Pulp Paper & Logistics


MAPAL GREEN ENERGY


Bubbles: the answer to treating waste water?


Already being used in the water industry, a new aeration technology could offer the pulp and paper industry cost savings, says Guy Stephenson


processes. Processing pulp requires huge quantities of water to deliver a consistent structure. The constituents of paper are processed into a sludge form and with water used at almost every stage of production, the result is the generation of a high quantity of highly-contaminated wastewater that must be treated to meet regulatory and environmental requirements. Some estimates suggest that up


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to 17,400 litres of water (or 3,827 Imperial gallons) are required to produce one tonne of paper, with the raw wastewaters from pulp and paper and board mills often requiring complex biological treatment processes. It’s a challenge the industry has embraced however, with around 92 per cent of the water used returned to the environment after it has been treated. The filtering and removal of contaminants from the waste water can be very energy intensive, with mechanical surface aeration and sub-surface jet aeration systems for biological treatment, known to consume high levels of electricity. Energy reduction, operational cost reduction and water recycling initiatives are therefore important objectives for many paper manufacturers.


In pulp and paper mills, waste


water treatment can take on several forms, from filtering to biological


ulp and paper making is one of the most water intensive of industrial production


INDUSTRY NEWS 19


treatment processes. For biological treatment to be effective, the waste water needs to be effectively aerated. Many mills will use mechanical


surface aeration techniques to supply the required oxygen for bacteria to achieve an aerobic biological treatment, especially where an activated sludge process is involved. However, mechanical surface aerators are typically expensive to operate and maintain, old, prone to breakdown, due to the number of moving parts and have considerable energy consumption, all of which adds up to relatively high operating costs. Mapal Green Energy has


developed its Floating Fine Bubble Aeration technology (FFBA), currently used in the UK by Anglian Water with further deals signed with Thames Water and United Utilities for systems to go live before the end of the year, where Mapal GE’s equipment will be used to treat domestic and industrial wastewater in a range of lagoons and reactors. The same technology has also been deployed successfully in South Africa


in the pulp and paper sector and again in factory farming installations in Israel, where the challenges of treating aggressive and hazardous liquids echo many of the issues faced in the pulp and paper industry. What is described as a


revolutionary solution – floating fine bubble aeration – approaches the challenge of wastewater oxygenation by marrying the strengths of mechanical surface aeration technology – easy to install and accessible for maintenance – with the efficiency that is derived from sub surface fine bubble aeration systems. With no moving parts generating friction and high energy consumption, a key benefit for users of Mapal Green Energy’s floating fine bubble aeration system is its dramatically reduced energy bill. Tests around the world have shown that in some cases, compared to mechanical surface aeration, a plant’s energy consumption can be reduced by up to 70 per cent using the Mapal system, with savings of 50 per cent regularly achieved. Commenting on the ease of


installation of the system, Mapal’s


UK sales manager Andy Carling said, “By substituting a surface mounted propeller for a system of blowers and fine bubble diffusers, not only is energy consumption reduced, but installation and maintenance is dramatically simplified. The system does not require a tank to be drained, nor does it need to be attached to a concrete floor. Aerators are automatically adjustable to water depth and because they float, are always level, thus delivering an even flow of oxygen within the reactor.” Mapal’s units are made from


stainless steel, so have a long life and as a modular system, the installation can be added to or taken away from quickly and easily. A technology that is creating


waves amongst the UK’s water utilities looks set to revolutionise wastewater treatment in selected sectors of the pulp and paper industry as well. More information from Mapal


Green Energy UK, 1 Hallswelle Road, London NW11 0DH, UK. Tel: 44 7503 685031. Email: andy@mapal-ge.com Website: www.mapal-ge.com


November/December 2014


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