Water Treatment Processes
Water Treatment is the use of one or more processes to improve water quality.
Sometimes only one process is required for adequate treatment. Commonly, multiple unit processes will be used in series. This is often done because no single process can treat all known contaminants. Multiple processes in a “treatment train” also give a “multi-barrier approach”, with each additional barrier reducing the probability that a contaminant breaks through.
Water purification is a subset of water treatment. Water purification refers to the removal of contaminants from the water. Instead of purifying, some water treatment processes add beneficial elements – for example remineralisation, residual disinfection, plumbosolvency (lead) control.
The processes vary widely depending on the raw water quality and the desired treated water quality. They can be as simple as leaving the water to settle for a period of time, or adding a disinfectant tablet to it; or complex high-tech processes employing nanotechnology, biotechnology or phase changes.
Importance of Disinfection
While there are many contaminants that may be removed by water treatment, the most critical ones tend to be microbial. The reason for this is that microbes can multiply, hence – even at very low initial concentrations – they have the potential to cause serious illness and other problems.
As such, a disinfective process will normally be included in any water treatment system. One exception to this would be if a raw water can be guaranteed to contain no pathogenic microbes and the conveyance system guaranteed to not introduce any. Another exception would be if the treated water could be guaranteed to not infect humans – for example sub-surface irrigation of non-root crops.
Categorisation of Water Treatment Systems
Water Treatment Systems can be categorised by either the treated water quality:
- Ultrapure water
- Potable/municipal water (drinking water)
- Process/industrial water
- Irrigation water
or by aspects of the raw water:
- Potable water – for further purification
- Treated effluent – polished for reuse
- Ground water – from boreholes & wells
- Surface water – from rivers & lakes
- Brackish water – slightly saline
- Sea water – saline
The level of treatment and type and number of processes varies dramatically based on these aspects and also the scale.
We also categorise water treatment systems by the location at which they are used, which implies its scale. ‘Point of use’ systems are the smallest scale, and this term is commonly used for treatment in the home. ‘Centralised treatment’ refers to one large treatment system to provide water for a city or region. ‘Decentralised treatment’ lies somewhere between centralised and point of use.
We are here to help
Aqueum’s principal expertise is in water quality, and the treatment systems required to deliver it. We can give independent advice on which processes to use & can help you design, specify or tender these systems. Feel free to contact us with any water treatment queries.