Toxicity screening and evaluating in chlorination disinfection of wastewater reclamation processes

2006 ◽  
Vol 53 (9) ◽  
pp. 239-246 ◽  
Author(s):  
Dongbin Wei ◽  
Lisha Wang ◽  
Jie Wei ◽  
Hong-Ying Hu
Keyword(s):  
Water Samples ◽  
Biological Effects ◽  
Reclaimed Water ◽  
Residual Chlorine ◽  
Toxicity Screening ◽  
Wastewater Reclamation ◽  
Peak Point ◽  
Chlorine Toxicity ◽  
Critical Problems ◽  
Microtox Test

Reclamation and re-use of wastewater is one of the most effective ways to alleviate the shortage of water resources, while the safety of reclaimed water becomes one of the critical problems for protecting human health and the ecosystem. While a toxicity test can vividly reflect biological effects of chemicals as a whole, in this study, the Microtox test was used to screen toxicity changes of wastewater during conventional reclamation processes. The results showed that toxicities of water samples decreased continuously along reclamation processes except chlorination/dechlorination in which the toxicity increased significantly. Furthermore, as for different forms of residual chlorine, toxicity of wastewater was quite different with increasing chlorine dosage. NH3-N had a trend to decrease toxicity of disinfected wastewater, while UV254 had a trend to increase toxicity. It was found that there was a good linear relationship between toxicity formation and UV254/NH3-N ratio for wastewater after disinfection with combined chlorine form before peak-point.

scholarly journals Validity of the Indicator Organism Paradigm for Pathogen Reduction in Reclaimed Water and Public Health Protection

2005 ◽  
Vol 71 (6) ◽  
pp. 3163-3170 ◽  
Author(s):  
Valerie J. Harwood ◽  
Audrey D. Levine ◽  
Troy M. Scott ◽  
Vasanta Chivukula ◽  
Jerzy Lukasik ◽  
...  
Keyword(s):  
Public Health ◽  
Water Samples ◽  
Reclaimed Water ◽  
Detection Limits ◽  
Enteric Viruses ◽  
Fecal Coliforms ◽  
Indicator Organism ◽  
Wastewater Reclamation ◽  
Indicator Organisms ◽  
Single Indicator

ABSTRACT The validity of using indicator organisms (total and fecal coliforms, enterococci, Clostridium perfringens, and F-specific coliphages) to predict the presence or absence of pathogens (infectious enteric viruses, Cryptosporidium, and Giardia) was tested at six wastewater reclamation facilities. Multiple samplings conducted at each facility over a 1-year period. Larger sample volumes for indicators (0.2 to 0.4 liters) and pathogens (30 to 100 liters) resulted in more sensitive detection limits than are typical of routine monitoring. Microorganisms were detected in disinfected effluent samples at the following frequencies: total coliforms, 63%; fecal coliforms, 27%; enterococci, 27%; C. perfringens, 61%; F-specific coliphages, ∼40%; and enteric viruses, 31%. Cryptosporidium oocysts and Giardia cysts were detected in 70% and 80%, respectively, of reclaimed water samples. Viable Cryptosporidium, based on cell culture infectivity assays, was detected in 20% of the reclaimed water samples. No strong correlation was found for any indicator-pathogen combination. When data for all indicators were tested using discriminant analysis, the presence/absence patterns for Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and infectious enteric viruses were predicted for over 71% of disinfected effluents. The failure of measurements of single indicator organism to correlate with pathogens suggests that public health is not adequately protected by simple monitoring schemes based on detection of a single indicator, particularly at the detection limits routinely employed. Monitoring a suite of indicator organisms in reclaimed effluent is more likely to be predictive of the presence of certain pathogens, and a need for additional pathogen monitoring in reclaimed water in order to protect public health is suggested by this study.

