Water & Wastewater Treatment Magazine
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Fighting the FOG Our innovation specials continue with an examination of new measures to improve sewer health by tackling fats, oils and grease (FOG) By Robin Hackett www.wwtonline.co.uk | WWT | JULY 2018 | 31 Innovation Zone wastewater treatment and sewer health A s fatbergs continue to make headlines, water companies have been trying to make the most of the opportunity to get the message across to the gen- eral public about the dangers of clogging up their drains. Public education remains pivotal to dealing with FOG, and the government's vow to tackle wet wipes could ulti- mately make a major impact if successful, but fatbergs are an international problem and there is a growing market for measures that water com- panies can use themselves to cut the problem down to size. Here, we look at some of the options on the market. GOAL 13 SEWER HEALTH HYDRAPULSE Flusher Gate (Reece Innovation) The HYDRAPULSE Flusher Gate tackles FOG by using the power of water to blast through congealed debris. Developed by engineers at Newcastle-based Reece Innovation, the device is installed in manholes and holds effluent in the adjacent stretch of sewer. Once sufficient water pressure builds up, the gate opens and closes rapidly to send turbulent fluid through the downstream sewer, providing sufficient power to help flush and cleanse deposits. The system also results in constant changes in effluent level upstream, which helps to cleanse both sides of the gate. The system features an override facility to ensure continued operation during peak periods and it is designed to be resistant to jams caused by rags. When installed in appropriate locations, the gates can be fitted with wireless instrumentation to monitor its effectiveness, but Reece Innovation says it is made for a long, unmonitored service life. Northumbrian Water recently held a successful 12-month trial that saw reduced levels of FOG as well as silt, without the need for manual jetting, and the gates are now being exported to Australia and North America. In addition to the Flusher Gate, Reece Innovation has been working with Northumbrian Water Group to develop further measures to help keep sewers clear, using Internet of Things (IoT) technology to develop 'smart sewers'. Among the products it is working on are an updated version of the TRAP – a sampling device that is placed in a sewer manhole chamber and used to identify the source of items that cause blockages in sewers, such as non-flushable wipes and silt – and ORCA, an acoustic system that uses sound to detect blockages or potential 'fatbergs' within minutes. eco-tabs (eco WMT) eco-tabs are solid, sustained release tablets that provide oxygen, nutrients and non- pathogenic bacteria. Instead of so ening FOG so that it can be moved downstream, the bacteria consume organic sludge, including natural oils and grease, and reduce hydrogen sulphide. eco-tabs allow water companies to tackle FOG without high-pressure jetting, which eco WMT says cuts annual cost by around one-third while also removing the associated risk of sewer damage, foul odours and disruption. Northumbrian Water dealt with a problematic section of its sewer in Stowell Street, Newcastle, in 2016 using eco-tabs and the company's sewerage support manager, Alison Wilson, said the process was "cost effective and definitely speeded up the process". United Utilities eliminated FOG that had caused flooding in an area of one of its sewers under Bolton within three weeks using eco-tabs. The tablets can be dropped directly into the required location – such as drains, sewers or grease traps – and remove the need to send operatives underground. eco-tabs are also available in powder form.