Using Septage to Accelerate Energy Generation in a Bioreactor Landfill

Residential septage is an on-going wastewater challenge for municipalities. Conventional methods of septage disposal – land application and waste water treatment plants – can result in surface water pollution, overloading of plant processes, and increased energy consumption. This paper presents a case history of an innovative (patented) technology that improves the management of both septage and municipal solid waste (MSW) to avoid these problems.This septage bioreactor landfill technology provides accelerated renewable energy generation while extending the life of an operating landfill. Mixing septage with MSW creates a “win-win” combination - residential septage is safely disposed and treated and MSW decomposition (bio-stabilization) and methane generation is accelerated. A septage bioreactor landfill project was developed to demonstrate the feasibility of this technology. This project included the construction and operation of a full-scale demonstration landfill cell. Landfill operations are conducted in an engineered and controlled manner that limits both groundwater pollution and air pollution.After four years of operation, monitoring results show that septage addition has dramatically increased the methane generation rate in the septage bioreactor landfill, making it possible for the owning municipality to construct a landfill gas-to-electricity facility. The electricity generated from this facility will be used to power on-site operations and sold to a local utility, generating revenue for the owner. Also, leachate collected from the bioreactor cell is comparable to conventional landfill leachate, demonstrating that this technology also offers a viable (and environmentally sound) method for septage disposal and treatment.