Ultrafiltration combined with ozone for domestic laundry wastewater reclamation and reuse

2001 ◽  
Vol 1 (5-6) ◽  
pp. 387-392 ◽  
Author(s):  
G.T. Seo ◽  
T.S. Lee ◽  
B.H. Moon ◽  
J.H. Lim
Keyword(s):  
Reclaimed Water ◽  
Cross Flow ◽  
Wastewater Reclamation ◽  
Cross Flow Filtration ◽  
Wastewater Reclamation And Reuse ◽  
Filtration Area ◽  
Injection Interval ◽  
Flow Filtration ◽  
Two Phases ◽  
Ozone Injection

Ozone was incorporated into an ultrafiltration system to produce higher quality reclaimed water from domestic laundry wastewater. Characteristics of the wastewater for initial washing waste were 488~2,847 mg/L COD, 62~674 mg/L MBAS, and 38~857 mg/L SS. The wastewater was contacted with ozone in a 10L storage tank and circulated through the membrane module for inner pressurized cross-flow filtration. The concentrate was returned back to the contact tank. The membrane used in this experiment was hollow fiber polysulfone UF membrane with MWCO 5,000 and 10,000. It has an effective filtration area of 0.06m2. The experiment was carried out in two phases with either continuous or intermittent ozone injection. For intermittent ozone injection, the mode of injection interval was changed to 5 min./5 min. and 5 min./10 min. for injection/idling. Ozone was dosed at the concentration of 1.5 mg/L. The permeate quality of UF (MWCO 5,000) was 57 mg/L as COD and 5 mg/L as MBAS at continuous ozone injection with removal of 95% in COD and 96.9% in MBAS. Using UF with MWCO 10,000, it was 93.7% and 95.5% of COD and MBAS, respectively. And using intermittent ozone injection, the removal efficiency was 93% in COD and 93.5% in MBAS without any deterioration in COD and MBAS removal. It could reduce the treatment cost. Using ozone injection, fouling of the membrane was also controlled by increasing organic degradation. The flux of UF (MWCO 5,000 and 10,000) was 0.13 and 0.20 m/d for 3 hour filtration (TMP 40≈45 kPa) without ozone injection. It was increased to 0.18 and 0.24m/d by ozone injection. The reclaimed water quality could be estimated well enough to reuse for rinsing purposes.

Chemical and bioanalytical assessment of coal seam gas associated water

2015 ◽  
Vol 12 (3) ◽  
pp. 267 ◽  
Author(s):  
Janet Y. M. Tang ◽  
Mauricio Taulis ◽  
Jacinta Edebeli ◽  
Frederic D. L. Leusch ◽  
Paul Jagals ◽  
...  
Keyword(s):  
Surface Water ◽  
Chemical Analysis ◽  
Coal Seam ◽  
Organic Compounds ◽  
Water Samples ◽  
Biological Effects ◽  
Poor Quality ◽  
Coal Seam Gas ◽  
Endocrine Activity ◽  
Comprehensive Study

Environmental context Water associated with coal seam gas is generally of poor quality and thus its management and potential further usage is a subject of concern. In a comprehensive study involving chemical and bioanalytical assessments of coal seam gas associated water, we found that less than 5% of the biological effects could be explained by chemical analysis. The use of bioanalytical tools to complement chemical analysis is recommended for monitoring the quality of water associated with coal seam gas. Abstract A comprehensive study was undertaken involving chemical (inorganic and organic) and bioanalytical assessments of coal seam gas associated water (CSGW) in Queensland, Australia. CSGW is a by-product of the gas extraction process and is generally considered as water of poor quality. CSGW is disposed of by release to surface water, reinjected to groundwater or beneficially reused. In this study, groundwater samples were collected from private wells tapping into the Walloon Coal Measures, the same coal aquifer exploited for coal seam gas production in the Surat Basin. The inorganic characteristics of these water samples were almost identical to the CSGW from the nearby gas field, with high sodium, bicarbonate and chloride concentrations but low calcium, magnesium and negligible sulfate concentrations. As for organic compounds, low levels of polyaromatic hydrocarbons (PAHs) were detected in the water samples, and neither phenols nor volatile organic compounds were found. Five of the fourteen bioassays tested gave positive responses (arylhydrocarbon-receptor gene activation, estrogenic endocrine activity, oxidative stress response, interference with cytokine production and non-specific toxicity), whereas the other nine assays showed no genotoxicity, protein damage or activation of hormone receptors other than the estrogen receptor. The observed effects were benchmarked against known water sources and were similar to secondary treated wastewater effluent, stormwater and surface water. As mixture toxicity modelling demonstrated, the detected PAHs explained less than 5% of the observed biological effects. These results showed that bioanalytical assessment can open new avenues for research into the potential environmental and health risk from CSGW.

