Use of a stable carbon isotope to assess the efficiency of a drinking water treatment method with CO2

2012 ◽  
Vol 65 (6) ◽  
pp. 983-988 ◽  
Author(s):  
M. Poberžnik ◽  
A. Leis ◽  
A. Lobnik

CO2 gas with a special isotopic signature (δ13C = −35.2‰ vs. VPDB) was used as a marker to evaluate the efficiency of a drinking water treatment method and the effect of an ultrasonic (US) stirrer. This treatment was developed to prevent precipitation and corrosion effects in water–supply systems. The research work was performed using a laboratory-scale pilot plant that was filled with tap water. The stable isotope analyses of δ13C-DIC (Dissolved Inorganic Carbon) in the water samples indicated that the maximum content of added CO2 gas in DIC was in the range of 35 to 45%. The use of the US stirrer during the entire experiment decreased the method's overall efficiency by 10%, due to degassing at a late stage of the experiment but accelerated the dissolution process in the early experimental stage.

2018 ◽  
Vol 63 (1) ◽  
pp. 96-112 ◽  
Author(s):  
Barış Şimşek ◽  
İnci Sevgili ◽  
Özge Bildi Ceran ◽  
Haluk Korucu ◽  
Osman Nuri Şara

One of the ways of fully securing the presence of fresh water is water treatment process. Nanomaterials and nanotechnology offers an innovative solution for water treatment. In this study, physical, chemical and microbiological improvement rates of raw water were analyzed after filtration with graphene oxide. Graphene oxide's water treatment performance; silver nanoparticles, silver nanoparticles & graphene oxide composites that are commonly used in water treatment were compared with a traditional treatment method. When compared to the traditional method, there were improvements of 50 %, 40.7 %, 86.8 % and 45.5 % for color, TIC, TOC and hardness properties, respectively in water treatment by GO-based filtration with solid liquid ratio of 0.7 % (v/v). In water treatment with GO-Ag based filtration, 39.8 %, 69.8 %, 10.3 % and 28.6 % of improvements were obtained for TIC, TOC, hardness and LSI value compared to the conventional method. Both GO at 0.7 % (v/v) solid-liquid ratio and GO-Ag nanocomposites were successful in the number of total viable microorganisms and inhibiting microorganisms such as Escherichia coli fecal (gaita-infected), Salmonella typhi, Enterococcus faecalis, Pseudomona aeruginosa and Staphylococcus aureus. Among the studied parameters GO-Ag nanocomposites found to be the most suitable for drinking water treatment.


2018 ◽  
Vol 62 (4) ◽  
pp. 141-147
Author(s):  
T. Prošek ◽  
V. Šefl

Abstract Main factors affecting the corrosivity of water in water treatment plants and water towers and other storage facilities, observed types of corrosion degradation of stainless steel and the effect of manufacturing and surface treatment on their corrosion resistance are discussed. A list of stainless steel grades currently used in the field of treatment, transport and storage of drinking water is given together with some other suitable ones. Based on literature resources, optimal stainless steel grades are recommended as a function of water composition and treatment method.


Author(s):  
Zhiquan Liu ◽  
Yongpeng Xu ◽  
Yuan Wang ◽  
Fuyi Cui

Abstract Quinolone (QN) antibiotics are widely used all over the world and have been frequently detected in source water, but the occurrence in tap water and the treatment efficiencies of QNs by drinking-water treatment plants (DWTPs) were rarely reported. In the present study, the occurrence and distribution of six representative QNs in three urban DWTPs of China were investigated. The results showed that the concentrations of total QNs in the three source waters ranged from 26.4 ng/L to 313.8 ng/L and all of the six QNs were detectable with a detection frequency of 100% (4.6 to 121.7 ng/L). Enrofloxacin (ENR) and ofloxacin (OFL) were the dominant species of QNs and accounted for 40.1% to 79.5% of the total QNs. After the treatments, there were still considerable QNs in the finished water (total amounts of 74.9 ng/L to 148.4 ng/L). The adsorbed QNs could be readily treated with the removal of turbidity by DWTPs, but only a part of the dissolved QNs (13.6% to 68.5%) can be removed. This implies that the dissolved QNs were more hazardous in the source water. Pre-oxidation and disinfection could remove 15.8 ± 8.3% and 16.9 ± 10.8% of dissolved QNs, respectively, depending on the chemical structure of QNs and the types of oxidant. Chemical oxidation was more efficient than coagulation-sedimentation and filtration for the treatment of dissolved QNs. Ozone-granular activated carbon filtration may fail to remove dissolved QNs in the actual DWTPs, because of the insufficient dosage of oxidant and the competition effect of natural organic matter.


