Canby Herald Online

Wastewater treatment facility to get upgrades

Council approves $2.2 million project

• By: John Baker  
• Published: 2/4/2010 10:27:08 AM

Canby’s Wastewater treatment facility is going to get a pretty significant facelift in the near future.
Canby’s City Council approved a contract for $2,250,740 to R&G Excavating Inc. for improvement to the city’s wastewater facility in January.

The project’s genesis occurred in the 2007-08 budget when council approved a contract with Curran-McLeod Consulting Engineers that included the design, study and recommendations about the type of equipment that would be the most cost effective and meet or exceed current and future DEQ requirements at the wastewater facility.

“This is a pretty big project, but it’s something we budgeted for,” said Amanda Klock, interim city administrator.

The projects that came out of that study were: biosolids drying, UV disinfection and a solid receiving station. Funding for the wastewater facility upgrades will come from a combination of funds that have been set aside for capital improvements.

The funding is split between system development (SDC) charges and the wastewater-sewer reserves. SDCs are charges set on new development such as housing, businesses and industries when wastewater services are provided. Wastewater reserves are funds that come from the rate payers, which are rolled over each year after all operations and maintenance activities have been paid.

Any remaining funds from the rate base are then accumulated in the sewer reserve for capital improvement projects or equipment.
“It is important to note that the wastewater phase III facility upgrade is being paid in cash, and there are no loans, bonds or rate increases due to this project,” said Darvin Tramel, wastewater treatment supervisor.

However, sewer rates continue to be adjusted annually based on the most recent sanitary and storm sewer financial plan and rate analysis.”

Biosolids Drying
A major portion of the $2.2 million project is the need to process biosolids to what is considered a “class A” product. Currently, the city produces a “class B” biosolid product, which as the consistency of manure, can have a strong odor and is heavily regulated by DEQ and EPA.

In the last year alone, the city has lost 360 acres of property normally used for the application of biosolids and DEQ has been reluctant in issuing new winter application permits for the Willamette Valley.

Moving to class A biosolids, which have the consistency of dirt, produces relatively little odor and are similar to granular fertilizer in texture, will allow the city to reduce the mass of solids from 70 to 80 percent.

Tramel said that currently, the city produces between 500 and 600 dry tons per year of biosolids, and the city believes that with the new drying process the treatment facility will produce in the neighborhood of 180 tons or more of biosolids annually.

“That will reduce the amount of winter storage needed, transportation costs, regulatory oversight and staff time associated with the production and application of biosolids,” Tramel said.

Additionally, class A biosolids have little to no potential for exposure to pathogens, can be used as a soil amendment, given away as a viable fertilizer for agriculture and public use and in the future could be used as a source of energy for heat recovery or electrical generation.

The city has been moving toward creating class A biosolids since 2003 when the wastewater facility was expanded. That expansion included equipment that would tie in to the next upgrade.
City Engineer Curt McLeod and staff chose Therma-Flite Bio-Scru Dryer as its biosolids dehydration system.

Estimated cost for the biosolids drying portion of the new project is $1,453,200.

UV Disinfection
The current ultraviolet disinfection system was installed at the wastewater facility in 1993 and has failed several times since its installation. While the system is functioning, it has been a continuous battle to keep it running and operating to meet the City National Pollution Discharge Elimination System (NPDES).

Additionally, the manufacturer of the current system has since gone out of business.

“The current UV disinfection system is slowly failing, prompting the city to need to move to a newer, more stable UV system,” Tramel said.

Staff and engineering recommended the Aquionics UV system to replace the current system.
Estimated cost to replace the current UV system is $651,600.

Solids Receiving Station
The solids receiving station is a covered, three-bay structure with drying beds, sand filter and a grease interceptor.

Two bays will be used to dump heavy grease material that is collected during the cleaning of sewer lines by the truck.

The third bay is a natural soil filter, where the truck can dump the soil, rock and debris that are accumulated when cleaning stormwater dry wells.

The improved drying bed and filter system will greatly reduce the amount of fats, oils and grease received at the wastewater treatment facility.

The new station will provide collection crews with a dedicated area for disposal of contaminated sewer wastes, which will protect the public, staff and the environment from any adverse impacts due to contaminated debris.

Estimated cost to construct the solids receiving station is $229,200.

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