SACRAMENTO — Hilmar Cheese Co. won state approval Friday for a change to its waste-water treatment process.
The Central Valley Regional Water Quality Control Board voted unanimously to let the company test a new method for one of the final treatment steps at its Lander Avenue plant.
Waste-water from the plant, the world's largest cheese producer, has drawn years of scrutiny from regulators and neighbors.
The change involves a part of the process that removes salts from the water. The current system uses reverse osmosis -- forcing water through a membrane to trap the salts -- for up to 1.4 million gallons a day.
Up to 500,000 additional gallons do not go through this step because of a lack of capacity. This water is still "highly treated" in the other steps, company representatives said last month.
The company will try replacing reverse osmosis with electrodialysis, which removes salts by applying an electrical current. This could reduce energy use and eliminate the need to clear trapped material from the membranes.
Hilmar Cheese will test electrodialysis in the next few months and install it by July 2011 if it proves worthwhile. If not, the plant would continue using reverse osmosis.
The proposal was endorsed by the agency's staff and approved with only minor amendments by the board, company spokeswoman Denise Skidmore said.
Hilmar Cheese paid $3 million in 2006 to settle a pollution case brought by the board. Since then, the company has operated under a permit aimed at preventing future problems.
Bee staff writer John Holland can be reached at email@example.com or 578-2385.