Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | XXXX 20XX | 15 THE SPEAKERS "If we just focus on the phosphorus aspect, there is risk we lose sight of everything else... you have got to try to think holistically about the whole process." Dr Ana Lanham Bath University "The strategy is to really join up the agricultural sector with the water sector… but farmers are all about pounds, and if the money is not there they will not do it." Thomas Gardiner Head of Asset Strategy, Northern Ireland Water "There are two types of innovation: the type that has a 100% chance of making a 2% difference, or the type that has a 2% chance of making 100% difference. Both benefit the customer." Prof. Tom Curtis Newcastle University "What is the right balance between water companies reducing their phosphorus output, and IN AssoCIATIoN WITH "Chemical dosing will take you so far, but when you've got a small treatment works under 1000 P/E you don't really want to be visiting it too o en." steve Wilson MD of Wastewater Services, Dwr Cymru Welsh Water "I don't think there's enough research going on to look at how you could feasibly and economically recover P farmers reducing theirs? We want to support farmers to do that." Luke de Vial Head of Environment and Water Markets, Wessex Water from a large works discharging to the sea." Gordon Reid Wastewater Service Strategy Manager, scottish Water These include COMAG, a ballasted coagulation technology, pile cloth media filters, and membrane processes, and we've also taken the opportunity to look at some innovative solutions like algae and ion exchange, that offer a more sustainable way of tackling the problem." One reason that multiple solutions are being considered is that the sort of solution that might be appropriate for a large, urban works will be out of the question at smaller sites with a lower population equivalent, which might be found in rural areas. Dwr Cymru Welsh Water's trials include two innovative types of filters that might be appropriate for these works (Blue Pro and Fuzzy Filter) as well as COMAG and Bio P. Steve Wilson, Managing Director of Wastewater Services at Welsh Water, says it is important to bear in the mind the context of these smaller sites. "Chemical dosing will take you so far, but when you've got a small treatment works under 1000 P/E you don't really want to be visiting it too oŽen, and it's when you have chemical dosing that the visit frequency starts to go up," says Wilson. "We are also looking for technologies that can cope with the kind of diurnal variations that you get at a small rural treatment works. There are technologies that have achieved 0.1 mg/l or 0.2 mg/l in the USA, but when you go over and visit they have got 20 or 30 people looking aŽer a small treatment works and they are not too worried about the way they do their flow regulation. So you've got to be careful about how you take some of these technologies and make them work in our environment." As well as opex costs, sustainability is a concern for any solution put in at a small site. Thames Water has also been focusing on this challenge and while it is likely that chemical dosing will still play a big role in its plans for PR19, the utility has a trial underway using reed beds, says Eve-Germain-Cripps, Thames' Innovation Wastewater Process Manager. "We are looking at reed beds for phosphorus removal; we are not going full scale yet, but it is very attractive because it's sustainable, low maintenance technology, it's quite good for capacity and has a high retention time," she says. "There are still some issues to address with the lifetime of the media used, and also potentially with pH increase aŽer the P removal. But if we can get it work it could be very good, and sustainable." While the Water Framework Directive calls for continuous improvement of water bodies with the aim of reaching good ecological status, this does not translate into a 'magic number' for P removal at any one treatment site. This opens the door for water companies to work with regulators on creative approaches to getting phosphorus down in a catchment. Wessex Water has trialled two such approaches with the Environment Agency. The first is in its Bristol Avon catchment,