Disinfection, chemical physical

Chemical/Physical. Hypochlorite ions, formed by the chlorination of water for disinfection purposes, may react with acetone to form chloroform. This reaction is expected to be significant within the pH range of 6 to 7 (Stevens et al., 1976). 

Disinfection Chemical or physical treatment that destroys most vegetative microbes or viruses, but not spores, in or on inanimate surfaces... 

Waterborne microorganisms are largely responsible for the transmission of diseases such as cholera, typhoid, dysentery, muscular paralysis (e.g., poliomyelitis), infectious hepatitis, gastroenteritis, giardiasis, cryptosporidiosis, and so forth. In a drinking-water potabilization procedure not all the microorganisms present in water need to be killed (sterilization), but only those disease-related (disinfection). Water disinfection can be achieved by chemical, physical, or mechanical action. Agents that provide chemical action for such purposes include ... 

The first membranes used, based on cellulose acetate, were uot very resistant to microorganisms, shocks, temperature or pH. Second-generation membranes, made from polysulfone or polyacrylonitrile polymers, were much tougher. Cur-reut third-geueration inorganic membranes have good chemical, physical and heat (temperature >100°C) resistance characteristics. They have almost unlimited lifetimes and are easily cleaned and disinfected. The operating parameters are as follows (a) transmembrane differential pressure,... 

A report released by the national environmental health group Women s Voices for the Earth (WVE) (htq> //www.womensvoices.org/wp-content/uploads/2010/05/ Disinfectant-OverkilLpdf) linked disinfectant chemicals with chronic illnesses and conditions such as asthma, hormone imbalance, and immune system problems in a report titled Disinfectant Overkill How Too Clean May Be Hazardous to Our Health, which cited more than 40 peer-reviewed reports and scientific studies. According to the report Triclosan and Triclocarban, two antibacterial disinfectants may have hormone-disrupting effects Triclosan adversely affects communication between cells in the brain and the heart while Triclocarban appears to amplify testosterone in the body (http //www.womensvoices.org/wp-content/uploads/2010/05/ Disinfectant-OverkilLpdf). The physical and chemical properties of disinfectants and their byproducts can influence their behavior in drinking water. 

Egerton, T.A., Kosa, S.A. and Christensen, P.A. (2006) Photoelectrocatalytic disinfection of E. coli suspensions by iron doped Ti02. Physical Chemistry Chemical Physics PCCP, 8, 398-406. 

Definitions. Physical and chemical agents that combat pathogenic and nonpathogenic microorganisms are often referred to as disinfectants. Attempts to standardize terminology by health agencies in the United States, such as the CDC, the Pood and Dmg Administration (PDA), and the EPA, have resulted in the following definitions. 

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. 

The control over human viral diseases is exercised by active immunization (Chapters 14 and 16) of the population, together with general hygiene and physical and chemical disinfection procedures. 

All disinfection and sterilization processes for equipment should be validated, for preference using a microbiological challenge with an organism of appropriate resistance to the disinfectant, sterilant or sterilizing conditions. Once the required log reduction of the challenge organism has been achieved, physical and/or chemical parameters can be set which form the critical control points for the process. 

When the water is too alkaline, swimmers experience similar physical discomfort—burning eyes and nose and itchy, dry skin. The effect on the pool, however, is different. When water is alkaline, calcium dissolved in the pool water can precipitate (fall) out of solution. A precipitate is a solid that forms from a solution due to a chemical reaction. This solid creates unsightly scales on the sides of the pool. Like water that is too acidic, alkaline water also affects the efficiency of the chlorine. More chlorine needs to be added to alkaline water to effectively disinfect the pool. Over time, a swimming pool that is not kept at a neutral pH can become very expensive to maintain. 

Physical disinfection of drinking water is mainly carried out through photodegradation by ultraviolet radiation (UV). Because many pharmaceuticals have chromophores that absorb UV wavelength, UV irradiation can lead to some transformation. Comparing to chemical oxidation, such as chlorination, UV disinfection has an advantage of minimizing the formation of DBPs [73]. However, at a... 

Some of the chemical classes of antiseptics, disinfectants, and sterilants are described briefly in the text that follows. The reader is referred to the general references for descriptions of physical disinfection and sterilization methods. 

A chemical or a physical process that kills pathogenic bacteria and other organisms in water. Chlorine is a common disinfectant. 

The regulation quoted lists all known physical and chemical means of disinfection and disinfestation. Similarly, a work guideline was released in 1943 by the Sanitation Institute of the Waffen-SS Ent-... 

Several physical and chemical approaches are used to inactivate parasites however, the level of disinfection is often limited. In addition, some conventional treatments may also generate harmful effects on the environment [51], Recent findings indicate... 

---