Process Modeling and Mass Balance Analysis using KBC WaterTracker® Software for Wastewater Discharge Improvements and Water Conservation at a Colorado Sugar RefineryPresented by Ray Hamilton, PE, BCEE

AMEC Environment & Infrastructure Inc., Denver, CO

April, 11, 2014

PWO Industrial Wastewater

SeminarGolden, CO

2

Outline

History of Sugar Refineries in ColoradoOverview of Sugar ProcessingExisting Wastewater Disposal SystemNew Regulatory EnvironmentMass Balance Model DevelopmentExisting System for CalibrationProposed System

Summary and Questions

3

Sugar Refineries in Colorado

Colorado “Sandwiched” Between Utah and Nebraska1890s - Sugarbeets grown in Colorado shipped to Utah or Nebraska for processing1899 – Colorado’s first sugar refinery opened in Grand Junction

Early Colorado Plains Sugar Refineries1900 – Rocky Ford and Sugar City in the Arkansas River valley of SE Colorado

4

Sugar Refineries in Colorado (cont.)

Production Moves to the Front Range1901 First Front Range sugar refinery opens in Loveland1903 new sugar refineries in Windsor and Greeley1904 Fort Collins and Eaton1905 Sterling and Brush1906 Fort MorganBoom and Bust leads to 23 Colorado sugar refineries

5

The Sugarbeet

Sugarbeet has Three PartsCentral Root – stores sugarTaproot – supplies moisture and mineralsTop – Photosynthesis provides energy

Sugar in Two FormsMonosaccharide sugar, C6H12O6

disaccharide sugar C12H22O11

Ideal Beet is 2 Pounds and >17% Sugar

6

Composition of a Typical Sugarbeet

7

The Sugar Refining Process

Beet WashingRemoves dirt and other field debris

SlicingProduces “cossettes”

DiffusionHot water soaking produces “juice”Still contains other beet products and impurities

8

The Sugar Refining Process (cont.)

Liming and PressingHigh pH precipitates impuritiesFiltration separates impurities

Recarbination and FiltrationLowers pHRemoves dissolved limePrecipitates calcium carbonateSecond filtration removes calcium carbonate

9

The Sugar Refining Process (cont.)

Acidification and FiltrationSulfuric acid to balance and bleachThird filtration produces “standard liquor”Sugar content of standard liquor + 50%

Evaporation and CondensationSeries of evaporators to drive off waterCondensers cool and recycle water

10

The Sugar Refining Process (cont.)

CrystallizationSuper saturated solution put under vacuum to crystallize sugar

SeparationCentrifuge spins out sugarFiltrate is “molasses”Purified sugar dried and packaged

11

Typical 1900 Era Sugar Refinery

Source: Silver Wedge: The Sugar Beet Industry In Fort Collins, SWCA Environmental Consultants, 2003

12

Wastewater Discharges at Sugar Refinery

Major Sources of WastewaterMud from beet washingCondenser waterPressed calcium carbonateBoiler blow-down to ash pond

Historic Discharge to Unlined PondsEvaporation and seepageIntegral part of water rights adjudication

13

Typical Flow Patterns at Sugar Refinery

Campaign Driven – September to April

14

Regulatory Concerns

Discharge to GroundwaterGroundwater standards apply

Total coliform standard – as if water supplyHigh Mn++ levels in ashSource well water above TDS standardPotential nitrite/nitrate problems

Pond Seepage to South Platte River Alluvial FlowWater Rights Issues Ignored

15

Regulatory Concerns (cont.)

CDPHE Applied Surface Water Standards to Groundwater DischargeSouth 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 FlowsSeepage does not equal influent - biasing mass

based parameters (BOD5 and TSS)No credit for effects of filtering through pond bottom

16

Client Concerns

Water RightsHigh Cost of TreatmentLow Hanging FruitPCC Press eliminated all liquid discharge to PCC pondMud Press significantly reduces flow to mud pond

How Much More Can be Saved with Water Recycling and Water Conservation?

17

Mass Balance Approach

Simplest Mass Balance

Unfortunately It’s not that Simple

18

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

19

Mass Balance Inputs – Internal to Process

SO2 and Sulfamic Acid:S, TDS, N

GypsumTDS, S

Limestone, Soda Ash & CausticTDS, TSS, S

20

Mass Balance Outputs

EvaporationMud, condenser, and ash pondsGranulator drier

SeepageMud, condenser, and ash ponds

DischargeFlue gasPressed mud

21

Mass Balance Outputs (cont.)

ProductsProcessed SugarMolassesPressed PCC (animal feed byproduct)

22

Mass Balance Software

23

WaterTracker Top Level View

24

WaterTracker Process Level View

25

Recycle Alternatives Modeled

Separate Fly Ash from Bottom AshClosed Loop Condenser Circuit with

Cooling Tower Mud Press EnhancementsInternal Redirection of Process and

Waste Streams

26

Results of Water Recycling and Conservation

27

Questions and Answers

QuestionsRay Hamilton – 303-975-2195 orray.hamilton@amec.com