Wilmington, Delaware

The challenge

More than a quarter century of O&M and capital improvements for regional wastewater treatment plant based on public-private partnership.

The project challenges are:

  • Veolia North America assumed operations/maintenance/management (O&M) responsibility for the solids processing facilities in 1985.

  • In 1998, the company was awarded a new 20-year, $224 million contract to manage the entire wastewater treatment process.

  • That includes a 134-MGD high-rate activated sludge plant, three pump stations, industrial pretreatment program, industrial leachate and 11,000 dry-tons-per-day sludge disposal.

  • The O&M project has met all of the city's requirements and the plant is an integral part of Delaware's innovative solid waste management plan.

The solution

Innovative solutions:

  • Finance, design and build $15 million in capital improvements, including SCADA system and fine-bubble diffused aeration to enhance system operation and conserve energy

  • Negotiate with labor unions and offer employment to all city employees

  • Replace labor-intensive belt filter press installation with more efficient centrifuges

  • Work with city to install sodium hypochlorite disinfection system to replace dangerous chlorine gas system

  • Work with city to maximize diversion of combined sewer overflows into treatment plant for effective treatment

  • Haul dewatered sludge from the city's wastewater treatment plant to a sludge stabilization facility where it is mixed with cement kiln dust, then used as a cover material at the Delaware Solid Waste Authority's landfill

Benefits for our clients


  • Provided city with more than $1.5 million in annual operating savings

  • Discharged $10 million of capital work 10 months early

  • Completed fast-track conversion to centrifuges in just 120 days and improved power efficiency and dewatering

  • Achieved excellent compliance record since taking over site-wide O&M responsibility