The Willow Lake Water Pollution Control Facility (WLWPCF) is responsible for treating the wastewater generated by the citizens of Salem, Keizer, Turner, and other unincorporated areas of Marion County served by the sewer collection system. The current service population is approximately 225,000 people.
The Willow Lake Facility’s goal is to meet or exceed the requirements of the federal Clean Water Act (CWA) and the Oregon Department of Environmental Quality (ODEQ) administration of these CWA rules. The performance of the facility is measured on a daily basis through the collection and analysis of influent and effluent samples. The results of the analysis confirm compliance with the operating permit regulatory standards. These standards are designed to protect in-stream water quality and the health of the organisms living in and around the receiving stream. Between 14 and 16 billion gallons of wastewater are treated annually prior to release to the river.
The River Road Wet Weather Treatment Facility (River Road) is a satellite treatment facility to the Willow Lake Water Pollution Control Facility (Willow Lake). River Road was built to help meet the objectives of the 1998 Mutual Agreement and Order (MAO) which required, by 2010, the elimination of sanitary sewer overflows (SSO) to the Willamette River under most conditions. River Road’s capacity is 50 million gallons per day (mgd) with a 60 mgd one hour peak flow. River Road treats excess flows exceeding the capacity of the 72 inch interceptor to the WLWPCF. A high rate clarification process is used at River Road. The River Road facility may be run from November 1 – May 31 of each year. During a high flow event, when River Road is running, foam may be seen at the outfall along the Willamette River at the west end of River Road Park. The foam is produced due to the large hydraulic drop from the treatment facility to the outfall. The foam is not a threat to water quality or aquatic life. The City is researching methods to reduce or eliminate the foam.
Highlights
Construction activities which began in 2007 to increase the Willow Lake Facility's wet weather capacity from 105 million gallons per day (mgd) to 155 mgd were essentially completed in 2009. Tuesday, August 25, 2009, was a significant day in the construction progress at the Willow Lake Facility. On this day, raw wastewater was diverted into the new Headworks facility for the first time. Nearly 12 mgd were allowed to flow through the new 96-inch diameter influent pipe, through the new barscreens, pumped with the new raw water pumps, and allowed to flow into the existing treatment process. This activity was a major step in the testing and fine tuning of the new treatment facilities. On September 21, 2009, all the wastewater flow was sent to the new facilities, which were run continuously, 24 hours a day, without going back to the old facilities. This 24/7 testing run was needed before the final decision was made to abandon the old facilities.
With the completion of construction and testing of the major process elements this fall in order to meet the December 31, 2009 deadline, the City was able to comply with the Mutual Agreement and Order (MAO) that it had with the ODEQ. The primary requirement of the MAO was to address sanitary sewer overflows (SSOs) caused by specific storm events. In order to meet this requirement, it was necessary to construct hydraulic and process upgrades at Willow Lake to increase the plant’s peak wet weather capacity to 155 mgd.
2010 Plans and Challenges
Operations
With the completion of the River Road Wet Weather Treatment Facility in the fall of 2008 and the hydraulic upgrades at Willow Lake in the fall of 2009, the operations staff has two new facilities to operate under high wet weather flow conditions. Under these conditions, two operators have to leave the main facility at Willow Lake and start the satellite River Road Facility which is approximately four and one half miles from the Willow Lake facility. Operations staff has to be in constant communications with the Operation and Technical Support Section to maintain flows at Willow Lake while bringing River Road on-line. Dry winter weather conditions have prevented staff from operating the River Road facility as frequently as necessary to fine-tune the facility. As a result, some operational challenges have not been resolved.
Maintenance
With the near completion of the construction activities at Willow Lake, the maintenance staff has had to learn the maintenance requirements of all the new equipment while keeping the existing facilities maintained and running. The River Road facility also added a large quantity of new equipment that needs to be maintained without the addition of any new staff. Although new facilities were added to Willow Lake, many older facilities remain which require a large amount of attention and finesse to keep them running.
Laboratory
Regulatory requirements are an ever changing target. One task that the laboratory staff will tackle this year is the sampling requirements for implementation of Senate Bill 737. The 2007 Oregon Legislature passed Senate Bill 737, which required the ODEQ to consult with all interested parties by June 1, 2009, to develop a list of priority persistent pollutants that could potentially discharge to surface waters and have a documented effect on human health, wildlife or aquatic life in Oregon. SB 737 also requires Oregon’s 52 largest municipal wastewater treatment facilities to develop plans by July 1, 2011, for reducing priority persistent pollutants through pollution prevention and toxics reduction. Before the plans can be developed, samples need to be taken to test for the list of pollutants. Many of the constituents will not be present in the waste water effluent. Those that are present will be at extremely low levels and some have no approved test methods.
Biogro
The Biogro program continues to work with local farmers to partner in establishing winter storage facilities where dewatered biosolids can be stored for summer distribution on adjacent farmland. One such site has been permitted by the ODEQ and has been in use for most of the 09/10 winter season. Staff is continuing to work to authorize enough local winter storage to provide storage space for all biosolids produced during the winter season. Substantial savings have been realized by not transporting the wintertime biosolids inventory to reuse sites in eastern Oregon.