Fate of pathogen indicators in a domestic blend of food waste and wastewater through a two-stage anaerobic digestion system

• Published in: Water science and technology Vol. 67; no. 2; pp. 366 - 373
• Main Authors: ROUNSEFELL, B. D, O'SULLIVAN, C. A, CHINIVASAGAM, N, BATSTONE, D, CLARKE, W. P
• Format: Journal Article
• Language: English
• Published: London International Water Association 01.01.2013; IWA Publishing
• Subjects: Anaerobic digestion; Anaerobic treatment; Anaerobiosis; Analysis methods; Applied sciences; Bacteria - isolation & purification; Bacteriophages - isolation & purification; Biodegradation, Environmental; Biofuels - analysis; Biological Oxygen Demand Analysis; Blackwater; Chemical oxygen demand; Clostridium perfringens; Clostridium perfringens - isolation & purification; Colony Count, Microbial; Communities; Detection limits; E coli; Escherichia coli; Escherichia coli - isolation & purification; Exact sciences and technology; Filtration; Food; Food waste; General purification processes; Household wastes; Hydrogen-Ion Concentration; Indicators; Load distribution; Loading rate; Membrane filtration; Municipal wastewater; Natural water pollution; Organic Chemicals - analysis; Organic loading; Organic wastes; Pathogens; Pollution; Refuse as fuel; Sanitation; Sewage - microbiology; Waste Disposal, Fluid; Waste management; Waste Products - analysis; Waste streams; Waste Water - microbiology; Waste Water - virology; Wastewater treatment; Wastewater treatment plants; Wastewaters; Water Purification - methods; Water treatment and pollution; Food waste; Organic waste; Domestic waste water; Blackwater; Microbiology; Pathogenic; pathogen; Biological treatment; Biological contamination; Anaerobic digestion; Indicator; Waste water
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2012.573

Anaerobic digestion is a viable on-site treatment technology for rich organic waste streams such as food waste and blackwater. In contrast to large-scale municipal wastewater treatment plants which are typically located away from the community, the effluent from any type of on-site system is a potential pathogenic hazard because of the intimacy of the system to the community. The native concentrations of the pathogen indicators Escherichia coli, Clostridium perfringens and somatic coliphage were tracked for 30 days under stable operation (organic loading rate (OLR) = 1.8 kgCOD m(-3) day(-1), methane yield = 52% on a chemical oxygen demand (COD) basis) of a two-stage laboratory-scale digester treating a mixture of food waste and blackwater. E. coli numbers were reduced by a factor of 10(6.4) in the thermophilic stage, from 10(7.5±0.3) to 10(1.1±0.1) cfu 100 mL(-1), but regenerated by a factor of 10(4) in the mesophilic stage. Neither the thermophilic nor mesophilic stages had any significant impact on C. perfringens concentrations. Coliphage concentrations were reduced by a factor of 10(1.4) across the two stages. The study shows that anaerobic digestion only reduces pathogen counts marginally but that counts in effluent samples could be readily reduced to below detection limits by filtration through a 0.22 µm membrane, to investigate membrane filtration as a possible sanitation technique.