UV disinfection of RBC-treated light greywater effluent: Kinetics, survival and regrowth of selected microorganisms

Gilboa, Yael; Friedler, Eran

doi:10.1016/j.watres.2007.09.027

Cited by 107 publications

(90 citation statements)

References 28 publications

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“…Although the results from the five participants were consistent (See Table S2), more replication of this study on a variety of greywater sources is necessary to confidently suggest total staphylococci as a performance surrogate for greywater treatment. A 1981 study by Abshire and Dunton [29] showed that S. aureus was more resistant to UV-C than the saprozoic pathogen Pseudomonas aeruginosa (also typically present in greywater [13]); however, a 2007 study by Gilboa and Friedler [13] found S. aureus to be the least resistant to UV-C irradiation when compared to faecal coliforms (FC), P. aeruginosa, and Clostridium perfringens at low doses. However, as shown in this study, given the dominating concentrations of Staphylococcus spp.…”

Section: Raw Hand-rinsementioning

confidence: 99%

“…as the most abundant bacterial genus in laundry greywater sourced from a university sports facility. To better understand the microbiological constituents of greywater, a literature review was conducted and identified 41 studies, however, only three studies measured greywater for total staphylococci [8][9][10], with several focusing on Staphylococcus aureus (S. aureus) [8,9,[11][12][13][14][15][16]. Of the three studies that measured total staphylococci, total staphylococci was found to be among the most abundant bacteria when compared to faecal coliforms (FC), total coliforms (TC), Escherichia coli (E. coli), Enterococcus spp., and other traditional faecal indicator bacteria (FIB).…”

Section: Introductionmentioning

confidence: 99%

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UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp.

Shoults

Ashbolt

2017

Water

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Greywater reuse is a feasible solution for decreasing raw water extraction in urban and rural settings. However, pathogen-specific performance guidelines and regulations have only recently been recommended; practical means to assess performance are missing. Here we examine the efficacy of Staphylococcus spp. as an endogenous surrogate for greywater pathogen reduction performance testing, by evaluating UV-C irradiation of hand-rinse greywater, and the variability in UV resistance between different wild Staphylococcus species. Hand-rinse greywater samples were collected from five participants, and a collimated UV-C beam (256 nm) was used to assess log 10 reductions. Assays of colony-forming units on tryptic soy agar (TSA) were compared to mannitol salt agar (MSA) using Lysostaphin TM to confirm Staphylococcus spp. After irradiating raw hand-rinse samples to a dose of 220 mJ·cm −2 , log 10 reductions of Staphylococcus spp. were similar (2.1 and 2.2, respectively, p = 0.112). The similarity of the reduction based on TSA and Staphylococcus-specific culture assays following UV irradiation and the dominating presence of Staphylococcus spp. suggests that Staphylococcus spp. could be used as an endogenous performance surrogate group for greywater treatment testing. Suspended wild Staphylococcus isolates were irradiated with 256 nm UV-C to compare the variability of different Staphylococcus species. Staphylococcus isolates exhibited significant variance in log 10 reduction values when exposed to 11 mJ·cm −2 of UV-C. Staphylococcus hominis subsp. hominis exhibited surprising resistance to UV-C, with only a 1.6-log 10 reduction when exposed to 11 mJ·cm −2 of UV-C (most other isolates exhibited > 5-log 10 reduction). The efficacy of UV-C was also significantly reduced when the sunscreen oxybenzone was present at a possible endogenous greywater concentration.

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Section: Raw Hand-rinsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp.

Shoults

Ashbolt

2017

Water

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“…For example, rotating biological contactor (RBC)-treated and UV-disinfected light GW resulted in a 2-log 10 decrease in fecal coliforms (FC), Staphylococcus aureus, and HPC densities and 1-log 10 decrease in Clostridium perfringens and Pseudomonas aeruginosa densities compared to raw GW (18). Similarly, HPC and FC densities were not significantly reduced by stand-alone sand filtration, whereas the use of RBC alone, RBC followed by sand filtration, and a membrane bioreactor with ultrafiltration treatment resulted in reductions of 2, 1 to 2, and 3 to 4 log 10 CFU, respectively (19).…”

Section: Cysts Litermentioning

confidence: 99%

Exposure to Synthetic Gray Water Inhibits Amoeba Encystation and Alters Expression of Legionella pneumophila Virulence Genes

