Effect of biodegradable organic matter concentration on phenol removal rate from oil refinery wastewater using anaerobic pond system

Phenol and its components are toxic materials found in various environmental resources due to industrial development. It is necessary to eliminate these toxic substances for the environment. The aim of this study was to evaluate the relationship between the concentration of biodegradable organic matter and the phenol removal rate from oil refinery wastewater using anaerobic pond.. In the present study a pilot-scale anaerobic pond system was used with dimension of 1 × 1 × 0.2 m and retention time of 2 and 5 days at two temperatures (above 20° C and below 10° C). To determine the relationship between phenol removal and concentration of biodegradable materials, retention time and various temperatures, two-way ANOVA and Scheffe’s post-hoc tests were used. the maximum rate of phenol removal (95.8%) (87.51%) were reported in the concentration of 500 mg/l of biodegradable materials with 5 days retention time and temperature of >20 ° C. Also, the minimum rate of phenol removal (16.8 %) and chemical oxygen demand (COD) (7.5%) were obtained in the concentration of 10000 mg/l of biodegradable materials with retention time of 2 days and temperature of <10 ° C. the maximum phenol removal rate in the anaerobic pond occurred in the retention time of 5 days, higher temperature, and concentration of 500 mg /l of biodegradable COD.