Implications of Solid and Liquid Waste Co-Disposal on Organic Stability and Biochemical Compatibility

Investigators: Colorado State University

Start Date:
Apr 2015

Award Amount:
$185,000

Anaerobic treatment of landfilled municipal solid waste via in situ moisture enhancement has been shown to be an effective waste treatment approach. Under the federal Research, Development, and Demonstration Program, liquid wastes can be directly landfilled, which serves as an effective moisture enhancement strategy towards in situ anaerobic waste treatment. Codisposal of solid and liquid waste can provide economic and environmental benefits to landfill owners. However, elevated moisture levels and biochemical compatibility of co-disposed wastes are concerns such that excessive leachate generation, leachate seeps, waste instability, and fugitive gas emissions do not adversely influence landfill operations. This project will focus on the effects of moisture enhancement strategies and the effects of co-disposing solid and liquid wastes on organic waste stabilization via three main objectives:

  1. Analyze full-scale landfill data to (i) improve biogas generation modeling used to assess organic stability and (ii) evaluate the state-of-practice in solid and liquid waste co-disposal;
  2. Evaluate the effects of moisture enhancement technique on biogas generation behavior; and
  3. Evaluate the effects of solid and liquid waste co-disposal on biochemical compatibility.

Objective 1 will lead to improved landfill gas modeling to enhance comparisons with gas collection data used to assess organic waste stabilization and the duration of post-closure care. Objective 2 will lead to empirical tools to predict the lag-time between waste disposal and onset of biogas generation and rate of biogas generation as functions of moisture enhancement strategy (i.e., addition at the working face, “co-disposal,” versus liquid injection following disposal, “dosing”). Objective 3 will lead to guidance on biochemical compatibility of liquid and solid waste via development of decision tools for co-disposal operations. These deliverables are relevant to current practice have potential to transition landfilling to a more holistic operation where solid and liquid wastes are co-managed to enhance sustainability of waste management.