Water district's composting odors leave local residents in a sour mood

Recent odors emanating from the Rancho Composting Facility in Calabasas forced neighboring residents to plug their noses and thumb those noses at water district officials whom they blame for years of offand-on smells at the plant.

The latest round of smelly fumes were the result of an aging biofilter at the Las Virgenes Municipal Water District (LVMWD) plant. The filter, which is about the size of a football field, has been refurbished and was fully effective as of late last week, district officials said.

Residents living in three surrounding neighborhoods blamed the water district for delays in eliminating the stench.

"This odor has been persisting for months. . .and it seems the LVMWD is just stroking us," said Dave Osman, a Calabasas resident.

Osman urged fellow homeowners to submit complaints to the area's public environmental agencies.

"The odors the last two nights have been horrendous," said resident Jason Romano in an e-mail to Carlos Reyes, the water district's reclamation manager.

Romano believed district officials wanted to blame the odors on nearby De Anza Park and Las Virgenes Creek.

"I personally checked the park and I can assure you the odors we are smelling are not from the park," Romano said in his note to Reyes. "The park smells great. The plant is the problem."

David Lippman, the district's director of facilities and operations, explained that the biofilter acts like a typical filter, but on a much larger scale.

"Air rises through a moist wood medium, and the odorous compounds attach themselves to that wood, freshening the air," Lippman said. "Like all filters, they have to be changed." Lippman said the odors became more noticeable because of the recent cool, moist air.

Arlene Post, director of resource conservation and public outreach for the district, said LVMWD had planned to update the biofilter over the summer. "Because we needed to do it sooner, we did," Post said.

Similar odors from the composting facility plagued the community in the late 1990s.

"Air from the building that houses the composting process is directed through ducts into the biofilter, where it rises through a 'media' that uses natural processes to remove objectionable odors from the air," the water district stated in a letter to its customers.

"At Rancho, we use ground up wood as filter media," the letter went on to say. "Biofilters are the most effective method of addressing composting odors and have the added benefit of using a natural process, avoiding the need for chemicals. But the same process that removes the odors also degrades the filter media over time. Periodically, the filter media begins to lose its effectiveness and must be replaced."

The plant, which transforms raw sewage into useable landscaping compost, was built in 1994.