STUDIES ON THE EFFECT OF PHENOL ON COD REDUCTION RATE KINETICS

Abstract

Phenols and its derivatives are commonly found in large number of industrial wastes such as petrochemicals, coal washeries, plastics, paints, pharmaceuticals, etc. Phenolibeing an aromatic ring structured compound, is not easily biodegradable. Though very low concentrations of phenols in medium are used as source of carbon by micro-organisms, however, higher concentrations are toxic and hinders the performance of biological wastewater treatment plants. The main objective of the present work was to study the influence of phenol dosages on the performance of aerobic biological wastewater treatment. The influence of phenol was measured in terms of change in COD reduction rate and in biokirketic parameters. The influence of temperature and pH on COD reduction rate as well as on specific growth rate has also been established. The results indicate that there is no adverse effect on COD removal upto the initial phenol dosage of 50 mg/L, however, above 50 mg/L, the COD reduction rate decreases drastically with increase in phenol concentration. The optimum temperature and pH of COD reduction does not alter on the addition of phenol, and remains 37°C and 7.0 respectively. The addition of phenol to the waste sample decreases the initial pH because of acidic nature of phenol. The maximum specific growth rate for the system was found to be 2.55 day 1 , at 37oC and pH around 7.0.