Coupling of sequencing batch reactor and UASB reactor for domestic wastewater treatment

Wastewater treatment performance of the combined process of upflow anaerobic sludge blanket (UASB) reactorand sequencing batch reactor (SBR) was studied. An experimental study has been conducted investigating theperformance of the system under different operating conditions. Three experimental runs were considered. Theretention time in the UASB was changed from 4 h to 3 h and the aeration time in the SBR cycle varied from 2 to 5,and then to 9 h. The results indicated that the average percentage removal for the three runs for COD, BOD andTSS was 94%, 97% and 98% respectively. Complete nitrification of ammonia was achieved after 5 h aeration in theSBR. The water quality of the treated wastewater resulted from the integrated system at different operating conditionscomplied with the local standards regulating wastewater discharge into agriculture drains. The main advantage ofthe proposed treatment system is the minimization of investment and operational costs as compared to the use ofthe SBR systems alone. The implementation of the anaerobic pretreatment leads to reduction of the plant area,sludge production and oxygen requirement 40%, 58%and 62% respectively.