Potential for the adoption of vermicomposting to stabilize sewage sludge in Mexico: Viewpoints from the main actors

Abstract: The treatment of sewage sludge is often a neglected part of wastewater treatment operation in developing countries. It is generally perceived as an additional operational cost and its importance for an adequate sanitation system is not fully recognized. Therefore, the production of sewage sludge represents a risk of human health and the environment due to the potential of spreading pathogens. In Mexico, only 5% of the total sewage sludge produced receives a further stabilization treatment. Cheap and effective treatment alternatives are needed in order to guarantee a safe management of this waste. Vermicomposting is an effective treatment option to achieve highest quality stabilization standards and a potential solution for the waste and sanitation problems derived from sewage sludge. The present study analyzes the drivers and barriers for the adoption of this technology and the conditions for its successful implementation. The stakeholders participating in this study have identified lower capital and operational costs, process simplicity, savings, compliance with current or future policies and laws, and the ease to obtain skilled operators as the main drivers for adopting this technology. The main perceived barriers include uncertainty regarding costs, operational performance and control parameters, as well as the lack of economic incentives, as the main barriers for the adoption of this treatment. In addition, a list of 41 elements that are important for the adoption, diffusion and long term implementation of vermicomposting in sewage sludge was identified and discussed.