File - HMGA Water Project

Soil Removal and
Turbidity Monitoring
for Carrot Washing
Tim Brook, OMAFRA
John Van de Vegte, OMAFRA
65th Annual Muck Vegetable Growers Conference
April 12, 2016
Overview
• Measure the amount of soil removed by
different de-dirting techniques.
• Quantify the benefit of soil removal on
water use and wash-water treatment.
• Test turbidity monitoring for active control
of carrot washing process.
2
Overview – Soil Removal
Carrot Harvest
Carrot
Harvest
Soil
Removal
Bins for
Storage
Soil
Removal
Washing
Carrot Wash
Bins from
Storage
Washwater
Treatment
Processing
and
Packaging
3
Method
•
•
•
•
•
Created “Lots” of Bushels
Weighed the Carrots
De-dirted each Lot
Washed each Lot
Monitored Washwater
Soil
Removal
4
De-dirting Techniques
Grade - Low
Grade - High
Equivalent Length
of Conveyor
Air - OFF
Air - ON
Air - OFF
Air - ON
3’
√
√
√
√
9’
√
√
√
√
15’
√
Soil
Removal
5
Monitoring Washwater
• Inexpensive Turbidity Sensor
• Grab Samples
– Turbidity
– Total Suspended Solids
– Total Phosphorus
• Turbidity as a Surrogate for
TSS/TP
Soil
Removal
6
TSS/TP vs. Turbidity Correlation
1200
6
1000
5
TSS = 0.9072*(NTU) + 4.6848
r² = 0.818
4
600
3
400
2
TP = 0.0034*(NTU) - 0.0736
r² = 0.5792
200
0
0
Soil
Removal
200
400
600
Turbidity (NTU)
TSS
800
1
0
1000
TP
7
TP (mg/L)
TSS (mg/L)
800
Washwater Turbidity Data
1400
Turbidity (NTU)
1200
1000
800
600
400
200
0
0
60
120
180
240
300
360
Time (Seconds)
Turbidity - grab
420
480
540
600
Turbidity - sensor
Soil
Removal
8
TSS Concentration and Loading
27
1600.0
24
1600.0
24
1400.0
21
1400.0
21
1200.0
18
1200.0
1000.0
15
Q = 10.8 L/min
12
1000.0
15
800.0
12
600.0
9
600.0
9
400.0
6
400.0
6
200.0
3
200.0
3
0.0
0
0
60
120
180
240
300
360
420
0.0
0
0
480
60
120
180
TSS - Calculated
TSS - Laboratory
TSS - Calculated
TSS - Loading
TP Concentration and Loading
6.0
5.0
0.075
5.0
0.060
3.0
0.045
2.0
0.030
1.0
0.015
0.0
0.000
Soil
120
180
240
300
Removal Time (seconds)
60
"TP - Calculated"
360
TP - Laboratory
420
360
420
480
TSS - Laboratory
TSS - Loading
480
TP - Loading
0.090
0.075
Q = 11.2 L/min
4.0
TP (mg/L)
Q = 10.8 L/min
TP Loading (g)
0.090
0
300
TP Concentration and Loading
6.0
4.0
240
Time (seconds)
Time (seconds)
TP (mg/L)
18
0.060
3.0
0.045
2.0
0.030
1.0
0.015
0.0
0
60
120
-1.0
180
240
300
360
Time (seconds)
"TP - Calculated"
TP - Laboratory
420
480
0.000
9
TP - Loading
TP Loading (g)
800.0
Q = 11.2 L/min
TSS Loading (g)
1800.0
TSS (mg/L)
27
TSS Loading (g)
1800.0
TSS (mg/L)
TSS Concentration and Loading
Washwater Quality and Loading
Washwater Quality and Loading
TSS
TP
Water
De-dirting
Technique
(g/kg)
As Harvested
1.3
3’, Low Grade
1.0
23%
3.4
26%
1.3
19%
9’, Low Grade
0.9
31%
2.9
37%
1.0
38%
3’, Low Grade with Air
0.9
31%
2.9
37%
1.2
25%
9’, Low Grade with Air
15’, Low Grade with Air
3’, High Grade
0.7
0.7
0.8
46%
46%
38%
2.2
2.1
2.8
52%
54%
39%
1.0
0.9
1.1
38%
44%
31%
9’, High Grade
0.7
46%
2.4
48%
1.0
38%
3’, High Grade with Air
0.9
31%
3.2
30%
1.1
31%
9’, High Grade with Air
0.7
46%
2.3
50%
0.9
44%
Reduction
(mg/kg) Reduction (L/kg) Reduction
4.6
1.6
Soil
Removal
10
Conclusions - Soil Removal
• Reduction in TSS, TP and water achieved
by:
– Additional de-dirting before wash process
– Longer de-dirting conveyor
– Addition of high velocity air
– Increased conveyor grade*
• Need to optimize de-dirting techniques
– harvest equipment
– packing house
Soil
Removal
* Increased
grade resulted in breakage of some carrots
11
Overview – Water Quality Monitoring
Carrot Processing
Bins from
Storage
Soil
Removal
Dump Tank
(1o wash)
Polisher
(2o wash)
Washwater
Treatment
Packaging
Final
Rinse
Processing
12
Washing
12
Carrot Washing
Fresh
Water
Carrots
Dump Tank
(1o wash)
Polisher
(2o wash)
Flume
Zone 2
Zone 1
Polisher Tank
Washwater
Treatment
Washing
Sensor Locations
13
Water Monitoring
Sensor installed
in Dump Tank
Sensor installed
in Dump Tank
Sensor installed
in Flume
Washing
Sensor installed
in Polisher Tank
14
Water Monitoring and Control
1000
3
2.7
US Carrots
(pre-washed)
800
2.4
2.1
10,000 kg/hr
2.8 L/kg
600
Ontario
Carrots
400
300
1.5
Break
500
1.2
0.9
200
100
0.6
12,000 kg/hr
2.4 L/kg
0
10:30
Washing
1.8
0.3
0
11:30
12:30
13:30
14:30
15:30
Time of Day (Hours:Minutes)
Sensor NTU
Grab NTU
Grab TSS
16:30
Grab TP
15
TP (mg/L)
700
Lunch Break
Turbidity (NTU) and TSS (mg/L)
900
Conclusions – Water Quality Monitoring
• Continuous turbidity monitoring can be used
to optimize wash process water
consumption.
– Control the operation of the waste valves in the dump
tank and polisher tank to reduce the overall volume of
washwater generated.
– Adjust washwater flow rates in polishers to appropriate
level for carrot soil loading.
– Maximize the use of recycled water (e.g. minimize the
need for fresh water added in the dump tank)
– Demonstrate the need for either reducing water use or
implement means to by-pass wash process for prewashed (e.g. US-sourced carrots).
Washing
16
Overall Impact
Multiple benefits to additional de-dirting
and continuous turbidity monitoring
Financial
- Reduce expenditure on washwater treatment systems
by reducing the soil loading and flow rate.
- Increase wash system throughput by optimizing
equipment speed and water consumption for actual
carrot soil loading.
Environmental
- Reduce Total Suspended Solids and Total Phosphorous
entering surface water (e.g. Holland Canal and Lake
Simcoe).
17
Acknowledgements
• Co-operator Growers/Packers
• Holland Marsh Growers
Association Water Project
• University of Guelph
Muck Research Station
• OMAFRA EMB Small
Research Fund
18