Chemicals can have unintended consequences, for example chemical leakage can cause environmental issues. Chlorine leakages, for instance, can cause damage to biota, including death, deformities and reproductive damage (Department of the Environment, 2014). Chemicals are expensive to dose and these prices will continue to increase in future, as supplies diminish. In 2008, the UK water industry used 12,243 tonnes of phosphate, which came to a total cost of £12.24 million but since then, as FAO (2015) said, global phosphate demand is currently growing at 2.1% every year, meaning that today’s figures, and those in future, are likely to be much greater (Knowledge Transfer Network, 2008). Although there is the interest to reduce chemicals, the full implications of reducing or removing these chemicals are not known.
A review of the best practices from countries using fewer chemicals than the UK identified that biological stability and maintaining this stability during distribution, is key to achieving safe drinking water with less chemicals. This PhD investigated the possibility of chemical free water in 3 key ways. Firstly, the concept of biological stability was defined, assessing how it applies to UK systems. Next, chlorine and phosphate were investigated, examining how they are applied at water treatment works, how they affect water quality and how their effectiveness is influenced by biological stability. Finally, multiple full scale and idealised pipe test loops were designed and constructed specifically for this project, which investigated different chemical regimes and varying biological stabilities at multiple sites.
This research has been completed and the PhD thesis has been submitted, on which there is an embargo. Several papers will be released in future to disseminate the findings of this project.