Fungal treatment of an effluent from sewage sludge digestion to remove recalcitrant organic matter

In this study, Phanerochaete chrysosporium was tested for first time to treat the liquid effluent from a sewage sludge digestion. This anaerobic digestion liquor (ADL) has a COD concentration of around 7500 mg/L, a very low biodegradability (BOD5/COD = 0.02) and deep colour, being impossible their effective treatment by conventional biological methods. Assays inoculating the fungi were carried out at 26 degrees C during 10 days in a batch reactor, following the evolution of colour, COD and BOD5. The effect of adding different concentrations of glucose was evaluated, resulting to be a key factor for increasing the efficacy of the treatment. Based on batch results, a continuous fungal water-jacketed bioreactor was successfully started up. COD removals above 65 % were achieved both in batch and continuous operations. These results show the possibilities of this sustainable and economic approach to remove refractory COD in the low-biodegradable effluents derived from anaerobic digestion of sludge or other complex wastes.

Automated summary

The study demonstrated the effectiveness of using Phanerochaete chrysosporium to treat liquid effluent from sewage sludge digestion, especially in cases of low biodegradability. The addition of glucose was shown to be a key factor in enhancing treatment efficacy, with COD removals above 65% achieved in both batch and continuous operations.