Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/904738
20 | DECEMBER 2017 | WWT | www.wwtonline.co.uk • VIEW FROM THE GROUND "People have just connected their dishwashers to the nearest drain and thought 'that'll do'." "Of the 83 bathing waters on Southern Water's coastal strip, 54 of these are already of excellent quality. Of the remainder, there are a few that we acknowledge are long term projects, because they have bigger issues that we are working on. These leaves us with 21 bathing waters where we undertook to carry out a detailed investigation in AMP6 as part of our Bathing Water Programme, to find out what the root causes of pollution were. As a result of this work, we have identified seven bathing waters which we think we can take through to excellent by the end of the AMP; we are now in the delivery phase on this. "There are a number of influencers on bathing water quality that we've identified, but the one that is a common contributor across all seven is misconnections. We sampled surface water outfalls at all of these locations, and where we've identified pollution then we start our misconnections campaign from there. "We use a specialist contractor called WERM, who work with our delivery partner MWH, to do a tracing study. Essentially they install small chicken wire mesh cages in the pipes near surface water manholes, leave them for a period of time and then come back to see if there is any debris being caught in the cages. If there is sewage litter, or fungus, this suggests a misconnection. If it's washing machines or dishwashers that have been misconnected, you might not get a lot of solid matter, but there will be some sort of deposit on the cage that will tell you what is going on. "Where they find evidence of pollution they work back up the route of the network, a manhole at a time, to work out where it's coming from. They will be able to identify part of a street as the source, so then it is a case of doing a door knock and asking to investigate. "Sometimes you can see visually from the street that a house is misconnected – if you can see a rainwater gulley with a downpipe and you can see something coming out of the bathroom into the rainwater pipe, for example. But other misconnections are underground, so in that instance they would ask to do a dye test – putting dye into the pipes to see where it emerges – which will establish for certain whether there is a misconnection from the property. "If the misconnection is on the public highway or on third party land – which might be 10-20% of cases - then it's a public misconnection and it's the responsibility of the water company to rectify it and our capital works delivery partner, which is MGJV [Morrisons Galliford Try joint venture] will carry out that work for us. "But in the majority of cases the misconnection is a private one, and in that instance it's the responsibility of the owner to rectify it. "Of course you will find some householders who are reluctant or resistant, but the majority are interested and want to do something about it if they find out they are misconnected. It's largely a lack of awareness that has caused the problem: people have just connected their dishwashers to the nearest drain and thought 'that'll do'. But if you tell them that their wastewater is going straight out onto the nearest beach, then that beach is local to them, so they've usually got a sense of ownership and pride about it. They will then be keen to get the problem sorted out. "Across our seven bathing water sites that we are talking about here, there are six local authorities covering those seven sites. Since it's the local authority's environmental health team which has the enforcement power in this area, our approach with these private misconnections is to get as much information as we can and then pass that information on to the relevant local authority. "For each of the six local authorities we've established a bathing water steering group for this project, and we are keeping the database of the misconnections that we've found and what status they are at, so that between us we can try and ensure that they are all rectified in good time. Our deadline for getting them all rectified will be the start of the bathing season in 2019. The councils we are working with have all been very enthusiastic and proactive, keen to get involved in this and see it through. "It's early days for the delivery of this project, as we only started a few weeks ago and have not reached all seven areas yet, but we have already discovered more than 100 misconnections including 15 misconnected toilets. We're also looking at other sources of diffuse pollution – working with Natural England on how we educate agriculture, and working with the local authorities on issues such as dogs and birds on the beach, litter, and all those other things that can have an impact on bathing water quality." BRIAN ROUSELL PROJECT MANAGER, SOUTHERN WATER The Works: wastewater and drainage networks Southern Water uses specialist contractors WERM to investigate misconnections