Anaerobic and aerobic sewage treatment plants in Northern India: Two years intensive evaluation and perspectives

The present study investigates the long term treatment performance of seven different sewage treatment plants located in different cities of north India for over a period of two years; two treatment technologies based on intensive aerobic processes — sequencing batch reactor (SBR) and moving bed bio-film reactor (MBBR) and; three combination of Up-flow Anaerobic Sludge Bed (UASB) reactor followed by aerobic processes — Polishing Ponds (PP), Aeration + PP and Down-flow Hanging Sponge (DHS). Effluent quality was not in accordance to the surface water disposal standards, Ministry of Environment, Forest and Climate Change Govt. of India, for UASB followed by PP and by Aeration +PP. However, a high effluent quality was observed in UASB followed by DHS; SBR and MBBR systems. In the last cases, NH ₄ -N and PO ₄ -P removal was higher than 85 and 60%, respectively; with a final effluent concentration of 20 mg BOD ₅ /L, 50 mg COD/L, 20 mg TSS/L, 10 mg NH ₄ -N/L and 5 mg PO ₄ -P/L. Although strictly intensive aerobic systems showed a better performance, UASB followed by simple aerobic systems, such as the DHS process is a promising technology, especially in India to reach required BOD level for water reuse at low costs.