CWA authorizes membrane

The San Diego County Water Authority voted to authorize a consultant agreement for a regional membrane bioreactor system study.

The February 24 CWA board vote approves a contract with MWH Americas, Inc., for up to $74,185. The study will evaluate siting membrane bioreactors at locations throughout the county where customers with recycled water demands exist nearby.

“This is a way to take advantage of the opportunities to use recycled water,” said Bill Jacoby, the CWA’s water resources manager.

The study stems from the Regional Recycled Water System Study which was initiated by the CWA in March 2000. Phase I, which identified potential opportunities to increase the use of recycled water, was completed in March 2002, while Phase II, which examined obstacles which would inhibit the use of recycled water, began in 2003. The Phase II study was funded by a State Water Resources Control Board (SWRCB) grant and a US Bureau of Reclamation grant, and the $1.15 million grant money also included pass-through funding for CWA member agencies to implement projects.

The CWA developed criteria for awarding the grants, and in June 2004 the CWA released a request for applications. Twelve applications were received and reviewed. Ten of those were approved for funding and one was rejected for not meeting SWRCB criteria.

The twelfth application was from the City of San Diego for a membrane bioreactor feasibility study. SWRCB staff identified that project as a prime research project best implemented on a regional level by the CWA. City of San Diego staff agreed with the approach, and when the CWA approved the member agency grants in August 2004 the implementation responsibility for the membrane bioreactor study was transferred to the CWA.

“It’s going to be a study to look at opportunities,” Jacoby said.

The distribution system to move recycled water from a plant to a distant user can often be expensive, so the bioreactor could allow recycled water to users remote from plant facilities to become economically feasible.

“It’s promising technology,” Jacoby said.

In January 2005 the CWA issued a request for proposals, and two firms responded. MWH Americas, Inc., was deemed the most responsive to the project needs and objectives.

The study is expected to be completed by the end of 2005. “Theoretically we could have some of these within a couple of years if everything goes right,” Jacoby said of the actual implementation.