A modified upflow anaerobic sludge blanket reactor as an alternative for decentralized domestic wastewater treatment in developing countries

2019 ◽  
Vol 14 (2) ◽  
pp. 249-258
Author(s):  
S. R. Amaral ◽  
L. V. dos Santos ◽  
L. M. Lima ◽  
D. V. Vich ◽  
L. M. Queiroz
Keyword(s):  
Oxygen Demand ◽  
Domestic Wastewater ◽  
High Strength ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Reinforced Plastics ◽  
Anaerobic Reactors ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

Abstract The aim of this paper was to evaluate the performance of two modified upflow anaerobic reactor (RAns) as a decentralized technology for the treatment of high-strength domestic wastewater. Two full-scale anaerobic reactors (Ran1 and Ran2) with the same configuration and total volume of 14.6 m³, total height of 2.57 m, and constructed from fibreglass reinforced plastics were operated with a 16-hour hydraulic retention time and submitted to a volumetric organic load less than 2.7 kg chemical oxygen demand (COD)·m−3·d−1. The RAns were monitored for 10 consecutive months and showed the capability to support the fluctuations of organic loading and volumetric rates. The compact anaerobic reactors proved to be effective in removing organic matter (biological oxygen demand removal efficiencies greater than 70% and the average soluble COD removal efficiencies greater than 57.4%). The solids profile in the reactor ranged from very dense particles with good settleability close to the bottom (sludge bed) to a more dispersed and light sludge close to the top of the reactor (sludge blanket), similar to conventional UASB reactors.

Impact of microaeration bioreactor on dissolved sulfide and methane removal from real UASB effluent for sewage treatment

2020 ◽  
Vol 81 (9) ◽  
pp. 1951-1960 ◽  
Author(s):  
C. S. Cabral ◽  
A. L. Sanson ◽  
R. J. C. F. Afonso ◽  
C. A. L. Chernicharo ◽  
J. C. Araújo
Keyword(s):  
Sewage Treatment ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Sulfide Removal ◽  
Dissolved Sulfide ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

Abstract Two bioreactors were investigated as an alternative for the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, aiming at dissolved sulfide and methane removal. The bioreactors (R-control and R-air) were operated at different hydraulic retention times (HRT; 6 and 3 h) with or without aeration. Large sulfide and methane removal efficiencies were achieved by the microaerated reactor at HRT of 6 h. At this HRT, sulfide removal efficiencies were equal to 61% and 79%, and methane removal efficiencies were 31% and 55% for R-control and R-air, respectively. At an HRT of 3 h, sulfide removal efficiencies were 22% (R-control) and 33% (R-air) and methane removal did not occur. The complete oxidation of sulfide, with sulfate formation, prevailed in both phases and bioreactors. However, elemental sulfur formation was more predominant at an HRT of 6 h than at an HRT of 3 h. Taken together, the results show that post-treatment improved the anaerobic effluent quality in terms of chemical oxygen demand and solids removal. However, ammoniacal nitrogen was not removed due to either the low concentration of air provided or the absence of microorganisms involved in the nitrogen cycle.

Mathematical modeling of upflow anaerobic sludge blanket (UASB) reactor treating domestic wastewater

2013 ◽  
Vol 67 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Tarek Elmitwalli
Keyword(s):  
Chemical Oxygen Demand ◽  
Dynamic Model ◽  
Empirical Model ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Model Based ◽  
Anaerobic Sludge Blanket

Although the upflow anaerobic sludge blanket (UASB) reactor has been widely applied for domestic wastewater treatment in many developing countries, there is no sufficient mathematical model for proper design and operation of the reactor. An empirical model based on non-linear regression was developed to represent the physical and chemical removal of suspended solids (SS) in the reactor. Moreover, a simplified dynamic model based on ADM1 and the empirical model for SS removal was developed for anaerobic digestion of the entrapped SS and dissolved matter in the wastewater. The empirical model showed that effluent suspended chemical oxygen demand (CODss) concentration is directly proportional to the influent CODss concentration and inversely proportional to both the hydraulic retention time (HRT) of the reactor and wastewater temperature. For obtaining sufficient CODss removal, the HRT of the UASB reactor must be higher than 4 h, and higher HRT than 12 h slightly improved CODss removal. The dynamic model results showed that the required time for filling the reactor with sludge mainly depends on influent total chemical oxygen demand (CODt) concentration and HRT. The influent CODt concentration, HRT and temperature play a crucial role on the performance of the reactor. The results indicated that shorter HRT is needed for optimization of CODt removal, as compared with optimization of CODt conversion to methane. Based on the model results, the design HRT of the UASB reactor should be selected based on the optimization of wastewater conversion and minimization of biodegradable SS accumulation in the sludge bed, not only based on COD removal, to guarantee a stable reactor performance.

