RUSA owns and operates the wastewater conveyance and treatment system for the City of Roseburg and the outlying area included in the Urban Growth Boundary. The wastewater system covers approximately 10,000 acres, 160 miles of mainline sewer pipe, eight lift stations and a wastewater treatment facility with a design capacity of 7.9 million gallons per day (MGD).
In anticipation of the discharge limits becoming more restrictive in the future, RUSA starting in 1997, began to purchase property with the idea of utilizing the wastewater effluent in some sort of land application method. RUSA was able to purchase 340 acres in three parcels located in the Sylman Creek Basin.
In 2006, DEQ completed its total maximum daily load (TMDL) study for the South Umpqua River. The new TMDL would affect RUSA discharge limits with regard to the pounds of phosphorus and nitrogen that could be released into the river during the summer months. The study also addressed the temperature of the effluent released to the river in these months. To help address these pending discharge limits established by the DEQ in accordance with the study, RUSA designed an built the Natural Treatment System (NTS) to polish the treated effluent from the Roseburg Regional Wastewater Treatment Facility (WWTF) to further protect the water quality of the South Umpqua River.
The NTS was selected, after an extensive options analysis, for implementation because it is cost-effective, reliable and sustainable. The NTS uses farm crops, soil organisms, and soil chemical reactions to consume or immobilize the nutrients in the treated effluent. The drainage waters from these natural processes that percolate through the soil and discharge to the nearby surface waters in compliance with the water quality criteria of the river.
The 340 acre NTS was constructed between 2009 and 2011 on the farm that RUSA owns near the WWTF on the southwest side of the South Umpqua River in the Sylman Creek Basin. The NTS farm will be operated from May 1st through October 31st in compliance with RUSA's Stipulation Order & Memorandum of Agreement between Roseburg Urban Sanitary Authority and the State of Oregon Department of Environmental Quality regarding the NPDES permit for the Roseburg Sewage Treatment Plant and the Total Maximum Daily Loads for Nutrients and Temperature for the South Umpqua River. RUSA will implement adaptive management protocols to meet the water quality standards through the 2025 permit cycle.