly physical whilst for HRT below 9 hours the removal mechanisms were mostly biological. Based on the above considerations and on the water quality parameters measured, it may be concluded that the start-up of an UASB reactor for domestic sewage treatment seeded with a low quality inoculum can be done with HRT as low as 15 or 12 hours. In this way, it is possible to reduce the starting-up period of these reactors down to 4 to 6 weeks, provided that the starting-up methodology is properly applied.

Fate and Effect of Detergent Chemicals in the Marine and Estuarine Environment

1991 ◽  
Vol 24 (10) ◽  
pp. 115-126 ◽  
Author(s):  
M. Stalmans ◽  
E. Matthijs ◽  
N. T. de Oude
Keyword(s):  
Surface Waters ◽  
Sea Water ◽  
Sewage Treatment ◽  
High Volume ◽  
Domestic Sewage ◽  
Consumer Products ◽  
Estuarine Environment ◽  
Biological Degradation ◽  
Linear Alkylbenzene ◽  
Removal Mechanisms

Detergents are high-volume consumer products which are discharged directly into domestic sewage after their use. They are removed in the treatment of domestic sewage and via instream removal mechanisms in surface waters. Important removal mechanisms are biological degradation, adsorption to sediments, etc. The degree of removal mainly depends on the physico-chemical and environmental properties of the chemical and on the type of sewage treatment. The continuous removal processes, combined with the continuous discharge to surface waters via treated or untreated sewage effluents, results in the presence of detergent chemicals in surface waters, where they can further biodegrade. Detergent chemicals can thus, ultimately, enter the marine environment. Data are presented on the discharged amounts of detergent ingredients, such as surfactants and phosphates, to surface waters and to the North Sea. Furthermore, the fate and effects of a typical surfactant in the marine and estuarine environment are described. Monitoring data for one of the major anionic surfactants, Linear Alkylbenzene Sulphonate (LAS), are presented. A comparison of the measured concentrations of LAS with the concentrations, predicted on the basis of a measured dilution of the river water with sea water, shows that this surfactant continues to biodegrade under marine conditions.

Feasibility of a pilot-scale UASB/trickling filter system for domestic sewage treatment

2001 ◽  
Vol 44 (4) ◽  
pp. 221-228 ◽  
Author(s):  
C.A.L. Chernicharo ◽  
M.C.P. Nascimento
Keyword(s):  
Sewage Treatment ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Trickling Filter ◽  
Treatment Unit ◽  
Promising Alternative ◽  
Operational Conditions ◽  
Belo Horizonte ◽  
Final Effluent ◽  
Bod Removal

This paper presents the results of pilot system comprised of one UASB reactor followed by one trickling filter (TF). The UASB reactor had a volume of 416 litres, being operated at an average hydraulic retention time (HRT) of 4 hours. The trickling filter had a useful volume of 60 litres, being operated at hydraulic and organic loading rates varying from 3.4 to 30.6 m3/m2.d and 0.3 to 3.9 kgBOD/m3.d, respectively. These different operational conditions characterised eight research phases. Both reactors were fed with domestic sewage pumped directly from the main interceptor of Belo Horizonte City, Brazil. After almost 16 months of continuous monitoring, the UASB/TF system produced very good results in terms of COD and BOD removal, and also very low solids concentration in the final effluent. The average results of COD and BOD removal varied from 74 to 88% and from 80 to 94%, respectively, sufficient to maintain the COD concentration in the final effluent in the range of 60 to 120 mg/L and the BOD values systematically below 60 mg/L. The overall averages of SS in the final effluent were kept below 30 mg/L. The UASB/TF system is a very promising alternative for the treatment of domestic sewage in Brazil and other developing countries, since the system can be designed with very short hydraulic retention times, resulting in a very compact and low cost treatment unit. Besides, the energy consumption and the labour costs are minimal.

