DAYTON -- City officials have less than eight years to make changes in how they deal with effluent from the sewage treatment plant.
Because the Touchet River, where the city discharges about 250,000 gallons of effluent daily, does not meet state water quality standards, discharge must be halted by Dec. 31, 2018.
Representatives from the state Department of Ecology spoke to about 40 people Monday during a special Council meeting at the Catholic Church Parish Hall.
A survey of the total maximum daily load of toxic chemicals, fecal coliform bacteria, temperature and pH and dissolved oxygen going into the Touchet River, and three other streams in the Walla Walla Watershed.
The treatment plant is not the only source of nutrients (phosphorous and nitrogen). Livestock manure, septic systems and fertilizers also contribute to the load.
It is possible the treatment plant discharge is warmer than the state standard when salmon and trout are trying to spawn and eggs are incubating.
The city will be required to eliminate any treated wastewater discharge to the river between May and October. During cooler months (November through April) and when flow is higher, effluent may be discharged.
There are options, including applying the wastewater to agricultural land during the growing season. Other options include irrigating public areas such as parks and the golf course with water that has had additional treatment, recharging a wetland area or soaking back into the ground as groundwater recharge, or providing treatment that would allow the water to be used for other commercial, agricultural or industrial applications, according to a city fact sheet.
In a move to increase reserves in the sewer fund, the Council approved a six percent rate hike for sewer, as well as raises in water rates. The total utility bill for residential customers went from $91 a month to $95 a month, Mayor Craig George said Tuesday.
The sewer plant was retrofitted with more modern equipment about 12 years ago. Cost of replacement or remodeling would be millions of dollars. The city needs to conduct a feasibility study to determine the best option, George said.
Carrie Chicken can be reached at firstname.lastname@example.org or 522-5289.