1. Process Modeling and Mass Balance Analysis using KBC WaterTracker ® Software for Wastewater Discharge Improvements and Water Conservation at a Colorado Sugar Refinery Presented by Ray Hamilton, PE, BCEE AMEC Environment & Infrastructure Inc., Denver, CO April, 11, 2014 PWO Industrial Wastewater Seminar Golden, CO

2. 2 Outline  History of Sugar Refineries in Colorado  Overview of Sugar Processing  Existing Wastewater Disposal System  New Regulatory Environment  Mass Balance Model Development  Existing System for Calibration  Proposed System  Summary and Questions

3. 3 Sugar Refineries in Colorado  Colorado “Sandwiched” Between Utah and Nebraska  1890s - Sugarbeets grown in Colorado shipped to Utah or Nebraska for processing  1899 – Colorado’s first sugar refinery opened in Grand Junction  Early Colorado Plains Sugar Refineries  1900 – Rocky Ford and Sugar City in the Arkansas River valley of SE Colorado

4. 4 Sugar Refineries in Colorado (cont.)  Production Moves to the Front Range  1901 First Front Range sugar refinery opens in Loveland  1903 new sugar refineries in Windsor and Greeley  1904 Fort Collins and Eaton  1905 Sterling and Brush  1906 Fort Morgan  Boom and Bust leads to 23 Colorado sugar refineries

5. 5 The Sugarbeet  Sugarbeet has Three Parts  Central Root – stores sugar  Taproot – supplies moisture and minerals  Top – Photosynthesis provides energy  Sugar in Two Forms  Monosaccharide sugar, C 6 H 12 O 6  disaccharide sugar C 12 H 22 O 11  Ideal Beet is 2 Pounds and >17% Sugar

6. 6 Composition of a Typical Sugarbeet

7. 7 The Sugar Refining Process  Beet Washing  Removes dirt and other field debris  Slicing  Produces “cossettes”  Diffusion  Hot water soaking produces “juice”  Still contains other beet products and impurities

8. 8 The Sugar Refining Process (cont.)  Liming and Pressing  High pH precipitates impurities  Filtration separates impurities  Recarbination and Filtration  Lowers pH  Removes dissolved lime  Precipitates calcium carbonate  Second filtration removes calcium carbonate

9. 9 The Sugar Refining Process (cont.)  Acidification and Filtration  Sulfuric acid to balance and bleach  Third filtration produces “standard liquor”  Sugar content of standard liquor + 50%  Evaporation and Condensation  Series of evaporators to drive off water  Condensers cool and recycle water

10. 10 The Sugar Refining Process (cont.)  Crystallization  Super saturated solution put under vacuum to crystallize sugar  Separation  Centrifuge spins out sugar  Filtrate is “molasses”  Purified sugar dried and packaged

11. 11 Typical 1900 Era Sugar Refinery Source: Silver Wedge: The Sugar Beet Industry In Fort Collins, SWCA Environmental Consultants, 2003

12. 12 Wastewater Discharges at Sugar Refinery  Major Sources of Wastewater  Mud from beet washing  Condenser water  Pressed calcium carbonate  Boiler blow-down to ash pond  Historic Discharge to Unlined Ponds  Evaporation and seepage  Integral part of water rights adjudication

13. 13 Typical Flow Patterns at Sugar Refinery  Campaign Driven – September to April

14. 14 Regulatory Concerns  Discharge to Groundwater  Groundwater standards apply  Total coliform standard – as if water supply  High Mn ++ levels in ash  Source well water above TDS standard  Potential nitrite/nitrate problems  Pond Seepage to South Platte River Alluvial Flow  Water Rights Issues Ignored

15. 15 Regulatory Concerns (cont.)  CDPHE Applied Surface Water Standards to Groundwater Discharge  South Platte River standards  EC/TDS/SAR limits controlled by downstream bean farmers  New ammonia limits  Measured as Weighted Average of In-Pond Values and Pond Influent Flows  Seepage does not equal influent - biasing mass based parameters (BOD5 and TSS)  No credit for effects of filtering through pond bottom

16. 16 Client Concerns  Water Rights  High Cost of Treatment  Low Hanging Fruit  PCC Press eliminated all liquid discharge to PCC pond  Mud Press significantly reduces flow to mud pond  How Much More Can be Saved with Water Recycling and Water Conservation?

17. 17 Mass Balance Approach  Simplest Mass Balance  Unfortunately It’s not that Simple

18. 18 Mass Balance Inputs – External to Process  Beets:  Sugar, TDS, TSS, N, H 2 O  Water Supply (wells and ditch):  TDS, N-NO 3, H 2 O  Stormwater/Snow Runoff:  TDS, TSS H 2 O  Coal:  TDS, TSS, N, S, Mn

19. 19 Mass Balance Inputs – Internal to Process  SO 2 and Sulfamic Acid:  S, TDS, N  Gypsum  TDS, S  Limestone, Soda Ash & Caustic  TDS, TSS, S

20. 20 Mass Balance Outputs  Evaporation  Mud, condenser, and ash ponds  Granulator drier  Seepage  Mud, condenser, and ash ponds  Discharge  Flue gas  Pressed mud

21. 21 Mass Balance Outputs (cont.)  Products  Processed Sugar  Molasses  Pressed PCC (animal feed byproduct)

22. 22 Mass Balance Software

23. 23 WaterTracker Top Level View

24. 24 WaterTracker Process Level View

25. 25 Recycle Alternatives Modeled  Separate Fly Ash from Bottom Ash  Closed Loop Condenser Circuit with Cooling Tower  Mud Press Enhancements  Internal Redirection of Process and Waste Streams

26. 26 Results of Water Recycling and Conservation

27. 27 Questions and Answers  Questions  Ray Hamilton – 303-975-2195 or  ray.hamilton@amec.com ray.hamilton@amec.com