Anaerobic reactors: specific methanogenic activity and potential for bioregeneration of recalcitrant compounds in powdered activated carbon

Abstract

This work is focused on anaerobic reactors. The process is a complex syntrophic interaction between many different microorganisms to degrade organic compounds and obtain methane as final product; To determine the “health” of the reactor a Specific Methanogenic Activity (SMA) test is performed. Unfortunately, there is no standard for this test. Pharmaceutical Active Compounds have been appearing in effluents of wastewater treatment plants, becoming post-treatment with Activated Carbon a major area of interest, but becomes saturated and needs to be replaced; bioregeneration could be an economically feasible option to solve this issue. The aim of this work was to find the best SMA conditions to evaluate digester health and to study bioregeneration of PAC under anaerobic conditions. When testing SMA this work had better results using glucose as main carbon source rather than acetate, opposite from literature predictions. It also was found that no centrifugation was needed, indicated that possible some important cofactor was excreted by some microorganism. FISH showed a predominance of Methanosaeta in one inoculum. No results on PAC bioregeneration where found, but when less than 50 mgL-1 of diclofenac was used an increase of methane production was detected, since diclofenac was not degraded it could imply that supplies energy to methanogens.