Impact of Adding Biopreparations on the Anaerobic Co-Digestion of Sewage Sludge with Grease Trap Waste

Abstract

The aim of the study was to evaluate the effect of using biopreparations on efficiency of the co-fermentation process. Commercial bacterial biopreparations DBC Plus Type L, DBC Plus Type R5 and yeast biopreparations were used in the study. The process of cofermentation of sewage sludge with grease trap waste from a production plant that manufactured methyl esters of fatty acids was analysed in the laboratory environment under mesophilic conditions. The sludge in the reactor was replaced once a day, with hydraulic retention time of 10 days. Grease trap waste accounted for 35%wt. of the fermentation mixture. The stabilization process was monitored everyday based on the measurements of biogas volume. Addition of yeast biopreparation to methane fermentation of sewage sludge with grease trap waste caused an increase in mean daily biogas production from 6.9 dm3 (control mixture) to 9.21dm3 (mixture M3). No differences in biogas production were found for other cases (mixtures M1, M2). A similar relationship was observed for methane content in biogas.

The importance of sustainable phosphorus management in the circular economy (CE) model: the Polish case study

“…Poland's problems relating to sludge management issues stem primarily from EU restrictions [72][73][74] placed on the conventional disposal and recovery options formerly used. Based on the implementation of Directive 99/31/EC on the landfill of waste [75], since 1st January 2016 it has not been possible to landfill completely untreated sewage sludge with a heat of combustion > 6 MJ/kg [76,77].…”