1. Will CWA 316b Regulations End Chemical Cooling Water Treatment Programs? Mary Wolter Glass President, Mexel USA, LLC February 17, 2015

2. No, but it will not be the same! Imposed opportunity to improve cooling water system performance Take control of the regulatory planning process to enhance operational and financial goals Challenge: craft unique solutions for the business that will succeed with regulators

3. Factors Permit Writers Will Consider Reliability and cost of electric service Technical feasibility and financial costs and benefits Land availability for BTA and ongoing operations Compatibility of entrainment BTA with impingement technology adopted Remaining useful life of the plant

4. Factors Permit Writers Will Consider Social costs and benefits of alternative entrainment technologies Water sources and alternatives available Numbers & types of organisms Potential to increase air and other pollution

5. Untreated Inlet Water Box - Hydroids

6. Treated Inlet Water Box

7. 7 “Before” “After” Macro Biofouling Prevention

8. Quagga Mussel Damage

9. Identifying 316b Options Define minimal performance requirements for plant – operating schedule, availability, and capital and maintenance costs Evaluate options for: – Ease and cost of compliance – Compatibility of combined options – Potential unintended impacts of compliance, e.g.- Increased fouling due to lower velocities Impingement devices that increase entrainment mortality and vice versa

10. Implementation BTA impingement technology options well-defined Entrainment BTA is site-specific and more complicated Impingement implementation can be delayed to allow planning for entrainment “Unknowns” still create risk for technology selections - Endangered Species Act, Federal Agency reviews, litigation

11. 316(b) & Chemicals Chemical treatment necessary for plant performance Mortality from impingement and entrainment linked –Mechanical, thermal and chemical factors –Intake and water circuit design affects fouling Multiple BTA solutions – –Carefully designed mechanical & chemical programs –Adjustments to operations, scheduling Collaboration of environmental and operations staff to balance –Optimal environmental performance –Operational/financial realities

12. Chemical Program Objectives Evaluate purpose of current program – What problems lead to current choices? – Do problems persist? New problems? – Is the program still achieving desired results? – Future viability of program with regulators? Examine plant design and fouling issues – Intake and water circuit characteristics – Plant operating conditions, schedules – Biological fouling – species, operating conditions, ambient environmental conditions – Corrosion, scaling, mud, etc.

13. Current Program Review Chemical program components – Inventory all chemicals and the purpose – direct and indirect – Document toxicity of each in detail Certified laboratory studies Field studies Related these to critical species at site Non-chemical devices and practices – Screens (travelling & fixed), filters, nets, etc. – Operating schedules and constraints Effects on impingement and entrainment Constraints on critical production schedules

14. Shaping the Best Program Detailed information on toxicity and other risks from manufacturers for in-house environmental review – MSDS and product label – Extensive lab and field research data, results Program should minimize number of chemicals based – Efficacy vs. adverse impacts – Safer alternatives Field and laboratory test results from existing and new studies – Species-specific studies – bench-scale, unit trials, laboratory, bench scale – Sensitivity studies for critical species – Whole Effluent Toxicity Tests (WET tests) – Local ecosystem and biodiversity studies

15. Combine technologies with chemicals for BTA – Acoustic or other fish deterrent systems divert target species before exposure to chemicals occurs – Passive and traveling screens, Mesh size and operating speed factors Entrainment mortality can vary widely Lower velocities may aggravate existing fouling problems – Increased blend of reclaimed water and other water sources to reduce mortality losses - increases chemical requirements and operating complexities Combine chemicals with operations and maintenance practices – Cleaning and operating practices to reduce chemical requirements Technology Combinations

16. 25 September 04 November - 1.5% - 1.0% - 0.5% Ref = 0.00 - 1.25% (.23% improvement) - 0.8% (.73% improvement) - 1,48% - 1.53% 6 weeks Condenser Backpressure Di-oxide chlorine treatment + mechanical ball cleaning MEXEL 432 treatment alone Chlorine & Ball System vs.Mexel 432/0

17. Making Your Case Factors to enhance regulatory acceptability – Lower chemical toxicity reduces direct lethality helps reduce the effects on organisms from other thermal and mechanical stressors – Shorter dosing pattern reduces total daily exposures – Reduced number of chemicals required – Chemicals that do not require detoxification or remediation for discharge Fully document the case for chemicals as a necessary part of BTA 17 www.mexelusa.com

18. Relative Toxicity Matters Freshwater Crustaceans – Mexel 432/0 Daphnia magna - Effect Concentration (EC) 50 (48 hour):554 ppb Daphnia magna - No Observed Effect Concentration (NOEC) (21 day)  200 ppb – NaClO invertebrate: Lethal Concentration (LC) 50 (24 hour) 5 ppb Seawater fish – Mexel Scophthalmus maximus (juvenile) - LC 50 (96hour): 3,700 ppb – NaClO Scophthalmus maximus (juvenile) - LC 50 (96 hour): 32 – 90 ppb Source: Mexel Industries, SAS 2013

19. Biofilm Control Untreated Treated

20. Condensers After 5 Months Unit 6 – Treated with Mexel 432/0 Unit 5 – Untreated

21. New Water Treatment Options - the Mexel 432/0 Example Based on filming amine technology, not lethal slug or continuous treatments –Molecular layer on the inside surfaces –Dispersant/detergent with mild biocide –Prevents and remediates fouling over time –Protects surfaces and equipment to avoid problems –Replaces multiple chemicals for corrosion, scaling, mud Application in once-through and cooling tower systems –Emulsion injected at intake for 30 minutes per day –Typical dosing rate of 4 to 5 ppm Works in fresh, saline, and reclaimed water systems

22. 22 Mexel Filming Process to Prevent Fouling Condenser tube Biofilm, etc. Mexel® 432/0 Full thermal transfer re-established Removal process

23. In Conclusion Opportunities to improve operational and financial performance along with environmental objectives Factors beyond environmental will be considered in determining BTA Numerous good chemical options available Best selections for BTA will balance plant public service responsibilities with the environment

24. 316(b)MUSA www.mexelusa.com Follow us on Twitter: www.twitter.com/mexelusa Follow us on LinkedIn: www.linkedin.com/company/mexel-usa