Buse

Ashbolt

2015

Appl Environ Microbiol

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bWater conservation efforts have focused on gray water (GW) usage, especially for applications that do not require potable water quality. However, there is a need to better understand environmental pathogens and their free-living amoeba (FLA) hosts within GW, given their growth potential in stored gray water. Using synthetic gray water (sGW) we examined three strains of the waterbased pathogen Legionella pneumophila and its FLA hosts Acanthamoeba polyphaga, A. castellanii, and Vermamoeba vermiformis. Exposure to sGW for 72 h resulted in significant inhibition (P < 0.0001) of amoebal encystation versus control-treated cells, with the following percentages of cysts in sGW versus controls: A. polyphaga (0.6 versus 6%), A. castellanii (2 versus 62%), and V. vermiformis (1 versus 92%), suggesting sGW induced maintenance of the actively feeding trophozoite form. During sGW exposure, L. pneumophila culturability decreased as early as 5 h (1.3 to 2.9 log 10 CFU, P < 0.001) compared to controls (⌬0 to 0.1 log 10 CFU) with flow cytometric analysis revealing immediate changes in membrane permeability. Furthermore, reverse transcription-quantitative PCR was performed on total RNA isolated from L. pneumophila cells at 0 to 48 h after sGW incubation, and genes associated with virulence (gacA, lirR, csrA, pla, and sidF), the type IV secretion system (lvrB and lvrE), and metabolism (ccmF and lolA) were all shown to be differentially expressed. These results suggest that conditions within GW may promote interactions between water-based pathogens and FLA hosts, through amoebal encystment inhibition and alteration of bacterial gene expression, thus warranting further exploration into FLA and L. pneumophila behavior in GW systems. G ray water (GW) usage has proven to be both an economically and a logistically suitable solution to alleviate the stresses from increasing potable water demand and climate/demographic change (1), when used (following adequate treatment) in largeand small-scale irrigation, toilet flushing, and car washing (2-4). Defined as household wastewater that is not contaminated with toilet waste, GW is further categorized as light (derived from bathroom showers, tubs, and washbasins) and dark (derived from laundry machines, dishwashers, and kitchen sinks) gray water (5). In households surveyed internationally, light GW constitutes about 47% of total GW, with the remaining 27 and 26% originating from kitchen sinks/dishwashers and laundry washing machines, respectively (reviewed in reference 5). The composition of GW varies greatly with light GW containing mostly personal care products and dark GW composed mostly of dish and laundry detergents, food residue, and fats, oils, and grease.Few studies report on the densities of microbial contaminants within treated GW, and of these, most present fecal indicator data, with less information on pathogens (6). When reusing GW there is concern for fecally borne pathogens (such as species in the bacterial genera Campylobacter, Salmonella, and Vibrio [7-10]), as well as an emerg...

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“…GWTUs process GW with varying levels of effectiveness, but many can significantly decrease the concentration of total suspended solids (TSS) ([70 % and in some systems [90 %), Fig. 1 Palestinian Hydrology Group's GWTU scheme composed of an initial settling tank (a), two anaerobic gravel-based filter tanks (b), a charcoal filter (c), and a reservoir to store water until used for irrigation (d) chemical oxygen demand (COD) ([70 %) and biochemical oxygen demand (BOD) in water ([90 %) (Friedler et al 2006;Morel and Diener 2006;Gilboa and Friedler 2008;Halalsheh et al 2008;Winward et al 2008;Li et al 2009;Ghaitidak and Yadav 2013). If designed with the right controls and maintained properly, GWTUs can be deemed safe for environmental and human health (Alfiya et al 2013).…”

Section: Reuse Guidelines and Treatmentmentioning

confidence: 99%

Is Gray Water the Key to Unlocking Water for Resource-Poor Areas of the Middle East, North Africa, and Other Arid Regions of the World?

Leas

Dare

Al-Delaimy

2013

AMBIO

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Support for the use of treated gray water as an alternative water resource in the Middle East and North Africa is high, especially given the lack of religious restrictions against its use, but several obstacles have kept application of treated gray water near 1 % in some areas. The largest of obstacles include the cost of treatment and the ambiguity surrounding the health safety of gray water and treated gray water. This paper aims to provide an overview of current gray water practices globally, with specific focus on household-level gray water practices in the Middle East and North Africa region, and highlight the need for cost reduction strategies and epidemiological evidence on the use of household-level gray water and treated gray water. Such actions are likely to increase the application of treated gray water in water-deprived areas of the Middle East and North Africa.

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UV disinfection of RBC-treated light greywater effluent: Kinetics, survival and regrowth of selected microorganisms

Cited by 107 publications

References 28 publications

UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp.

UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp.

Exposure to Synthetic Gray Water Inhibits Amoeba Encystation and Alters Expression of Legionella pneumophila Virulence Genes

Is Gray Water the Key to Unlocking Water for Resource-Poor Areas of the Middle East, North Africa, and Other Arid Regions of the World?

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