Drinking water, treatment methods

In addition, it is important to continue research on contaminant DBFs. With increased drought and increased populations in many parts of the world, our rivers contain increasingly higher concentrations of anthropogenic contaminants, which can also form hazardous DBFs. It is important to study their formation and devise wastewater and drinking water-treatment methods that will remove them. 

In recent years, large consumer panels have been employed for sensory assessments of drinking water. As a result of these assessments, water treatment methods have been adjusted. 

The practical use of solar disinfection in drinking water was first studied by Acra et al., who filled polyethylene bags with water before exposing them to full sunlight. Recently, a review of solar disinfection used as a water treatment method has been published (Reed 2004). 

Y. Richard, "Biological Methods for the Treatment of Ground Water , in Oxidation Techniques in Drinking Water Treatment, eds. H. Sontheimer and W.Kuhn, EPA-570/9-79-020,1979. 

The phenomenon of viral adsorption to various surfaces was extensively studied from an environmental standpoint as reviewed by Daniels (14) and Gerba (15) for prevention of various waterborne viral transmissions. The problem of virus removal from complex protein solutions is very different from that of sewage and drinking water treatment processes because most protein molecules compete for the active sites of the adsorbents. Hence, both the adsorption rate and capacity diminish in the presence of protein molecules (16). It is the intention of this paper to demonstrate and to compare the antiviral activity of a surface-bonded QAC in aqueous solutions against 2 model viruses with and without the presence of proteins. The efficacy of the accepted antiviral thermo-inactivation was compared with the viral inactivation method by the surface-bonded QAC treatment. Beta-lactamase was used as a thermolabile model protein (17), and bacteriophage T2 and herpes simplex virus type 1 (HSV-1, an enveloped animal virus) were used as model hydrophilic and hydrophobic viruses to test these chemical inactivation methods. 

Chlorine is not the only means of disinfection available, but other methods can also produce toxic by-products. In addition, alternative disinfectants do not provide the residual protection offered by chlorine-based disinfectants, so they must be used in combination with chlorine. Drinking water treatment must satisfy the competing objectives of maximum microbial decontamination and minimum production of toxic by-products. This is a difficult task that will require research by chemists and chemical engineers in collaboration with a variety of other experts to continuously improve the safety and quality of the world s drinking water. 

Expert systems for predicting the nature of transformation products -Work should focus on the development of methods to identify the most probable transformation pathway in a particular environmental system. The approaches need to be evaluated against high-quahty experimental data on degradation pathways in different media. New expert systems need to be developed for systems where they are not yet available, e.g. drinking water treatment processes. 

Gregor, J., Marsalek, B., Sipkova, H. (2007). Detection and estimation of potentially toxic cyanobacteria in raw water at the drinking water treatment plant by in vivo fluorescence method. Water Research, 41, pp. 228-234, ISSN 0043-1354. 

R420 A. Matilainen, E. T. Gjessing, T. Lahtinen, L. Hed, A. Bhatnagar and M. Sillanpaa, An Overview of the Methods Used in the Characterization of Natural Organic Matter (NOM) in Relation to Drinking Water Treatment , Chemosphere, 2011, 83, 1431. 

The first documentation of drinking water treatment, describing procedures used for purifying water, can be found in Egyptian hieroglyphics. The basic methods were the same as they are today, i.e., boiling, chemical treatment, and filtration. The importance of drinking water quality and its influence on human health were known, but the specific contaminants would not be identified for centuries to come. 

Preconditioning of the sand surface of filters by adding polyelectrolytes is an alternative use of sand filters as a coagulator-flocculator. In the treatment of drinking water the method depends on the limitations of these products in foodstuffs. 

In a recent study, which analyzed influent and effluent concentrations from drinking water treatment plants, it was concluded that only the treatment plants with membrane filtration removed PFCs efficiently [90]. However, PFCs analyzed did not include compounds with carbon chain lengths shorter than C6, thus not revealing the removal capacity for, e.g., PFBA and PFBS at process scale [90]. The generation of a concentrated waste stream when membrane filtration is used and the relatively high operation costs make this treatment method not widely used yet in the drinking water treatment process. 

Matilainen A, Gjessing ET, Lahtinen T, Hed L, Bhatnagar A, Sillanpaa M. An overview of the methods used in the characterisation of natural organic matter (NOM) in relation to drinking water treatment. Chemosphere 2011 83 1431-1442. 

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