Herbal pharmaceutical wastewater treatment by a pilot scale upflow anaerobic sludge blanket (UASB) reactor

2009 ◽  
Vol 59 (11) ◽  
pp. 2265-2272 ◽  
Author(s):  
S. Satyanarayan ◽  
A. Karambe ◽  
A. P. Vanerkar
Keyword(s):  
Biogas Production ◽  
Oxygen Demand ◽  
High Strength ◽  
Cost Effective ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Anaerobic Sludge Blanket

Herbal pharmaceutical industry has grown tremendously in the last few decades. As such, literature on the treatment of this wastewater is scarce. Water pollution control problems in the developing countries need to be solved through application of cost effective aerobic/anaerobic biological systems. One such system—the upflow anaerobic sludge blanket (UASB) process which is known to be cost effective and where by-product recovery was also feasible was applied for treatment of a high strength wastewater for a period of six months in a pilot scale upflow anaerobic sludge blanket (UASB) reactor with a capacity of 27.44 m3. Studies were carried out at various organic loading rates varying between 6.26 and 10.33 kg COD/m3/day and hydraulic retention time (HRT) fluctuating between 33 and 43 hours. This resulted in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and suspended solids (SS) removal in the range of 86.2%–91.6%, 90.0%–95.2% and 62.6%–68.0% respectively. The biogas production varied between 0.32–0.47 m3/kg COD added. Sludge from different heights of UASB reactor was collected and subjected to scanning electron microscopy (SEM). The results indicated good granulation with efficient UASB reactor performance.

Advanced Monitoring of an Anaerobic Pilot Plant Treating High Strength Wastewaters

1999 ◽  
Vol 40 (8) ◽  
pp. 237-244 ◽  
Author(s):  
A. Puñal ◽  
A. Lorenzo ◽  
E. Roca ◽  
C. Hernández ◽  
J. M. Lema
Keyword(s):  
Pilot Plant ◽  
Gas Flow ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
High Strength ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Anaerobic Sludge Blanket

The operation of an industrial pilot scale treating wastewater from a fibreboard-processing factory was monitored by an advanced system. The plant, an anaerobic hybrid UASB-UAF bioreactor (Upflow Anaerobic Sludge Blanket-Upflow Anaerobic Filter), was equipped with the following measurement devices: biogas flow-meter, feed and recycling flow-meters, thermometer Pt-100, biogas analyser (CH4 and CO), Hydrogen analyser and pH-meter. Other parameters such as alkalinity, Chemical Oxygen Demand (COD) and Volatile Fatty Acids (VFA) were determined off-line. All the on-line sensor measurements were monitored, through a PLC (Programmable Logic Controller), which indicated about the plant failures, including the measuring devices (giving messages or alarms to the operator) and provided the set points for the PLC. The pilot plant was started-up at an initial Organic Loading Rate (OLR) of 2 kg COD/m3.d (Hydraulic Retention Time (HRT) 5 days and 10 kg COD/m3), this value increasing up to 10 kg COD/m3.d by decreasing HRT to 1 day. The behaviour of the bioreactor during start-up and steady state operation was studied. After that, an experiment was performed to analyse the response of the bioreactor to an organic overload. From the results, different variables were evaluated as useful control parameters. Monitoring of CO concentration did not permit the prediction of destabilisation of the bioreactor. However, H2 concentration is quite a sensitive variable, which must be analysed together with other parameters such as methane composition or gas flow-rate. Besides, alkalinity is easy to measure and provides immediate information about the state of the plant, as was shown through the off-line measurements.