Low temperature treatment of domestic sewage in upflow anaerobic sludge blanket and anaerobic hybrid reactors

1999 ◽  
Vol 39 (5) ◽  
pp. 177-185 ◽  
Author(s):  
Tarek A. Elmitwalli ◽  
Marcel H. Zandvoort ◽  
Grietje Zeeman ◽  
Harry Bruning ◽  
Gatze Lettinga
Keyword(s):  
Low Temperature ◽  
Sewage Treatment ◽  
Average Diameter ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Removal Efficiencies

The treatment of sewage at a temperature of 13°C was investigated in three reactors (each 3.84 litre) a UASB and two anaerobic hybrid (AH) reactors with small sludge granules with an average diameter of 0.73 mm. The media used in the AH reactors were vertical polyurethane foam sheets. The reactors were operated at a HRT of 8 h. The use of small sludge granules and operating the reactors at low upflow velocity (1.8 m/d) improved suspended COD removal efficiencies for the UASB reactor. Moreover, the use of sheets in the AH reactors significantly increased suspended COD removal efficiencies as compared to the UASB and reached to 87% for pre-settled sewage treatment. The treatment of pre-settled sewage instead of raw sewage in AH reactors significantly increased colloidal and dissolved COD removal efficiencies with 13% and 12% respectively and colloidal COD removal efficiency for the UASB reactor with 13%. At ‘steady state’ for pre-settled sewage treatment, the AH reactors removed 64% of the total COD which is significantly higher by 4% than the UASB reactor. Therefore, the anaerobic treatment of domestic sewage at low temperature can be improved by treating pre-settled sewage in shallow AH reactors containing small sludge granules.

Development of Technology for the Use of the UASB Reactor in Domestic Sewage Treatment

1986 ◽  
Vol 18 (12) ◽  
pp. 109-121 ◽  
Author(s):  
Sonia M. M. Vieira ◽  
Marcos E. Souza
Keyword(s):  
Steady State ◽  
Ambient Temperature ◽  
Initial Phase ◽  
Hydraulic Retention Time ◽  
Sewage Treatment ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Technical Feasibility ◽  
Feasible Option ◽  
The Cost

The lack of a simple and economic option for the treatment of sewage created the need to develop and make the UASB reactor adequate for low strength wastes. Thus a UASB reactor with 106 ℓ capacity was built, which was specially designed for sewage treatment. Several treatability tests were conducted with raw and settled domestic sewage, with only A hours of hydraulic retention time. This proved the reactor's technical feasibility in treating raw sewage at ambient temperature in São Paulo. Based on these experiments, the reactor was scaled up to 120 m3 and built for the treatment of raw sewage at ambient temperature. The operation is in its initial phase, and good COD removals are already being observed, although steady state has not been achieved yet. Since the cost of the system was extremely low, it is a feasible option to be applied in this country.

Association of a UASB reactor and a submerged aerated biofilter for domestic sewage treatment

1998 ◽  
Vol 38 (8-9) ◽  
pp. 189-195 ◽  
Author(s):  
Ricardo Franci Gonçalves ◽  
Vera Lúcia de Araújo ◽  
Carlos Augusto L. Chernicharo
Keyword(s):  
Granular Media ◽  
Sewage Treatment ◽  
Experimental Period ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Hydraulic Load ◽  
Reactor Operating ◽  
Anaerobic Sludge Blanket

This paper presents exploratory results on the association of an Upflow Anaerobic Sludge Blanket - UASB reactor (46 L) and a submerged aerated biofilter – BF (6.3 L) for domestic sewage treatment. The experimental period extended for 322 days, during which the hydraulic and organic loads were gradually increased in both reactors. Having the UASB as a reference, the following hydraulic loads were tested: 0.4 m3/m2.h (θ = 16 h); 0.6m3/m2.h (θ = 10h); 0.8 m3/m2.h (θ = 8 h); 1.0 m3/m2.h (θ = 6 h) and 1.45 m3/m2.h (θ = 4h). During the experiments carried out with the UASB reactor operating at a hydraulic detention time of 6 hours, related to a θ < 11′ in the granular media of the BF, the mean removal efficiency in terms of SS, BOD5 and COD, in both reactors, were respectively 94%, 96% and 91%. The final effluent, related to the BF effluent, presented the following mean characteristics: SS = 10 mg/L, BOD5 = 9 mg/L and COD = 38 mg/L. The results obtained in the last phase of the experiments, when the hydraulic load in the UASB reactor reached 1.45 m3/m2.h (θ = 4h), were similar to those obtained in the previous phase. These results demonstrate that submerged aerated biofilters can be considered a viable alternative for the post-treatment of effluents from UASB reactors treating domestic sewage. These reactors are capable of being operated with very short hydraulic detention times.

