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Consultative Workshop on Desalination and Renewable Energy Environmental Implications of Desalination: Concentrate Management Dr. Fulya Verdier, Dr. Rudolf Baten Fichtner GmbH & Co.KG Muscat, Oman 22-23 February 2011. Table of Contents. Need for Concentrate Management

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  1. Consultative Workshop on Desalination andRenewableEnergy Environmental Implicationsof Desalination: Concentrate ManagementDr. Fulya Verdier, Dr. Rudolf BatenFichtner GmbH & Co.KGMuscat, Oman 22-23 February 2011 6543P07/FICHT-6989854-v1

  2. Table of Contents • Need forConcentrate Management • CharacteristicsofConcentrate • Potential Environmental Impacts • Impact MitigationMeasures • Concentrate Management Options • Conclusions 6543P07/FICHT-6989854-v1

  3. Concentrate Management • Thereisincreasingneed, becauseof: • Increasingnumberandsizeofdesalinationplants • Increasingaccumulationofdesalinationplants in certainregions • Increasingconcentratevolumes • Limited availabledisposaloptions • More strict environmental regulations (e.g. groundwaterprotection) • Increasingpublicawarenessand environmental concerns 6543P07/FICHT-6989854-v1

  4. Characteristics of Concentrate • Typicallytherearethreetypesofdesalination plant discharges: • Brackishwaterconcentrate • Seawaterconcentrate • Processeffluents • Salinitylevelofconcentratehighlydepends on feedwatersalinityandrecovery • Volume ofconcentrateismuchgreaterthanvolumeofprocesseffluents 6543P07/FICHT-6989854-v1

  5. Characteristics of Concentrate Overview on the relevant discharge flows 6543P07/FICHT-6989854-v1

  6. Potential Impacts of Concentrate Physio-chemical Impacts • Increasedsalinity, temperatureanddensityofconcentrate relative toreceivingenvironment • Contaminants • Biocides (e.g. NaOClorCl2) • Dechlorinationusing SBS (sodiumbisulfite) • Antiscalants (polymericsubstances) • Cleaningchemicals (acid, base, detergents) • Coagulantsfrom RO plants (e.g.FeCl3) causingreddishcolor • Antifoamingagentsfrom thermal plants (polyethylene, polypropylene) • Tracesof heavy metalsifthereiscorrosionof plant equipment 6543P07/FICHT-6989854-v1

  7. Cause - Impact Assessment “Cause Impact Assessment” is difficult to determine since • there is no direct link • the receiving eco-system is complex • thorough investigations and analysis with adeaquate replication on annual basis are required to establish • statistical analysis of results • comparative analysis of trends • Even if some cause and effect relationships are not fully established scientifically, “precautionary measures” should be considered 6543P07/FICHT-6989854-v1

  8. Impact Mitigation • The approachesaretwo-fold: Environmental Impact Mitigation of Concentrate Process Effluent Treatment Concentrate Management Options: Concentrate Disposal & Volume Reduction 6543P07/FICHT-6989854-v1

  9. Impact Mitigation Measures • Waste water treatment plant (WWTP) including sludge treatment 6543P07/FICHT-6989854-v1

  10. Impact Mitigation Measures • Surface Water Discharge • Measures to reduce the extent of impacts i.e. diffusers for enhanced mixing and dispersion of concentrate • Source: Bleninger (2007) • Source: Wilf (2007) 6543P07/FICHT-6989854-v1

  11. Impact Mitigation Measures • “Best practice” desalination plant • Minimization of plant wastes (liquid, solid) • Process optimization in order to minimize the discharge flow quantity and contamination • Involvement of waste water treatment plants (WWTP) including sludge treatment • Neutralization of chemicals prior to discharge (~ pH=7) 6543P07/FICHT-6989854-v1

  12. Further Measures Relevant Legislations and Guidelines • Generally subject to national water framework • MENA countries like Saudi Arabia, Oman, Israel and Egypt have introduced discharge limits for selected effluent pollutants and mixing zone regulations • e.g. Omani discharge requirements limit parameters in the concentrate • Temperature, Suspendedsolids, Total chlorine, Copper, Nickel, Molybdenum, Iron • Besides the discharge limits, a mixing zone of 300 m in diameter around the outfall is specified. Within the mixing zone, no marine life at the seabed may be destroyed. • Beyond the mixingzone • the ambient water temperature must not be increased by more than 1 °C (weekly average) • the average ambient salinity must not be changed by more than 2 g/l • the average dissolved oxygen level should not be reduced by more than 10% 6543P07/FICHT-6989854-v1

  13. Further Measures Appropriate Site Selection • Data collection and evaluation including installed desalination plants in the vicinity of plant • Semi-closed areas such as Red Sea and Arabian Gulf can be more susceptiple to cumulative impacts due to limited flushing • Impact modeling and assessment (EIA) prior to environmental permit Measures for Permit Granting • Evaluation on case-by-case basis • Establishment of discharge quality standards • Definition of minimum requirements for outfall structure • Prohibition of discharge at coast Appropriate Monitoring • Before-After/ Control-Impact Monitoring 6543P07/FICHT-6989854-v1

  14. Further Measures Additional (international) environmental requirements • EquatorPrinciples • World Bank Standards Measures for Institutional Water Authorities • Preparation of master plans for water bodies • Integrated, multi-scale water resources planning • Development of local, regional, national water regulations • Conducting studies to promote national water program • Assessment of desalination guidelines • Establishment of incentives, task forces 6543P07/FICHT-6989854-v1

  15. Concentrate Management Options Thereisnouniversal concentrate disposal solution for all plants and sites • Surfacewaterdischarge (oceans, seas, rivers) isthemosteconomicandcommonoptionfor large concentratevolumes • Sewerdisposalmayrequirefeesandpermitbylocalsewageagency • Deep well injectionrequireshighly permeable, unusablesalineaquifernearby. Itsfeasibilitydepends on hydro-geologicalconditions • Evaporation pondisland intensive andthusratherapplicableforsmallervolumes • Zero liquid dischargemeansno liquid dischargeacross plant boundary. Itismoreappliedbyindustrybyusing thermal evaporatorsandprocessingtosolids • Selectivesaltrecoveryneedsmarketdevelopment in thelongterm 6543P07/FICHT-6989854-v1

  16. Concentrate Management Options & Costs • (1) Costs include CAPEX and OPEX costs after Greenlee et al., 2009 6543P07/FICHT-6989854-v1

  17. Conclusions • Pioneer installations are operated for backwash water treatment (e.g. Perth SWRO, Sydney SWRO, planned for RazAzzour hybrid plant), the related costs are not significant • Eco-toxicity and chemical dosing rates has been reduced • Measures to mitigate concentrate impacts are state-of-the-art • Concentrate minimization is not yet established. Currently limiting factors are related to economics rather than technical feasibility • Today’s best practice is expected to become minimum requirement for future desalination plants • MENA countries can provide a suitable platform to establish a common consensus 6543P07/FICHT-6989854-v1

  18. Concentrate Management Thank you! 6543P07/FICHT-6989854-v1

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