CVSan Celebrates Award for Reducing Toxic Runoff
Ora Loma’s sewage plant, partly owned by CVSan, at the end of Grant Avenue in San Lorenzo. The new blowers and new aeration basins installed as part of the Nutrient Optimization Project are visible.
The Oro Loma Sanitary District, which runs the San Lorenzo sewage plant partly owned by the Castro Valley Sanitary District (CVSan), just won an innovation award for a new technology that greatly cuts nutrient discharge into the Bay.
The award came just after the venerable organization celebrated being 110 years old on August 7. CVSan, by contrast, is a relative youngster at 82, having been founded in 1939.
Oro Loma’s Nutrient Optimization Program (NOP) — jointly funded with CVSan — greatly reduces the amount of nitrogen compounds in treated water discharged into the Bay, according to the managers of both districts. This leads to fewer blooms of algae and other aquatic plants that can choke off oxygen and light to fish, crabs, and other sea life.
“We’ve seen fishing hurt and shortened or canceled crab seasons because of too many nutrients going in the Bay and ocean in recent years,” said CVSan General Manager Roland Williams.
The award was for Outstanding Capital Project and came from the California Association of Sanitation Agencies (CASA).
In a statement, Oro Loma noted the project was the first of its kind in the Bay Area was completed on time and came in under budget.
It was hoped the new process would remove more than half of the ammonia the old technology let escape into treated discharge. After a year of operation, though, it is removing closer to 95% of the ammonia discharges, the district said.
Oro Loma District Engineer Jimmy Dang explained that ammonia, a natural breakdown product of organic waste contains nitrogen, which combines to form other compounds in water that can cause aquatic plants to grow wildly. The resulting reduced oxygen and sunlight in water can seriously harm fish and other sea creatures.
The new treatment method feeds treatment bacteria much more air than previously, which allows them to turn almost all the ammonia in the wastes into nitrates, Dang said. A second stage then turns the nitrates into nitrogen gas, a natural component of air, which is then released in amounts that are small relative to how much air is in the atmosphere.
The project, completed last year, cost $24.7 million. That was split between CVSan and Oro Loma, who have worked together since the 1950s.
Any major project, such as this one, requires the approval of both organizations’ boards, according to Jason Warner, Oro Loma general manager.
“For a pretty modest cost, we hit a grand slam. We’d hoped for a 50% drop in nutrients and instead got 75% after the first year. It took just under 2 years to build.”
The cost of the plant is already reflected in rates, so customers won’t see future rises due to it, CVSan’s Williams said, adding, “This only works regionally if all the other agencies on the Bay join in. Then we’ll see significant changes in the Bay’s health.”
Those stricter mandates for everyone are probably coming, Williams said.
It’s usually best to do things before you’re ordered to, Williams said, adding that he hoped this helps CVSan’s in its future work with regional and state water agencies.