Use of Natural Coagulants for Removal of COD, Oil and Turbidity from Produced Waters in the Petroleum Industry.

The biggest amount of wastewater that produced from industry of petroleum is produced water, it contains suspended and dissolved solids, residual hydrocarbons, numerous organic species and heavy metals. It is very important to remove the organic pollutant compounds from the contaminated water before discharge into any natural water. This paper studies the effect of dose of natural coagulants, pH of produced water, and oil concentration on the removal of turbidity, COD and Oil from oilfield produced waters. The efficiency of turbidity, oil and COD removal was studied via three different natural coagulants (Cicer arietinum seed, eggplant seed and radish seed) used to decrease the turbidity and organic pollutants of produced water. The experiments of the jar test showed that Cicer arietinum seed at dose 1.5 mg/L and the best pH and oil concentration can remove 95.2% of chemical oxygen demand (COD), 83.8% oil content and 98.89% of turbidity. Also, the eggplant seed at optimum condition removed COD, turbidity, and oil content by 92.18%, 99.42%, and 81.8%, respectively from the produced water. Moreover, when radish seed was used, the removal of oil content, COD and turbidity will reach to 88.2%, 93.48%, and 98.78%, respectively.