Burns & McDonnell worked with the City of Atchison to develop a long-term control plan that details the steps necessary to bring Atchison’s combined sewer system (CSS) into compliance with the federal Combined Sewer Overflow (CSO) policy. The plan characterizes Atchison’s combined sewer system, identifies traditional control alternatives, evaluates the control alternatives, and identifies an operational CSO control plan and an implementation schedule.
Characterization of the CSS included:
A review and summarization of water quality data collected for overflow events
Identification of nine distinct combined sewer service areas
Inventory of the CSS in each service area including descriptions of the existing piping
Diversion structures and receiving streams
Estimation of the capacity of each CSS within each service area
Evaluation of historical overflow data and correlation of overflow data with rainfall data for each service area
Identification of receiving streams classified as sensitive areas
A range of CSO control alternatives, which included source controls, collection system controls, storage technologies and treatment technologies, were identified for each of the combined sewer service areas. Alternatives were considered if it was reasonable to expect that implementation would bring Atchison’s combined sewer system into compliance with federal policy using the presumption approach. The presumption approach is based on providing a minimum level of treatment.
An evaluation of the CSO control alternatives was presented. Opinions of probable cost were developed for each CSO control alternative. Sewer separation was recommended for each of the combined sewer service areas. The total budgetary opinion of probable construction cost for sewer separation was $54 million. Atchison’s financial capability was evaluated based on U.S. Environmental Protection Agency guidelines. Guidance for funding options was provided.
An operational plan detailing the necessary steps for implementing the separation of Atchison’s combined sewer was presented. An implementation schedule that included input from the state regulatory agency, the Kansas Department of Health and Environment, was provided.
Combined sewer system data assessment and characterization
Combined Sewer Overflow (CSO) long-term control plan