MBR PLANTS: LARGER AND MORE COMPLICATED

The consideration and use of the membrane bioreactor (MBR) technology is advancing rapidly around the world as the need for high levels of treatment and small footprint technologies increases and the confidence with the MBR technology grows. Until recently, this technology was typically limited to small scale satellite/scalping type facilities. Now MBRs are being designed for plants as large as 117,350 m3/d (31 mgd) average flow. While many issues are the same regardless of size, the design of a large scale MBR facility has increasing complexity due to the complications of solids treatment, flow variation, and end of the line reliability issues. There are several MBR manufacturers in the marketplace today, each with a varying range of experience both in number of facilities and size of facilities. Several manufactures have developed new systems which economize the cassette design in order to accommodate larger scale plants. However, the varied membrane design still makes traditional methods of “design-bid-build” challenging and warrants consideration of early procurement.