Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/801555
www.wwtonline.co.uk | WWT | APRIL 2017 | 7 Water companies and environmental campaigners have joined forces to call for a comprehensive ban on microbeads in consumer products, amid warnings that the current government proposals do not go far enough. Proposals contained in the Government's consultation on the issue, which recently closed, would see the ban limited to microplastic ingredients of 5mm or less in 'rinse off ' personal care and cosmetic products. However, other products containing microplastics could continue to be sold, leading campaigners from the Microbeads Coalition to call for a more complete ban to be implemented. The campaign group includes businesses such as Neal's Yard Remedies; NCH Europe, which produces industrial cleaning prod- ucts; Anglian Water, the Environmental Investi- gation Agency, Fauna & Flora International, Green- peace UK, and the Marine Conservation Society. It is calling for the 'Make or break' time for microbeads ban adoption of alternative guidelines developed by Fauna & Flora International, and recommended by the Environmental Audit Committee, which would include all solid water insoluble plastic ingredients smaller than 5mm used for any purpose (not just for exfoliation) with no lower size limit. Furthermore, the campaigners say that so-called 'biodegradable' plastics should not be allowed to be used as alternatives, as these materials do not degrade in the marine environment. The group also want a clear and prompt timeline for phasing out the ingredients. The Microbeads Coalition said: "It's make or break time for the microbeads ban, which must be expanded from the government's current proposals to ensure that it covers any products containing microplastic ingredients that are likely to enter our seas. It makes no sense for the Government to apply this ban to one industry, whilst leaving others to pollute our oceans with these tiny plastics." Scottish Water is facilitating the generation of more renewable power than it consumes for the first time. The company requires about 445 Gigawatt hours (GWh) per year across 4,500 sites such as water and wastewater treatment works - enough to power nearly 140,000 homes. Through a combination of Scottish Water's own investment in renewable energy and hosting private investment on its estate, new figures confirm that the Scottish Water reaches renewables milestone company now generates and hosts more renewable power than it consumes annually and is on course to double this by 2018. Scottish Water's increase in renewable power generation, which supports the Scottish Government's ambitious renewable heat and carbon reduction targets, has been achieved by improving energy efficiency, increasing self-generation and hosting private renewable investment on the company's estate. Expert view sponsored by Specialist microbes to remove wastewater hydrocarbons Dr. John Lear Technical Director Biological Preparations Ltd Hydrocarbon-rich effluents from the petroleum, pharmaceutical and chemical industries tend to be high in COD and can result in heavy fines if consent limits are not met. Moreover, the compounds present may show significant toxicity and environmental persistence, so must be removed from effluents before discharge. Complex hydrocarbons are o en resistant to biological degradation but this can be achieved with specialist bacteria and fungi. Hydrocarbons, defined in chemistry as compounds consisting of hydrogen and carbon, are produced in significant quantities by human activity. They may be aliphatic (in chains or simple rings) or aromatic (in particularly stable ring form). As the hydrogen molecules may be substituted for other atoms or functional groups the structural possibilities are almost endless, and hydrocarbon molecules can be very large and complex. There are a number of microbial species which can degrade complex hydrocarbons, including bacteria of the Acinetobacter, Bacillus and Pseudomonas genera, and fungi such as Penicillium and Phanaerochaete. However given that such compounds tend to be resistant to degradation it is essential to select microbes with the correct metabolic abilities. Organisms with mixed and broad enzyme activity are likely to be required, and use of a consortium, i.e. a mixed population of microbes, o en yields greater success as one particular species or strain may not be able to carry out all steps in the reaction. A typical reaction for the microbial breakdown of a hydrocarbon molecule would involve initial attack by oxygenase enzymes followed by step-by-step degradation by peripheral enzyme pathways, resulting in simpler compounds that the microbes can use for energy and growth. An example pathway for the degradation of a straight chain alkane is:1) Oxidation of the terminal methyl (CH3) group, resulting in an alcohol; 2) Dehydrogenisation of the alcohol to an aldehyde and to the corresponding carboxylic acid; 3) Metabolism via the β-oxidation fatty acid pathway to produce energy. Biological Preparations supplies consortia of bacteria and fungi that are capable of breaking down a wide range of hydrocarbons including: short- and long-chain hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, and complex substituted hydrocarbons. The products are available in liquid or powdered form and have a shelf life of up to 18 months. Providing the correct conditions is also of the utmost importance to ensure optimum degradation rates. The most efficient reactions for hydrocarbon degradation take place aerobically, i.e. in the presence of oxygen. Temperature affects growth rate as well as the chemistry of the pollutants and the correct nutrient balance must be provided to ensure that lack of nitrogen or phosphorous do not become limiting factors for microbial growth. Surfactants may be used to increase solubilisation of contaminants and make them more bio-available to the degrading microbes. The products are normally added to the aerated zone of the treatment plant and Biological Preparations experts can advise on the correct microbial consortium to degrade the compounds likely to be encountered at a particular facility, as well as providing the correct conditions in order to achieve optimum results.