FAIRFIELD — Eastern Solano County ranches in 2013 had less tons of treated sewage sludge applied as a fertilizer to more acres of land than in 2012.
About 4,965 dry tons of biosolids got brought to the county, a 27 percent decrease. It got spread by a company called Synagro across 1,169 acres of ranch land, a 5 percent increase, a county report said.
That information was included in the county’s recently released, annual biosolids report.
The practice of spreading biosolids on farmland generated controversy in Solano County a decade ago. Some residents complained of odors and worried about health effects. The county in 2003 created stricter rules and a monitoring program that includes the annual reports.
Solano County received three complaints in 2013 alleging rules violations in local biosolids spreading. One alleged biosolids were being applied in buffer zones and the odor left the site, a second that biosolids got spread in high winds and a third that biosolids increased flies in the area. Investigators did not substantiate any of the complaints.
Spreading biosolids on farmlands gives sewage treatment plants a way to dispose of the treated sludge. It also gives farmers a free fertilizer. Sewage treatment plants sending biosolids to Solano County serve such communities as American Canyon, San Francisco, Petaluma, Union City, Newark, Windsor, Calistoga and Millbrae.
The Fairfield-Suisun Sewer District doesn’t spread its treated sludge on farmlands. Its sludge has another destination – the local dump.
“All of our biosolids go to Potrero Hills Landfill for daily cover,” district Assistant General Manager Talyon Sortor said. “You’ve got to cover the garbage each day.”
Solano County allows Class B biosolids to be spread on local ranches. According to the Environmental Protection Agency, Class A biosolids have no detectable pathogen levels. Class B can still contain detectable pathogen levels and has such requirements as buffers and crop harvesting restrictions.
Most of Solano County’s biosolids come from San Francisco. Officials there say that, although not certified as Class A, these biosolids pretty much meet Class A standards, Solano County Environmental Health Division Program Manager Terry Schmidtbauer said.
Class B biosolids must be tested or go through a federally approved process, he said.
Solano County during some years has tested to see if pathogens can regrow in the Class B biosolids. Results found some regrowth during transportation of the biosolids that rapidly died off in the field, Schmidtbauer said.
Reach Barry Eberling at 427-6929 or firstname.lastname@example.org. Follow him on Twitter at www.twitter.com/beberlingdr.