scholarly journals Reduction of trihalomethane formation and detoxification of microcystins in tap water by ozonation

2008 ◽  
Vol 6 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Orapin Thapsingkaew ◽  
Vilailuck Kijjanapanich ◽  
Werawan Ruangyuttikarn

The efficiency of ozonation in comparison to chlorination for removal of microcystins and production of trihalomethanes (THMs) in water was investigated. One hundred and ninety water samples of ozone and chlorine treated water were collected at a water treatment plant between August 2004 and March 2005. The level of THMs, total organic carbon and residual chlorine were determined. Protein phosphatase 2A inhibition assay was used to detect microcystins and the presence of microcystins was confirmed by HPLC. The results show that 91.5% of the THM species in treated water was chloroform and 8.5% was bromodichloromethane. The mean THM level± standard error of mean in chlorinated water (CW) (45.1±3.0 μg/L) was higher than the mean of THM level in ozonated water (OW) (18.6±2.2 μg/L). In addition, no OW sample exceeded the first stage U.S. EPA maximum THM contaminant level for drinking water (80 μg/L) and only 8% of these samples exceeded the second stage level (40 μg/L). On the other hand, 3% of CW samples exceeded 80 μg/L and 68% exceeded the 40 μg/L level. The microcystin level in all water samples was below the WHO guideline value (1 μg/L) for drinking water.

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Belay Desye ◽  
Biniam Belete ◽  
Zinabu Asfaw Gebrezgi ◽  
Tsegaye Terefe Reda

Introduction. Access to safe drinking water is essential to health, and it is a basic human right. However, drinking water treatment plant efficiency and its water quality are not well investigated in low-income countries including Ethiopia. Methods. A laboratory-based cross-sectional study was conducted among 75 water samples. Data analysis was carried out using SPSS version 22 to generate descriptive statistics, and one-way ANOVA was used to test statistically significant difference. Results. Physicochemical qualities of the water samples from tap water sources were found to be pH (6.88 ± 0.05), turbidity (5.15 ± 0.006 NTU), electrical conductivity (170.6 ± 0.1 μS/cm), residual chlorine (0.19 ± 0.003 mg/L), and fluoride (1.17 ± 0.009 mg/L). The removal efficiency of turbidity, total hardness, and nitrate was found to be 94.4%, 52.3%, and 88.7%, respectively. Removal efficiency of the treatment plant for total coliforms up to 91.6% (15 ± 0.26 CFU/100 mL in tap water) and faecal coliforms up to 99% (1.51 ± 0.03 CFU/100 mL in tap water) was recorded. Parameters of pH, temperature, and faecal coliform were statistically significant different at p < 0.05 in tap water source. The overall efficiency of the treatment plant (68.5%) and the water quality index (76) were recorded. Conclusion. Based on the results, some of the investigated parameters of water quality (turbidity, residual chlorine, total coliform, and faecal coliform) were found to be not within the permissible limits of WHO guideline values for drinking water quality. The water quality index of the water samples was categorized under good water quality. To adequately treat drinking water and improve the treatment plant, adequate preliminary treatments like screening to reduce the incoming organic loading, proper chlorination of the drinking water system, and frequent monitoring and maintenance of the treatment plant system are required.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
C Pignata ◽  
S i Bonetta ◽  
S a Bonetta ◽  
S M Cacciò ◽  
A R Sannella ◽  
...  

Abstract Over the past decade, several outbreaks of cryptosporidiosis have been reported in many EU countries in association with the consumption of contaminated drinking water, recreational waters, food consumption and contact with animals. The aim of this study was to evaluate the occurrence of Cryptosporidium oocysts in a drinking water treatment plant (DWTP) located in a rural area of northern Italy. Influent and effluent samples at the DWTP, together with tap water samples from a public fountain were collected for three years (2013-2016). All samples were analysed for the presence of Cryptosporidium spp. oocysts by the EPA Method 1623 based on immunomagnetic separation (IMS)/immunofluorescence assay (IFA), complemented by 4,6-diamidino-2-phenylindole (DAPI) staining. The detection has been implemented with a reverse transcriptase-PCR (RT-PCR) protocol to evaluate the oocyst viability. The results highlighted a high variability of oocyst concentrations in all samples (mean 4.3 - 5.8/100 L) and a high percentage variability of the DAPI-positive specimens (mean 48.2% - 40.3%). Conversely, RT-PCR did not reveal the presence of any viable C. parvum and C. hominis oocysts. A nested PCR targeting Cryptosporidium 18S ribosomal DNA was carried out in two water samples to deepen the understanding of the obtained results. This test revealed the presence of a particular Cryptosporidium genotype associated with wild animals in the river and in tap water. Although the recovered Cryptosporidium genotype is not a human pathogen, its presence demonstrates the existence of a potential pathogen Cryptosporidium spp. contamination risk. Moreover, these results underline the importance of considering unconventional (not bacterial) biological contaminations (protozoa) in water resources in rural areas, including those of developed countries. Key messages The supply source and the drinking water treatment plant examined represent a classic example of a system that requires continuous monitoring to guarantee population health. Cryptosporidium oocysts may still be a Public Health problem even in industrialized countries, especially in rural and mountain areas.