Impact of Electronic Faucets and Water Quality on the Occurrence ofPseudomonas aeruginosain Water: A Multi-Hospital Study

2014 ◽  
Vol 36 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Dominique Charron ◽  
Emilie Bédard ◽  
Cindy Lalancette ◽  
Céline Laferrière ◽  
Michèle Prévost
Keyword(s):  
Water Quality ◽  
Flow Rate ◽  
Water Samples ◽  
Cold Water ◽  
Residual Chlorine ◽  
Increased Risk ◽  
High Concentrations ◽  
Enzymatic Detection ◽  
Enzyme Detection ◽  
Hospital Study

OBJECTIVETo comparePseudomonas aeruginosaprevalence in electronic and manual faucets and assess the influence of connecting pipes and water quality.SETTINGFaucets in 4 healthcare centers in Quebec, Canada.METHODSWater samples from 105 electronic, 90 manual, and 14 foot-operated faucets were analyzed forP. aeruginosaby culture and enzymatic detection, and swab samples from drains and aerators were analyzed by culture. Copper and residual chlorine concentrations, temperature, and flow rate were measured.P. aeruginosaconcentrations were analyzed in 4 consecutive volumes of cold water and a laboratory study was conducted on copper pipes and flexible hoses.RESULTSP. aeruginosacontamination was found in drains more frequently (51%) than in aerators (1%) or water (culture: 4%, enzyme detection: 16%). Prevalence in water samples was comparable between manual (14%) and 2 types of electronic faucets (16%) while higher for foot-operated faucets (29%). However, type 2 electronic faucets were more often contaminated (31%) than type 1 (14%), suggesting that faucet architecture and mitigated volume (30 mL vs 10 mL) influenceP. aeruginosagrowth. Concentrations were 100 times higher in the first 250 mL than after flushing. Flexible hoses were more favorable toP. aeruginosagrowth than copper and a temperature of 40°C led to higher counts.CONCLUSIONSThe types of faucets and connecting pipes, flow rate, and water quality are important parameters influencing the prevalence and the concentrations ofP. aeruginosain faucets. High concentrations ofP. aeruginosain the first 250 mL suggest increased risk of exposure when using the first flush.Infect Control Hosp Epidemiol 2014;00(0): 1–9

scholarly journals Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

Poor efficacy of residual chlorine disinfectant in drinking water to inactivate waterborne pathogens in distribution systems

1999 ◽  
Vol 45 (8) ◽  
pp. 709-715 ◽  
Author(s):  
Pierre Payment
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Clostridium Perfringens ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Epidemiological Studies ◽  
Residual Chlorine ◽  
Residual Concentration

To evaluate the inactivating power of residual chlorine in a distribution system, test microorganisms (Escherichia coli, Clostridium perfringens, bacteriophage phi-X 170, and poliovirus type 1) were added to drinking water samples obtained from two water treatment plants and their distribution system. Except for Escherichia coli, microorganisms remained relatively unaffected in water from the distribution systems tested. When sewage was added to the water samples, indigenous thermotolerant coliforms were inactivated only when water was obtained from sites very close to the treatment plant and containing a high residual chlorine concentration. Clostridium perfringens was barely inactivated, suggesting that the most resistant pathogens such as Giardia lamblia, Cryptosporidium parvum, and human enteric viruses would not be inactivated. Our results suggest that the maintenance of a free residual concentration in a distribution system does not provide a significant inactivation of pathogens, could even mask events of contamination of the distribution, and thus would provide only a false sense of safety with little active protection of public health. Recent epidemiological studies that have suggested a significant waterborne level of endemic gastrointestinal illness could then be explained by undetected intrusions in the distribution system, intrusions resulting in the infection of a small number of individuals without eliciting an outbreak situation.Key words: drinking water, chlorine, disinfection, pathogens, distribution system.

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