Anaerobically digested biosolids odor generation and pathogen indicator regrowth after dewatering

Chen, Yen Chih; Higgins, Matthew J.; Beightol, Steven; Murthy, Sudhir; Toffey, William E.

doi:10.1016/j.watres.2011.02.014

Cited by 43 publications

(51 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to reactivation, bacterial "regrowth" of fecal coliforms (i.e., density increases occurring over days) has also been documented in biosolids (WEF, 2006;Higgins and Murthy, 2006;Higgins et al, 2007;Gardner and Ormeci, 2008;Chen et al, 2007). This regrowth is thought to be due to a microbial response to food released during centrifugal shearing .…”

Section: Introductionmentioning

confidence: 99%

“…This regrowth is thought to be due to a microbial response to food released during centrifugal shearing . Chen et al (2007) suggested that secondary stabilization may occur during storage. The regrowth of E. coli and fecal coliforms in biosolids may limit their usefulness as indicators of treatment efficacy and pathogen reduction, particularly for pathogens that do not exhibit regrowth outside a living host (such as viruses and parasites).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pathogen Characterization of Fresh and Stored Biosolids and Implications of a Screening Level Microbial Risk Assessment

Flemming¹,

Soller²,

Simhon³

et al. 2009

proc water environ fed

View full text Add to dashboard Cite

A limited study of enteric pathogens from different stages of mesophilic anaerobic digestion (MAD), i.e., primary sludge, and liquid and dewatered (cake) biosolids, was conducted in six wastewater treatment plants (WWTP) in Ontario, Canada. In addition, bacterial pathogens were re-analysed for regrowth after 2 to 3 days storage in a laboratory at 30°C. Pathogen datasets were used in a preliminary screening level quantitative microbial risk assessment (QMRA). The QMRA assumed conservative human health exposure scenarios for ingestion of soil containing freshly surface-applied or incorporated sewage biosolids, and also considered the aerosol pathway. Culture methods (Most Probable Number or plate count) were used to analyse for bacterial pathogens, including: Campylobacter spp., Salmonella spp., Listeria monocytogenes and Yersinia enterocolitica; as well as fecal indicators: fecal coliforms, E. coli, enterococci and Clostridium perfringens. Two additional pathogens, Cryptosporidium parvum and Giardia lamblia, were quantified in a select few samples by polymerase chain reaction coupled with Most Probable Number (PCR-MPN). Salmonella and Listeria were found frequently in primary sludge and liquid digested biosolids (70-100% of samples) but less so in dewatered cake (50-60%). Yersinia was found less frequently (in 20-30% of samples) across all treatment stages. Giardia was found in 80% of cake biosolids while Cryptosporidium was found in 20%. E. coli reduction during MAD was more than 2-log (at 4 of the 6 plants), while reduction of bacterial pathogens was variable, as shown in other literature. Increases in bacteria levels immediately upon dewatering (i.e., "reactivation"), were generally not significant. Salmonella and E. coli densities increased 1 to 3-log after 2-3 days storage at 30°C, signifying potential for regrowth. Significant correlations between E. coli and Salmonella were observed after the regrowth period (r >0.55, p<0.02). Pathogen datasets from dewatered biosolids were used in a preliminary screening level QMRA, using Monte Carlo analyses. For QMRA simulations pathogen data were fit to log normal distributions using censored regression, which statistically accounts for the non-detects in pathogen data. QMRA results must be interpreted with caution given the limited datasets and conservative nature of the assumptions applied; QMRA results were intended solely for research, to identify data gaps and inform priorities. QMRA revealed that median risks of enteric infection and illness from indirect ingestion of aerosolized particulates were orders of magnitude lower than those from direct ingestion. Median risks of gastrointestinal illness from Salmonella were very low, even after regrowth (e.g., 10 -16 ). Giardia and Cryptosporidium posed higher risks compared to Salmonella, but estimates for these protozoan pathogens were based on very few samples (n=9) which were highly censored. In addition these data were derived from molecular detection methods that did not distinguish viable and/or infectious organis...

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pathogen Characterization of Fresh and Stored Biosolids and Implications of a Screening Level Microbial Risk Assessment

Flemming¹,

Soller²,

Simhon³

et al. 2009

proc water environ fed

View full text Add to dashboard Cite

show abstract

“…However, none of these factors has been found to be correlated with the bacterial regrowth. Recently, Chen et al (2011a) have suggested that both odor production and regrowth are signals of microbial activity which is induced upon the shear and oxygen increase during centrifuge dewatering. Results obtained in this present research additionally postulate that the rise in temperature, along with the exposure to more favorable conditions (for example oxygen abundance) could be one of the factors that lead to the reactivation and rapid increase of indicator bacteria.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, Chen et al (2011a) have suggested that both odor production and regrowth are signals of microbial activity which is induced upon the increase in shear and oxygen levels during centrifuge dewatering. However, most of the attention in the literature related to regrowth after dewatering is directed to a special microbial state that bacteria display.…”

Section: Introductionmentioning

confidence: 99%

Can sludge dewatering reactivate microorganisms in mesophilically digested anaerobic sludge? Case of belt filter versus centrifuge

Erkan

Sanin

2013

Water Research

View full text Add to dashboard Cite

“…This might be due to the presence solids materials which might protect the bacterial cells form the temperature actions. Chen et al (2011) indicated that the pathogenic bacteria in the treated biosolids could regrow again during the storage periods of biosolids. This is due to the microbial response to substrate release and environmental changes, such as oxygen, which favour the bacterial regrowth during 1-2 weeks of storage period.…”

Section: Anaerobic Digestionmentioning

confidence: 99%

Removal of pathogenic bacteria from sewage-treated effluent and biosolids for agricultural purposes

et al. 2018

View full text Add to dashboard Cite

The reuse of treated sewage for irrigation is considered as an important alternative water source in the new water management strategy of the countries that face a severe deficiency of water resources such as the Middle East countries. The organic material and fertilizing elements contained in biosolids are essential for maintaining soil fertility. However, both treated sewage and biosolids contain a large diversity of pathogens that would be transmitted to the environment and infect human directly or indirectly. Therefore, those pathogens should be reduced from the treated sewage and biosolids before the reuse in the agriculture. This paper reviews the considerations for reuse of treated sewage and biosolids in agriculture and further treatments used for reduction of pathogenic bacteria. The treatment methods used for the reduction of pathogens in these wastes have reviewed. It appeared that the main concern associated with the reduction of pathogenic bacteria lies in their ability to regrow in the treated sewage and biosolids. Therefore, the effective treatment method is that it has the potential to destruct pathogens cells and remove the nutrients to prevent the regrowth or recontamination from the surrounded environment. The removal of nutrients might be applicable in the sewage but not in the biosolids due to high nutrient contents. However, the reduction of health risk in the biosolids might be carried out by regulating the biosolid utilization and selecting the plant species grown in the fertilized soil with biosolids.

show abstract

Anaerobically digested biosolids odor generation and pathogen indicator regrowth after dewatering

Cited by 43 publications

References 22 publications

Pathogen Characterization of Fresh and Stored Biosolids and Implications of a Screening Level Microbial Risk Assessment

Pathogen Characterization of Fresh and Stored Biosolids and Implications of a Screening Level Microbial Risk Assessment

Can sludge dewatering reactivate microorganisms in mesophilically digested anaerobic sludge? Case of belt filter versus centrifuge

Removal of pathogenic bacteria from sewage-treated effluent and biosolids for agricultural purposes

Contact Info

Product

Resources

About