McKinleyville pursues massive sewer upgrade

From the 1.23.13 issue


By Jack Durham

Press Editor & Reporter


McKinleyville is embarking on the biggest sewer upgrade since the town’s collection system was installed 32 years ago.

At its meeting Jan. 15, the McKinleyville Community Services District Board of Directors voted unanimously to hire an engineering company for more than $1 million to design the sewer plant upgrades.

The project, which is estimated to ultimately cost $8.5 million including engineering and construction, will convert the Wastewater Treatment Facility at Hiller Park from a low-tech pond system to a mechanical sewer plant similar to what can be found in larger cities.

The purpose of the upgrade is to improve the treatment process so the sewer system can continue to meet state standards and regulations, which will ratchet up in the coming years.

One of the biggest problems with current system is “acute toxicity” in the wastewater effluent, which is discharged into the Mad River during winter months when river flows are high enough. During the summer, or when river flows drop, the wastewater is used to irrigate pastures at the MCSD’s Fischer Ranch at the corner of School and Fischer roads.

This toxicity in the wastewater is caused by excessive amounts of ammonia, a naturally occurring chemical found in wastewater. In order to remove the ammonia, and generally increase the quality of the treatment process, the MCSD plans to build mechanical aerators and clarifiers at the plant.

Major change

The upgrades will fundamentally change the way McKinleyville treats its wastewater, something the unincorporated community has wrestled with for decades.

Prior to 1978, the town relied on individual septic tanks. There were multiple septic tank failures, with raw sewage seeping into the ditches that lined Central Avenue at the time.

“As far as the ditches along Central Avenue, yes it was a mess. In the summer it was smelly to say the least,” stated former MCSD board member Ben Shepherd in an email interview.

“All of McKinleyville was on septic systems and the level of failure was incredible,” stated Shepherd, who was first elected to the MCSD board in 1979.

The year before Shepherd got on the board, sewer lines were installed in town.

Initially, the wastewater was pumped through a pipeline that crosses the Hammond Bridge and dumped into the City of Arcata’s treatment plant.

“We were sending the wastewater to Arcata and were discussing the future of the Humboldt Bay Wastewater Authority, which planned to build a regional wastewater treatment plant with direct ocean outfall,” Shepherd stated. “That is the reason for the Fisher Road pump station, which would have pumped all of McKinleyville’s wastewater to the regional plant. HBWA fell apart because the City of Arcata and others became concerned over the impacts of the plant and a raw sewage line from Arcata across the bay to the proposed regional plant in Samoa.  Also the cost of the regional plant would have been huge. We began the process of identifying our own options for treatment and eventually settled on the system at Hiller Road.”

In 1983, the MCSD built the Wastewater Treatment Plant at what’s now Hiller Park, the town became self-contained.

The existing treatment plant is a low-tech pond system. The wastewater circulates through a series and ponds and marshes, which remove solids and destroy bacteria before the water is chlorinated and then disposed of in either the Mad River under the Hammond Bridge, or on fields at Fischer Ranch.

The new plant will contain a new headworks, aerators and clarifiers, which filter, screen and stir the sewage, thereby cleaning it up.

The project will be built within the confines of the existing sewer plant and won’t spill out beyond the chain-link fence which encircles the facility.

To accomplish this, the MCSD will remove sludge from a portion of its ponds and fill the area in to provide a foundation for the new sewer structures.

At last week’s MCSD board meeting, it was noted that the existing pond system was built without any plans for the removal of sludge. Solids in the wastewater settle to the bottom of the ponds. The break down somewhat, but over time the sludge builds up.

In order to build the new plant, some of the sludge will need to be removed, In addition, the MCSD plans to have a system in place for disposing of sludge in the future,.

MCSD Interim Manager Greg Orsini said that the district is looking at all options for sludge disposal and will be “thinking outside the box.”

Some companies compost the sludge and sell it as fertilizer. Having such a company take the sludge would be cheaper than trucking it over Highway 299 to a disposal facility in the Central Valley.

The MCSD board’s decision last week grants a contract not to exceed $1,013,502 to the engineering company of Kennedy/Jenks.

The company will design the upgrades over a period of a year and a half. Construction would begin in 2015.




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