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
PWO Industrial
Wastewater
Seminar
Golden, CO
April, 11, 2014
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
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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
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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
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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, C6H12O6
disaccharide sugar C12H22O11
Ideal Beet is 2 Pounds and >17% Sugar
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Composition of a Typical Sugarbeet
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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
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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
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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
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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
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Typical 1900 Era Sugar Refinery
Source: Silver Wedge: The Sugar Beet Industry In Fort Collins, SWCA Environmental Consultants, 2003
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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
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Typical Flow Patterns at Sugar Refinery
Campaign Driven – September to April
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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
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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
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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?
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Mass Balance Approach
Simplest Mass Balance
Unfortunately It’s not that Simple
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Mass Balance Inputs – External to Process
Beets:
Sugar, TDS, TSS, N, H2O
Water Supply (wells and ditch):
TDS, N-NO3, H2O
Stormwater/Snow Runoff:
TDS, TSS H2O
Coal:
TDS, TSS, N, S, Mn
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Mass Balance Inputs – Internal to Process
SO2 and Sulfamic Acid:
S, TDS, N
Gypsum
TDS, S
Limestone, Soda Ash & Caustic
TDS, TSS, S
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Mass Balance Outputs
Evaporation
Mud, condenser, and ash ponds
Granulator drier
Seepage
Mud, condenser, and ash ponds
Discharge
Flue gas
Pressed mud
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Mass Balance Outputs (cont.)
Products
Processed Sugar
Molasses
Pressed PCC (animal feed byproduct)
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Mass Balance Software
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WaterTracker Top Level View
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WaterTracker Process Level View
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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
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Results of Water Recycling and Conservation
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Questions and Answers
Questions
Ray Hamilton – 303-975-2195 or
ray.hamilton@amec.com
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