EFICIÊNCIA DO REUSO DE ÁGUAS RESIDUÁRIAS NA IRRIGAÇÃO DA CULTURA DO MILHO.

Irriga ◽  
2010 ◽  
Vol 15 (3) ◽  
pp. 231-247
Author(s):  
Antonio Javarez Júnior ◽  
Túlio Assunção Pires Ribeiro ◽  
Durval Rodrigues De Paula Júnior
Keyword(s):  
Sewage Treatment ◽  
Wastewater Reuse ◽  
Domestic Sewage ◽  
Production Costs ◽  
Uasb Reactor ◽  
Small Communities ◽  
Wastewater Disposal ◽  
Modular Systems ◽  
Anaerobic Reactors ◽  
Lower Production

Este trabalho apresenta uma alternativa para o tratamento de esgotos domésticos de pequenas comunidades, com a aplicação do efluente no solo para a cultura do milho. O experimento é constituído de sistemas modulares, que são compostos por dois reatores anaeróbios, um reator UASB e outro reator anaeróbio compartimentado (RAC), ambos combinados com quatro filtros anaeróbios. Os sistemas funcionaram, utilizando-se os seus efluentes como fonte de nutrientes para a cultura do milho. Foram feitos dois tratamentos testemunhas, sendo um em sequeiro (sem irrigação) e outro com suplementação hídrica, através de um sistema de irrigação por sulcos. Avaliou-se o desenvolvimento da cultura e sua respectiva produtividade em dois ciclos. Utilizaram-se sistemas modulares por ser uma maneira adequada e viável de promover o tratamento sanitário do esgoto de pequenas comunidades com o objetivo de maior e melhor preservação do meio ambiente. O emprego desta técnica propicia a vantagem de diminuição nos custos de produção e aumento na produtividade do milho, obtendo-se valores de 6307 e 6593 kg ha-1 na safrinha com efluente do UASB e RAC respectivamente, e na entressafra de 6323 e 5424 kg ha-1.   Palavras-chave: tratamento de esgoto, sistemas modulares, reatores anaeróbios, disposição no solo, reuso. Efficiency of wastewater reuse for irrigation of corn.   Abstract This paper presents an alternative for the treatment of domestic sewage from small communities, with the application of effluent in the soil for growing corn. The experiment consists of modular systems, which are composed of two anaerobic reactors, one UASB reactor and another a compartmented anaerobic reactor (CAR) both combined with four anaerobic filters. The systems were operated, using the effluent as a source of nutrients for the corn crop. Two control treatments were operated, one being rainfed (no irrigation) and another with water supply, through a system of furrow irrigation. We evaluated the development of culture and its productivity in two cycles. The use of modular systems are an appropriate and viable way to promote the sanitary treatment of wastewater from small communities with the goal of greater and better preservation of the environment. The use of this technique provides the advantage of lower production costs and increased productivity of maize, and the values of 6307 and 6593 kg ha-1 for second season with the effluent of UASB and CAR, respectively, and in dry season of 6323 and 5424 kg ha-1. Keywords: sewage treatment, modular systems, anaerobic reactors, wastewater disposal, reuse.

Flocculation, Anaerobic and Microaerobic Treatment Process of Normal Temperature Low Concentration Domestic Sewage

2012 ◽  
Vol 518-523 ◽  
pp. 2530-2534
Author(s):  
Li Jun Nie ◽  
Hua Wen Zhong ◽  
Mei Huang ◽  
Xu Dong Yin
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Removal Rate ◽  
Sewage Treatment ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Low Concentration ◽  
Cod Removal Rate

