Volume No. 3 Issue No.: 2 Page No.: 442-448 Oct-Dec 2008

 

ANAEROBIC-ANOXIC-AEROBIC THREE STAGE ATTACHED GROWTH SYSTEM FOR REMOVAL OF AMMONIA

 

Bhaskar Jyoti Deka1, Biju Prabha Sahariah and Saswati Chakraborty2*

1. Department of Civil Engineering, Indian Institute of Technology Guwahati, (INDIA)
2. Center for the Environment, Indian Institute of Technology Guwahati, (INDIA)

 

Received on : July 10, 2008

 

ABSTRACT

 

Present study was conducted in a continuous three-stage attached growth system consisting of anaerobic (R1) -anoxic (R2) -aerobic (R3) reactors with synthetic wastewater containing phenol (1800 mg/l), COD (5000 mg/l) and NH4+-N (250 mg/l) as pollutants. Well-acclimated heterogeneous microbial cultures were used for this work with sponge as the support media for biomass immobilization. The final effluent (containing nitrate) from aerobic reactor was recycled (recycle ratio 1) to R2 for denitrification with total system HRT of at 4 days. Anaerobic reactor removed almost 48% of phenol and reduced load on successive reactors. Specific methanogenic activity of anaerobic sludge was observed as 0.446 g CH4-COD/ g VSS. day. In anoxic reactor phenol was removed completely with partial denitrification. This reduced phenol toxicity on aerobic nitrifying reactor. Overall COD removal efficiency of 93% was achieved in three-stage system. Overall NH4+-N and total nitrogen removal efficiencies in three-stage system were 93% and 61% respectively.

 

Keywords : Phenol, Ammonia-nitrogen, Three-stage attached growth system

 

 

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