The use of bottle caps as submerged aerated filter medium

2014 ◽  
Vol 69 (7) ◽  
pp. 1518-1525
Author(s):  
Laurence Damasceno de Oliveira ◽  
Amir Mohaghegh Motlagh ◽  
Ramesh Goel ◽  
Beatriz de Souza Missagia ◽  
Benício Alves de Abreu Filho ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Filter Medium ◽  
Upflow Anaerobic Sludge Blanket ◽  
Nitrifying Bacteria ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Aerated Filter ◽  
Anaerobic Sludge Blanket

In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m−3_media.day−1. The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m−3_media.day−1 resulting in 78% conversion of NH4+-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4′-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4+-N.

scholarly journals Performance Comparison of Conventional and Modified Upflow Anaerobic Sludge Blanket (UASB) Reactors Treating High-Strength Cattle Slaughterhouse Wastewater

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 806 ◽  
Author(s):  
Mohammed Ali Musa ◽  
Syazwani Idrus ◽  
Hasfalina Che Man ◽  
Nik Norsyahariati Nik Daud
Keyword(s):  
Oxygen Demand ◽  
High Strength ◽  
Performance Comparison ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Slaughterhouse Wastewater ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

Cattle slaughterhouse wastewater (CSWW) with an average chemical oxygen demand (COD) and biochemical oxygen demand of 32,000 mg/L and 17,000 mg/L, respectively, can cause a severe environmental hazard if discharged untreated. Conventional upflow anaerobic sludge blanket (UASB) reactor is used in the treatment of slaughterhouse wastewater to meet the discharge standard limit of wastewater discharge set by the Department of Environment Malaysia (DOE). However, at higher loading rates the conventional systems are characterized by slow-growing microorganism resulting in long startup period, surface scum formation, and sludge washout. In this work, the performance of two laboratory scale (12 L) conventional (R1) and modified (R2) UASB reactors treating CSWW at mesophilic (36 ± 1 °C) condition were investigated. Both reactors were subjected to increasing organic loading rate (OLR) from 1.75 to 32 g L−1 day−1. The average COD, BOD5, and TSS removal efficiencies were ˃90%, at an OLR between 1.75 to 5 g L−1 day−1. The study revealed that R1 drastically reduced to 50, 53, and 43% with increasing OLR until 16 g L−1 day−1, whereas R2 maintained 76, 77, and 88% respectively, under the same OLR. Sign of reactor instability was very much pronounced in R1, showing poorly active Methanosaeta spp., whereas R2 showed a predominantly active Methanosarcina spp.

Biomass Acclimatization to Sequentially Varying Substrates in an Upflow Anaerobic Sludge Blanket (UASB) Bioreactor

2006 ◽  
Vol 41 (4) ◽  
pp. 437-448 ◽  
Author(s):  
Yee Ying Jennifer Tan ◽  
Mohd. Ali Hashim ◽  
K.B. Ramachandran
Keyword(s):  
Loading Rate ◽  
Biogas Production ◽  
Domestic Wastewater ◽  
High Strength ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Start Up ◽  
Time Required ◽  
Volumetric Loading ◽  
Anaerobic Sludge Blanket

Abstract In this study, an upflow anaerobic sludge blanket (UASB) bioreactor was sequentially subjected to high-strength synthetic, low-strength synthetic and domestic wastewaters. From COD removal data, supported by volumetric loading rate, hydraulic retention time, pH and qualitative biogas production data, it was observed that the biomass in the bioreactor took about twice the time required to acclimatize to a change in substrate characteristics or composition compared to a much more drastic quantitative change, i.e., more than 95% difference, in substrate concentration. As the initial experiment coincided with the bioreactor start-up, it could also be concluded that the feeding regime did not shorten the overall start-up time of a UASB bioreactor meant to treat domestic wastewater, but its eventual success was probably more assured.

scholarly journals Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge

2017 ◽  
Vol 76 (8) ◽  
pp. 2003-2014 ◽  
Author(s):  
Pollyane Diniz Saliba ◽  
Marcos von Sperling
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Nitrite reduction and methanogenesis in a single-stage UASB reactor

2015 ◽  
Vol 72 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
L. I. Borges ◽  
C. M. López-Vazquez ◽  
H. García ◽  
J. B. van Lier
Keyword(s):  
Domestic Wastewater ◽  
High Strength ◽  
Single Stage ◽  
Nitrite Reduction ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
N Removal

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO2−-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO2−-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO2−-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO2− reduction to N2. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

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