1. Chilean Mill uses PeCOD® COD Analyzer for Determination of Chemical Oxygen Demand (COD) for Savings in Bleaching Process

2. Facts on the Chilean Mill
Global company that produces many types of wood products
Produces pulp used for:
Paper
Packaging material
Diapers
Produces board and wood used for:
Furniture
Construction

3. What is COD and How is it Significant to the Bleaching Process?
COD is Chemical Oxygen Demand
COD is the amount of oxygen required to fully oxidize organic matter
It is used as a measurement of the oxygen-depletion capacity of a sample contaminated with organic waste
It is significant to the bleaching process because it impacts the required chemical dosage of chlorine dioxide (ClO2) used for pulp bleaching
Higher COD concentrations can result in greater consumption of ClO2, which means excess bleaching chemical must be added to the process to compensate for the loss

4. Traditional Method for Determining COD
Traditional method for measuring COD in the wash water was by the SCAN:45-00 –test
The SCAN-test method is used for measuring the washing efficiency of the process
The final equation calculates COD removal by washing in units of kg per ton oven dried pulp
The test involves sample collection, COD analysis, and sample drying
COD of the wash water is measured by
photometric method (~3hrs)
Sample drying ~4hrs
Total time of the test = ~ 7 hours

5. Pulp Washing and Bleaching Challenges
Experiencing deficiency in pulp washing
Current SCAN-method for determining COD removal during washing takes too long
Results aren’t timely for operation control
Improper ClO2 dosing:
Excess bleaching chemicals are used from accidental over-dosing, or to compensate for higher COD concentrations

6. Pulp Washing and Bleaching Challenges Cont’d
COD concentration in the delignification stage (pre-bleaching) must be less than 12 kg COD/dry ton
Knowing the deviations of the organic load in the process would allow operators to adjust ClO2 dosages, reducing excess chemical consumption, which is key to the profitability of the process

7. Objectives and Goals to Improve the Bleaching Process
Reduce the COD analysis time in the pulping process, to deliver a timely result to operations, thereby avoiding excess consumption of ClO2
Goal:
Decrease analysis time by 90%, to allow operators to respond to process deviations

8. Mill Uses PeCOD® COD Analyzer for Fast COD Analysis
Implementation in the lab:
Validated the new method with respect to the standard SCAN test
Implementation into operations:
Faster COD results lead to closer monitoring of the wash area and improved bleaching process control
2 phases of integrated the peCOD method:
Lab for validating peCOD compared to SCAN method
Operations for evaluating the impact of faster results

9. What is the PeCOD® COD Analyzer?
A patented technology that measures COD by oxidizing organic matter by photoelectric method
peCOD method eliminates the use of mercury and potassium dichromate
Safe for both the environment and the analyst
Results in less than 15 minutes
Accurate method with a detection limit of 0.7 mg/L, and upper range of 15,000 mg/L
Specify mercury and dichromate

10. Nanotechnology
The core of the technology is the PeCOD sensor, which consists of a UV-activated nanoparticle titanium dioxide (TiO2) photocatalyst coupled to an external circuit
The powerful oxidizing potential of UV-illuminated TiO2 ensures that virtually all species will be fully oxidized giving a true measure of COD

11. A Nanotechnology Based Approach
To external circuit and auxiliary electrode
Photocurrent e-
Immobilized TiO2 nano-particle
Conducting substrate
(Eapp = 0.2V vs Ag/AgCl)
Oxidation of organics
hv (λ < 400 nm)
**Refer to Methodology section of paper _Horner** Paragraph 4 – 5
*******Look for a better graphic/ make one with same font*****
When a sample analysis is initiated, the sample is introduced into a microcell containing the TiO2 sensor. The TiO2 is irradiated by UV light, and a potential bias is applied. The UV light creates a photo hole in the TiO2 sensor allowing for photocurrent to be measured.
The TiO2 is a very powerful oxidizing agent (+3.1 V) that will readily lead to the transfer of electrons from organic species in the cell. It is because of this increased oxidizing power that peCOD is able to measure certain organics such as nicotinic acid, benzene, diethylamine, and many others that are difficult to oxidize.
By applying an appropriate potential bias to the system, liberated electrons are forced to pass into the external circuit where the reduction of oxygen (or other species) takes place. The charge is monitored and gives a direct measure of the oxidation of organic compounds. The measured charge, Q, is simply the total amount of electron transfer that results from the degradation of all compounds in the sample. Given that one oxygen molecule is equivalent to 4 electrons the measured Q value can be easily converted into an equivalent O2 concentration (or oxygen demand) in mg/L.
Roughly 2 times the oxidizing power vs. dichromate
i.e. Benzene, 1.8 by CODCr and 2.6 by PeCOD®

