Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | APRIL 2014 | 19 Project focus: Emergency dosing installation Custom bulk-bag loading frame the most efficient ways of removing pesticides from water. It adsorbs the chemicals out of the water safely and is removed at flocculation stage as a part of the process sludge. The project required a quick reaction from all teams involved to complete the system installation, with rapid mobilisation of commissioning engineers to get the kit up and running at the ailing site. Same-day delivery In keeping with the urgency of the issue, the unit was collected from one site by a Hiab lorry and positioned at the new site on the same day. Transvac came up with the idea to house the system within a shipping container In order to make installation as easy as possible, as it meant it could be transferred from site to site in a day. The strong structure means the water company does not need to dig- up, build-on or otherwise disrupt the site, provided suitable hard-standing is available. This reduces the need for unsightly buildings or noisy machinery, minimises the need for planning permission and has minimal impact on the environment. This factor makes it unique in the carbon dosing sector. Testing and training As soon as water, a dosing-line out and power was provided to the unit, the system was ready for testing. To get the site back up-and- running quickly, onsite training was provided by Transvac's experienced commissioning engineers at the same time as the installation checks. Once this was completed, the site could start dosing carbon to remove the pesticide traces from the incoming water. Unlike installation of traditional granulated activated carbon (GAC) plants, this project did not require any ground or construction works prior to relocation of the unit. This meant the project had a much lower carbon footprint compared to building GAC plants, which can cost millions and take years to design and build. Transvac has demonstrated the ability to help the water treatment industry deal with urgent contamination issues. For further reading please go to www.wwwtonline.co.uk • Perspectives The contractor "A quick reaction was key to the success of this project, with priority given to get the system into place. Once on site, the main challenges included getting the rig integrated with the facility's systems so that continuous dosing could be maintained from the control room. "A few modifications were required to gearbox ratios and instrument sensitivity to tailor the dose rate to the site requirements. Once this was complete, the works had a rig that was practi- cally custom made for them." David Moss, senior com- missioning engineer, Transvac "With traditional batch dosing methods, where large amounts of carbon are dosed in one go, over-dosing and carbon build up are common problems. With an Ejec- tor at the core of this kit, specifically designed not to block with high concentrations of PAC slurry, unnecessary waste is eliminated along with messy conditions found with batch dosing applications. The TransPAC system's low cost and efficient method of dosing carbon is exactly what the industry needs during times of tight budgets and increasing focus on energy efficiency. " Peter Ainge, marketing manager, Transvac • Innovations ● Powder activated carbon (PAC) is a difficult substance to handle, so detailed design has gone into creating a system that can transfer the carbon with the minimum human intervention and wastage. ● A compact packaged system called a TransPAC has been developed to include a bulk-bag handling frame that is easily remov- able from the container via a fork-li truck. ● The system also includes carbon transfer equipment, booster pump, header tank, control panel and ejector skid - all within a 6m steel shipping container. ● The system is run by a simple control panel, with the only input being the flow-rate of carbon, which is set by the operator as required. It doses the exact amount required to remove the pesticide without the need for large batch-mixing tanks and multiple pumps. ● The system has an automated control sequence that transfers carbon from a half- tonne bulk-bag to an intermediate storage hopper, which is then dosed at a set rate into a wetting hopper above a custom-designed Transvac Ejector. ● This Ejector is designed to take a fixed motive water flow from the booster pump and entrain the carbon slurry, sending it along dosing pipes to the point of application - normally at the dissolved air flotation (DAF) plant inlet. ● A low maintenance control philosophy means that the system washes all dosing lines clean between treatment episodes and with only clean water passing through the booster pump the seals have been shown to last for years without the need for replacement. ● With the system only being switched on when necessary it does not use any resources when action is not required and can easily be put into storage for later use.

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