Comparative Study of the Effect of Natural and Synthetic Coagulants on the Treatment of Industrial Effluents

Ground seeds of Jatropha curcas were tested for their coagulatory activities on industrial effluents from a vegetable oil producing company Port Harcourt, Nigeria. These were treated within six hours of collection using synthetic coagulants (Aluminum sulphate and ferric chloride) and Jatropha curcas, as the natural coagulant. Concentrations of coagulants ranged from 0.5mg/ml to 3.5mg/ml; the set up was in duplicate sets. Physicochemical parameters and microbial load were measured using standard techniques. Ground dried seeds of J. curcas showed good coagulatory properties. For instance, they resulted in the reduction of the turbidity, microbial load and biological oxygen demand (BOD) of the industrial effluent. The chemical oxygen demand (COD) of the industrial effluent was enhanced by more than four folds. The results obtained from testing the industrial effluent with Jatropha curcas were comparable to those obtained using synthetic coagulants such as aluminum sulphate and ferric chloride. The turbidity of the industrial effluent was reduced by as much as 72.7% while the microbial load was reduced by 99.9%. The effect of the ground seed of Jatropha curcas on the temperature and pH of the effluent were mostly moderating, but the effluent became slightly alkaline after treatment. Slightly alkaline condition enhances overall hydrocarbon biodegradation in industrial effluents. Apart from the above characteristics of the effluent affected by the treatment with Jatropha curcas, the effluent produced after treatment was colorless and odorless. The apparent removal of color and odor from the effluent were important for these are some of the most objectionable properties of industrial and domestic effluents.