Combining biological and physical processes for complete treatment of oily wastewaters

A novel process systems for wastewaters treatment has been developed that combines the use of biological and physical processes. This system, called the membrane biological reactor (MBR) system, consists of a suspended growth biological reactor combined with a membrane ultrafiltration unit process. The MBR system is particularly attractive when applied in situations where long biological solids retention times are necessary, and physical retention and subsequent hydrolysis are critical to achieving biological degradation of pollutants. In order to develop full scale process and design information, field pilot studies were conducted for several months. These pilot studies involved assessing system performance and developing system design information in the treatment of wastewaters from metalworking automotive plants. The results of the pilot studies provided the basis forthe design of a full scale demonstration MBR system for treatment of industrial oily wastewaters. Information is presented on system design as well as operation and performance. Despite certain design issues, to date the system has met or exceeded performance expectations.