Owner/Client
Bridgeton Landfill, LLC (A Subsidiary of Republic Services Inc.)
Republic Services
Location
Bridgeton, MO
CEC Services
- Leachate Management, Monitoring and Analysis
- Design/Build
- Operations and Maintenance Support
- Odor Control
Owner Objective
The 52-acre Bridgeton Sanitary Landfill began operations in 1985 and stopped accepting waste in 2004 with a total waste thickness of 320 feet. Detected elevated temperatures on some gas extraction wells in 2012 were caused by a significant subsurface reaction (SSR) that adversely affected the landfills leachate composition. In January 2013, the Metropolitan St. Louis Sewer District (MSD) prohibited Bridgeton landfill leachate from entering their plant due to elevated concentrations of certain constituents.
CEC Approach
CEC was engaged to help address the subsurface reaction at the facility and to return the leachate disposal back to the MSD. Significant odor controls and immediate management and disposal of leachate generated at the site began with design and construction management of four one-million-gallon onsite storage tanks. This process led to a CEC design-build project that incorporated the tanks into an onsite leachate pretreatment plant with the goal of having the MSD accept Bridgeton’s leachate once again and return the landfill back to an acceptable financial model.
Analytical tests, bench-scale tests conducted at CEC’s laboratory in Charlotte, North Carolina, and pilot tests at the site helped create the basis of CEC’s design. An existing 316,000-gallon aerated tank is now utilized as an equalization tank, and leachate is pumped to a treatment building for pH adjustment, metals removal and clarification before entering the four separate one-million-gallon aeration tanks.
The sludge from the clarifier enters a sludge thickener and then is pumped to a primary sludge storage tank and a screw dewatering press. The liquid flow from the four aeration tanks is pumped to an ultrafiltration system to separate the solids from a relatively clear effluent. As the treated leachate interfered with the MSD’s recently installed UV disinfection system, technologies to remove the UV interference were incorporated in the pretreatment plant design. The effluent is pumped to an existing storage tank before discharge to the MSD’s Missouri River Treatment facility. The dewatered solids from the press are placed in trailers for transport to the Roxana Landfill.
