Pre-Treatment of industrial mineral oil wastewater using response surface methodology

Abstract

This study focuses on the process optimization of coagulation floatation by cross-interaction effects of the following multiple factors: pH, coagulant dosage and floatation time on the response of chemical oxidation demand (COD), soap oil and grease (SOG), turbidity and total suspended solids (TSS). The results from the response surface methodology incorporated with Box Benken design (BBD) models reveals significant correlations and interactions between the manipulated and response variables. To establish the optimum pre-Treatment conditions, the experiment used the design BBD, using Design Expert (Design Expert 10.0.3) software. This ensures that the process engineers and scientists gain a better understanding of the practical application of the experimental results over the conventional method of one-factor-At-Time (OFAT). The recent trend in industrialization and population growth has indeed deepened the demand on the world's energy (oil) and water resources. However, the need to meet the significance of energy and water for sustainable social economy growth and development has resulted in extremely adverse effects on water and environmental pollution. South Africa, well known as a water scarcity country, has also intensified its policy and increased fines for offenders who do not meet its regulations and discharge limits. In this context, the treatment of industrial mineral oil wastewater, which is regarded as hazardous and harmful to the environment, derived from petrochemical and oil refinery industries, has a recovery value. This has raised attention for systematic technology and approach in recovering oil and water for reuse to conserve the supply of fresh water and energy resources.