Evaluating Usage of Effluent From Anaerobic Bio-Digester During Vermicomposting Process.

In Mexico, the number of anaerobic digesters installed has been increasing lately. This is attributed to the interest in biogas production as an alternative to the use of hydrocarbons. However, generation of large amount of untreated effluents has become a new problem. There are few alternatives to use it, however content of pathogenic microorganisms and the great loss of nitrogen when is combined with other processes limited its exploitation. Therefore, we developed an experimental design using effluents from two anaerobic digesters considering two different stages of the process of vermicomposting (pre-composting and during the composting) for its application. Diverse dilutions were tested to evaluate its toxicity, measured as percentages of earthworms´ survival. Variation of pH, temperature and quality of the compost were also determined. It was found direct application of the effluent is toxic to earthworms (97 % of death). Also, a dilution 2:1 of effluent-water permits the development and growth of the organisms. Further work is needed to establish better conditions for earthworms to allow them achieve similar levels as controls without effluents. This work is a preliminary study about the usage of effluents from anaerobic biodigester during the process of vermicomposting.