Abstract: The rapid growth of the population, the technological and industrial
boom has brought enormous problems and degradation of the environment.
Pollution caused by sewage discharged from cities and towns is the primary
cause for degradation of water resources. Hence a proper and planned sewage
treatment is needed. Gurgaon city hosts two sewage treatment plants located in Dhanwanpur
village. These plants are designed and constructed with an aim to manage
wastewater so as to minimize and/or remove organic matter, solids,
disease-causing organisms and other pollutants, before disposal. This article
evaluates and compares the actual behaviour of full-scale anaerobic and aerobic
wastewater treatment plants in operation in Gurgaon, providing information on
the performance of the processes in terms of the quality of the generated
effluent and the removal efficiency achieved. The observed results of effluent
concentrations and removal efficiencies of the constituents TSS, BOD, COD, VSS
and BOD/COD ratio have been compared with the typical expected performances as
per the standards given by CPCB. The treatment technologies selected for study
were anaerobic-UASB and aerobic-ASP plants. The results, confirmed by
statistical tests, showed that, in general, the best performance was achieved
by ASP, but closely followed by UASB reactor, when operating with any kind of
post-treatment. It was revealed from the performance study that efficiency of
the two treatment plants was adequate with respect to removal of TSS, BOD, COD
and VSS. In UASB, TSS, BOD, COD and VSS removal efficiency was 90.2, 87.4,
86.96 and 86.4% respectively, while in ASP, TSS, BOD, COD and VSS removal
efficiency was 88.8, 90.07, 84.15 and 90.5 % respectively. The order of removal
efficiency was VSS < COD < BOD < TSS and COD < TSS < BOD <
VSS respectively in UASB and ASP STPs. Additionally, the problems associated
with the operation and maintenance of wastewater treatment plants is
discussed.
