Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | XXXX 20XX | 23 out maintenance and build new parts of our water and wastewater infrastructure. Fatbergs and wetwipe blockages might not be nice to look at, but viewers can see first-hand the inconvenience and the upset that they can cause to customers." In some circumstances, United Utilities has also undertaken targeted community engagement programmes, including one in the small market town of Burscough in West Lancashire which produced dramatic results. "There was a lot of concern in Bur- scough about the frequency of sewer flooding, which was being experienced. There was also some concern in the com- munity that a new housing development would only increase that frequency," adds Griffiths. "The sewer network in that area was not too hydraulically challenged, so the predominant cause was blockages. We did a concentrated marketing and educa- tion campaign with schools and shop- pers at the local supermarkets to help raise awareness. The way we maintain our network and the operational methodology are effectively reducing the number of inci- dents, but these benefits are being inhibited because we are fighting against a rising tide of sewer misuse," adds Griffiths. "If people only flush the 'three p's' – pee, poo and paper – then the number of sewer blockages and pollutions would dramatically decrease, and we would reap the benefits from that. Then sewer network operators could divert the cash they are currently spending reactively and invest in new technology, so we can ef- fectively manage the network, rather than have it manage us. "We have incident prediction models to help identify areas where we may want to focus campaigns and CCTV inspections on," he adds. "As part of our programme of work for the next five-year period, com- mencing in April, we are using historical data to predict where the next sewer block- ages will be. We will carry out extensive CCTV surveys and cleaning of the network in those areas, so we can prevent those blockages occurring in the first place." Changing customer behaviour Southern Water's FOG and unflushables project manager, Elvira Gabos says they have been working hard to change cus- tomer behaviour and drive down block- ages over the last four years by looking at the geographical spread of blockages across its areas. www.wwtonline.co.uk | WWT | MARCH 2020 | 23 By mapping the region and looking for "hotspots" where there was at least one incident a year, Southern Water discov- ered that 2,000 postcodes were responsi- ble for 20 per cent of all the blockages in the region. "We decided to go out and knock on the doors of people who live in those hotspot areas and we also trained our teams, who went out, so they could examine the local sewers and get visual evidence of any local blockages. If they found any visual evidence, they show it to local people, which has an effect on the customers," explains Gabos. Southern Water has also targeted the 28,000 food businesses in the region, where the biggest problem is oil and grease being poured into the sewers. "We have delivered close to 600 presentations over the last four years and talked to 90,000 customers," says Gabos. "This has led to a 17 per cent decrease in blockages." She adds that one of the issues that has come up in recent years is custom- ers not realising there is a link between plastic pollution and unflushable material down the sewers. "People still do not know that un- flushables are up to 90 per cent plastic," she explains. "Last year, our leaflets made the connection between unflushables and the plastic content clearer. People are surprised when they see that figure." Analysts at Southern Water have also been examining data sets on blockages, flooding and pollution in the region to get a fuller picture. According to Gabos, a new customer engagement campaign will target hotspots across its region. As important as direct customer en- gagement is, technology and specifically data-driven systems are also playing an increasing role in sewer management, as Dr Benjamin Tam, managing director of tech consultancy Isle UK explains: "One of the UK water companies ambi- tions from the last AMP was to drive the shiŸ from being reactive to proactive. In order to do this, water companies need to make best use of available data and prioritise what other data is required," says Tam. "Data from the sewer network is playing catch-up to the clean water side but there is potentially a greater upside overall, especially with environmental drivers increasing. "The difficult condi- tions in which to deploy new sensors and the unknown payback has slowed the rate at which new data is used. How- ever, the future will depend on water companies being able to monitor sewer conditions in closer to real time than currently and filling the data gap with better network modelling. "For example, using sewer condition assessment data to promote proactive interventions to prevent fatbergs and keep our sewers flowing by tackling the problem at source. Data from within the sewers will play an important part in alerting water utilities of when there are the beginnings of an issue and be able to identify the source. This evidence can be used to effect change," adds Tam. Academics are also looking into FOG deposits, including scientists at Cranfield University, who are researching how they can be effectively rehabilitated and inhib- ited using bio-additives. "The current work questions previous- ly held views that saponification and lipid solidification control deposit formation in sewers," explains research engineer, Natalia Jawiarczyk. "Instead it is becoming evident that more focus should be directed towards compounds other than lipids. Effective degradation of FOG under laboratory conditions is possible, but the translation of this within the sewer environment has proven to be challenging." In many ways, challenging is the oper- ative word. Improved sewer maintenance will require innovation on the part of the sector, capital expenditure and resources, not to mention a large change in con- sumer behaviour. With sustainability and plastic pollution still a big issue for many households, the war on unflushables is only just beginning. A sewer in Worthing being cleaned out. SEWER NETWORKS

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