Water & Wastewater Treatment

10 | MARCH 2016 | WWT | www.wwtonline.co.uk To take away 1. Sludge treatment is a natural field for the opening up of a competitive market; the main constraint is the cost of transporting sludge significant distances by road. 2. Future scenarios could see water companies strike deals to treat each other's sludge, share sludge treatment facilities or outsource sludge treatment to contractors. 3. Utilities should also be starting to think of phosphorus as a valuable resource, with several technologies being developed for extracting and recovering it. 4. Advanced anaerobic digestion is attractive as a tool for getting the most energy out of sludge, but gas-to-grid technology will be less appealing if RHI subsidies are removed. 5. Removing fine grit from the wastewater treatment process can both protect your assets from damage and provide a resource that can be reused as pipe bedding. NEXT EVENT: WWT Smart Water Networks conference, March 17th, Birmingham. Details: www.wwt- smartnetworks.net Events Utilities urged to think differently on resource recovery W hether it is the opening up of the market for energy- producing sludge, the sale of extracted phosphorus or reusing sewer grit, wastewater utilities now have increasing opportunities for resource recovery which they should make the most of, delegates at WWT's Wastewater Treatment conference heard. The inaugural event, held in Birmingham on January 28th and sponsored by Hach and CDEnviro, explored topics including catchment- based and technological approaches to removing phosphorus, the commercialisation of sludge, screening for grit and rag removal, energy neutrality in treatment works and advanced anaerobic digestion. Neil Corrigall, head of strategy at Severn Trent Water, outlined the huge economic potential of opening up the market for sludge, saying that his company spends up to £700M annually on sludge treatment compared to £130M on water retail services. "Of the three areas opening for competition, sludge is the most material from an investor perspective," he said. "There is far more potential there, but also more at stake if it goes wrong." He pointed out that with technology changing rapidly, it was important to invest wisely. "If you are going to sink money now into something that is going to last 20 years, you had better be sure that it is worth it," he added. Since sludge from small sites is routinely driven to larger sites for processing, it is a natural area for market forces to operate, he said. While at the moment it was only makes economic sense to transport sludge a distance of around 30km, this might well increase to 50km or 70km in future. Jon Brigg, Innovation Manager at Yorkshire Water, said that the industry had long relied on local agriculture as a customer for its sludge, but it was now time for "systems-based thinking" where the sludge ends up at the company or organisation best able to exploit it. Water and sewerage companies might agree joint venture arrangements where sludge from both their areas is processed at a single site, speakers in the subsequent panel discussion mused. Nick Mills, Wastewater Innovation Manager at Thames Water, said the idea of "driving sludge all around the country to find the cheapest treatment" is flawed, because transport is the biggest cost involved in sludge treatment. However, he thought it more likely that commercial contractors could bid to run sludge treatment works and make money from the resource. THE SPEAKERS "The move to Totex is a positive thing because it gets us away from the siloed thinking of capex and opex, but there is still a lot we have to learn." Gordon Reid Wastewater asset strategy manager Scottish Water "The organic material in sewage contains more energy than is required to decontaminate it. It's all about how we get that energy out." David Rose Energy & Carbon Manager, South West Water "If you need to start burning fossil fuel to dry your sludge, then it's game over – it makes the whole process unsustainably expensive." Nick Mills Wastewater Innovation Manager, Thames Water James Brockett reports from Birmingham "Phosphorus is a finite resource vital for human life. We need to change our mindset from it being a problem to it being a resource." Paul Hickey Deputy Director, Water Quality Environment Agency

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