No abstract

No abstract

For chemical industries, fresh water availability is a pre-requisite for sustainable operation. However, in many delta areas around the world, fresh water is scarce. Therefore, the E4 Water project (www.e4water.eu) comprises a case study at the Dow site in Terneuzen, The Netherlands, which is designed to develop commercial applications for mild desalination of brackish raw water streams from various origins to enable reuse in industry or agriculture. This study describes an effective two-stage work process, which was used to narrow down a broad spectrum of desalination technologies to a selection of the most promising techniques for a demonstration pilot at 2-4 m³/hour. Through literature study, laboratory experiments and multi-criteria analysis, nanofiltration and electrodialysis reversal were selected, both having the potential to attain the objectives of E4Water at full scale.

High variability, stringent effluent permits, and often extreme operating conditions define the practice of wastewater treatment in the chemical industry. This paper reviews the benefits and challenges of applying dynamic simulation to chemical-industry wastewater treatment plants by describing case studies at full-scale wastewater treatment plants (WWTP). The applications range from process troubleshooting to optimization and control. The applications have been valuable and useful in developing a deeper understanding of the plants as integrated systems. However there still remains substantial work to implement the dynamic simulations for daily real-time use by plant engineers and operators. This opportunity to improve plant operations is still largely untapped and will remain so until dynamic state estimation and data reconciliation are incorporated into simulation packages for use in developing the on-line simulations.

ab s t r ac tThe DECO water treatment facility (built and operated by Evides Industriewater B.V.) is using an integrated membrane system to produce demineralised water for the production facilities of Dow Benelux B.V in Terneuzen, the Netherlands. The system consists of large-scale continuous microfi ltration (CMF) unit and two-pass reverse osmosis (RO) unit with FILMTEC TM membranes. It is the fi rst time in the Netherlands that domestic waste water is re-used in such a large scale for industrial use. This is an excellent example of a full scale process which was adjusted to preserve scarce fresh water resources in the region. The main goal-to minimize the environmental impact and to maximize water recovery through water recycling loops, thereby supporting the chemical industry movement to improve sustainability. This paper discusses the operational experience of the first 18 months operation with wastewater. The plant was started in 2000 and was originally designed to desalinate estuary water, due the lack of fresh water in the region. The water source was challenging due to high chemical and biological variability, which lead to operational diffi culties like biofouling and high maintenance costs due to corrosion. In 2006 the plant was re-engineered to treat municipal waste water originating from the nearby city of Terneuzen. Re-engineering consisted of new RO membrane design, low pressure feed pumps and process automation adjustments. The DECO plant uses fouling resistant membranes (BW30-400/34i-FR) with a thick feed spacer. The spacer reduces the fouling potential and facilitates cleaning. In addition, the plant is using frequent preventive cleanings, which is only possible with robust membranes. These actions have led to stabile operation in terms of permeate fl ow and the good quality of the produced permeate (<10 μS/cm). This case shows that operational problems caused by the biologically active wastewater can be eliminated by a good plant design (membrane selection) and good operational practices. The facility reports signifi cant savings, 20% increase in the system recovery and 50% reduction in the operational cost (OPEX) with the implementation of the waste water treated system. The savings in OPEX are mainly related to energy costs and decreased use of chemicals for water treatment. In addition, the environmental impact is reduced as the city's waste water is no longer discharged to the sea, but given another life as process water.Trademark of The Dow Chemical Company ("Dow") or an affi liated company of Dow.