Ozone, disinfection

Disinfection. Ozone is a more effective broad-spectmm disinfectant than chlorine-based compounds (105). Ozone is very effective against bacteria because even concentrations as low as 0.01 ppm are toxic to bacteria. Whereas disinfection of bacteria by chlorine involves the diffusion of HOGl through the ceU membrane, disinfection by ozone occurs with the lysing (ie, mpture) of the ceU wall. The disinfection rate depends on the type of organism and is affected by ozone concentration, temperature (106), pH, turbidity, clumping of organisms, oxidizable substances, and the type of contactor employed (107). The presence of oxidizable substances in ordinary water can retard disinfection until the initial ozone demand is satisfied, at which point rapid disinfection is observed. 

TOC Sampling Point Not Disinfected Ozone Chlorine Dioxide Chloramine Chlorine... 

OZONE. [CAS 10028-15-6]. Ozone, O3, is an allolropic form of oxygen first recognized as a unique substance in 1840. Its pungent odor is detectable at "0.01 ppm. It is thermally unstable and explosive in the gas, liquid, and solid phases. In addition to being an excellent disinfectant, ozone is a powerful oxidant not only thermodynamically, but also kinetically, and has many useful synthetic applications in research and industry. Its strong oxidizing and disinfecting properties and its innocuous... 

As was shown previously in some examples [15-18] in a large ozonation plant for water treatment, residual ozone in the gas exiting the ozonation stages could be sent back to the head of the water plant where it is injected in another compartment to aid flocculation, remove iron and manganese, or reduce the trihalomethane formation potential (see Fig. 8). In these cases, it is not surprising that these plants could also have a final disinfection ozonation step. 

In addition to disinfection, ozone has been used in municipal wastewater treatment to enhance biodegradability of recalcitrant organic chemicals, control odor, improve suspended solids removal, improve the performance of granular activated carbon, and condition sludge. ... 

Intensive physical and chemical treatment, extended treatment and disinfection e.g. chlorination to break-point, coagulation, flocculation, decantation, filtration, adsorption (activated carbon), disinfection (ozone, final chlorination). 

Disinfeetion. Chlorine, as gaseous chlorine or as the h5rpochlorite ion, is widely used as a disinfectant. However, its use in some cases can lead to the formation of toxic organic chlorides, and the discharge of excess chlorine can be harmful. Ozone as an alternative disinfectant leads to products that have a lower toxic potential. Treatment is enhanced by ultraviolet light. Indeed, disinfection can be achieved by ultravifflet light on its own. 

Ozone caimot be employed for the disinfection of distributed water because of its short lifetime. Unless removed from the treatment plant, the presence of low molecular weight, oxygenated, and biodegradable organics that ozone produces can promote biological growth. 

The pharmaceutical industry employs ozone in organic reactions to produce peroxides as germicides in skin lotions, for the oxidation of intermediates for bacteriostats, and in the synthesis of steroids (qv) such as cortisone (see Disinfectants and antiseptics). Vitamin E can be prepared by ozonation of trimethyUiydroquinone. 

Sanitizers. Spa and hot-tub sanitation is dominated by chlorine- and bromine-based disinfectants. Public spas and tubs usually employ automatic feeders, eg, CI2 gas feeders, to maintain a disinfectant residual. Private or residential spas and tubs can use automatic chemical feeding or generating devices, or they can be sanitized manually with granular or liquid products. The most widely used products for private spa and tub sanitation are sodium dichloroisocyanurate and bromochlorodimethylhydantoin. Granular products are normally added before and after use, whereas solids, eg, stick-bromine, are placed in skimmers or feeders. Bromine generating systems can also be used and are based on oxidation of bromide ions (added to the water as sodium bromide) by peroxymonosulfate, chloroisocyanurates, hypochlorites, or ozone to generate the disinfectant HOBr. 

Chlorine Dioxide. Like ozone, chlorine dioxide [10049-04-4] is a powerflil oxidant. It is usually generated as used. It has been used for disinfecting drinking water and bleaching paper pulp. Its effectiveness in killing microorganisms is well documented (305,306), and it has received recent study as a gas to sterilize medical devices. It requites 50% rh or higher to be effective. Bacterial cells had a D-value of 2.6 min and spores of 24 min (307). 

For inactivation of microorganisms disinfection. Typical disinfectants are chlorine, chlorine dioxide, chloramines, and ozone. 

Ozone is used extensively in Europe to purify water. Ozone, a moleeule eomposed of 3 atoms of oxygen rather than two, is formed by exposing air or oxygen to a high voltage eleetrie are. Ozone is mueh more effective as a disinfectant than... 

Can ozone be used as the only means of water disinfection in a treatment facility If not, why not, and what other technologies do you think would work in combination with ozone treatment ... 

Disinfection - water completely free of suspended sediment, is treated with a powerful oxidizing agent usually chlorine, chlorine and ammonia (chloramine), or ozone. A residual disinfectant is left in the water to prevent reinfection. Chlorine can form harmful byproducts and has suspected links to stomach cancer and miscarriages. 

Ozone applications in the United States for drinking water are far fewer than in Europe. However, the potential market is large, if environmental or health needs ever conclude that an alternate disinfectant to chlorine should be required. Although energy costs of ozonation are higher than those for chlorination, they may be comparable to combined costs of chlorination dechlorination-reaeration, which is a more equivalent technique. One of ozone s greatest potential uses is for municipal wastewater disinfection. 

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