Water Journal : Water Journal July 2011
new products & services water JULY 2011 109 COST-EFFECTIVE SELF-PRIMING PUMPS FOR WATER INTAKE Vertical sump pumps and submersible pumps require full disassembly of the pump and flanges for maintenance. Horizontal pumps with an external priming device require instrumentation and control signals for start/stop procedures. Even a small quantity of solid particles can block installations with back valves at the suction pipe. Typical installation of the AHLSTAR self-priming pump. Sulzer's AHLSTAR self-priming pump offers a reliable, cost-effective solution in suction-lift pumping installations, and is especially suited as a seawater intake pumps in small to medium-sized desalination plants, and water treatment plants. With its internal liquid ring vacuum impeller, it is able to prime the suction pipe. Easier installation and maintenance help lower life cycle cost. No back valve or external priming device is needed, saving in instrumentation, pipe works, and control signals. The pump is easy-maintenance due to its horizontal dry-mounted, back pull-out design. OVIVO DESIGNS AND CONSTRUCTS ADVANCED WATER TREATMENT PLANT USING MBR-RO TECHNOLOGY Viterra is a global agribusiness providing premium quality ingredients to leading global food manufacturers. Its Tamworth malt facility has a grain capacity of 45k tonnes, supplying malt both domestically and internationally. With Viterra's holistic approach to water management and conservation of this precious resource, an Advanced Water Treatment Plant (AWTP) was required by the company to treat malting steep water to a quality suitable for reuse within the facility. Ovivo Australia designed and constructed a cutting-edge AWTP using MBR (membrane bioreactor) and RO (reverse osmosis) technology. MBR technology was used because it is highly suitable for the treatment and filtration of municipal and industrial waste. The MBR and RO perform all the necessary steps to treat the influent to a condition suitable for reuse within the client's facility and to maintain discharge agreement conformance for the reject stream generated. The malting steep waste is initially screened, balanced and pH corrected, and biologically treated to reduce BOD/COD, Nitrogen and Phosphorus. Permeate is drawn through two immersed membrane trains reducing TSS levels and pathogens. The MBR permeate is further treated through a dual-stage RO system to remove dissolved content and pH-corrected before being stored for reuse. The process designed by Ovivo incorporates the use of a bio-selector that conditions the wastewater prior to bio-treatment and enhances biological phosphorus removal. The AWTP, which is capable of treating a hydraulic load of 300kL per day, can recover 75% of the wastewater, equating to around a 50% reduction in the client's reliance on local potable water supply. Ovivo was able to provide the client with capital cost savings over conventional activated sludge systems. The AWTP performed the same function but with a reduced footprint and associated civil installation costs. The technology used resulted in a compact and efficient means of improving water quality and is well suited for reuse applications. The AWTP, which was delivered as design, build and operation (DBO), enables water savings of 50ML per year. The aeration system comprises Ovivo's AEROSTRIP Fine Bubble Diffusers, a high performing membrane diffuser that has provided high SOTR against power input. Efficiency has been shown as 4--4.2kg O2/h per kW input. Optimisation of the positive displacement blowers is achieved through Ovivo's DO control strategy. With proper management of the sludge age and MLSS, permeability of the submerged membrane modules has been found to be consistent and well above accepted levels of 300 LMH/Bar. The membrane flux rate selected reflects the high residual COD that is commonly experienced in industrial trade waste, when compared to sewage, due to slow or non-biodegradable organic fractions. Even though the designed influent data is much lower than actual influent loads, the recovered water surpasses design estimates. The excess biomass generated by the aeration phase is wasted through the MBR tank and dewatered using a horizontal solid bowl decanter centrifuge. The output of the centrifuge is a spadable cake that is beneficially reused within the region. Centrate is captured and returned to the head of the plant. The plant is controlled via a SCADA system that allows for remote monitoring and trending. Automation is critical to the long-term success of the wastewater treatment plant. Validated UV Small Footprint Energy Efﬁcient Ph: 038795 7711 . E: ﬂuidquip@ﬂuidquip.com.au . www.ﬂuidquip.com.au/Berson-UV-Disinfection Validated UV for drinking water & wastewater The AWTP allows water savings of 50ML/a.
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