Nature Environment and Pollution Technology

P. Sundar Kumar ¹, I. Naga Babu ², T. V. Praveen ³

Affiliations
1 Department of Civil Engineering, K. L University, Vaddeswarum-522 502, Guntur District, A.P., IN
2 Dept. of Civil Engineering, R.V.R. & J.C.College of Engineering, Chowdavaram, Guntur District, A.P., IN
3 Department of Civil Engineering, Andhra University, Visakhapatanam-530 003, A.P., IN

Abstract

Phenol and thiocyanate are present inmany industrial effluents like chemical industries, oil refineries, coal gasification, coke and steel plant, synthetic fuel processing operations, coal carbonization, etc. The objective of the present research is to investigate the removal of phenol, thiocyanate and nitrate-N in anoxic fixed-film reactors. Cultures were acclimatized in three continuous reactors (named R1, R2 andR3) under anoxic environmentwith sponge cubes asmedia for biomass immobilization.Acclimatization time was around 41 days. Studywas conducted with synthetic feed containing varying concentrations of phenol, thiocyanate (SCN-) and nitrate-N. HRT of anoxic reactors was maintained at two days. In reactor (R1), NO₃-N concentration was varied from 50-200 mg/L at a constant phenol and COD concentrations of 200 and 480 mg/L respectively. COD to NO₃-N removal ratio varied from 1.58 to 10.12 in R1. In reactor R2, feed SCN- concentration was varied from42 to 350mg/L. It was observed that due to change in feed SCN- concentration, phenol removal remained unaffected and complete phenol removal was achieved frominfluent concentration of 200mg/L. In R2 higher concentration of SCN- in feed had inhibitory effects on both denitrification and thiocyanate removal efficiencies. In reactor R3, feed phenol concentration was varied from 200-600 mg/L. COD removal increased due to increase in influent phenol concentration. However, SCN- andNO₃-N removals decreased. Sulphatewas generated in anoxic reactor from thiocyanate. It was observed that performance of bioreactors remained unaffected due to sudden increase of influent phenol andSCN- concentrations of 1.3 times and 1.7 times respectively.

Keywords

Phenol Removal, Thiocyanate Removal, Nitrate-N Removal, Fixed-Film Bioreactor, Denitrification, Anoxic Reactor.

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