Domestic sewage was treated by adopting flocculation, anaerobic and microaerobic combined process under normal temperature. The result demonstrates: total hydraulic retention time is 5.5h (chemical flocculation 1.0h, UASB reactor 2.0h and MUSB reactor 2.5h). UASB reactor can achieve anaerobic sludge granulation under normal temperature and is fairly feasible for low concentration domestic sewage treatment. Compared with single stage UASB reactor, hydraulic retention time of flocculation-UASB combined technique reduces from 4h to 2h. COD removal rate rises from 45% to 50%-60% and suspended COD is mainly removed. DO of microaerobic MUSB technique after anaerobic treatment is 0.2mg/L-0.5mg/L with air and water ratio of 1:1. Effluent quality is stable, in accordance with first standard of Synthetical Draining Standard of Sewage, GB8978—1996.

Development and Evaluation of a Partitioned Upflow Anaerobic Sludge Blanket (UASB) Reactor for the Treatment of Domestic Sewage from Small Villages

1999 ◽  
Vol 40 (8) ◽  
pp. 107-113 ◽  
Author(s):  
Carlos Augusto L. Chernicharo ◽  
Marcílio dos Reis Cardoso
Keyword(s):  
Rural Areas ◽  
Low Cost ◽  
Sewage Treatment ◽  
Field Evaluation ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Attractive Alternative ◽  
Improved Performance

This paper presents the development and field evaluation of a partitioned UASB reactor, conceived for the treatment of domestic sewage from small villages and areas with large variation of the daily flowrate. In such situations, conventional single compartment UASB reactors are submitted to very extreme hydraulic conditions, that can disturb the behaviour of the treatment system. In the partitioned reactor, which is constituted of three digestion compartments, three gas separation devices and a single settler compartment, an adequate distribution of the variable incoming wastewater into one, two or three digestion chambers, allows the establishment of more stable up flow velocities and less occurrence of dead zones. As a result, a better contact between substrate and biomass can be achieved and an improved performance of the system can be expected. The partitioned UASB reactor was evaluated during a period of 16 months of continuous operation. The system presented a vary good performance during most of the operational period, showing very high efficiencies when the reactor was operated at a HRT of 7.5 hours. In this phase, the unit presented COD removal efficiencies around 80% and an average SS concentration in the final effluent of 32 mgSS/L. The research is still going on, focussing on the evaluation of the system under higher hydraulic loads and on the assessment of sludge activity and dehydration potential. Due to the operational simplicity and low cost of the system, it is believed that this type of reactor can become a very attractive alternative for domestic sewage treatment in small villages, particularly in Brazil where the number of rural areas with wastewater treatment is negligible.

Domestic sewage treatment in an upflow anaerobic sludge blanket - sequencing batch reactor system

1996 ◽  
Vol 33 (3) ◽  
pp. 73-84 ◽  
Author(s):  
J. T. de Sousa ◽  
E. Foresti
Keyword(s):  
Organic Matter ◽  
Batch Reactor ◽  
Sewage Treatment ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Excess Sludge ◽  
Aerobic System ◽  
Anaerobic Sludge Blanket

Domestic sewage treatment in up-flow anaerobic sludge blanket (UASB) reactors has presented significant results in tropical regions. This reactor configuration has proven to be efficient in removing organic matter and total suspended solids as well as in producing smaller amounts of excess sludge than conventional aerobic reactor. On the other hand, its effluent often requires to be post-treated in order to achieve the emission standards. This paper is concerned with the alternative proposed here for treating domestic sewage in a combined anaerobic-aerobic system composed of an UASB reactor followed by sequencing batch aerobic reactors (SBR). In such a system, the UASB reactor removes considerable fraction of the influent organic matter, while the SBRs oxidize part of the remaining organic matter and ammonium nitrogen. A proper system operation would also permit the removal of nutrients (N and P). In order to investigate on the performance of this system for sewage treatment, a bench scale installation fed with synthetic substrate simulating domestic sewage was operated continuously during 38 weeks. The results permit to confirm the hypothesis proposed, since the system has consistently produced high quality effluents (BOD5 and VSS lower than 10 mg.L-1). The results also indicate that such combined anaerobic-aerobic system compete favorably with conventional aerobic systems in three essential cost features: energy consumption, excess sludge production and nutrient removal.

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