Merced waste-water treatment facility gets green upgrades

Waste-water plant produces fertilizer

jsmith@mercedsunstar.comMay 4, 2013 

The city announced Friday the opening of a $27.4 million project at its waste-water treatment plant, which turns sewage into high-grade fertilizer using solar power.

"I really appreciate our city's growth, growing in a good, green fashion," said Mayor Stan Thurston.

The project is the largest such operation in North America, and is the final stage of the city's waste-water treatment facility, according to city officials.

"Without this facility, we could not attract new industry, new business, which, of course, equates to jobs," said City Manager John Bramble.

The city uses the fertilizer and treated water to farm about 300 acres, growing wheat, alfalfa and other feed crops. Sales from the crops help subsidize the cost of running the plant.

"Instead of simply disposing of our sewage, Merced now produces recycled water and fertilizer that is safe for the environment and is used for agricultural production," said Michael Wegley, director of water resources and reclamation.

The centerpiece of the project is a solar dryer, which covers about 1.7 acres. Seven greenhouse bays have "robotic moles" that work the waste sludge until the material has dried and can be used on the crops.

The drying of solid waste was previously done on unlined, earthen beds and was open to the winter elements, raising concerns about groundwater contamination, city officials said.

Environmental regulations now require the city to dry the waste in a controlled environment, such as the new facility, said Bill Osmer, manger of the treatment plant.

"It used to be drying beds," he said. "Now it's a much more complicated system and environmentally safer."

The original facility was built in 1977 when Merced had about 35,000 residents, according to city officials.

The upgrade included equipment for another stage in the treatment of the sewage, which uses ultraviolet light to further clean the water -- all designed to avoid the use of chemicals.

It also included upgrades to pumping equipment and aeration basins.

Reporter Joshua Emerson Smith can be reached at (209) 385-2486 or

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