Environmental EngineeringCENG 4539: Senior Project

Fall Semester 2013

Faculty Advisor: Dr. George Fu

Team Leader: Matthew Usry

Group Members: Abel Sualevai Andrew Waters

Taylor VailBernard Scott

Presentation Outline Introduction Objectives and Scope Materials and Methods Results & Discussion Conclusions Further Studies

Color Removal from Pulp Mill Effluent using Coal Ash produced from Georgia

Coal Combustion Power Plants

**Images obtained from Georgia Power

Introduction Georgia Power plants

produce an immense amount of coal/fly ash

Physical properties of fly ash that provide means for filtration/treatment of some types of wastewaters, such as pulp mill effluent produced at the Weyerhaeuser plant.

Pulp Mill Effluent Effects of the

effluent on the Environment :• Harms liver function

in fish• Decrease levels of

dissolved oxygen• Loss of aesthetic

beauty• High concentration

of pollutants

Objectives

• To determine if coal ash is an effective adsorbent for color removal from pulp mill effluent

• Complete data analysis in order to provide insight into large scale application

Scope of Task The focus will be on such affection

factors for color removal efficiency:• The dosage of ash• Shake speed• Contact Time

Kinetic Study to determine equilibrium time

Isotherm study performed to model the adsorption mechanism

Materials and Methods Thus far only the Batch Absorption

experiment has been run. The procedure for this is as follows:

1. Coal ash is added into conical flasks with raw pulp mill effluent.

2. The mixture is shaken in a rotary shaker for a certain time period.

3. The mixture of pulp mill effluent and coal ash will then be separated using a vacuum filter.

4. The color of raw pulp mill effluent and the filtrate will be tested using Spectrophotometer in order to calculate the color removal efficiency.

Materials and Methods

Sieve Analysi

s

Initial pH Test

Massing of Coal

Ash

Materials and Methods

Thermo Scientific

Shaker Table

Millipore Vacuum

Membrane Filtration (.45µm)

DR 5000 Spectrophotom

eter

Materials and Methods

Vial Color Comparison and Storage

Results (Batch 1) Dosage Optimization

Dose = 20 g/LMeasurement Shake Speed = 300 RPM

Mass (g) Shake Time = 720 min

Initial Diluted Color Reading (Pt-Co)

405 317 404 362 404.5 339.5Notes:

Dilution Factor 4 4 4 4 4 4

Initial Color (Pt-Co) 1620 1268 1616 1448 1618 1358

Final Diluted Color Reading (Pt-Co)

309 307 312 308 310.5 307.5

Dilution Factor 4 4 4 4 4 4Final Color (Pt-Co) 1236 1228 1248 1232 1242 1230

% Removed 23.70 3.15 22.77 14.92 23.24 9.43

Initial pH

Final pH

Initial COD (mg/L)Final COD (mg/L)

8.1 8.06 8.08

430 442 436

Preliminary Screening __9/18___Sample 1 Sample 2 Average

2.0267 2.0204 2.02355

**Initial color reading were after 2 times (5mL:5mL) diltuion. COD is

measure of raw effl uent. Mass noted was added to 100 mL of effl uent

7.9 7.9 7.9

Results (Batch 1- cont’d)Dosage Optimization

92.78 20086.95 15060.67 10026.47 5016.33 20

Concentration (g/L)% Color

Removal

Results (Batch 2)Shake Speed determination

Dose = 100 g/LMeasurement Shake Speed = 150 RPM

Mass (g) Shake Time = 720 min

Initial Diluted Color Reading (Pt-Co)

374 371 382 378 378 374.5

Notes:

Dilution Factor 4 4 4 4 4 4

Initial Color (Pt-Co)

1496 1484 1528 1512 1512 1498

Final Diluted Color Reading (Pt-Co)

459 489 464 479 461.5 484

Dilution Factor 2 2 2 2 2 2

Final Color (Pt-Co) 918 978 928 958 923 968

% Removed 38.64 34.10 39.27 36.64 38.96 35.38

Initial pH

Final pH

Initial COD (mg/L)Final COD (mg/L)

Preliminary Screening __9/18___Sample 1 Sample 2 Average

2.0267 2.0204 2.02355

**Initial color reading were after 2 times (5mL:5mL) diltuion. COD is

measure of raw effl uent. Mass noted was added to 100 mL of effl uent

8.106 7.987 8.0465

7.9 7.9 7.9

Results (Batch 2 – cont’d)92.64 20090.10 17579.63 15052.60 12537.17 100

Concentration % Color

Results (Batch 2 – cont’d)RPM Comparison, 150 vs. 300

% Color Removal Concentration (g/L) % Color Removal Concentration (g/L)92.7752 200 92.64065 200

86.94526 150 90.10023 17560.66714 100 79.62828 15026.47189 50 52.59843 125

16.3321 20 37.16777 100

Batch 1 (300 RPM)Color Removal Comparison by RPM

Batch 2 (150 RPM)

