By disinfection

Tertiary treatment is required often to meet the industry or irrigation standards, especially when disinfection is needed. This step is known as water regeneration. Typical tertiary treatment proposed in the literature [23] is composed of the following stages low pressure membrane filtration (e.g., MF) followed by disinfection stage and finally high pressure membrane filtration (e.g., RO). Industrial... 

Susceptibility of viruses to antimicrobial agents can depend on whether the viruses possess a lipid envelope. Non-lipid viruses are frequently more resistant to disinfectants and it is also likely that such viruses cannot be readily categorized with respect to their sensitivities to antimicrobial agents. These viruses are responsible for many nosocomial infections, e.g. rotaviruses, picornaviruses and adenoviruses (see Chapter 3), and it may be necessary to select an antiseptic or disinfectant to suit specific circumstances. Certain viruses, such as Ebola and Marburg which cause haemorrhagic fevers, are highly infectious and their safe destruction by disinfectants is of paramount importance. 

Richardson SD, AD Thurston, C Rav-Acha, L Groisman, 1 Popilevsky, O Juraev, V Glezer, AB McKague, Ml Plewa, ED Wagner (2003) Tribromopyrrole, brominated acids, and other disinfection byproducts produced by disinfection of drinking water rich in bromide. Environ Sci Technol 37 3782-3793. 

Wang, L.K. Wood, G.W. Water Treatment by Disinfection, Flotation and Ion Exchange Process System, PB82-213349 US Department of Commerce, Nat. Tech. Information Service Springfield, VA, 1982. 

Insecticides. Whereas fleas can be effectively dealt with by disinfection of clothes and living quarters, lice and mites require the topical application of insecticides to the infested subject. 

Viruses (enteric) Require 99.99% removal/inactivation by disinfection and filtration Gastrointestinal illness, diarrhea, vomiting, cramps... 

Several operations may be employed to treat water prior to use. Aeration is used to drive off odorous gases, such as H2S, and to oxidize soluble Fe2+ and Mn2+ ions to insoluble forms. Lime is added to remove dissolved calcium (water hardness). A12(S04)3 forms a sticky precipitate of Al(OH)3, which causes very tine particles to settle. Various filtration and settling processes are employed to treat water. Chlorine, Cl2, is added to kill bacteria. Formation of undesirable byproducts of water chlorination may be avoided by disinfection with chlorine dioxide, C102, or ozone, 03. 

Schmidt, W., Boehme, U., Sacher, F. and Brauch, H.-J. (1999) Formation of chlorate by disinfection of drinking water (in German). Vom Wasser 93,109-126. 

Bacteriological cleanness obtained by disinfection that kills all pathogenic bacteria and most, but not all, other bacteria. 

Real-World Connection Many Third World regions have outbreaks of deadly diseases, such as cholera and typhoid fever, that could easily be prevented by disinfecting water supplies with chlorine. 

Thus, the 1.29-log inactivation achieved by disinfection in this system exceeds the 1-log additional inactivation required to meet overall treatment objectives. 

The types of chemicals produced by disinfectants and some specific examples are provided in Table 1. The reader should not be deceived by the fact that the list of by-products associated with chlorination is much longer than that of other disinfectants. This is the result of more thorough study, not necessarily an actual reflection of the numbers of by-products that are formed by each process. 

Killed vaccines. Killed vaccines are suspensions of bacteria, viruses or other pathogenic agents, that have been killed by heat or by disinfectants such as phenol, ethanol or formaldehyde. Killed microorganisms obviously cannot replicate and cause an infection and so it is necessary for each dose of a killed vaccine to contain sufficient antigenic material to stimulate a protective immune response. Killed vaccines therefore usually have to be relatively concentrated suspensions. Even so, such preparations are often rather poorly protective, possibly because of partial destruction of protective antigens during the killing process or inadequate expression... 

The treatment of sewage by disinfectants has been tried out to some extent and according to some authorities has considerable possibilities. The disinfectants used are chlorine and copper salts. 

The setting of plaster when mixed with HgO, is due to the conversion of the anhydrous into the crystalline, hydrated salt. The ordinary plastering should never be used in hospitals, as, by reason of its irreg ularities and porosity, it soon becomes saturated with the transferrers of septic disease, be they germs or poisons, and cannot be thoroughly purified by disinfectants. Plaster sur-... 

The rhythm of racking must also be taken into account. In a cellar where the barrels are stored with the bung on the side, racking and adjustment of the free SO2 level, accompanied by disinfection of the barrels, must be carried out every 3 months during the first year of barrel aging. If racking is delayed, as shown in Table 8.9, the quantity of free SO2 remaining at the end of the period is too small to protect the wine effectively. The wine is subject to rapid contamination by Brettanomyces yeasts and its ethyl-phenol content inevitably increases. 

JD Druce, D Jardine, SA Locarnini, CJ Birch. Susceptibility of HIV to inactivation by disinfectants and ultraviolet Light. J Hosp Infect 30(3) 167-180, 1995. 

Lilly HA, Lowbury EJL, Wilkins MD. Limits to progressive reduction of resident skin bacteria by disinfection. J Clin Pathol 79 107-119, 1979. 

The quality of drinking water is very important to human welfare. The pollution of water by sewage has been linked to the spread of diseases such as cholera and typhoid fever. Elimination of these diseases in developed countries has been a direct result of purification of such water, principally by disinfection using chlorine. 

Vacuum lines protected by disinfectant traps and HEPA filters... 

As counteractions, proper mechanical cleaning followed by disinfection and replacement of wom-out parts and surfaces should be promptly undertaken to eliminate... 

Water treatment by disinfection processes is considered a major public health achievement of the twentieth century. Consequently, there has been a shift in the identification methods of water contaminants from microbiological to chemical. The number of chemicals determined in drinking water has grown exponentially however, out of hundreds of them, only very few have been studied or have documented proof of their health effects. 

A disinfectant, such as a water solution of isopropanol, destroys some but not all organisms. Spores, for example, aren t destroyed by disinfectants. Sterilants are capable of completely eliminating or destroying all forms of microbial life, including spores. Isopropanol is not a sterilant isopropanol Is a good and versatile disinfectant. For chemical sterilization, ethylene oxide is frequently specified. 

To produce potable water which is safe to consume and free from turbidity, colour, odour and taste natural (raw) water abstracted from rivers, lakes, reservoirs and wells, etc., must be treated to remove pathogenic organisms, and mineral and organic contaminants. This is normally done by a process train comprising coagulation, flocculation, sedimentation and filtration followed by disinfection using either chlorine or ozone. 

Restrictions on materials near food processing lines Requirements for materials not to be damaged by disinfecting Firebreak requirements on ducts, pipe runs, shafts Flame spread rate limits Fire endurance limits... 

Short-chain halocarbons, volatile halogenated organic compounds (VHOCs), are another part of the VOCs group. Many of these compoimds are used in the industry. A subset is formed by disinfection by-products such as THMs, haloacetonitriles, etc. VOSCs lead to unpleasant odor in water by action of microorganisms. 

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