Water & Wastewater Treatment Magazine
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22 | MARCH 2018 | WWT | www.wwtonline.co.uk The Works: sludge quality Wessex Water was one of the water companies to have published data on the sludge produced by its wastewater treat- ment works; it is keen to talk to potential partners who might want to trade sludge or make proposals for exploiting the re- source better, according to George Taylor, Wessex Water's Wastewater Director. "These are exciting times for the bioresources industry," says Taylor. "We think that a competitive market has an incredibly valuable part to play in getting the most out of the energy and nutrients in bioresources and passing financial benefits back to customers. We're very interested to see if there are opportuni- ties to trade this valuable product with others." The data confirms that the centre- piece of Wessex's sludge operations is Avonmouth WWTW near Bristol, which produces 21,079 tonnes of sludge per year. Wessex has invested in significant energy generating capacity on the site, a co-located food waste plant and a gas-to- grid connection and has set up a subsidi- ary (GENeco) to run these operations. In the competitive market a large site like Avonmouth with co-located sludge treat- ment facilities would be looking to import more sludge, confirms Taylor. "With GENeco we've set ourselves up to be ready for the market, to be ready for when this change happens. We have the knowledge and expertise in that area, as well as the processes in place at Avon- mouth, that can make the most of it and we're gearing ourselves up for that," he says. At the other end of the scale, Wes- sex Water has 130 WWTWs which are less than 2000 P/E in size; the only data published about these sites are their loca- tion and volumes of sludge. While Taylor says that the utility "doesn't want to rule anything out", it is not anticipated that the volumes of sludge involved at these plants will be attractive enough for third parties to get involved. However, in between, Wessex has 98 wastewater treatment works over 2000 P/E in size where sludge is collected by tanker and taken to a treatment centre. These range from the relatively large - such as Weston-Super-Mare WWTW which produces 3313 tonnes of sludge a year and from which sludge is collected daily – to smaller works producing as lit- tle as 30-50 tonnes a year and visited by a tanker fortnightly. This group of sites are likely to be of most interest to third par- ties; neighbouring water companies, local waste management companies, or others might bid to take, treat, and exploit the sludge. "There are a number of companies out there that provide waste management and recycling services; we've already talked to a few of them to sound out the opportunities and see what possibilities there are," says Taylor. "Yes it's some- thing we're doing, and we are keen to hear from companies out there who are offering these services." Minimising transport costs will be a key part of the market, as "it doesn't make sense to be hauling sludge hun- dreds of miles," adds Taylor. Third party facilities which are close to sludge-pro- ducing WWTWs are those that are likely to be able to make the most compelling case for deals. • WATER COMPANY VIEW "We're very interested to see if there are opportunities to trade this valuable product with others." Avonmouth is the centrepiece of Wessex Water's sludge operations George Taylor, Wessex Water