Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/904738
screens will continue, as it seems unlikely that the UK government will continue to improve the environmental standards that the EU legislation has imposed. The technology is available to further improve the quality of CSO discharges, such as vortex, settlement or filtration of discharges, but the government is not likely to increase the burden upon the public to pay for this. Many of the sewerage systems in the UK are combined and the majority of CSOs are sited where hydraulic problems occurred, o en being no more than pressure relief pipes for the system. However, the aesthetic appearance of many watercourses deteriorated forcing the government to set limits of discharge. In addition, good practice dictated that the overflow chamber should be designed to minimise the deposition of solids into the environment by the use of baffles. CSOs are essential safety features for the sewerage network and screen technology design and performance have developed significantly as a result of experiences gained from operating these assets. www.jacopa.com The Talk: opinion constitutes 'excessive cost' differs from regulator to operator. Effectively, CSOs must be provided with 'primary treatment', defined in the regulations as 'water treated by a physical and/or chemical process involving settlement of suspended solids, or other processes in which the BOD5 of the incoming wastewater is reduced by at least 20% before discharge and the total suspended solids of the incoming wastewater are reduced by at least 50%' Most member countries use screens to meet the regulations, while in the UK the requirements for solids separation depend on the level of amenity and the number of spills per year. CSO screens of various designs have been installed since the regulations were introduced, including perforated plate/ wedge wire static screens fitted in many locations where expected spills do not exceed 5 per annum, on the basis that these screens would be inspected and cleaned at least once per year. A range of mechanical screens have also been installed where spill frequencies are higher, supplied in various designs from 4 mm Raked Bar Screens (approved as 6 mm equivalent), Brush Screens, wedge wire and perforated plate, all automatically cleaned by various methods. Many of these have now been in service for 15 to 20 years with minimal maintenance, and are probably due for serious maintenance, servicing or replacement over the coming five years, something that water companies need to factor into their future workload. The UK has decided to leave the EU, but intends to transfer EU regulations into UK law en masse, so the regulations outlined above are unlikely to change in the foreseeable future. It is anticipated that for new CSO schemes the use of 4mm raked bar screens and 6mm aperture "CSOs are essential safe- ty features for the sewer- age network and screen technology design and performance have de- veloped significantly as a result of experiences gained from operating these assets." Bio-Nitrifier naturally effective waste water treatment Ammonia build-up can cause signicant issues to plant performance and cause nes if outside of consent level. Nitrifying bacteria remove ammonia but are easily interrupted compared to other biological waste water treatment processes because of their slow growth and susceptibility to chemical and physical challenges which leads to slow plant recovery. Bio-Nitrifier can help you: Stricter regulations, lower consent levels and rising costs are forcing municipal, industrial and other wastewater producers to look for the best solutions to improve treatment efficiency. The water quality of industrial effluent is directly linked to the costs charged by Water Companies using the Mogden formula. Being able to reduce Chemical Oxygen Demand (COD) and Suspended Solids (SS) offers significant direct cost savings and is a primary reason for introducing biotechnology. Many producers face difficult to achieve consent levels resulting in significant tankering costs or fines. Bioprep technical wastewater experts work with customers to assess the issues facing the plant. After a complete analysis of the waste using advanced laboratory techniques and evaluation of the operating conditions, recommendations are made to provide the best solution for that specific site. T: +44 (0)29 2067 4090 www.biologicalpreparations.com ● Fermented in the UK using a bespoke process ● Arrives at site refrigerated for maximum efficiency ● High activity product allowing ammonia removal to being as soon as product is added ● Suitable for establishing oxidation in newly constructed or seasonally operated plants ● Reseeds plants after toxic shock ● Improves efficiency of existing biomass How does Bio-Nitrifier help? L E T B I O L O G I C A L P R E P A R A T I O N S W A S T E W A T E R E X P E R T S H E L P Y O U T O D A Y Remove all the bullet points and change to: ● Fermented in the UK using a bespoke process ● Arrives at site refrigerated for maximum efficiency ● High activity product allowing ammonia removal to being as soon as product is added ● Suitable for establishing oxidation in newly constructed or seasonally operated plants ● Reseeds plants after toxic shock ● Improves efficiency of existing biomass Reduce waste water costs Achieve consent levels Improve plant efficiency 1 2 3 12 | DECEMBER 2017 | WWT | www.wwtonline.co.uk