Klarifi tracks 130 publicly owned wastewater treatment plants in Mississippi with a combined average flow of 86 MGD, serving about 164,263 residents. 23 plants treat more than 1 MGD and 1 more than 10 MGD; 102 use lagoon systems and 1 have digesters or biogas infrastructure. The largest is West Rankin Utility Authority WWTF in Richland at 12.02 MGD. 7 NPDES permits expire this year and 22 next year.
Every plant below links to a profile with average and design flow, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city. Treatment technology and verified contacts are shown with a free Klarifi account.
130 plant locations in Mississippi; dot size follows average flow. Boundaries: U.S. Census Bureau.
NPDES permits and renewals in Mississippi
Every plant discharges under an NPDES permit that is renewed every five years, usually with tighter limits. The renewal year is the year a plant budgets for upgrades.
Largest wastewater treatment plants in Mississippi
The 10 largest publicly owned wastewater treatment plants in Mississippi by average flow, with NPDES permit, expiry and three-year violation count. Source: EPA ICIS-NPDES via Klarifi.
Klarifi tracks 130 publicly owned wastewater treatment plants in Mississippi with a combined average flow of 86 million gallons per day, serving about 164,263 residents. 23 of them treat more than 1 MGD and 1 more than 10 MGD.
West Rankin Utility Authority WWTF in Richland is the largest plant in Mississippi by average flow, treating about 12.02 MGD.
102 of Mississippi's plants use lagoon systems and 1 have biogas or anaerobic digestion infrastructure, based on Klarifi's aerial imagery review.
7 permits held by Mississippi plants expire in 2026 and 22 in 2027. Renewals typically bring new limits and trigger upgrade projects.
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
