Purification of oily wastewater in thermal power plant by coal fly ash

The removal of oil from oily wastewater in thermal power plant by coal fly ash(CFA) was investigated. It contained about 2.5 g/L of mineral oil,which had to be treated efficiently before it was discharged. The experiments were carried out as a function of different initial concentrations of oil,mass dosage,contact time and pH value to obtain the optimum conditions for the removal of oil from oily wastewater. The experimental results show that CFA presents the most suitable conditions for the removal of oil from waste-water at a dosage of CFA 2.5 g/L,15 min of contact time and a pH value of 4.8. The adsorption process is performed with almost 96% of oil removal from wastewater. The kinetic data meet the second-order kinetic model. The Langmuir and Freundlich adsorption models were applied to describing the experimental isotherms and isotherm constants. The equilibrium data fit very well with the Freundlich model.