Bioremediation of crude oil tar balls in a mangrove environment in the Maxus field

Abstract The problem of handling spilled oil in mangrove forests occurs due to limited technology and incomplete clean up of spilled oil. Biological treatment of spilled crude oil is one way to solve the problem with limited adverse impact. However, biodegradation rates for crude oil depend on several factors including the specific hydrocarbon component types present. Most technology enhances the naturally occurring biodegradation processes through nutrient addition, dilution, aeration, mixing and pH control (manipulating environmental parameters). Principally the rate of biodegradation of crude oil is greatly enhanced by detritivore (decomposer organisms) combined with nutrient addition. The testing program used a Stratified Square Design experiment, field applied microbial inoculant, nutrient and emulsifier with three curde oil tarball sizes and crude oil finger printing analysis for database comparison. The results show that the combination between exogenous and indigenous bacteria, applied with nutrient plus emulsifier work well and microorganisms mixed specially together with the indigenous bacteria work more effectively than the indigenous bacteria alone in optimizing the rate of crude oil biodegradation. The work of indigenous bacteria with or without nutrients supplement is very slow. There is no indication that the indigenous bacteria alone can degrade the crude oil completely. The end result of the biodegradation process is that the crude oil is converted to carbon dioxide, water and microbial protoplasm which has nitrogen and phosphorus compound, especially orthophosphat. This compound is very useful in mangrove ecosystem. It can be concluded that crude oil biodegradation using specialty blended detritivore bacteria and nutrient addition is an environmentally practical technique for spilled oil removal from mangroves ecosystem.