Water & Wastewater Treatment

Project focus remainder will come from borehole sources around the city, from South Staffs Water's Barr Beacon reservoir, and from an existing connection to our strategic grid into Birmingham. Those sources will make up the shortfall from the Trimpley and Lickhill sources to keep it going." When this resilience plan is in operation, the city will be drawing water from at least four sources rather than just one; and the EVA will be able to be shut down for maintenance for periods of up to 50 days at a time. Applications pending Severn Trent will submit its four plan- ning applications for the project – covering the four local authority areas the project spans – in December. At around the same time it will also submit an abstraction licence of 130 megalitres per day for the new Lickhill intake; the terms of this will specify that water is only to be abstracted during the winter (between October and March) when River Severn flows are at their highest. This level of abstraction (130 M/L day) only repre- sents around 5% of the river's winter flow, ensuring that environmental impact will be minimal. Work on the environment impact assessment for the project has been going on since the end of last year, and public consultation is also ongoing. If all goes to plan, construction on the pipeline will be able to start in late summer 2016. The abstraction point at Lickhill was chosen from a list of 22 possible sites for its favourable river conditions, good access and low level • Innovations ● The new River Severn intake at Lickhill will operate for only 50 days in the year, at up to 130 ML/day, while the EVA is shut down ● A Veolia Actiflo process is being put in place to treat the turbid water from the River Severn ● Water from Severn Trent's Strategic Grid, together with borehole sources and water transferred from South Staffs, will make up the balance of demand 18 | AUGUST 2015 | WWT | www.wwtonline.co.uk off – Severn Trent has installed a £3M Actiflo pilot plant at Trimpley, including pilot scale rapid gravity filters, to assess how the plant works with different proportions of the two water types. "When we first switch this on, we'll be drawing down water from the holding reservoir at Frankley which is wholly made up of Elan Valley water," Hinsley explains. "Then when we switch the Elan Valley Aqueduct off, the reservoir will start to see River Severn water from the new site, and over a period of a couple of weeks the water in that reservoir will change from EVA water to River Severn water. It's that transition that we need to make sure it deals with." This pilot plant will run until February and the results will be used to inform the final operating regime put in place at Frankley. Frankley will also be fitted with a new Powdered Activated Carbon (PAC) process in order to cope with the pesticides in the new river water. The new processes will need to be approved by the Drinking Water Inspectorate before they can be implemented. Supply chain partners Severn Trent has recently awarded the contract for the first stage of the pipeline work to Lang O'Rourke Imtech; it is helping to develop the planning submissions and, subject to of impact on the public. Meanwhile, eight possible corridors were evaluated for the pipeline route before the preferred 500m-wide corridor was chosen. This route, which runs south of Kidderminster and crosses underneath the M5, is largely rural while avoiding any particularly environmentally sensitive areas. However, it is does involve a climb of around 250m. "The chosen solution involves a break pressure tank – effectively a mini-reservoir - at the highest point, a¢er which the water flows down the hill into Frankley," says Hinsley. "It's a big pumping li¢ - around 250m or so to take it from the River Severn up to that high point near the M5 - so it will require some seriously powerful pumps." Treatment and blending Frankley Water Treatment Works is also receiving an overhaul as part of the project in order to help it deal with the more turbid, solids-laden water expected from the River Severn. A Veolia Actiflo treatment process, which uses enhanced coagulation, has been chosen for this purpose, the first time Severn Trent will have used this solution. Because the system will have to cope with various concentrations of EVA and River Severn water – as the two types of water blend in Frankley Reservoir when the EVA is turned New Lickhill Quarry River Intake Severn Siphon River Severn Severn Aqueduct Trimpley River Intake 118km Elan Valley Reservoirs New pump sta>on New pipeline Asset can be maintained when alterna>ve supply in use Elan Valley Aqueduct (West Free flow) Elan Valley Aqueduct (East Free flow) Norton & Beechtree boreholes Birmingham Resilience – Overview

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