Project Portfolio

Southside Wastewater Treatment Plant Design and “Green” Improvements


City of Clinton


Clinton, Mississippi · Hinds County

WGK, Inc., completed a study to service the entire City of Clinton and outlying communities considered for future annexation, a total area of 90 square miles. When the findings were published, the firm was directed to design a new 3.5 MGD treatment facility and decommission the three smaller wastewater treatment plants it would replace.

The firm carried out the design, environmental impact study, construction review and administration, with the project receiving the American Council of Engineering Companies’ Grand Award in 2002 for creative design to enhance energy efficiency and operator efficiency while reducing the offsite impact on neighbors. In 2008, the plant was named Plant of the Year for operations and performance by the Mississippi Water Environment Association.

After 10 years of successful operation, the award-winning plant had filled its sludge storage lagoons almost to capacity, with only 24 months of operating time remaining before they overflowed. The city was facing the possibility of paying to have 42 million gallons of sludge hauled away, but had few disposal options—a 4-year attempt to permit acreage for land-application had failed. WGK helped the city’s wastewater plants go “green,” installing large solar dryers—“greenhouses”—to dry sludge and convert it to Class A Exceptional Quality Biosolids that can be land-applied without stringent environmental permitting. The project met “green infrastructure” requirements laid out by the American Recovery and Reinvestment Act” for capital forgiveness, and went on to win the Mississippi Municipal League’s 2011 Excellence Award. It is the only other plant besides the Natchez Wastewater Treatment Plant – also a WGK design – producing Class A Exceptional Quality Biosolids in Mississippi.

  • Development of 20-year plan, including recommendations for improvements and design of new 3.5 million GPD wastewater treatment facility.
  • Inclusion of large sewer interceptors and collection systems for unsewered areas and pump stations.
  • Addition of 50,000 feet of 18” to 36” gravity sewer.
  • Installation of sludge dredge, three-belt press, equalization tank and press equipment.
  • Construction of two Parkson Thermo-System Solar Dryers.
  • Sensory system that monitors and maintains environmental conditions.
  • Automatic “mole” robot controlled by system that turns and stirs material.
  • Construction of access road with generous paved area to service control buildings.
  • Use of operator-controlled CCTV system to reduce personnel requirements.
  • Total Project Cost: $13.1 million

New wastewater treatment standards are here…

The release of new wastewater discharge permit limits next year could require extraordinary changes for smaller Mississippi towns operating treatment lagoons, while larger cities’ mechanical plants may also need some upgrades to meet the new restrictions.

The Mississippi Department of Environmental Quality (MDEQ) is developing water quality standards for nutrients in order to meet court-mandated environmental reforms authorized decades ago by the federal Clean Water Act of 1972, but not fully implemented. The new regulations will require wastewater treatment systems to meet total nitrogen and total phosphorous limits for the first time, and could render some lagoons and plants obsolete overnight.

If you are unsure of how new nutrient standards will affect wastewater treatment in your city, town or industry, WGK can chart a course for your facility’s future. Call Greg Gearhart, PE, BCEE, CEE at 601-925-4444 for an assessment of your treatment operation.

How can we help?

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There’s a lot at stake with every infrastructure decision you make. Our team of engineers are dedicated to providing reliable, cost-effective solutions for your infrastructure needs.


204 West Leake Street
Clinton, MS 39056

210 Woodgate Drive, South
Suite D
Brandon, MS 39042

132 West Cherokee Street
Brookhaven, MS 39601