Cost-efficient sustainable control of lead solubility in Bristol Water drinking water network

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Lead piping continues to be used in domestic pipelines of older properties around the UK and globally. The primary approaches to limiting the release of lead into the water network are replacement of lead pipes and orthophosphate treatment of water. Orthophosphate treatment is known to reduce lead solubility by forming alternative lead precipitates. Despite this there is limited knowledge on the lead-phosphate minerals formed and the impact of water quality on mineral identity and character. Studying how water quality effects lead solubility will be a major aim of the project. Similarly, new alternative water treatment techniques are currently being sought to limit lead solubility. This research will investigate these alternative treatments, including orthophosphate-polyphosphate blends, and their potential to limit lead solubility within piping.The project anticipates utilising multiple approaches to study water treatment methods. The expectation is that results from these techniques approaches can be correlated linking industrial scale observations with those determined in the molecular level. Analytical chemistry will study eluent water from lead pipes and lead piping scales determining whether these are consistent between different water quality parameters and treatment techniques. This work is expected to require several analytical techniques including, but not limited to, X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Electron Microscopy and Energy Dispersive X-Ray Microanalysis. Previous research has not attempted to carry out this type of analysis while controlling the water quality or alternative water treatment techniques.Similarly previous research involving use of lead rigs to test orthophosphate treatment have neglected to properly test the importance of orthophosphate dose or major water quality parameters, both which likely affect lead solubility. This study will use lead rigs within the lab and Bristol Water sites to utilise Designed Experiments testing lead, colour, phosphorus and other metals solubility through lead pipes while varying factors including several water quality parameters, treatment techniques and treatment concentrations. Finally, by critically assessing the existing water quality and orthophosphate treatment data within the Bristol Water network the study can determine how relevant the results are. This is critical to confirm whether large scale, real-world network data correlates to that of lab studies. Considerations such as equilibria, kinetics and thermodynamics all contribute to real-world lead solubility and while studies are commonly carried out in laboratories, they often neglect to consider whether they can demonstrate a clear correlation to industrial data. As a result of this project there will be a greater understanding of the water quality and water treatment factors which affect lead solubility. This can help policy makers, including Bristol Water, refine their treatment techniques balancing the need to control lead with desire to produce colour-free, low-eutrophication potential water. All the project focus areas directly relate to the core topic of EPSRC by investigating more sustainable drinking water treatment and delivery within framework of more resilient and prosperous UK society.