Quantification and risks associated with bacterial aerosols near domestic greywater-treatment systems

Benami, Maya; Busgang, Allison; Gillor, Osnat; Gross, Amit

doi:10.1016/j.scitotenv.2016.03.200

Cited by 48 publications

(28 citation statements)

References 66 publications

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“…Typical resuscitation (enrichment) will produce an unknown number of cell divisions depending on the cell physiology, making direct plating unsuitable for quantification. Quantification methods are available which utilize enrichment and Most Probable Number (MPN) determination by either culture methods or PCR methods (Mcegan et al, 2013 ; Orlofsky et al, 2015 ; Benami et al, 2016 ). However these methods are labor intensive, especially if a large number of samples is involved.…”

Section: Introductionmentioning

confidence: 99%

Optimized Co-extraction and Quantification of DNA From Enteric Pathogens in Surface Water Samples Near Produce Fields in California

2018

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Pathogen contamination of surface water is a health hazard in agricultural environments primarily due to the potential for contamination of crops. Furthermore, pathogen levels in surface water are often unreported or under reported due to difficulty with culture of the bacteria. The pathogens are often present, but require resuscitation, making quantification difficult. Frequently, this leads to the use of quantitative PCR targeted to genes unique to the pathogens. However, multiple pathogen types are commonly in the same water sample, both gram + and gram –, leading to problems with DNA extraction. With Shiga toxin-producing Escherichia coli (STEC), Salmonella enterica and Listeria monocytogenes as target, a method was optimized to co-extract all three and quantify the level of each using droplet digital PCR (ddPCR). Multiplexed target genes in STEC were virulence genes, shiga toxin 2 (stx2) and hemolysin (ehx). Likewise, multiplexed targets in Listeria and Salmonella were the virulence genes listeriolysin (hly) and invasion protein A (invA). Water samples were processed using microbiological techniques for each of the pathogens and duplicate water samples were quantified by ddPCR. A significant correlation was found between culture and ddPCR results indicating detection primarily of culturable cells by ddPCR. Average virulence gene levels were 923, 23 k, 69 and 152 copies per sample for stx2, ehx, hly and invA, respectively. Additionally, stx2, ehx and inv levels were significantly correlated (P < 0.05, R = 0.34) with generic E. coli MPN levels in the duplicate samples. Indirect quantification with ddPCR will improve understanding of prevalence of the pathogens and may reduce risks associated with contaminated surface water.

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Section: Introductionmentioning

confidence: 99%

Optimized Co-extraction and Quantification of DNA From Enteric Pathogens in Surface Water Samples Near Produce Fields in California

2018

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“…In the HIC context, most studies considered wastewater treatment or other water management strategies [22–32] or the treatment of food products before consumption [33–38]. A handful of papers considered hand or fomite disinfection [39–41], household-level water treatment [42], or vaccination of animals against waterborne pathogens [43]. In LMICs, there was more emphasis on household water treatment [44–47] and less on wastewater treatment or water management [48–52], the latter primarily coming from upper-middle-income countries.…”

Section: Resultsmentioning

confidence: 99%

Quantitative Microbial Risk Assessment and Infectious Disease Transmission Modeling of Waterborne Enteric Pathogens

Brouwer

Masters

Eisenberg

2018

Curr Envir Health Rpt

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QMRA research has focused on food contamination and recreational water in high-income countries (HICs) and drinking water and wastewater in low- and middle-income countries (LMICs). IDTM research has focused on large outbreaks (predominately LMICs) and vaccine-preventable diseases (LMICs and HICs). Human ecology determines the niches that pathogens exploit, leading researchers to focus on different risk assessment research strategies in different settings. To enhance risk modeling, QMRA and IDTM approaches should be integrated to include dynamics of pathogens in the environment and pathogen transmission through populations.

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“…More plausible is the transfer of the tracer organism E. coli to the absorbent via urine aerosols (Benami et al 2016, Heinonen-Tanski et al 2009. Transfer of the smallest microorganisms reported in urine (0.1 µm) (Dong et al 2011, Shepard et al 1974, Waites and Talkington 2004, Wang et al 2007 could have happened through the hydrophobic membrane which had an average measured pore size of 0.274 ± 0.003 µm, whereas the manufacturer reported 0.1 µm (SI Table B.1).…”

Section: A Hydrophobic Membrane Prevents Transfer Of Contaminating Bamentioning

confidence: 99%

Membrane stripping enables effective electrochemical ammonia recovery from urine while retaining microorganisms and micropollutants

et al. 2019

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Ammonia recovery from urine avoids the need for nitrogen removal through nitrification/denitrification and re-synthesis of ammonia (NH3) via the Haber-Bosch process. Previously, we coupled an alkalifying electrochemical cell to a stripping column, and achieved competitive nitrogen removal and energy efficiencies using only electricity as input, compared to other technologies such as conventional column stripping with air. Direct liquid-liquid extraction with a hydrophobic gas membrane could be an alternative to increase nitrogen recovery from urine into the absorbent while minimizing energy requirements, as well as ensuring microbial and micropollutant retention. Here we compared a column with a membrane stripping reactor, each coupled to an electrochemical cell, fed with source-separated urine and operated at 20 A m-2. Both systems achieved similar nitrogen removal rates, 0.34 ± 0.21 and 0.35 ± 0.08 mol N L-1 d-1 , and removal efficiencies, 45.1 ± 18.4 and 49.0 ± 9.3%, for the column and membrane reactor, respectively. The membrane reactor improved nitrogen recovery to 0.27 ± 0.09 mol N L-1 d-1 (38.7 ± 13.5%) while lowering the operational (electrochemical and pumping) energy to 6.5 kWhe kg N-1 recovered, compared to the column reactor, which reached 0.15 ± 0.06 mol N L-1 d-1 (17.2 ± 8.1%) at 13.8 kWhe kg N-1. Increased cell concentrations of an autofluorescent E. coli MG1655+prpsM spiked in the urine influent were observed in the absorbent of the column stripping reactor after 24 h, but not for the membrane stripping reactor. None of six selected micropollutants spiked in the urine were found in the absorbent of both technologies. Overall, the membrane stripping reactor is preferred as it improved nitrogen recovery with less energy input and generated an E. coli-and micropollutant-free product for 3 potential safe reuse. Nitrogen removal rate and efficiency can be further optimized by increasing the NH3 vapor pressure gradient and/or membrane surface area.

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Quantification and risks associated with bacterial aerosols near domestic greywater-treatment systems

Cited by 48 publications

References 66 publications

Optimized Co-extraction and Quantification of DNA From Enteric Pathogens in Surface Water Samples Near Produce Fields in California

Optimized Co-extraction and Quantification of DNA From Enteric Pathogens in Surface Water Samples Near Produce Fields in California

Quantitative Microbial Risk Assessment and Infectious Disease Transmission Modeling of Waterborne Enteric Pathogens

Membrane stripping enables effective electrochemical ammonia recovery from urine while retaining microorganisms and micropollutants

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