Providing Sustainable Green Technology Solutions 

Flagship India

  • Requires a great deal of heat
  • Time to bring water to boil and cool before use
  • Can give water stale taste
  • Typically limited capacity
  • Not an in-line treatment system
  • Requires separate storage of treated water



  • Requires contact time of 30 min for simple chlorination
  • Turbidity (cloudy water) can reduce the effectiveness of chlorine
  • Gives water a chlorine taste
  • May combine with organic contaminants to form cancer-causing compounds
  • Does not kill giardia cysts at low levels
  • Careful storage and handling of chlorine is required (Curators of the University of Missouri, 1995)



  • Turbidity (cloudy water) can reduce the effectiveness of chlorine
  • Gives water a chlorine taste
  • May combine with organic contaminants to form cancer-causing compounds
  • Does not kill giardia cysts at low levels
  • High concentration of chlorine accelerates corrosion
  • Chlorine decompose at elevated water  temperature
  • Carcinogenic by-product: Trihalomethanes
  • Chlorine in tap water causes miscarriage in pregnant women
  • Careful storage and handling of chlorine is required 

Superheat-and-Flush of the plumbing system


  • Tedious.
  • Recolonization may occur
  • Scalding
  • To be used with caution

Ultraviolet Germicidal Irradiation


  • Low penetration power
  • Shielding by turbidity
  • Slime layer develops on tube
  • No simple test of results
  • No residual effect
  • Ultraviolet tube gradually loses power.

Colloidal Silver


  • Easy to use
  • Recolonization can happen only when the unit is shut for a period more than 6-12 weeks.
  • Pathogens are killed and not suppressed.
  • Hitherto there is no evidence of Silver resistance. ​​​​​​

  • Water can serve as a reservoir or source for pathogens, which can lead to the transmission of infectious diseases.
  • Water systems harboring pathogens, such as Legionella and Pseudomonas spp., can also foster the growth of persistent biofilms, presenting a great health risk.
  • Water can be disinfected with heat, chemicals, or light.
  • For chemical disinfection of water the following disinfectants can be used: chlorine (Cl2); chlorine dioxide (ClO2); hypochlorite (OCl¯); ozone (O3); halogens: bromine (Br2), iodine (I), bromine chloride (BrCl); metals: copper (Cu2+), silver (Ag+); kalium-permanganate (KMnO4); phenols; alcohols; kwartair ammonium salts; hydrogen peroxide; several acids and bases.
  • Chlorine also oxidizes iron and manganese so they can be filtered out.
  • Ozone may be used to disinfect public water supplies, but is rarely used for private supplies (Liukkonen, 2006).
  • Many antimicrobial agents that are effective against planktonic cells turn out to be ineffective against the same bacteria growing in a biofilm state.
  • Planktonic and biofilm cells also exhibit different susceptibilities to a certain antimicrobial concentration.
  • Bacterial adaptive responses play a role in the design of control strategies.
  • The factors that determine the selection of disinfectants are mainly availability, cost factors, logistics, cost of equipment and safety factor.


  • Several pathogens causing healthcare-associated infections (HAIs) can be transmitted through a waterborne route.
  • Legionella, a bacterium that thrives in warm water and can become aerosolized through evaporation of contaminated water and then inhaled, is probably the most recognized.
  • In hospitalized patients who usually have a concurrent illness, legionellosis can range from a mild pneumonia to a life threatening disseminated disease.
  • Some pathogens that survive in water systems are opportunistic; they are part of the human microbiome (organisms that normally live harmlessly in or on humans) and cause infection only under certain conditions.
  • For example, Pseudomonas aeruginosa, bacteria; that can harmlessly live in the human intestinal tract, can cause a wide range of serious diseases including wound infection, pneumonia, and bloodstream infection when it contaminates water used in patient care.
  • Additional bacteria include Acinetobacter spp., which, although a low virulence organism, frequently causes pneumonia or bloodstream infections in patients residing in the intensive care unit, in part because of its ability to persist in the environment.
  • Acinetobacter spp. can replicate on environmental surfaces that collect moisture.
  • Non-tuberculous mycobacteria including Mycobacterium fortuitum can colonize in hydrotherapy pools or can be transmitted as aerosol from showerheads (Squier, Yu, & Stout, 2000).
  • Molds such as Fusarium are less common causes of infection arising from water sources (Anaissie et al., 2001).
  • Transmission of pathogens from water sources occurs through contact with contaminated water or through aerosolization of contaminated water.
  • Disinfectants employed hitherto are harsh, allergens or carcinogenic.



Comparison of Different Disinfectant