Integrated nutrient removal design for very low phosphorus levels.
The State of Washington has found that the Spokane River is DO impaired, and is requiring dischargers to reduce phosphorus inputs to the river. Spokane County elected to build a new water recovery facility with a target effluent total phosphorus level of 50 microg/L on a seasonal average basis. Spokane County elected to use a private company to design/build and operate their facility. The very low nutrient requirements, and lack of historical operating information, necessitated an integrated approach to the nutrient removal design while considering the risks and benefits of the various treatment options. The process selection evaluated membrane bioreactors and tertiary membranes for the primary liquids process in combination with chemical and/or biological phosphorus removal. The final process selection included chemically enhanced primary treatment, membrane bioreactor with metal salts, and dewatering liquor treatment with an innovative post aerobic digestion step.
Johnson
Bruce R
BR
CH2M HILL, Inc, 9193 South Jamaica Street, Englewood, CO 80112, USA. bruce.johnson2@ch2m.com
Daigger
Glen T
GT
D001674:Bioelectric Energy Sources; D004784:Environmental Monitoring; D010100:Oxygen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D014861:Washington; D014874:Water Pollutants, Chemical
D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D010100:Oxygen