The Orange County Sanitation District is studying how much water runoff from lawns and streets can be treated before it ends up in the Santa Ana River and ocean.
The challenge, sanitation district officials say, is processing additional runoff without jeopardizing its primary mission of treating raw sewage.
The district processes about 2 million gallons of runoff daily during the dry season but can treat about 10 million gallons a day, General Manager Blake Anderson said. Winter rains create too much runoff to be diverted to treatment facilities, so it flows directly into the Santa Ana River or the ocean.
Between 40 million and 100 million gallons of runoff a day course through the county in the dry season, Anderson said, and local agencies are trying to improve their water-diversion systems so more of it can flow first to sewage treatment centers before it is dumped in the ocean.
“We can’t capture and treat all of it, but treatment is an effective tool,” said Larry McKenney, manager of watershed and coastal resources for the county Department of Resources and Development Management. “So having enough capacity to deal with runoff is vitally important.”
Sanitation district officials say it is unclear, however, whether its Huntington Beach and Fountain Valley facilities have the capacity to process more than 10 million gallons of runoff water daily.
To determine that, a $223,000 contract to conduct the capacity assessment was awarded Wednesday by the district’s board of directors to Integrated Program Management Consultants, a joint venture of Parsons Infrastructure & Technology Group Inc. and CH2M Hill Inc. The report is due in the fall.
Storm channels that carry surface water runoff are separate from sewage pipes, but the systems can be interconnected to allow runoff to be treated by the sanitation district. The sanitation district processes about 240 million gallons of sewage daily.
Untreated runoff is so polluted, mostly with animal waste, that the Santa Ana Regional Water Quality Control Board issued pollution violation notices in December to the county and the cities of Santa Ana, Fountain Valley, Costa Mesa, Huntington Beach and Newport Beach. The letter presses the cities and county to more quickly find solutions to the runoff problem.
Urban runoff pollution of the ocean, which frequently triggers beach closures after heavy rains, has frustrated public health officials for years. About four years ago, the sanitation district began treating dry-season runoff in addition to conventional sewage. The runoff picks up bacteria as it runs across yards, sidewalks, streets and gutters and flows into storm channels.
“The treatment has helped, and we’d like to see the sanitation district handle more,” said Ken Theisen, a staff environmental scientist for the regional water quality control board.