NELSON WASTEWATER TREATMENT FACILITY IMPROVEMENTS PROJECT

The Nelson Wastewater Treatment Facility (WWTF), also referred to as the Nelson Complex, was constructed in phases, beginning in the 1940s, to address the needs of the growing community. 

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The Nelson WWTF is located in the northeastern corner of the City of Mission with Roeland Park to the east and Wyandotte County to the north. The Nelson WWTF serves two main tributary basins in northeast Johnson County – containing all or part of the cities of Fairway, Merriam, Mission, Overland Park, Prairie Village, Roeland Park, and Shawnee. (view map of service area)

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The Environmental Protection Agency (EPA) and the Kansas Department of Health and Environment (KDHE) are requiring stricter discharge limits for constituents such as ammonia, nitrogen, and phosphorus. The treatment technology currently in place at the Nelson WWTF is not capable of meeting these stricter future water quality standards.

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The collection system was also sized and constructed with materials and technologies that are now outdated. As a result, it can experience issues during wet weather events. In addition, the system contains four satellite peak excess flow treatment facilities (PEFTFs), which discharge directly to adjacent waterways during significant wet weather events after primary treatment and disinfection.

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In 2018, Johnson County Wastewater (JCW) commissioned engineering and environmental services company HDR, in association with CH2M and WCS, to determine the optimum solution to these issues and develop a long-term capital improvement plan for the Nelson service area. The plan recommended a new Nelson WWTF to address the issues of the aging facility and regulatory obligations.  The plan is also flexible to allow for the collection system issues to be mitigated over a 25-year period.