Water. desalination + reuse

February/March 2013

Water. Desalination + reuse

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SHOWCASE LiqTech's ceramic membranes find chinese parTner Ceramic membrane manufacturer LiqTech International Inc announced on 21 December 2012 that it has entered into an original equipment manufacturer (OEM) supply agreement with Shanghai Denovo Environment Protection Co Ltd of China. The OEM agreement includes progressive minimum order quantities for the years 2013-2016 for Denovo to maintain the supply agreement. The Chinese market, being one of the fastest growing markets for industrial wastewater treatment, has been earmarked as the focus region for Denovo. With increasing stringent discharge limits within the Chinese environmental legislation for water treatment, Denovo - one of the leading industrial waste water firms in China - will be able to provide solutions to the industrial sectors using its advanced biological treatment systems and LiqTech's advanced membrane technology. Copenhagen-based LiqTech manufactures and globally markets ceramic membranes/filters using its developed silicon carbide (SiC) technology for drinking water, wastewater, produced water and reverse-osmosis pretreatment. Dr Chen Yegang, chairman of Denovo, explains, "We have near-term projects at hand, where we will utilize the SiC membrane as a key process component. The LiqTech membrane technology is superior in its field and will add value for our customers." LiqTech International's CEO, Lasse Andreassen, commented, "Denovo is a leading Chinese EPC contractor of wastewater treatment plants, and the company has shown remarkable growth in a strategic market to LiqTech. This agreement with Denovo is a milestone for LiqTech in our efforts to penetrate the Chinese market for water treatment with our SiC membranes." Denovo and LiqTech have already encountered a strong market demand for water treatment technologies requiring high-performance membranes to reduce costs and operate under harsh conditions, which are some of the trademarks of SiC membranes. exTernaL mbr sysTem Launched by aquaTech Aquatech International has launched a membrane bioreactor (MBR) system in which the ultrafiltration (UF) membrane is positioned outside the bioreactor rather than submerged in it or in a downstream membrane tank. Aquatech says its new Aqua-EMBR offers several benefits over submerged MBR systems, which already have advantages over conventional activated-sludge systems. Because the Aqua-EMBR system has no membrane tank, it can be built more quickly. Installed as one or more skids on a flat concrete slab, the system eliminates the need for complex civil engineering and lowers the risk for contractors due to construction delays caused by weather conditions, environmental or other local uncertainties. The UF membrane modules are arranged vertically and aerated continuously at the bottom. Mixed liquor is transported via "air lift pump" action through the module, while the membrane feed/recirculation pump is only used to overcome the hydraulic losses and maintain a relatively constant flow of mixed liquor through the membrane. This innovative design reduces much of the feed-pumping energy requirement needed to maintain high crossflow velocity. Permeate flow, which is inside-out from the membrane modules, is collected by a permeate pump. Because no membrane components are submerged in the biological mixed liquor, the biological and membrane systems can be operated and optimized independently. The membrane operation is automatically controlled. With its tight membrane pore size (nominal / maximum 30 nm /50 nm), Aqua-EMBR produces high effluent quality an important factor for reuse purposes and future regulations. Applications for Aqua-EMBR include wastewater treatment or reclamation in new industrial and municipal wastewater treatment plants (WWTP) or in existing plants undergoing upgrades. Importantly, the Aqua-EMBR system offers an operatorfriendly working environment. Operators do not see, smell or come in contact with the biosludge, nor do they work on top of open membrane tanks where the air could contain harmful aerosols. Should maintenance be required, Aqua-EMBR's membrane modules can be removed or replaced without any contact with the biosludge. Another significant benefit is the Aqua-EMBR's higher operating flux - approximately 50% higher than submerged systems. Because 50% less surface area of membrane is needed per unit volume of permeate production, the low membrane cost per unit volume filtrate means savings in capital and operating costs. Maintenance costs, such as labor and chemicals, are also reduced. One of the first applications for Aqua-EMBR was treatment of effluent generated from a chemical manufacturing plant, where Aquatech successfully commissioned a 50 m3/d capacity plant. After proper sludge acclimatization, it was possible to reduce chemical oxygen demand by 85% and consistently achieve a reduction of more than 95% of biochemical oxygen demand. deserT siTe success for porTabLe mbr uniT Excellent results have been obtained from a portable membrane bioreactor (MBR) sewage treatment plant from ACWA Emirates that is installed at the US$ 9 billion Habshan 5 gas project in Abu Dhabi. The company, part of ACWA Services, set up the state-ofthe-art plant on behalf of CCC Contractors to treat wastewater from the 5,000-worker construction camp and has been undertaking operations and maintenance since start-up. The portable MBR plant consists of two containerised Memtreat units, which treat roughly half of the flow each (with an average flow of 501 m3/d through one and 480 m3/d through the other). On some days the treatment plant has capably surpassed its 1,000 m3 design flow thanks to its ability to cope well with widely varying flows. The cost savings achieved using the portable MBR solution are considerable. Removing the wastewater by tanker from the remote desert site to the nearest treatment facility, 100 km away, and bringing in water for wastewater treatment, would have cost an estimated AED 42 million (US$ 11.43 million). Factoring in the investment costs of the plant, tank, pipelines, pumping stations, operation and maintenance, chemicals and February-March 2013 | Desalination & Water Reuse | 37 |

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