Project Title : Oily Wastewater Treatment and Reuse System – a Demonstration Project

Applicant : Hong Kong University of Science and Technology

Project Proponent : Dr. Guohua Chen

Total Approved Grant : $330,980.89

Duration : 1/12/2003 to 31/12/2005

Project Status/Remarks : Completed

Scope :
The project aims to develop a prototype treatment and reuse system for oily wastewaters generated from various sectors such as garages, auto cleaning centres, gas stations, bus depots and marine operation.

Summary of the Findings/Outcomes :
Various wastewaters generated from different sectors such as bus depot, gas station, marine operation, garage, and car washing center were collected and characterized. Some of the wastewaters were treated using the bench top system available at HKUST. The effects of operational variables on performance were investigated. The removals of oil and grease, COD, TOC and suspended solids were examined. Under the reasonable and optimistic condition, the maximum oil and grease and suspended solids removals were both over 90% with COD and TOC removals at 85% and over 70% respectively. Neutral pH is helpful for the pollutants removal. Conductivity has little effect on the efficiency but much influences on the cell voltage and energy consumption at a constant charge loading.

The pilot plant system with a capacity of treating 20m3 wastewater/day was designed, fabricated, installed and tested on the campus of HKUST. The process control system with necessary sensors was incorporated with the system. It has been tested to obtain the optimal operating conditions using the wastewater generated from a Chinese restaurant. Simulated oily wastewater similar to that from a bus depot was tested using the pilot plant system. Real wastewater generated from a local bus depot was collected and treated with the pilot plant system. The results show that over 90% of O&G was removed the COD and turbidity removals from the pilot plant system are similar to those obtained by the laboratory unit.