Why disinfect rather than chlorinate?
The current water treatment choices
In around 2003 our technical director, my father Bob Wilson introduced Huwa-San, silver stabilised hydrogen peroxide into the water treatment market place. This was the start of an interesting and at times controversial journey into getting Huwa-San disinfection accepted as a better, safer alternative to chlorine for disinfection of water systems.
Currently the water treatment disinfectants of choice in the UK are chlorine, chlorine dioxide and silver stabilised hydrogen peroxide (S.S.H.P).
Chlorine and the S.S.H.P.’s are used for one off disinfection of water systems (both tank and mains fed) and chlorine dioxide and occasionally S.S.H.P are used for constant dosing (where a small amount of chemical is introduced to a water system in proportions to the incoming supply water to help keep it free from bacteria).
How to successfully disinfect using Huwa-San based on the science.
Huwa-San Disinfection Dose Rates
Life after lockdown: Ensuring water safety
Health and Safety
Huwa-San silver stabilised hydrogen is a strong oxidising agent and it is important that normal heath and safety protocol is followed.
- A risk assessment should be carried out prior to carrying out any disinfection.
- Huwa-San disinfection never be used where there is a risk of people using dialysis machines. This may be in hospitals or social housing. No oxidising chemical should come into contact with a dialysis machine.
- Huwa-San disinfection should not be used in the water supply to hospital laboratories as it will effect the result of certain tests.
- Suitable PPE must be worn. PPE requirements can be found on the material safety data sheets.
- Water systems dosed at 100ppm Huwa-San would not be considered potable however this level is safe for drinking and bathing. The National Sanitation Foundation (N.S.F) have carried out a report on Huwa-San and 728ppm is the suggested reference dose- the level that can be drunk in a single draft without causing ill effect.
In this blog we want to explain the science behind the dose rates of Huwa-San as we want to ensure that our customers have as much knowledge as possible.
The dose rates provided are based on science and experience. We know, for example that legionella is easier to kill than pseudomonas with Huwa-San therefore a different dose would be applied if it is known that there is a pseudomonas based biofilm in the system.
The dose rate and contact time are inversely proportional- increasing the Huwa-San dose allows the contact time to be reduced.
Chlorine has been around for over 100 years but remains the disinfectant of choice of the HSE. It is quoted in all the guidance. We are challenging this perception. Chlorine when added to water produces hundreds of different by-products many of them toxic or carcinogenic in water while hydrogen peroxide breaks down to oxygen and water. Which chemical would you rather use?