Author(s):  
Wenjin Xue ◽  
Christopher W. K. Chow ◽  
John van Leeuwen

Abstract The bacterial regrowth potential (BRP) method was utilised to indirectly measure the assimilable organic carbon (AOC) as an indicator for the assessment of the microbial regrowth potential in drinking water distribution systems. A model using various microbial growth parameters was developed in order to standardise the experimental interpretation for BRP measurement. This study used 82 experimental BRP data sets of water samples collected from the water treatment plant to locations (customer taps) in the distribution system. The data were used to model the BRP process (growth curve) by a data fitting procedure and to obtain a best-fitted equation. Statistical assessments and model validation for evaluating the equation obtained by fitting these 82 sets of data were conducted, and the results show average R2 values were 0.987 for treated water samples (collected at the plant prior to chlorination) and 0.983 for tap water (collected at the customer taps). The F values obtained from the F-test are all exceeded their corresponding F critical values, and the results from the t-test also showed a good outcome. These results indicate this model would be successfully applied in modelling BRP in drinking water supply systems.


2020 ◽  
Vol 69 (5) ◽  
pp. 469-477
Author(s):  
Hongyuan Liu ◽  
Haoran Liu ◽  
Yawei Xie

Abstract Residual aluminum in drinking water is widely concerning due to its potentially harmful effect on human health and drinking water distribution systems. The fate and fractionation of aluminum and the factors influencing residual aluminum in a full-scale Al-based drinking water treatment plant (DWTP) was presented in Jiaxing, China. The results showed that treated water residual aluminum concentration was less than 0.1 mg/L regardless of the seasonal change of raw water aluminum concentration. The addition of secondary flocculation had a negligible influence on treated water residual aluminum concentration due to the efficient removal of particulate aluminum by sand filter. Residual aluminum concentration of treated water was lower (mean 0.037 mg/L) in summer (average water temperature was 29 °C) than that (mean 0.067 mg/L) in winter (average water temperature was 16 °C). Significant positive relationships between particulate aluminum concentration and particle counts, as well as the total aluminum concentration of treated water and turbidity, were found. Those relationships provided the possibility to estimate residual aluminum concentration by monitoring particle counts and turbidity.


2018 ◽  
Vol 10 (2) ◽  
pp. 601-607
Author(s):  
Poonam Kundan ◽  
Deepika Slathia

In the present study, an attempt has been made to evaluate the water quality changes in River Tawi water treated at Sitlee water treatment plant, and supplied for drinking to Old Jammu City, Jammu, J&K, India. Water samples from the treated water unit of Sitlee water treatment plant and around ten houses from the distribution point (Old Jammu City) were analyzed monthly for various physicochemical parameters for a period of one year (February 2014 to January 2015). The study indicated deterioration of drinking water quality during its passage through the distribution network which has been attributed to the leakages and defects in the old pipe system supplying water to the Jammu city. Comparison of analyzed water quality parameters with the drinking water standards prescribed by World Health Organization (WHO) and Bureau of Indian Standards (BIS) indicated that parameters like DO (7.49-8.24mg/l), calcium(49.93-67.08mg/l), magnesium(16.14-25.21mg/l) and potassium(6.99-7.93mg/l) were almost nearing the desirable limits but were within the permissible limits and parameters like turbidity(3.5-8.17 NTU) and total hardness(78.87-120.50mg/l) were above the desirable limits in the water samples collected from the distribution point. The collected primary data for the thirteen water quality parameters has been used to calculate the Arithmetic Water Quality Index(WQI) which has shown monsoon increase with higher values at distribution point(65.65). One time microbial analysis (MPN/100ml) for total and faecal coliform has indicated presence of faecal coliform (<1/100ml) in water samples from eight households at distribution point which indicates contamination of water with human faecal matter during its passage through the distribution network. According to microbial standards laid down by Central Pollution Control Board (2008), water contaminated with faecal coliform is unfit for drinking without conventional treatment.


1999 ◽  
Vol 45 (8) ◽  
pp. 709-715 ◽  
Author(s):  
Pierre Payment

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.


