Oily Wastewater Treatment by Ultrafiltration: Pilot-Scale Results and Full-Scale Design

Abstract

A West Virginia company that produces an oily waste decided to upgrade their wastewater treatment facilities to prevent possible ground and surface water contamination. The contaminant of concern was oil/grease. West Virginia University's Department of Civil and Environmental Engineering was asked to perform pilot-scale studies using the following treatment technologies: chemical-addition-dissolved air flotation, ultrafiltration, biological filter, constructed wetlands, and land application. Based on data collected over a 2-year period, the following treatment train was proposed: settling ponds → oil/water coalescer → tubular ultrafiltration → constructed wetlands. The ultrafiltration effluent had an oil/grease content that was consistently below 100 mg/L and very low total suspended solids. Ultrafiltration effluent will be sent to a 15-acre hybrid constructed wetlands/land application system for tertiary treatment. The ultrafiltration residual (2,600 gal/day, >5% oil) will be concentrated by a factor of 10 (260 gal/day, >50% oil) using a high-shear rotary ultrafiltration system. The highly concentrated oil waste will be disposed of via an off-site oil recycler.