Ultraviolet (Uv) Disinfection of Grey Water: Particle Size Effects

Winward, Gideon P.; Avery, Lisa M.; Stephenson, Tom; Jefferson, Bruce

doi:10.1080/09593330802030069

Cited by 34 publications

(29 citation statements)

References 33 publications

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“…The turbidity and total suspended solids were 1.6 NTU and 2.71 mg/L, respectively, in W2 wastewater, compared with 0.2 NTU and 0.56 mg/L, respectively, in W1 wastewater. This suggests that particles might account for the decreased UV inactivation in W2 wastewater, as attached or embedded bacteria have shown increased resistance to UV inactivation (Winward et al, 2008). Cantwell and Hofmann (2008) reported that particles as small as 11 mm, which are naturally …”

Section: Resultsmentioning

confidence: 99%

Synergistic effect of the sequential use of UV irradiation and chlorine to disinfect reclaimed water

Wang

et al. 2012

Water Research

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a b s t r a c tThe effectiveness of UV and chlorination, used individually and sequentially, was investigated in killing pathogenic microorganisms and inhibiting the formation of disinfection by-products in two different municipal wastewaters for the source water of reclaimed water, which were from a microfilter (W1) and membrane bioreactor (W2) respectively.Heterotrophic plate count (HPC), total bacteria count (TBC), and total coliform (TC) were selected to evaluate the efficiency of different disinfection processes. UV inactivation of the three bacteria followed first-order kinetics in W1 wastewater, but in W2 wastewater, the UV doseeresponse curve trailed beyond approximately 10 mJ/cm 2 UV. The higher number of particles in the W2 might have protected the bacteria against UV damage, as UV light alone was not effective in killing HPC in W2 wastewater with higher turbidity. However, chlorine was more effective in W2 than in W1 for the three bacteria inactivation owing to the greater formation of inorganic and organic chloramines in W1 wastewater. Complete inactivation of HPC in W1 wastewater required a chlorine dose higher than 5.5 mg/L, whereas 4.5 mg/L chlorine gave the equivalent result in W2 wastewater. In contrast, sequential UV and chlorine treatment produced a synergistic effect in both wastewater systems and was the most effective option for complete removal of all three bacteria. UV disinfection lowered the required chlorine dose in W1, but not in W2, because of the higher chlorine consumption in W2 wastewater. However, UV irradiation decreased total trihalomethane formation during chlorination in both wastewaters. ª

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Section: Resultsmentioning

confidence: 99%

Synergistic effect of the sequential use of UV irradiation and chlorine to disinfect reclaimed water

Wang

et al. 2012

Water Research

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“…A notable concern within this study was the lack of bacterial reduction by 256 UV-C at a dose of 220 mJ·cm −2 , which should have yielded at least a 5-log 10 reduction in viable bacteria (as previously shown by Shoults and Ashbolt [7]). This is not surprising, however, as Winward et al showed a significant decrease in UV-C efficacy of bacterial reduction in water with high turbidity and low UV transmittance [20]. The 256 nm absorbance (A 256 nm) readings ranging from 0.164 to 0.360 (see Table S1) and were not normalized, as given in the unadjusted Equation (1); the A 256 readings would likely have been increased by the use of soap in this study, and thus soap wasn't used.…”

Section: Raw Hand-rinsementioning

confidence: 92%

“…While the effects of large/many suspended particles on the efficacy of UV are understood [20], the role of micro-pollutants and personal care products (PCP) on the efficacy of UV irradiation are relatively unknown. Given the high reported concentrations of the sunscreen benzophenone (BP3), commonly referred to as oxybenzone [21], the effects of oxybenzone on the efficacy of UV irradiation for staphylococci was also studied.…”

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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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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“…The greater amount of particulates in the concentrated samples might have interfered with antibody specificity and adherence, thus affecting IMS and staining performance. [35,36] The turbidity of the initial sample may be correlated with increased variability of the oocyst counts, as evidenced by the standard deviation value of the recovery (∼15%). Nevertheless, a variability value of approximately 80% for oocyst recovery in >20 NTU surface water was reported for commonly used capsule filters.…”

Section: Number Of Avg Turbidity (Ntu)mentioning

confidence: 98%

Recovery ofCryptosporidiumandGiardiaorganisms from surface water by counter-flow refining microfiltration

Pires

Dong

2013

Environmental Technology

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As waterborne parasitic cryptosporidiosis and giardiasis outbreaks continue globally, monitoring of Cryptosporidium parvum and Giardia lamblia in surface water continues to be challenging. Lack of non-clogging and high-efficiency methods for recovery of C. parvum oocysts and G. lamblia cysts in environmental water strongly limits the sensitivity of detection methods for these protozoan organisms. In this work, the Counter-Flow Micro-Refinery (CFMR) system was developed by employing the novel counter-flow microfiltration principle to enrich (oo)cysts for subsequent analytical purposes. The CFMR system was constructed with multiple counter-flow concentration units that were arranged into two refining levels. By use of different numbers of units, the CFMR offered an adjustable concentration ratio allowing the concentration of 10 L and 100 L to hundreds of mL with no recirculation processing. With spiked samples, recovery of 81.3% oocysts and 86.2% cysts at a variance of < 7% was achieved for concentrations as low as 0.5-100 organisms L(-1). The recovery efficiency showed consistent for a wide range of water turbidities as well as different sample volumes. No significant clogging has been observed in the experiments. Moreover, the refining filter was able to enrich and separate oocysts and cysts in water, simultaneously. This work verifies a feasible solution for recovering C. parvum oocysts and G. lamblia cysts in large-volume surface waters. The refining system has potential to be a high-efficiency monitoring tool when combined with proper analytical detection methods.

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Ultraviolet (Uv) Disinfection of Grey Water: Particle Size Effects

Cited by 34 publications

References 33 publications

Synergistic effect of the sequential use of UV irradiation and chlorine to disinfect reclaimed water

Synergistic effect of the sequential use of UV irradiation and chlorine to disinfect reclaimed water

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

Recovery ofCryptosporidiumandGiardiaorganisms from surface water by counter-flow refining microfiltration

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