Use of Sugar Mill Effluents for Growth
of Louisiana Co-culture
Water Treatment and Added Value Strategy
Jacob Foy
Louisiana State University
Department of Civil and Environmental Engineering
Advisors: Dr. M. Teresa Gutierrez-Wing and Dr. Ronald Malone
SUBI Annual Meeting 5/28/14
1
OBJECTIVES
• Collect and characterize effluent waters from a sugar mill
• Sugar mill acting as surrogate for bioprocessing facility
• Develop water quality model for effluents of a multi-feedstock bioprocessing facility
• Determine suitability of effluents for algal growth
• Algae can add value to process through additional biomass, valuable by-products and additional
water treatment
• Quantify biomass, lipid and pigment production of algae grown in effluents
2
COLLECTION OF EFFLUENTS
• Monthly sampling events at Alma sugar mill in Lakeland, LA
• Dissolved oxygen, pH, temperature, ORP and conductivity
• Eight retention ponds and one evaporator water pond
• Duplicate samples from each pond analyzed in Wetland
Biogeochemistry Lab (WBAS) in LSU Oceanography
department
• Extra water from pond #4 and evaporator pond collected
for algal growth experiments
Evaporator
pond
Pond #4
3
Ponds 4 and 5 Pond 6
ALMA PICTURES
4
Evaporator pond after
milling season
Filter mud, ash slurry, bagasse
mixture
View of Alma from bagasse
mounds
5
CHARACTERIZATION OF EFFLUENTS
• Poor water quality
• Extremely large volume of water being discharged
• High levels of nitrogen, phosphorus, and carbon (BOD/COD)
• Current treatment: retention ponds
• Proposed treatment: algal growth in retention ponds
• Deplete N, P, and BOD
• Additional biomass
• Valuable by-products, such as pigments, can offset costs
6
WATER QUALITY
Conductivity Comparison
Pond
2 3 4 5 6 7 8 EEO
S
0
500
1000
1500
2000
2500
3000
3500
During milling
Post milling
D.O. Comparison
Pond
2 3 4 5 6 7 8 EEO
mg
-O2/L
0
2
4
6
8
10
12
14
During milling
Post milling
ORP Comparison
Pond
2 3 4 5 6 7 8 EEO
mV
0
100
200
300
400
500
During milling
Post milling
•Highly variable due
to wind
•ORP corrected to EH
EH = ORPmeasured + EC
Temp (°C) EC
10 251
15 247.5
20 244
25 241
30 238
35 235
40 232
45 229
•Range of 7-8.5
•EEO slightly less
pH Comparison
Pond
2 3 4 5 6 7 8 EEO
pH
0
2
4
6
8
10
During Milling
Post Milling
•More particulate
matter in water
during milling
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VOLUME OF EFFLUENTS
Alma water
usage
Wash water: 12.5 mgd
1.05 billion gal/season
Retention
ponds
Evaporation
Evapotranspiration
Infiltration into soil
Evaporator water: 23 mgd
1.9 billion gal/season
Cooled in evaporator
pond
Discharged daily
• 84 day season (10/16/13 – 01/07/14)
• 1.556 million tons of cane processed
• Total effluent waters = 2.95 billion gallons per season 8
RETENTION PONDS: VOLUME ASSESSMENT
• 1.05 billion gal = 3,975,000 m3 flowing into retention ponds
• Data from 10/16/13 to 5/15/14: Ben Hur Research Station in Baton Rouge
• Evaporation: 95,381 m3
• Evapotranspiration: 27,450 m3
• Precipitation: 139,561 m3
• Total retention pond volume at average depth of 1.8 m = 303,000 m3
• Water is infiltrating the soil at alarming rates
𝑉𝑝𝑜𝑛𝑑𝑠 = 𝑉𝑖𝑛𝑓𝑙𝑜𝑤 + 𝑉𝑝𝑟𝑒𝑐 − 𝑉𝑒𝑣𝑎𝑝 − 𝑉𝑒𝑣𝑎𝑝𝑜𝑡𝑟 − 𝑉𝑟𝑒𝑢𝑠𝑒 − 𝑉𝑖𝑛𝑓𝑖𝑙𝑡𝑟𝑎𝑡𝑖𝑜𝑛 9
EVAPORATOR WATER
• Average of 23 mgd discharged
• Retention time of < 10 minutes
• Relatively low N and P levels
compared to wash water
• High temperature during milling
• High organic loading
• EPA requirement of BOD < 5 ppm
not being met
• COD on 4/28/14: 34 ppm 10
11
2 NH4+ + 3 O2 → 2 NO2
- + 2 H2O + 4 H+
2 NO2- + O2 → 2 NO3
-
NH3 + O2 → NO2− + 3H+ + 2e−
NO2− + H2O → NO3
− + 2H+ + 2e−
NITROGEN ANALYSIS
PHOSPHORUS ANALYSIS
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**Note: COD in
pond 4 measured
at 159 ppm on
4/28/14
ALGAL PRODUCTION IN RETENTION PONDS
• Current treatment process is inadequate in removing BOD
• Proposed treatment process will incorporate a mixed co-culture of microalgae and
cyanobacteria (Chlorella vulgaris/Leptolyngbya sp.) in retention ponds
• Robust, native Louisiana co-culture
• Lower N, P, and BOD levels before discharge
• Added value through biomass
• Added value through valuable by-products, specifically pigments
• C-phycocyanin: natural blue pigment
• Applications in pharmaceuticals (anti-inflammatory, anti-oxidant, anti-cancer)
• Purified form: $1505/gram
• Analytical grade: $4657/gram 13
Design by: Mary Katherine Bledsoe (Graphic Artist)
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PRECIPITATION
EVAPORATION
EVAPOTRANSPIRATION EVAPOTRANSPIRATION
WASH WATER
INFLOW
OUTFLOW TO
NEXT POND
WHAT’S NEXT?
• Development of water balance model
• Microalgae/cyanobacteria batch experiments in mixture of pond
water and evaporator water
• Quantification of biomass, lipids and pigments
• Determine purity level of pigment
• Measure nutrient uptake
• Additional growth trial in pond #4 at Alma sugar mill beginning in
July 2014 15
