Water & Wastewater Treatment Magazine
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Project focus: Water quality of the sources if necessary so we don't get a metaldehyde exceedance. But it will also be upstream of the new treatment process, so we can make sure the treatment process is optimised for inlet concentrations. "The instrument has never been installed in a treatment works before, so one of the challenges has been managing the inlet water quality to the instrument: the water at this site is karstic groundwater, which reacts to rainfall quite rapidly, and that will have an impact on the instrument. We've had to modify the environment for the instrument quite significantly, making sure it is kept at a steady temperature, and have also had to install an inline filtration system, a turbidity inlet of less than 1 NTU and more sophisticated so ware to ensure the instrument can read to our online SCADA system." Remote laboratory Putting what it is effectively a remote laboratory on an operational site has meant a number of specific challenges have needed to be overcome, says Lo us-Holden. Problems associated with leaving the instrument unattended – such as broken needles and the way it copes when it encounters anomalies – needed to be set against the health and safety implications of having a lone worker working full time in the cabin. "When this piece of kit is used in our laboratory, it doesn't have automated sampling and there is always that manual interaction with the scientist," explains Lo us-Holden. "So the so ware that is currently standard with the instrument simply gives you the results and that's it. The novel application of what we've done here is the intelligent so ware that we've installed on it, and also the inline filtration system." Solving these challenges and getting the trial off the ground required intensive collaboration between Affinity Water, contractor JRP Ltd and equipment supplier Anatune. Ray Perkins, CEO of Anatune, said: "Working with Affinity Water has been a great opportunity to see how our GCMS instrument can be used in other ways and we are excited by the promising results of this trial and the implications for the water industry." The trial started in September in order to capture the period of time when metaldehyde is typically used because of wet weather and the prevalence of slugs. The results to date are promising, with several spikes detected which were later correlated with metaldehyde use in the catchment; testing accuracy has been shown to be in line with that of the equipment used in the laboratory. The company is planning to share its detailed results with the wider industry and other water companies are monitoring the outcomes closely. Affinity Water tested three different metaldehyde treatment technologies last year. While activated carbon is the chosen treatment solution at the treatment works where the online monitoring trial is taking place, Affinity Water is still working with other novel treatment technologies and may implement different solutions at other sites. Meanwhile, the company's catchment management programme has run since 2010 and was expanded in 2012/3; it covers the use of a number of pesticides and herbicides in addition to metaldehyde. It is possible that online monitoring could be extended to these other substances in future, further supporting the pesticide programme, added Lo us- Holden. ● Intelligent so ware allows GCMS to operate automated sampling and report online ● Inline filtration used to protect instrument ● Remote laboratory short- cuts lengthy lab analysis • Innovations Affinity's Alice Elder, Debbie Lo us-Holden and Matthew Rawlinson with the GCMS instrument The installation has effectively established a remote laboratory at the works www.wwtonline.co.uk | WWT | MARCH 2017 | 19