Water Journal : Water Journal September 2014
water SEPTEMBER 2014 40 Conference report IWA ConferenCe on Pre-TreATmenT of WATer And WAsTeWATer Mitch Laginestra, Principal Engineer based in South Australia and GHD's Technical Leader of Industrial Wastewater, was a keynote speaker at the recent IWA Conference on Pre-Treatment of Water & Wastewater and provides this report. The International Water Association (IWA) conference on Pre- Treatment of Water and Wastewater was held at Tongji University in Shanghai, China, 18–20 May 2014. Shanghai is reportedly the largest or highest-populated city in the world, so perhaps 110 delegates among some 25 million inhabitants doesn’t sound that significant. However, considering the attendees were from all over the world – and considering Putin and other Asian leaders were in Shanghai at the same time (albeit not at the same conference!) the status of the venue at least was somewhat elevated! Day 1 Professor Fengting Li, Vice Dean of the College of Environmental Science and Engineering, Tongji University and United Nations Environmental Program Tongji Institute of Environment for Sustainable Development, and Chair of the organising committee of IWA, welcomed the delegates and passed the baton to the first of an impressive array of keynote speakers: Dr Juihui Qu, from the Chinese Academy of Engineering (Research Centre for Eco-Environmental Sciences) spoke about the priorities for improving water and environmental quality in China, nominating key issues of sanitation, nutrient reduction from point sources, arsenic contamination in Inner Mongolia and fluoride. Currently there is a push for simple, efficient and sustainable technologies in rural and urban situations. Current standards for effluent quality include BOD 20 and 60 mg/L for municipal sewage treatment plants (Class 1A and 1B respectively), and 100 mg/L for industrial wastewater effluent. Dr Ioannis Alexiou, of Scientists International based in the UK, followed with a talk on sustainable industrial management, applying pre-treatment in a European context and evolving a circular economy. He spoke of renewed environmental conscience in Europe creating a shift in industrial production, and use of resources and energy (use of energy-efficient technologies and the introduction of renewable energy resources including solar, biomass, wind and hydro-power). The talk also focused on use of legislation and economic incentives to adopt ecologically friendly design. Anaerobic digestion, bioethanol production, membranes and tri-generation are some of the most promising technologies, allowing the recovery of by-products and simultaneous production of heat, cooling and power with technical, economic and environmental benefits. The third keynote speaker was Professor Arturo Keller, Professor of Biogeochemistry, Bren School, University of California, Santa Barbara, USA, who spoke on the application of nanotechnology, and the opportunities and risks for water and wastewater treatment and soil remediation. Management strategies for contaminants (such as pesticides) include application of a number of emerging technologies such as nano-particles, biochemical injection materials (including reactants, catalysts, adsorbents) and nano-membranes. Keynote speaker #4, Dr Baoyu Gao, Environmental Engineering, Shandong University, China, spoke of coagulant behaviours and effect on membrane fouling in a coagulation/ultrafiltration hybrid process. The key emphasis on the paper was use of a new coagulant Al13, which reportedly formed stronger flocs that are larger and more stable than PAC and alum. The coagulant (yet to become commercially available) performed better than PAC at acidic pH, although there is only low DOM removal. Professor Fengting Li, from Tongji University, Shanghai, presented his research on development of the coagulant industry in China. The Chinese market involves a high production rate of a multitude of chemicals for pre-treatment and coagulation of drinking water. China has adopted grading of water sources for drinking water (I–V, with I representing the best for drinking water). It was noted that grades III and IV are the most commonly used treatments for drinking water. PAC is a common chemical applied, with different grades being used for drinking water versus industrial water pre-treatment. Dr Santino Di Bernardino, Waste and Biogas Director, Professor at National Laboratory for Energy, Lisbon University, spoke on pre-treatment of industrial wastewater in a sustainable context (environmental, economic and societal) and talked about development of regulations and aspects in Europe. Before 1980, end-of-pipe pollution reduction was typically adopted. The following decade involved a strong focus on legislation. In 2000, cleaner technologies emerged, and in 2010 the advent of sustainable production has now largely been adopted in Europe. Wilbert Menkveld, from Nijhuis Water Technology in the Netherlands, spoke on development of a novel Dissolved Air Flotation system for pre-treatment of industrial wastewater. Termed the intelligent DAF, it reportedly uses some 30% lower energy consumption (0.03 kWh/m3) per volume wastewater treated in comparison to conventional DAF installations. This high efficiency is partly the result of the air bubble size being around 20-40 μm (some 50% smaller than typical). Examples of application in the poultry and oil refinery wastewater were presented and reportedly showed results of 99% removal of suspended solids and oils and greases and up to 85% COD removal. The I-DAF can also be used without chemicals, but lower reduction of contaminants is achieved. Guido Kooijman, Sanitary Engineering, Civil Engineering, University of Technology Delft, Stevinweg, Netherlands, spoke on the influence of chemically enhanced primary treatment and its impact on digestion and sludge dewaterability. Sludge land application has been prohibited in Europe since the 1990s, and consequently incineration is now advocated, which requires high dewaterability for cost effectiveness. The application of flocculants in primary sedimentation of wastewater plants increases sludge production. Cationic and Shanghai by night is a spectacular sight.
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