Dosage• Optimal dosage

range was determine to be between 150 g/L and 175 g/L

• The increase in color removal hit a plateau as dosage increased past 200 g/L

Shake Speed• 150 RPM was

determined to be the most efficient shake speed

• Due to the marginal increase in color removal at high dosages for 300 RPM

• Cost effective

Results Finalization of Dosage and Shake Speed

Results (Batch 3)pH Alteration @ 175 g/L (2, 4, 6, 8, 10, 12)

pH2 98.984 95.936 94.878 86.9510 75.3512 74.21

%color removal

Results (Batch 3)Impact of Initial pH on color removal

Dose = 100g/LShake Speed= 300RPMShake Time = 720 min

0 2 4 6 8 10 12 140

200

400

600

800

1000

1200

1400

1600

1800

Affection Factor Adjustment (Batch #4)

Raw EffluentWith Coal Ash (100g/L)pH adj. only

pH

Colo

r U

nit

s (

Pt-

Co)

Dosage = 175 g/LRPM of shaker = 150Shake Time = 12 hours

Results (Batch 4)Impact of Initial pH on color removal

It was determined that pH adjustment was not an appropriate catalyst for color removalRequired large volume of acid/base

to adjust pH of effluentHarsh nature of extreme pH levelspH adjustment provided too large of

an initial color level change No pH adjustment was performed

on Kinetic and Isotherm Studies

Results Conclusion regarding effective pH

Kinetic Study Properties of the

adsorption processHow quickly color

can be removed by coal ash

Determine equilibrium contact time

Kinetic Study

5 98710 96215 94930 90260 865120 719240 660360 597720 348.75

1440 345.752880 322

Time (min)

Final Color Reading (Pt-Co)

As shown, equilibrium contact time is approx. 12 hours

0 10 20 30 40 50 600

200

400

600

800

1000

1200Color Units vs Time

Time (Hours)

Colo

r U

nit

s (

Pt-

Co)

12 hr

Isotherm Study Determination of equilibrium at

different dosages Equilibrium models based on

Langmuir and Freundlich Isotherm patterns

Describe the nature in which the adsorptive process takes place

Equilibrium ModelingLangmuir

Process: Relates the adsorption of

mono-layer molecules onto a solid surface area to concentration of adsorbate

Langmuir Isotherm Equation is:

1/qe 1/Ce0.097491 0.000730.019339 0.0010710.014456 0.0017180.013972 0.0026770.014126 0.0048780.015801 0.0055630.017695 0.005814 mg/g -2.72919.72386588

Expected Asorption Rate (q) b

[Linear]

[non-linear]

*note: linear Langmuir equation is in y=mx+b form

0 0.001 0.002 0.003 0.004 0.005 0.006 0.0070

0.02

0.04

0.06

0.08

0.1

0.12

f(x) = − 7.22752841287096 x + 0.0507360883129053R² = 0.258298097121113

Langmuir Isotherm Model

Concentration of Color at Equilibrium (Ce)

1/a

dsorp

tion c

apacit

y (

1/q

e)

Equilibrium ModelingFreundlich

Process: Relation of concentration

of a solute on the surface of the media to the concentration of solute left in liquid

o Freundlich Isotherm Equation is:

log (qe) Log Ce

1.011 3.1364031.714 2.9703471.840 2.7649231.855 2.5722911.850 2.3117541.801 2.2546691.752 2.235528

K 1/n3.153 -0.5617

[Linear]

[non-linear]

*note: linear Freundlich equation is in y=mx+b form, but on log scale

1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.30.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.800

2.000

f(x) = − 0.56168523627979 x + 3.15302743630778R² = 0.449399377664806

Freundlich Isotherm Model

Log Ce

log (

qe)

Equilibrium ModelingSummary

Langmuir Based on the intercept of the best fit linear regression line, the

expected adsorption capacity of about 19 mg of color units per g of coal ash

FreundlichFreundlich constants (K and 1/n) represent the adsorption

capacity and intensity, respectivelyThe expected adsorption capacity for this method was about

3.1 mg/g and the intensity of the reaction was very low at -.56

 Based on the very low value of correlation coefficient R2, we could conclude that:

the mechanism of color removal by coal ash could be more complicated than physical adsorption

chemical reaction could also play an important role.

Conclusion Dosage optimization was first performed and was

found to be approx. 175 g/L Optimal shake speed was found to be 150 RPM as

the difference in color removal of 300 RPM was marginally greater

Equilibrium contact time was determined to be approximately 12 hours (720 min) from the Kinetic Study

The Isotherm models suggested that the adsorptive process taking place was not efficient and could be more complicated than physical adsorption and chemical reaction could also play an important role

Further Studies Received Georgia Southern Undergraduate

Research Grant Submitted complete abstract of our

research for the “National Conference of Undergraduate Research at Columbus University” in Columbus, GA

Plan to submit abstract and poster for Undergraduate Research Symposium on our campus Spring 2014

Further Studies Adsorption in terms of COD levels

before and after mixing Fixed-bed Continuous Column Study

Column Study Diagram

Questions???