King County, Wash. demos first USFilter immersed membrane bioreactor system

KING COUNTY, Wash., Oct. 9, 2001 — The first immersed membrane bioreactor (MBR) unit developed by USFilter is being demonstrated for wastewater reuse in the Sammamish Valley, King County, Wash.

The new process represents the union of two native USFilter technologies. USFilter's Jet Tech Products conceived the mixing system to transport dissolved air and mixed liquor uniformly and positively around and across microfiltration modules. These membrane modules have been adapted by USFilter's Memcor Products to withstand the rigors of continuous immersion in activated sludge. The result is an efficient, trouble-free wastewater treatment process producing high quality effluent suitable for direct reuse.

The demonstration project is a partnership between King County, Carollo Engineers (Seattle, WA) and USFilter. King County is evaluating the technology for a full-scale reclamation facility that would supply irrigation water to local landscaping businesses, sod farms, nurseries, and a golf resort. These facilities currently supplement their potable irrigation supply with water from the Sammamish River, a salmon-bearing watercourse threatened by low flows and high water temperatures. Hence the project would provide a drought protected irrigation supply while enhancing King County's salmon restoration efforts.

Unique Membrane Technology Provides Cost-Effective Solution

Organics, bacteria, and most viruses which are not oxidized by the biological process are rejected by the membrane system and retained in the mixed liquor where they are expelled from the process with the waste activated sludge. This separation process eliminates the need for clarifiers, weirs, and return sludge pumping. Eliminating the clarification process not only eliminates the maintenance associated with these processes, but also permits a much smaller, compact footprint. Without clarifiers, sludge settleability is no longer a concern so the biological process can be optimized for maximum treatment efficiency at minimum solids production. The MBR process offers the following advantages over conventional activated sludge processes:

� No clarifiers and attendant operation and maintenance

� Elimination of clarifiers permits the biological process to be designed and operated for treatment efficiency, not sludge settleability

� Without concern for sludge settleability, the biological process can be operated at very high MLSS concentrations (typically 10 - 15 g/l) and concomitant sludge ages (typically 50 - 100 days.)

� High MLSS concentration promotes better oxidation, complete nitrification, and reduced biosolids production

� High MLSS concentration and compact membrane separation process significantly reduce the footprint needed for both biological oxidation and solids separation

� Final effluent quality meets the strictest reclamation standards and (with disinfection) can be used directly for unrestricted reclamation

"The USFilter MBR technology brings an innovative and effective solution to maintaining the ideal operating environment around the membranes, assuring stable long-term performance," says Ed Jordan, vice president and general manager of USFilter's Jet Tech Products.

"The technology can be used to retrofit existing plants to increase capacity, as well as in the design of new plants to provide advanced treatment performance," says Jordan.

For more information, contact Ed Jordon, vice president and general manager of USFilter's Jet Tech Products at 913-422-7600 x297 or jordanej@usfilter.com.

USFilter offers more than 50 biological treatment processes, including closed loop biological reactors, diffused aeration, and fixed-film biological processed with premiere product names such as the Orbal(tm)system, OMNIFLO® SBR, Biostyr, and PACT® system. All are supported by technical personnel, operations specialists and product managers who—together—represent hundreds of years of process development and application experience. With thousands of biological treatment systems installed across the globe, USFilter is the industry leader in biological treatment solutions.

USFilter is a Vivendi Water company, the global provider of commercial, industrial, municipal and residential water and wastewater treatment systems, products and services, with operations in more than 100 countries. Together, Vivendi Water, Onyx (solid waste and industrial services), Dalkia (energy management), and Connex (transportation and logistics) comprise Vivendi Environnement, the largest environmental services company in the world with annual revenues of more than $23 billion. USFilter invites you to visit its web site at http://www.usfilter.com.