2015 ◽  
Vol 3 (3) ◽  
pp. 528-536
Author(s):  
Yehia A. Osman ◽  
Waled M. El-Senousy ◽  
Adel A. El-Morsi ◽  
Mohammed K. Rashed

The fecal bacteria have been taken as the gold standard for water industry. However, the spread of viral gastroenteritis due to drinking water have given a momentum to a recent push by microbiologists to consider viruses as important pollution indicator as fecal bacteria. Therefore, we designed a study to evaluate the efficiency of two types of water purification systems: the traditional water treatment plant and two types compact units. Both systems produced drinking waters free of bacteria, chemical contaminants and mostly viruses free.  However, recent advances in molecular biology techniques, such as RT-PCR have detected Rotaviruses in chlorinated drinking waters resulted from all systems. The frequency of Rotaviruses since October 2010 till September 2012 in Shark El-Mansoura WTP in drinking water samples was 12.5% similar to raw water. While the compact unit at Depo Awam (American design) the frequency of Rotavirus was 16.6% in both raw and drinking water samples.  On the other hand the virus frequency in the raw and drinking water sample in El-Danabik unit (Egyptian design) were 12.5% and 4.16% respectively. Signifying failure of the chlorination process in removing viruses completely.  However, detection of Rotavirus genome in the drinking water samples does not means the presence of its infectivity. The infectious ability of the rotaviruses was confirmed by CC-RT-PCR in all positive samples, where viral RNA was not detected in the collected drinking water samples.  In conclusion RT-PCR and CC-RT-PCR techniques high lightened the need to include viruses as mandatory pollution indicator in water treatment plants. Int J Appl Sci Biotechnol, Vol 3(3): 528-536


Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 669 ◽  
Author(s):  
Elane D.C. Oliveira ◽  
Raquel Castelo-Branco ◽  
Luis Silva ◽  
Natalina Silva ◽  
Joana Azevedo ◽  
...  

Human poisoning by microcystin has been recorded in many countries, including Brazil, where fatal cases have already occurred. The Amazon River is the main source of drinking water in municipalities such as Macapá, where there is no monitoring of cyanobacteria and cyanotoxins. This study investigated the presence of cyanobacteria and cyanotoxins in samples from a drinking water treatment plant (DWTP) that catches water from the Amazon River. The toxin analyses employed ELISA, LC/MS, and molecular screening for genes involved in the production of cyanotoxins. The sampling was carried out monthly from April 2015 to April 2016 at the intake (raw water) and exit (treated water) of the DWTP. This study reports the first detection of microcystin-LR (MC-LR) in the Amazon River, the world’s largest river, and in its treated water destined for drinking water purposes in Macapá, Brazil. The cyanobacterial density and MC-LR concentration were both low during the year. However, Limnothrix planctonica showed a density peak (± 900 cells mL−1) in the quarter of June–August 2015, when MC-LR was registered (2.1 µg L−1). Statistical analyses indicate that L. planctonica may produce the microcystin.


1970 ◽  
Vol 23 (2) ◽  
pp. 133-136 ◽  
Author(s):  
M Alamgir Hossain ◽  
Tahmina Begum ◽  
ANM Fakhruddin ◽  
Sirajul Islam Khan

Bacteriological and physicochemical parameters of the raw and treated water of the Saidabad Water Treatment Plant were analysed during the period January through December 2004. It was found that during dry season Sitalakhya River water was adversely polluted and most of the bacteriological and physicochemical parameters increased to an alarming level. Total coliform and thermotolerant-coliform counts of raw water were highest in months of January through March and lowest during the months of April through November. Ammonia concentration of the raw water was very high (3.08-7.06 mg/l) during the dry months from January to April that coincided with high (2.57-6.08 mg/l) ammonia contamination in the treated water. The others physicochemical parameters like turbidity, conductivity, total dry solid (TDS), hardness and alkalinity were high during the dry months. The residual chlorine in treated water was always below 0.50 mg/l. The study clearly indicated that the load of coliform increased when the concentration of ammonia was high in raw water that, to some extent, influenced the aesthetic properties of the treated water like turbidity, colour, taste, odour, alkalinity, TDS, etc. In spit of that the treated water could be used for domestic and drinking purposes for most of the year. Keywords: Water quality, Total coliform, Thermotolerant-coliform, Ammonia, Physicochemical properties, Residual chlorine   DOI: http://dx.doi.org/10.3329/bjm.v23i2.878 Bangladesh J Microbiol, Volume 23, Number 2, December 2006, pp 133-136


2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
M. R. Siti Farizwana ◽  
S. Mazrura ◽  
A. Zurahanim Fasha ◽  
G. Ahmad Rohi

The study was to determine the concentration of aluminium (Al) and study the physicochemical parameters (pH, total dissolved solids (TDS), turbidity, and residual chlorine) in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S), the treatment plant outlet (TPO), and at the nearest houses (H1) and the furthest houses (H2) from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90). The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU). Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L). Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems.


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