Contamination of water sources may occur in a variety of ways, whether it is contamination by sewage containing harmful microorganisms; waste leachate containing heavy metals; or agriculture and industrial run-off comprising of nitrates, pesticides, and other organic pollutants.
Water used for potable purposes should be treated to ensure all pollutants that may be present are removed to deliver safe drinking water. The quality of the source water will determine the level of treatment required.
Several stages are required to effectively treat water, as summarised below:
- Primary treatment should remove all coarse matter and suspended material in the water, providing a clear and debris free water source. Settling helps with the degradation of organic matter while aeration may reduce the corrosiveness of the water and remove iron and manganese from solution. Corrosive properties of water should be treated to minimize possible damage to the distribution system.
- Particles like clays, metal oxides, proteins, organics, etc. that cause discolouration and turbidity in the water can be removed by coagulation and flocculation.
- Passing water through various filter methods can be employed to remove harmful chemical compounds, leaving water colourless and free of any additional aesthetic effects, including tastes and odours. Nano-filtration can be used to remove humic acids, trace organics, parasites and microorganisms.
- Disinfection of the water should minimise the amount of microorganisms in the water; this includes residual disinfection so that microorganism populations remain low when reaching the end-user. Substances supporting microorganism growth should also be kept to a minimum.
In South Africa, acceptable drinking water criteria are compared to the SANS 241-1:2015 drinking water standards. In order to test the quality of your water, kindly make use of our SANAS accredited laboratory. Direct all queries to firstname.lastname@example.org.