Degradation of hydrocarbons in oil polluted wastewater using biofilms formed by microorganisms on coconut fiber carrier

Abstract

In nature, many microbial communities exist in close association with surfaces and interfaces as complex assemblages known as biofilms where multicellular aggregates hold together by an extracellular matrix. It is possible to take advantage of natural trans-formation processes on the constituent cells to have high resistance to environmental stresses and diverse microenvironments that help generate cellular heterogeneity. In this study, the authors focused on biofilms composed of mixed populations which were immobilized on the surface of coconut fibers. Coconut fibers were used as a crude oil sorbent as well as a biocarrier for microorganism immobilization. Microbial biomass reached 4.3 x 1010 cells/cm3 at the beginning time and 4.5 x 109 cells/cm3 after 7 day-incubation. The efficiency of degrading a number of particular xenobiotic compounds containing in crude oil wastewater by this biocarrier was demonstrated. After 7-day culture, all of values such as pH, total crude oil and PAHs (polycyclic aromatic hydrocarbons) were reduced remarkably, and they all satisfied the Vietnam waste-water standard records. This study explored the role of biocarrier in enhancing biodegradation of hydrophobic contaminants such as crude oil, and discussed the function of biocarrier in improving oxygenmass transfer and water holding capacity in soil, etc.