Disinfection advantages/disadvantages

Table 20.2 Alternative disinfection methods with their advantages and disadvantages...

Compare the advantages and disadvantages of chlorine gas and ozone gas as disinfectants for municipal water supplies. 

The EPA Surface Water Treatment Ruse (SWTR) requires public water supplies, under the direct influence of surface water, to be disinfected. Some disinfectants produce chemical by-products SWTR requires that their concentration remain within the MCL. Currently, one such by-product is trihalomethanes. Water disinfection is effective when combined with conventional treatment, such as coagulation, flocculation, sedimentation, and filtration. The latter is accomplished by sand or diatomaceous earth. The effectiveness of disinfection is evaluated by determining total coliform bacteria which are not pathogenic, but their presence suggests that certain pathogens may have survived. The various chemicals commonly used as disinfectants are presented below and some of their advantages and disadvantages are listed. 

The disadvantages of mercurials for antiseptic and disinfectant uses far outweigh any pos.siblc advantages that they might have. Hence, other more effective and lc.ss potentially toxic agents are preferable. 

US Environmental Protection Agency has compared ultraviolet radiation with other disinfection processes in terms of their technological status (Table 5), disinfectant production (Table 6), operation and maintenance (Table 7), process advantages and disadvantages (Table 8), and applicahon points (Table 9). 

Paul Chen et al. Table 8 Advantages and Disadvantages of Five Disinfection Processes ... 

McCoy, Stimson, and Hasseltine give the following list of advantages and disadvantages of some common disinfectants ... 

List the compounds used as antiseptics and disinfectants and describe their advantages and disadvantages. 

The use of iodine, hke all disinfectants, has its advantages and disadvantages. These must be evaluated for populations that may have sensitivity to iodine, such as a thyroid condition. 

AU IC methods used for bromate, chlorite, and chlorate analyses have some advantages and disadvantages. Nevertheless, at present IC is the only accepted standard method for the analysis of inorganic oxyhalide disinfection by-products. The choice of the most convenient and the best method for the determination of specific oxyhahdes depends on many factors, such as expected concentration of analyte, sample matrix, limit of determination obtainable by the method used, and its availability. 

Complete protection of operator and product can be achieved by an isolator (see Sect. 28.3.7). Apart from complete product and operator protection other advantages are controlled disinfection procedures, lower initial investments costs of the background area and exploitation costs. Disadvantages are higher costs compared to a LAF unit and its elaborate cleaning and maintenance. Therefore, in practice the choice of type of local exhaust equipment is determined by a risk assessment of the... 

In comparison with ozone and chlorine dioxide, the main advantage of chlorine species as disinfectants is their reservoir effect in a system over increased time. The main disadvantage is the formation of halogenated by-products. Because of this, and to avoid microorganism adaptation effects, continuous use of disinfection cells without periodic interruption is not recommended. 

Give one major advantage and one major disadvantage of using chlorine dioxide for water disinfection. 

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