A study on Feasibility of Bioremediation of Crude Oil contaminated soil from Kalol with Indigenous Mixed Culture

Abstract

Bioremediation is an efficient technique for treatment of various kinds of contaminants with application of microorganisms and the provision of their kinetics renders implementation of various biochemical characterizations based on rates of decomposition. The present study is based on feasibility of bioremediation for crude oil contaminated soil from agricultural land of Kalol area of Ahmedabad district, Gujarat, India. The experiment was arranged in five batches with descending levels of contamination measured in terms of Total Petroleum Hydrocarbon (TPH); batch A and B with initial contamination of 11.7% TPH and batch C, D, E with 7.3%, 7.24%, 2.3% TPH respectively. The indigenous consortium from collected soil sample was cultured in lab and applied to batch A, C, E whereas unknown culture provided by OTBL (ONGC TERI Biotech Limited) was applied to batch B, C and treated as reference to the other three batches. The growth pattern of indigenous consortium was observed from total colony counts in CFU/ml/day that revealed diauxic growth pattern during stages of development after lag phase. The kinetics of microbial growth using Verhulst model based on diauxic isotherm was plotted. Also the degradation of crude oil in all batches of soil was estimated using solvent extraction technique at regular intervals of time. The degradation rate of crude oil contamination within soil was studied using integral method which showed first order kinetics. Other characteristics of indigenous consortium including morphology and substrate utilization were observed using standard determination methods. The variation in physical and chemical properties of soil such as pH, ORP, conductivity, colour, TPH are observed on prior and latter basis of bioremediation.