Water storage tank disinfection is a common practice done regularly to manage the quality of water stored in plastic tanks, commonly known as Jojo tanks. Due to the pumping in and tapping out of water at different times, and gaps forming inside the tank environment, microbial populations can often colonise and survive these environments. Thorough disinfection is done to rid the tanks of any existing micro-organisms and create an environment that discourages their proliferation.

Disinfection Methodology

Water storage tanks range between 1,000l and 20,000l. The disinfection process is one of sterilisation whereby all viable organisms are removed through physical and chemical processes. For microbiological disinfection, chemicals are selected, and the correct dosage based on the size of the tank is measured. The dosage is site specific to ensure there are enough chemicals to destroy all pathogens. It must be noted that in most instances, the viruses or spores may not be destroyed. A standard protocol applied by Letsolo ensures that the process is conducted safely and successfully.

A pre-disinfection water sample is collected from each tank to determine the quality of water prior to disinfecting. The tank is then emptied before the disinfectant is applied. A Chlorine- based chemical is poured into the tank, filling it to the brim. A compressor is used to encourage proper mixing. The ratios for disinfection are pre-calculated by the chemical supplier. The tank is then disconnected from the distribution network to stand overnight for at least nine to 12 hours for the chemicals to mix with the water and reach all internal surfaces of the tank. After enough contact time, the chemically treated water is disposed of safely. A post-disinfection sample is collected to determine the new quality of water. Samples for before and after disinfection are taken to the laboratory for chemical and microbial analyses.

Letsolo Water and Environmental Services has a growing portfolio that includes, amongst others, the maintenance and disinfection of water tanks. To view all our services, please visit: https://lwes.co.za/services/