Ultraviolet Disinfection

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Ultraviolet is an electromagnetic emission with a wave length from 10 to 400 nm. Electromagnetic emission within the range of 200-350 nm with a peak within 260± nm is characterized by the higher bactericidal effect. Action of ultraviolet emission causes changes in the structure of microorganism cell walls leading to their death.

 

UV-sterilant represents a metal body with bactericidal lamp inside it. It, I nits turn, is placed in a protective quartz tube. Water contacts with quartz tube and becomes treated with ultraviolet and, accordingly is disinfected.

 


 

Advantages

  • Uv rays destroy vegetative and spore-forming bacteria
  • Physical and chemical composition of treated water remains unchanged
  • No limit restriction on upper radiation dose limit
  • No secondary products

 

Disadvantages

 

  • Less effective at treatment of incompletely clarified water (turbidity, color)
  • Regular system cleaning is required at treatment of turbid or hard water
  • Short period of bactericidal effect, i.e. there is a chance of secondary water infection in pipeline system.

 Ozone Treatment

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Ozone treatment is one of the promising methods for drinking water disinfection. Ensuring a high degree of disinfection, ozone treatment provides for the best organoleptic indicators without any toxic and cancerigenic products in treated water. Ozone treatment allows to achieve water discoloration, iron and manganese oxidation, removal of flavor and odor. The ozone bactericidal effect mechanism is concluded in penetration into microorganism cell and oxidation of vital bioactive compounds (protein, enzymes, DNA, RNA). Ozon is especially efficient if water is contaminated with bacteria or contains any pathogen microorganisms, enteroviruses and lamblia cysts resistant to conventional chlorination.

 


 

Advantages

 

  • No chemicals are added to water; oxygen is a reduction product.

 

Disadvantages

 

  • Short effect
  • Technically complicated and expensive equipment requires significant power consumption and skilled servicing.
  • Toxic by-products (aldehydes, cetones and other compounds) may be formed

Chlorination with Sodium Hypochlorite

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Today sodium hypochlorite (SHPC) is one of the best and safest disinfecting reagents. Hypochlorite ion is characterized by a strong antibacterial activity. It kills microorganisms very fast at low concentrations because decomposition of SHPC is accompanied with formation of a number of active particles (radicals), particularly, singlet oxygen characterized by a high biocidal action. Particles (radicals) formed at SHPC breakdown kill microorganisms destroying their biofilm. There are several types of sodium hypochlorite solutions (120-190 g/l on active chlorine) produced industrially and SHPC solution (0.6-0.9%) produced by common salt solution catholysis at the place of consumption.


 

Advantages

  • Simple and safe chlorination process
  • Residual chlorine in water (0.3-0.5 mg/l) provides for a long bactericidal effect
  • High efficiency of bactericidal effect on microorganisms
  • Environmentally safe
  • In terms of efficiency of oxidation-disinfection and disinfection action, sodium hypochlorite solution is similar to chlorine action, and in terms of safety – it is much better.

Disadvantages

  • Chlorination may result to formation of adverse chloroorganic compounds.