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ENHANCING RESOURCE EFFICIENCY AND SUSTAINABILITY IN FOOD PROCESSING:
FOOD PROCESSING WASTE STREAM UTILIZATION
CHRISTOPHER SIMMONS, PHDFOOD SCIENCE & TECHNOLOGY
ENERGY EFFICIENCY CENTERUNIVERSITY OF CALIFORNIA, DAVIS
GOALFind opportunities to recover waste heat in food processing and develop applications for that recovered heat.
Waste Heat Recovery
Tomato processing example:Tomato water – hot condensate from evaporation step of paste production.
EVAPORATOR
Condensed water (Tomato water)
(120 – 200 °F)
Waste Heat Recovery
*California Energy Commission. Industrial Water Energy Nexus Assessment: Campbell Soup California Tomato Processing Facility. Sacramento:California Energy Commission, 2013. Print.
SAVED
WASTE HEAT RECOVERY TO OFFSET STEAM PRODUCTION
How many MMBTU?
ELECTRICITY
236,800 kWh/season$35,520/season
Reusing the cooled tomato provides further energy savings. WELL WATER
PUMPING176,400 kWh/season$22,050/seasonELECTRICITY SAVED
WASTEWATER TREATMENT29,400 kWh/season$4,305/seasonELECTRICITY SAVED
FACILITY SAVINGS = $???/SEASON
Waste Heat Recovery
CONCEPTUse tomato water waste heat as part of the hot break.
HEAT EXCHANGER
Crushed tomatoes at 200 °F
Chopped tomatoes at 75 °F
Hot steam
Condensate
Waste Heat Recovery
HEAT EXCHANGER
Chopped tomatoes at 200 °F
Hot steam
Less hot steam/water
EVAPORATOR
Hot tomato water
HEAT EXCHANGER
Chopped tomatoes at 120 °F
Tomato juice Tomato paste
Cooler tomato water
Chopped tomatoes at 75 °F
Waste Heat Recovery
Modeling heat transfer in first stage of a 2-stage hot break process:
Inputs:1. Tomato temperature2. Tomato flow rate3. Tomato water temperature4. Tomato water flow rate5. Type of heat exchanger6. Heat exchanger heat transfer
coefficient and area
Waste Heat Recovery
Image: Allegheny Bradford
Hot tomato water
Hot chopped tomatoes
Coolchopped tomatoes
Cooltomato water
OBJECTIVE 2 – MODELING 1ST STAGE OF 2-STAGE HOT BREAK
Effectiveness-NTU method:
Heat transfer rate: q=mcpΔTHeat capacity rate: C=ṁcp
KNOWN𝑁𝑇𝑈 =
𝑈𝐴
𝐶𝑚𝑖𝑛Number of transfer units (NTU):
𝑞𝑚𝑎𝑥 = 𝐶𝑚𝑖𝑛 𝑇𝑇𝑊,𝑖𝑛 − 𝑇𝐶𝑇,𝑖𝑛
Maximum heat transfer rate (W):
Heat capacity rate ratio:=𝐶𝑚𝑖𝑛
𝐶𝑚𝑎𝑥
Calculated from facility data and heat exchanger properties
Effectiveness: 𝜀(𝑁𝑇𝑈,𝐶𝑚𝑖𝑛
𝐶𝑚𝑎𝑥) =
𝑞
𝑞𝑚𝑎𝑥
DETERMINE
OUTPUTHeat transfer rate to tomatoes (energy savings), qTemperature of tomatoes at end of first stage, TCT,out
Time to heat tomatoes in first stage, t
Waste Heat Recovery
Image: Allegheny Bradford
Hot tomato water32.7 kg/s
74 °C
Cool chopped tomatoes
73.5 kg/s
26.7 °C
Modeling results:
>9 million kWh recovered over 2250 hr season
Offset 10.6 million kWh of natural gas energy in boilers
$217,000 in natural gas savings/season
Cool tomato water
44.6 °C
Hot chopped tomatoes
40.3 °C
Waste to Energy
GOALEnhance conversion of agricultural and food processing residues into renewable energy.
Anaerobic Digestion: Converting waste organic matter to biofuel
Digester
Biogas•Methane•Carbon dioxide
Residual biomass and waterFood processing waste
Waste to Energy
Waste to Energy
Anaerobic digestion is a complex network of microbial activity.
There are many potential points of inhibition.
We can use recent advances in metagenomics to understand and design more robust and functional digester communities.
Waste to Energy
Xylanase activity Endoglucanase activity
Thermophilic community has more xylanase and
endoglucanase activity than mesophilic community.
thermophilic
mesophilic
Example: finding bacteria and enzymes for high-solids deconstruction of rice straw:
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA
Waste to Energy
Waste to Energy
0
10
20
30
40
50
60
70
80
90
100
Mesophilicenrichment
Thermophilicenrichment
All other phyla
Fungi
Bacteroidetes
Proteobacteria
Firmicutes
Actinobacteria
0
10
20
30
40
50
60
70
80
90
100
Mesophilic
enrichment
Thermophilic
enrichment
Re
lativ
e a
bu
nd
an
ce
(%
)
Waste to Energy
Thermophilic
community
Mesophilic
community
Cellobiohydrolases with
carbohydrate binding
module 2 are
overrepresented in
thermophilic community
Waste to Energy
Example: Using microbial communities for wastewater treatment, electricity generation, and desalination:
anode cathodesaline water
+
+
+
-
-
-
wastewater
exoelectrogenicbacteria
cationexchange
membrane
anion exchange
membrane
Simultaneous
-wastewater treatment
-electricity generation
-water desalination
GOALS
• Develop new applications for agricultural and food processing solids wastes.
• Turn waste streams into co-products.
• Advance sustainable waste management and agriculture.
Solid Waste Management
Inactivate plant
pathogens and
weed seeds in soil
via passive solar
heating and
microbial activity.
Replaces need for soil fumigants.
Adds nutrients to
soil.
Solid Waste Management
Biosolarization
Field soilStable green
waste compost
Agricultural or food
processing organic
residues
Induce microbial activity with waste biomass soil amendment:
+ +
Solid Waste Management
Plastic tarp
Soil
Acid fermentation:-Lactic acid-Butyric acid-Acetic acid
Solid Waste Management
Solid Waste Management
Inactivation of black mustard seeds:Combination of soil microbial activity and passive solar heating is significantly more effective than heating alone.
NATIVE SOIL
AMENDED SOIL
S = 100% soil
C = 100% compost
SCW = 90% soil
+ 8% compost
+ 2% wheat bran
n=5
Nonmetric
multidimensional scaling
2D representation of
community similarity.
Similar communities
appear closer together.
NON-SOLARIZED
CONTROLS
Solid Waste Management
Amended soil shows enrichment of potentially
beneficial bacteria following solarization.
•Azotobacter beijerinckii
enriched in amended soil
(10.5% of total community).
•Azotobacter species can
secrete phytohormones.
•Not detected in native soil
after solarization.
Solid Waste Management