Method of disinfection in accordance with BSEN806.
Prior to work commencing we flush and swab the installation until clear, then we measure background total chlorine residual.
The pipes are measured and the exact amount of sodium hypochlorite solution (cl2) is added to ensure complete disinfection is achieved. We normally use a cl2 solution at a concentration of 50 mg/l with a minimum contact time of 1.5 hours depending on particular site requirements.
The cl2 solution is then drained and flushed from the pipes, sodium thiosulphate is used to neutralise the cl2 and the background residual cl2 is returned to the original level.
When the water is bright and clear with no odour or taste other than slight background chlorine we will submit a sample for bacteriological testing.
We will provide the customer with a copy of the laboratory results and a disinfection test certificate on completion of the work.