Improving the quality of our drinking water
With a shift towards catchment-based holistic approaches to water management, it has become increasingly important to protect and improve inland and coastal aquatic environments. The 91¶¶Òõ’s research has focused on protection of surface waters used for drinking water provision.
Finding a low-cost, effective solution for the problem of contamination of surface waters is crucial. In 2011, 91¶¶Òõ researchers developed a novel low-cost bacteriophage-based microbial source tracking approach that could be used to identify unknown sources of faecal contamination. The method has provided a powerful tool for the identification of contamination pathways within river basins. Subsequent work has then established an integrated framework for monitoring and managing faecal pollution in catchments.
In 2013, Thames Water commissioned and to determine the removal efficacy of a full-scale membrane bioreactor water reuse system at the Old Ford water plant, Olympic Park, London, the largest wastewater recycling facility in the UK. The research confirmed the suitability of membrane bioreactor technology to augment potable water supplies and concluded that the technology could be used to protect human health as it effectively removed bacterial, viral and protozoan pathogens.
Pesticide contamination is also a major problem for drinking water systems. In 2014, Sarah Purnell partnered with South East Water Ltd to assess whether hydrometric monitoring data could be used to predict levels of the hazardous pollutant metaldehyde that can accumulate in drinking water sources. The research showed that threshold levels of water clarity, rainfall and river flow can be used to predict when levels of metaldehyde are likely to be exceeding the industry standards. The success of this work led to research with Southern Water Services in 2015 to identify low-cost catchment-scale modelling approaches that could predict the timing and location of peaks in the pesticide, leading to the conclusion that open-source modelling approaches provided a cost-effective method for targeting the best locations for catchment management interventions. Importantly, the research demonstrated that the model was suitable for deployment in complex catchments. The work with Southern Water was nominated for the Institute of Water Innovation Award in 2018.
Working with South East Water for improved water quality
In 2014, a jointly led monitoring strategy between the university and South East Water brought about the identification of priority areas in the River Ouse (Sussex) that were affecting water quality at a major drinking water intake, supplying 300,000 of South East Water's customers. In 2015, South East Water initiated a pilot project to reduce metaldehyde contamination of surface waters. The success of this project led to a roll out of the catchment management programme which has resulted in effective control of metaldehyde concentrations in source waters. This has reduced the need for South East Water to introduce additional water treatment to remove the pesticide, and has saved the companies and their customers tens of millions of pounds against construction and management of alternative treatment options.
In 2016, Sarah Purnell built on this research by assessing the health risks associated with augmenting river water with recycled wastewater, again with South East Water. Results confirmed that water reuse can potentially improve water quality in surface waters already heavily impacted by wastewater discharges.
By increasing the ability of water companies to predict contamination levels accurately and providing positive evidence for the option of viable wastewater reuse to augment water supplies, this research has changed water management policy. Treated wastewater has been recognised as a valuable and sustainable resource that can supplement conventional water supplies, informing global water reuse guidance.