Evaluation of Thermophilic Anaerobic Digestion to Meet Class a Biosolids Criteria

Aitken, Michael D.; Sobsey, Mark D.; Walters, Glenn W.; Hill, Vincent R.; Shehee, Mina; Blauth, Kimberly E.; Crunk, Phillip E.; Nappier, Sharon P.; Abel, Nicole A. Van; Farrell, Jay A.; Schafer, Perry; Willis, John; Arnett, Cliff; Turner, Billy G.

doi:10.2175/193864703784755157

Cited by 3 publications

(3 citation statements)

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“…This is much less than the 24‐h requirement of the Part 503 equation. Aitken et al (2003) obtained similar results. Additional research will likely establish the excessive degree of conservatism in the USEPA equation with an expected reduction in the holding times required for a given temperature.…”

Section: Recent Developmentssupporting

confidence: 62%

Processes for Managing Pathogens

Godfree

Farrell²

2005

J of Env Quality

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Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

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Section: Recent Developmentssupporting

confidence: 62%

Processes for Managing Pathogens

Godfree

Farrell²

2005

J of Env Quality

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“…Chauret et al (1999) evaluated the inactivation of C. perfringens across an anaerobic digester that was operated at 35°C, and no statistically significant reduction was observed. In a study conducted by Aitken et al (2005), the inactivation of pathogens and bacterial indicators in a continuous flow thermophilic anaerobic digester was evaluated. There was no significant removal of C. perfringens under any condition.…”

Section: Introductionmentioning

confidence: 99%

The effect of volatile fatty acids on the inactivation of Clostridium perfringens in anaerobic digestion

Salsali

Parker

Sattar

2007

World J Microbiol Biotechnol

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The application of sludge digestion systems to remove pathogens has been employed to generate biosolids suitable for reuse in agriculture. Traditionally, temperature is considered the principal agent responsible for pathogen reduction in anaerobic digestion. However, other substances such as volatile fatty acids may also have an antimicrobial effect. The objective of this study was to assess the impact of fatty acid mixtures on the inactivation of C. perfringens over a range of digestion temperatures. An equimolar mixture of acetic acid, propionic acid and butyric acid was applied to digester effluent for a period of 24 h at temperatures of 35°C, 42°C, 49°C and 55°C. C. perfringens inactivation in digester effluents, when dosed with volatile organic acids, was found to depend on pH, acid concentration and temperature. Temperatures above 55°C appeared to increase the inhibitory effects of the organic acids at higher concentrations. An interaction between temperature and pH on survival of C. perfringens was observed. The results suggest that high concentrations of organic acids at a pH value of 4.5-5.5 during thermophilic digestion substantially reduce concentrations of C. perfringens in municipal sludge.

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“…After startup was completed the digester was found to maintain FC concentrations of 100 MPN/g TS and Salmonella concentrations were less than 3 MPN/4g TS. Aitken, et al, (2003) investigated the removal of pathogens and indicator organisms at laboratory scale (20 L) in a completely-mixed thermophilic anaerobic digester operated at 55°C and a four-day HRT. Digester feed and effluent samples were analyzed for these two species as well as Salmonella spp., FC, Clostridium perfringens spores, and somatic and male-specific coliphages.…”

Section: Watanabementioning

confidence: 99%

Producing enhanced quality biosolids through anaerobic digester optimization

Salsali¹

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Evaluation of Thermophilic Anaerobic Digestion to Meet Class a Biosolids Criteria

Cited by 3 publications

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Processes for Managing Pathogens

Processes for Managing Pathogens

The effect of volatile fatty acids on the inactivation of Clostridium perfringens in anaerobic digestion

Producing enhanced quality biosolids through anaerobic digester optimization

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