The effect of pre-treatment and anaerobic digestion for pathogens reduction in agricultural utilization of sewage sludge

Abstract

The aim of the research work was to explain the possibilities of application of waste activated sludge (WAS) pretreatment processes prior to anaerobic digestion (mesophilic fermentation). Hydrodynamic disintegration and freezing/thawing disintegration methods were used. Based on the microbiological and parasitological analyses, a significant decrease in pathogenic bacteria, coliphages, and parasite eggs was observed. The number of bacteria analyzed (Salmonella sp., Escherichia coli, Clostridium perfringens) and coliphages were reduced from 19.3to 42.3% after hydrodynamic cavitation. A similar effect was achieved for destruction by freezing/thawing with dry ice between 7.8 and 14.9%. The effectiveness of parasite eggs reduction (Ascaris sp., Trichuris sp., Toxocara sp.) for these disintegration methods ranged from 10.7 to 29.3%. The highest results were observed for the hybrid disintegration method (hydrodynamic cavitation + dry ice disintegration) caused by a synergistic effect. Salmonella sp. in 1 gd.w. decrease about 69.7%, E. coli by 70.0%, Clostridium perfringens by 38.4%, and coliphages by 48.2%. Disruption of WAS by a hybrid method led to a reduction in the number of helminth eggs Ascaris sp. (63.8%), Trichuris sp. (64.3%), and Toxocara sp. (66.4%). After anaerobic digestion under mesophilic conditions, an additional reduction of analyzed bacterial pathogens and helminth eggs were observed. The introduction of hybrid disintegrated WAS to the fermentation chamber resulted in higher efficiency in decrease (from 1 to 23%) in comparison to the control sample (70%WAS + 30%DS (inoculum-digested sludge)).

Sewage sludge pretreatment: current status and future prospects

“…The pretreatment methods of sewage sludges are used to support the process of methane fermentation (Patinvoh et al 2016 ; Wluka et al 2021 ; Nguyen et al 2021 ; Machnicka and Grübel 2023 ). Methods used for the pretreatment of biomass for biogas production on a large scale are chemical, or physical, including thermal and mechanical.…”

Advanced Technology for Energy, Plant Nutrients and Water Recovery at Wastewater Treatment Plants

“…In sewage sludge, a large number of bacteria cells can be found [30]. A number of bacteriological analyses carried out in municipal wastewater and sewage sludge indicated the presence of pathogenic bacteria species.…”

“…was found in wastewater from a slaughterhouse by Paszkiewicz [34]. Machnicka et al [30] made a discovery while testing disintegration and anaerobic digestion as factors for removing pathogens from waste activated sludge. Tests were carried out on the reference samples for Salmonella spp., E. coli, and Clostridium perfrigens and positive results were reported.…”

Exploratory Research on the Use of Energy Recovery Technology in Sewage Treatment in Indonesia

“…Most residential areas in Indonesia still use conventional sewage treatment systems, which can be a serious environmental problem if there is no proper design and planning [7]. There are several studies on sewage treatment in Indonesia, including the evaluation of the operational and structural design of sewage treatment plants, the implementation of sewage treatment plants, and the development of appropriate concepts for sewage disposal and treatment in rural areas [11]. One study focused on reducing costs and increasing the income of business owners by designing a sewage treatment plant for an apartment building in Surabaya.…”