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Industry reduces its thirst for water (2/2)

| By Chemical Engineering

Read Part 1: Industry Reduces its Thirst for Water

    • Recycling – state of the art recycling is a good investment
    • Enery and water management become one

 Industrial water management will be one of three focal topics at ACHEMA 2015 on June 18th – 22nd in Frankfurt/M

Membrane process: learning from Mother Nature

The use of membranes in water treatment technology has been on the increase for many years. There are good reasons why that is the case. Membranes run continuously and are fully automatic. Membrane materials are now cheaper and more effective. The membranes operate at lower pressure and that reduces energy consumption.

More than 2/3 of new desalination capacity being installed worldwide is now based on reverse osmosis. In contrast to traditional evaporation-based technologies, no heat energy is needed for reverse osmosis. This reduces the cost of desalinated water. Even in regions where energy costs are relatively low such as the Middle East, reverse osmosis is increasingly the solution of choice. Given the right plant design and the right equipment (60% of total energy consumption is used to power the pumps), nothing can match reverse osmosis technology, reports Sulzer.

Sea water is not the only option. Desalinated ground water is another potential source, for example in the dry American South, claims GTAI (Germany Trade & Invest). Texas, Florida and California are leading users of the technology. Seawater desalination is becoming an increasingly significant factor, particularly in California where megaprojects are in the planning pipeline. Demand for high-efficiency pumps and rugged membranes continues to increase. Financing for many projects is now provided by public-private partnerships.

Jim Taft, Executive Director of the Association of State Drinking Water Administrators (ASDWA), says that mobile desalination systems have very significant potential. Demand is likely to increase because these systems in the South could help the water industry to manage more frequent periods of drought or temporary supply shortages.

Some membrane system suppliers have now started to standardize their systems. Higher production volumes drive down the manufacturing costs for these plug-and-play solutions which are used to purify service water and drinking water and also for treatment of industrial wastewater. It takes minimal effort to connect the pre-assembled systems.

Recovery of energy and re-usable materials

When there is direct contact, it is impossible to prevent production materials from contaminating the process water. As a result, the process water contains varying concentrations of contaminants (ranging from a few ppb to several %). If a substance can be re-used, recovery can make economic sense in addition to helping protect the environment.

The French startup Magpie Polymers has developed a highly efficient filtration method for capturing re-usable substances even if they are only present in minute amounts. Various filters made of polymer beads are installed, and the metals form selective bonds with the beads. The technique is already being deployed at several European companies to filter out minute amounts of precious metals.

The chemical group Lanxess also provides techn ology for recovering re-usable materials. Ion exchangers function as selective adsorbers for fine purification of wastewater flows and process electrolytes. Heavy metals and other substances such as boric acid, chromate, arsenate, fluoride and ammonia in salt solutions can be selectively captured.

Little use has been made so far of wastewater as a heat source. In the past, utilization of this energy was seldom possible, one of the constraining factors being the 65°C flow temperature limit for heat pumps. Ochsner now markets high-temperature heat pumps with flow temperatures up to 100°C, opening the door to totally new industrial and commercial heat pump applications.

Water and hygiene management

Cooling systems play an important role in industrial process flows. Cooling water needs to be treated to prevent deposits and corrosion and also to maintain hygiene standards. The water in the cooling loop is permanently infested with legionella and pseudomonads, creating a health hazard for staff working at industrial companies and also putting neighbors at risk. The hazard can be minimized by reducing aerosol release and implementing active legionella control measures.

VDI guideline 2047-2 dated January 2014 contains a code of practice for hygienically sound operation of systems which release heat through the evaporation or spraying of water. The guideline recommends that a risk assessment be carried out for the complete system. The measures include inspection and documentation as well as identification, evaluation and minimization of risks. Companies such as EnviroChemie and BWT offer legionella management solutions. The Cillit CEE Facility Management & Risk Analysis Package includes holistic risk analysis and verified monitoring of evaporative chilling systems. To eliminate water-related deposits and corrosion as a potential source of biofilm formation, Dipolique recommends installation of a properly designed water treatment system, use of suitable conditioning agents and management of total salt content based on data acquired with inductive conductivity probes.

Summary: Resource conservation and economic considerations make it imperative to make intelligent “use” of industrial process water and to “consume” as little as possible. Water should not be transported, heated or contaminated more than is absolutely necessary to meet process needs.  Water re-circulation and re-use are two crucial aspects of “smart water”. Companies will be putting proven, enhanced and recently developed products, technologies and system solutions on display at ACHEMA 2015 on June 18th – 22nd in Frankfurt/M. Panta rhei – “everything flows” and water technology is no exception.

ACHEMA is the world forum for chemical engineering, process engineering and biotechnology. Every three years the world’s major fair for the process industry attracts around 4,000 exhibitors from over 50 different countries to present new products, processes and services to 170,000 professionals from all over the world. The spectrum ranges from laboratory equipment, pumps and analytical devices to packaging machinery, boilers and stirrers through to safety technology, materials and software, thus covering the entire needs of the chemical, pharmaceutical and food production industries. The accompanying congress, featuring 800 scientific lectures and numerous guest and partner events, complements the wide range of themes of the exhibition. The next ACHEMA will take place from 15-19 June 2015 in Frankfurt am Main. More at