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APCD working with Nipomo to address waste treatment odor

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Dust from the Oceano Dunes isn't the only issue giving SLO County air quality officials a headache in the county's southern region.

The SLO County Air Pollution Control District is trying to work with officials from the Nipomo Community Services District to address complaints about a pungent odor emanating from the CSD's Southland Wastewater Treatment Facility.

The stench has been called "ripe," "strong," and "earthy," all apt descriptions for what could be more accurately, albeit crudely, described as the smell of feces.

The facility opened in 2014, and is operated by the Nipomo CSD. As part of the sewage treatment process, a partially treated biosolid "sludge" is pumped into large concrete beds to dry in the sun via evaporation before being hauled off to an offsite facility. APCD Officer Larry Allen said the process is usually very effective, but this year's wet and rainy weather hampered the drying, leaving the sludge with a higher than usual water content and forcing the plant to mechanically mix the beds to help facilitate the evaporation.

"That process itself is what generates the odor," Allen told members of the APCD's board of directors at a June 21 meeting "because every time they turn it, a fresh batch of that stink comes out."

The problem generated enough complaints that the APCD has already sent a warning letter to the CSD. Gary Willey, an engineering and compliance officer for the APCD, said the district was very close to taking formal action as a result of the ongoing stench.

"If we get more verified complaints, then a nuisance violation will be issued, and they will be required to take action." Willey said.

Willey said that the CSD could be forced to make technical and mechanical upgrades to the plant to ensure the sludge was drier before it's moved to the beds. To try and avoid formal action, the CSD is attempting to empty the concrete drying beds more quickly.

"They explained to us that they are trying to dry it out faster, and ship it out wetter," Willey said.

By trying to speed up the process, the CSD hopes to have all the biosolid material out of the drying beds by mid-July.

Until then, nearby residents and drivers on Highway 101 will just have to hold their noses while airing out their grievances to their representatives on the APCD board.

"Some of you may be hearing from your constituents about this," Allen told board members at the June 21 meeting.

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