Jesus Arciniega: Chief Operator (left) Coffey: Asst. Operator (Middle) Corey Wilder Water Department (right)
The change
The change to containerized composting of the biosolids at the wastewater treatment plant is in keeping with the city’s participation in the National Environmental Management System pilot program. The City of Omak’s treatment facility was one of twenty-five facilities nationwide chosen to participate in this program. The compost program earned an award for environmental excellence from the Department of Ecology. The Containerized Compost System installed at the Omak wastewater treatment plant is an in vessel process for composting dewatered biosolids (sludge). The system produces Class A biosolids by mixing dewatered sludge with a bulking agent and composting the mixture in 40 cubic yard containers. In-vessel composting is included in the Federal regulations (40 CFG 503) as an approved process to further reduce pathogens in biosolids. The resulting Class A biosolids have the fewest restrictions in their end use and the compost product can be sold or given away to the public.
The City of Omak provides
The City of Omak provides central sewer treatment services to all areas within the corporate limits. The treatment process can be divided into three major areas. The first area is the collection system. The second area is the wastewater treatment and disinfecting system that is the treatment of the liquid wastes and ultimate return to the hydrologic cycle. The final area is the bio-solids handling system which covers the separation of solids from the liquid waste stream, treatment and disposal. The sewer collection and treatment facility is a typical activated sludge oxidation ditch system with outfall to the OkanoganRiver. The collection system is well laid out with good configuration of trunk and interceptor lines coupled with feeder of collector laterals. The city system consists of approximately 126,600 feet of gravity collection and interceptor sewers, manholes and 4 lift pump stations. The wastewater collected by this system is routed southward to the wastewater treatment plant located at 635 Fir Street. Collection pipes are mostly concrete and PVC lines.
Treatment plant Facts:
The wastewater treatment plant processes an average of 550,000 gallons of wastewater per day. This equals approximately 100 gallons of wastewater per person per day as well as the total of inflow and infiltration from the entire system. The monthly flows can total from 45 million gallons during flood conditions to as low as 12.5 million gallons during the fall and winter months. Historically, the total flow has remained static with the wide variations caused by an aging infrastructure, which allows a large amount of infiltration during periods when the water table rises above the level of the collection lines.
Goal's
The department strives to exceed the performance standards called for in the discharge permit. The installation of the new ultra violet disinfecting system will end the use of the only chemical currently added to the plant’s discharge into the OkanoganRiver. This will enhance the aquatic ecosystem and hopefully forestall a zero discharge rule in the future.
Waste Water Treatment
The city’s governing regulations for sewer service are contained in Chapter 9.08 of the Omak Municipal Code. The city is also bound to regulations from the Washington Administrative Code (WAC). Revised Code of Washington (RCW), Department of Health (DOH), Department of Ecology (DOE), Environmental Protection Agency (EPA) and the Okanogan County Health Department.
