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

Abstract

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.

Sequencing Batch Reactor and Bacterial Community in Aerobic Granular Sludge for Wastewater Treatment of Noodle-Manufacturing Sector

“…According to the investigation of Dockhorn et al [26], which used a SBR system to treat municipal wastewater, the efficiency of COD removal was also remarkably high after the acclimatization process of bacteria in the system, which grew to 94.5% after 20 days. Similar results were also reported in previous studies [27][28][29]. The value of the organic load rate (OLD) in this study was significantly higher, reaching 7.4 kg COD/m 3 ·day when the system was in a stable state, which was two times higher than the similar operating SBR system for municipal wastewater treatment reported by Jungles et al [30].…”

Treatment of domestic wastewater in an up-flow anaerobic sludge blanket reactor followed by moving bed biofilm reactor

“…COD removal ranging from 90 to 94% has been found by Tawfik et al [30] at lower HRT (10.7 h) using a combined system consisting of UASB-down flow hanging sponge (DHS) system. Sousa and Foresti [2] investigated UASBsequencing batch reactor (SBR) for sewage treatment. The total system achieved an overall removal efficiency of 95% of COD.…”

“…Within the spectrum of anaerobic sewage treatment technologies, the up-flow anaerobic sludge blanket (UASB) reactor offers great promise, especially in developing countries that are usually located in hot and moderate climatic zones [1,2]. These reactors remain robust highrate treatment systems, generally without moving mechanical parts, limiting both capital and operating costs [3].…”

Aerobic and Anaerobic Sewage Biodegradable Processes: The Gap Analysis

“…A study on the use of UASB-SBR to treat domestic sewage with average COD of 587 mg/L at 25 0 C has resulted to the circulation of excess SBR sludge to the UASB reactor (Guimaraes et al, 2003). The aid of SBRs excess sludge circulation has led to the increment of OLR by 0.7% which resulted in CODtot removal rate of 95% compared to 91% CODtot removal rate by UASB reactor alone under low temperatures between 15 0 C and 30 0 C [34]. Another study on UASB-SBR system was conducted by Guimaraes et al [35] which used 10 L UASB reactor and 7 L SBR reactor to treat domestic sewage with an average COD of 587 mg/L and anaverage temperature of 25 0 C. The UASB reactor was operated at 4 h HRT, with a loading rate of 3.8 kg COD/m 3 /day and up flow velocity of 0.3 m/h; while the SBR was operated at 1 h aeration time and 0.5 h settling time.…”