2013 ◽  
Vol 4 (3) ◽  
pp. 11-16 ◽  
Author(s):  
W. Chali ◽  
I. Yakub

The demand and market growth of activated carbon (AC) in drinking water treatment have been increasing over the recent years. This is because of the better properties and relatively lower cost of AC compared to inorganic adsorbents like ceramics. However, there have been limited studies on the effects of AC preparation including type of cleansing agent on the adsorption of metal and the turbidity of treated tap water. Therefore, this research investigated the effect of types of cleansing agent and sorbent dosage on turbidity reduction and metal removal in drinking water treatment. The analysis showed that 200 g dosage of AC that has been cleansed with FeCl3 has the turbidity and metal removal improved the most. For aesthetic value of drinking water though, filtration by using AC cleansed with KOH gave better taste and increasing the sorbent dosage up to 300 g increased this performance.


2020 ◽  
Vol 1 (1) ◽  
pp. 10-19
Author(s):  
Emmy C. Kerich

Access to safe and clean drinking water is a major challenge to the people living around Ahero Irrigation Scheme (AIS). Water sources in the area are constantly and increasingly polluted by agrochemical like pesticides from rice farming. 2, 4-Dichlorophenoxyacetic acid (2,4-D) is an herbicide extensively used in AIS. The neurotoxic, immunosuppressive, cytotoxic and hepatoxic effects of (2,4-D) have been well documented. Residues of (2,4-D) have been documented in ponds, rivers, lakes and irrigation canals. Therefore this study surveyed agrochemicals used in AIS, the drinking water source for the residents and finally water treatment option for the obtained water in the year 2013. The study established that (52.8%) of the farmers used hand-weeding and 20.8% of them use (2,4-D) for the weeds control. Results indicated that the most preferred water source was lined improved well (47.2%) followed by irrigation canal (22.2%), the least preferred was rain water with (2.8%). The most used method of water treatment was chlorination (45.8%). Spearman’s coefficient of correlation ( ) revealed that there was positive correlation between the two variables ( =0.145, 72, p=0.224>0.05). As  is positive, it implies that the type of treatment given to water depend on its source of the water. Despite the use of chlorinate with almost half of the residents, some of them (22.2%) do not treat their water at all, which may pose a risk of getting water related diseases. Furthermore, despite a proportional number of residents obtaining their water from irrigation canal, all of them do not have appropriate method/s for treating water contaminated with organic pollutants such as herbicides. There is a need to promote water appropriate drinking water treatment method/s in the study area to prevent water related diseases at the family level. Doi: 10.28991/HEF-2020-01-01-02 Full Text: PDF


2005 ◽  
Vol 3 (2) ◽  
pp. 173-184 ◽  
Author(s):  
John M. Colford ◽  
Sona R. Saha ◽  
Catherine C. Wright ◽  
Alan Hubbard ◽  
Joseph N.S. Eisenberg ◽  
...  

Although immunocompromised persons may be at increased risk for gastrointestinal illnesses, no trials investigating drinking water treatment and gastrointestinal illness in such patients have been published. Earlier results from San Francisco suggested an association (OR 6.76) between tap water and cryptosporidiosis among HIV+ persons. The authors conducted a randomized, triple-blinded intervention trial of home water treatment in San Francisco, California, from April 2000 to May 2001. Fifty HIV-positive patients were randomized to externally identical active (N = 24) or sham (N = 26) treatment devices. The active device contained a filter and UV light; the sham provided no treatment. Forty-five (90%) of the participants completed the study and were successfully blinded. Illness was measured using ‘highly credible gastrointestinal illness’ (HCGI), a previously published measure. There were 31 episodes of HCGI during 1,797 person-days in the sham group and 16 episodes during 1,478 person-days in the active group. The adjusted relative risk was 3.34 (95% CI: 0.99–11.21) times greater in those with the sham device. The magnitude of the point estimate of the risk, its consistency with recently published observational data, and its relevance for drinking water choices by immunocompromised individuals support the need for larger trials.


2009 ◽  
Vol 75 (17) ◽  
pp. 5714-5718 ◽  
Author(s):  
Chuanwu Xi ◽  
Yongli Zhang ◽  
Carl F. Marrs ◽  
Wen Ye ◽  
Carl Simon ◽  
...  

ABSTRACT The occurrence and spread of antibiotic-resistant bacteria (ARB) are pressing public health problems worldwide, and aquatic ecosystems are a recognized reservoir for ARB. We used culture-dependent methods and quantitative molecular techniques to detect and quantify ARB and antibiotic resistance genes (ARGs) in source waters, drinking water treatment plants, and tap water from several cities in Michigan and Ohio. We found ARGs and heterotrophic ARB in all finished water and tap water tested, although the amounts were small. The quantities of most ARGs were greater in tap water than in finished water and source water. In general, the levels of bacteria were higher in source water than in tap water, and the levels of ARB were higher in tap water than in finished water, indicating that there was regrowth of bacteria in drinking water distribution systems. Elevated resistance to some antibiotics was observed during water treatment and in tap water. Water treatment might increase the antibiotic resistance of surviving bacteria, and water distribution systems may serve as an important reservoir for the spread of antibiotic resistance to opportunistic pathogens.


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