Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/775086
www.wwtonline.co.uk | WWT | FEBRUARY 2017 | 5 The lack of a clear framework for the maintenance and performance of Sustainable Drainage Systems (SuDS) is seen as the key barrier to their effective delivery and adoption, a national survey has found. The research, conducted by Engineering Nature's Way, the knowledge-sharing initiative for SuDS, also revealed that most (79%) of respondents working with SuDS day-to-day believed the UK Government is not fully committed to long-term delivery, and 72% believed it had not committed sufficient funds for satisfactory flood resilience. SuDS: The State of the Nation 2016 sought the views of professionals working with SuDS at the 'grass roots'. As the Government prepares for a review next year of the effectiveness of delivering SuDS through the planning Uncertainty over SuDS maintenance holds back sustainable schemes system in England, the survey generated more than 360 detailed responses from consulting engineers, local authority professionals and developers across the UK. The majority of respondents (69%) believed that uncertainty around the maintenance and through- life performance of SuDS components is presenting barriers to adoption. Most (73%) also believe more standard technical guidance is needed on the long- term maintenance of SuDS components. "Strong concerns were expressed about the lack of a clear national framework for maintenance and adoption, together with uncertainty over which authorities or organisations should be liable for SuDS components over their lifecycle," said Phil Collins, European Sales Director of Hydro International. Veolia has applied for a water supply and sewerage licence, which will allow it to participate in the business retail market when it opens in April. Veolia UK chief operating officer for water John Abraham said that the licence will enable the company to continue providing a combination of waste, energy and water services to its existing private, public sector and industrial customers. Veolia Water Retail's customers will include those eligible customers located in the Tidworth area and supplied by Veolia Water Projects. "Veolia is interested Veolia preparing to enter water retail market in growing retail water activities and welcomes further competition that enables us to deliver our global innovation and experience to the UK," Abraham added. "Retail water, resource management and sludge treatment and disposal are all areas where we can provide investment, technology and global best practice, which promote greater sustainability and efficiency." Ofwat has predicted as many as 40 companies may apply for water retail licenses in the coming year:: at the time of writing, 21 have already done so. Expert view sponsored by Bacteria to help meet the ammonia wastewater challenge Dr. John Lear Technical Director Biological Preparations Ltd Preventing the discharge of ammonia into water bodies is a significant issue, as it is not only highly toxic to fish and other wildlife but also causes considerable oxygen depletion in receiving waters. Consent limits can be lower than 5 mg/L, so it is essential that ammonia is removed in the wastewater treatment plant (WWTP). Ammonia is removed both in nature and in the WWTP by nitrification and this process is carried out by nitrifying bacteria. These specialised microbes are chemolithotrophs, meaning that unlike most bacteria, they use inorganic substances as an energy source. They are also obligate aerobes - they require oxygen to survive and grow. The addition of nitrifying bacteria to the WWTP is a highly effective way of optimising ammonia removal and meeting consent limits, avoiding costly fines. The nitrification process takes place in two stages: 1) the oxidation of ammonia to hydroxylamine, then conversion to nitrite, carried out by species such as Nitrosomonas; and 2) the oxidation of nitrite to nitrate by species such as Nitrobacter. Nitrifying bacteria do not form spores and are extremely sensitive to physical and chemical challenges. They cannot be dried or freeze- dried into powders and die rapidly if stored in liquid form at ambient temperatures. Care should be taken with commercial products that claim to contain true nitrifiers but instead utilise other species of bacteria which are more suited to removing organic matter in the treatment plant and can provide little or no ammonia or nitrite removal. Biological Preparations uses a bespoke in-house fermentation process to produce and supply Nitrosomonas and Nitrobacter in concentrated liquid form. Each batch is activity-tested before dispatch and the products are shipped in refrigerated containers for immediate use or storage in a fridge where they have a shelf life of up to 6 months. Nitrifying bacteria are extremely slow-growing as the amount of energy that can be generated from nitrification is low – their doubling time may between 7 and 20 hours. But this means that they have evolved to become extremely efficient at oxidising ammonia and nitrite. Our standard products have an activity of 5000mg ammonia or nitrite oxidised per kg product per hour. The bacteria are normally added to the nitrifying zone of the WWTP and ammonia and/ or nitrite removal begins immediately. They may be used to establish activity in newly constructed or seasonally operated plants, to reseed a plant a er toxic shock or to improve the ability of the existing biomass to meet ammonia consent levels. Nitrifiers have fairly exacting growth requirements in terms of dissolved oxygen, temperature, pH and levels of organic matter, which are normally present or readily achievable in the WWTP. Biocides and other inhibitory substances should also be absent. We can advise on optimising conditions and given information on ammonia loading, effluent flow and hours of operation, can devise a dosing programme in order for operators to take full advantage of these remarkable bacteria. For more information on our nitrifying products please contact our offices on 029 2067 4090.