12. Electrons to COD Area under curve = Qnet COD = k· (Qnet – Qblank)
Time 5 min
Area under curve = Qnet
COD = k· (Qnet – Qblank)

13. Chilean Mill’s Findings Using the peCOD Method
Figure 1: peCOD (blue) versus traditional method (red) for COD analysis at Diffusor Line 2.
Figure 2: peCOD (blue) versus traditional method (red) for COD analysis at Press 2, Line 2.

14. Findings Using the peCOD Method Cont’d
Decreased time in analysis:
SCAN method
3 hours for COD analysis + 4 hours for drying
Total Time: 7 hours
peCOD method
0.27 hours (16 min.) for COD analysis hours (5 min.) for review
Total time: 0.35 hours (20 min.)

15. Findings Using the peCOD Method Cont’d
November 2013
December 2014
The graph shows a decrease in events for 2014 (with peCOD) compared to 2013 (pre-peCOD)

16. Annual reagents cost for COD analysis
Economic Evaluation
Annual reagents cost for COD analysis
Methods
Total Analyses
Boxes Monthly
Cost (USD)
Cost Monthly (USD)
Cost Annually (USD)
Daily
Monthly
Annually
SCAN
Method 12
360
4320
15 (25 vials per box)
30.00
450.00
5,400.00
Reagent Use Monthly [L]
Cost Reagents (USD/1L)
 PeCOD
2.5
60.00
150.00
1,800.00
Switching from the SCAN method to peCOD method resulted in savings in reagents costs by 66.4%
Saving 3,600 USD/year

17. Economic Evaluation Cont’d
Excess ClO2 per event
Line 2
Line 1
COD
[kg /ton]
ClO2 consumption [kg/ton]
ClO2 consumtion [kg/day]
ΔClO2
[kg/day] 
ClO2 Consumption [kg/t]
ClO2 consumption
[kg/day]
10-12
16.3
23,651.3
3,337.3
16.5
12,969
1,807.8
13-19
18.6
26,988.6
18.8
14,776.8
Production (ton/d)
1,451
Production (ton/d)
786
Adt = air dry ton of pulp product, weight of pulp product is corrected to reflect the weight that the pulp product would be if it were composed of 10% water and 90% fibre
Savings per event in L2 = $ 6,341 USD / day
13-19 kg/ton of COD represents a COD “event”
An increase in 3kg COD/ton = increase in 1kg of ClO2 consumption in the bleaching process
Chemicals saving of approximately 2,237kg of ClO2 per day, considering an event in both lines

18. Risk Assessment of COD Test Method
SCAN-test Method:
Heat
Hazardous chemicals
Hazardous waste disposal
Significant
peCOD Method:
No heat
Reagents are safe
Waste is safe (can go down the drain)
Tolerable
contact with aggressive chemicals such as vials, heat, etc. and with pecod reduces the risk of accidents

19. Conclusions Safety: Decreased risk from significant to tolerable
Improved health and safety for workers
Environment:
Reduced contamination to the effluent (eliminated excess ClO2 use)
Eliminated hazardous waste, generated using the traditional COD method
Savings:
COD analysis time reduced by 95%
Consumption of chemical reagents for COD analysis decreased by 66.4%
Management of ClO2 consumption in the bleaching process resulted in bleaching chemical savings, over 2000kg of ClO2 when an event was avoided each day

20. Conclusions Operators have peCOD results in less than 20 minutes
PeCOD generated chemical savings, which means money savings!
Improved Health & Safety, and Profitability
Mill receives national award for improving sustainability
5 PeCOD units now in 2 mills

21. Thank You!

22. Questions? Website: http://mantech-inc.com/
Maggie Grierson