BIODEGRADTION OF HAZARDOUS WASTEWATER POLLUTANTS

Abstract

Disposal of produced waste water causes an environmental impact which has been reported since the mid-1800s when the first oil and gas wells were drilled and operated. The most commonly reported environmental concerns are as follows: degradation of soils, ground water, surface water, and ecosystems they support. In recent years, interest in biological treatment, especially to remove the petroleum-derived compounds in produced waste water, has increased due to more stringent environmental standards and the desire/need to reuse the increasing amounts of water rather than pumping the mat high pressure back down the aquifers which is energy intensive and expensive. Biological treatment is an effective and economical way that can be used in oil de-emulsification and waste water treatment. Crude oil degrading microorganisms, namely bacteria, yeast and fungi, which can grow using crude oil as carbon source, have been reported as oil degraders. The main objective of this study was concentrated on using bacteria in treatment of produced wastewater from gas reservoir. Also, studying the chemical characteristics and properties of produced waste water. In this study pH value and water/sludge ratio is very important for enhancing the treatment process of the produced water. An experiment is done to chose the best pH value and water/ sludge ratio, aerobic treatment of produced waste water was done with different sludge/ water ratio (1:3, 1.5:2.5, 2:2 and 3:1) and at different pH value from 3 to 10, it was observed that the treatment reached its best removal values for COD, BOD5, TSS, TDS , oil and grease when pH was between 7 – 9 and water to sludge ratio was 2.5/1.5.