1. Sorting Technologies for CCA Treated Wood

2. Objective
To design and implement an automated system to effectively sort CCA treated wood from other wood types at facilities such as C&D facilities

3. Automated System Designed using x-ray fluorescence technology or
Designed using laser induced breakdown spectroscopy technology

4. Motivation
CCA treated wood => ~ 6 % of all wood waste at C&D facilities
Amounts of CCA treated wood at C&D facilities increasing
At 6 % level, cannot be used as mulch or burned to generate fuel

5. Sorting Studies Chemical stain method X-ray fluorescence (XRF)
laboratory results
field results from pilot studies
X-ray fluorescence (XRF)
Laser Induced Breakdown Spectroscopy (LIBS)

6. Training and monitoring
Automated System
X-ray fluorescence
Laser induced breakdown spectroscopy
Training and monitoring
chemical stains

7. Chemical Stains
Chrome Azurol S
PAN Indicator
Rubeanic Acid

8. Performance on whole wood
0.25 pcf
0.6 pcf
2.5 pcf

9. Laboratory Results Colors get darker with increasing retention levels
Chrome Azurol and PAN indicator performed best:
colors not usually found in C&D waste materials
reacted fastest and easy to apply
Rubeanic acid:
green color could be mistaken for other material
inconvenience of spraying with two different solutions

10. Field Studies
Performed to determine if chemical stains could be used at C&D facilities to sort CCA treated wood from other wood types
Three facilities studied

13. Findings from Field Studies
PAN indicator and Chrome Azurol S performed best
Time and labor intensive
Assumed untreated wood waste piles contained
9 % to 30 % of CCA treated wood
CCA treated wood found mostly in construction type debris
Demolition debris contains increasing amounts of CCA treated wood

14. Current Practical Applications
Sorting Small Quantities of Treated from Untreated Wood
Screening Fuel Quality
Training Tool

15. Design for Shelter

16. Detector Mounting Design

17. XRF Based on emission of x-rays
Characteristic x-ray emitted by the element is read by the instrument

18. Model 400 No special training required Analyzer User friendly
Printout or output easy to read and understand
Analyzer
Head

19. XRF Instruments Low maintenance, few consumables, easy cleaning
No repetitive calibration necessary
(6 mo. to 2 yrs.)
Life span of 10 years

20. XRF Instrument Cost range from $20,000 - $100,000
Detector replacement cost of $1,800 - $2,400
(life span of 5 years)
Licensing may be required
Sensor protected by a small beryllium window
($100 for replacement)

21. Results of XRF Studies
Arsenic is the best indicator metal, although all three metals can be analyzed for
Optimum count time of 2 seconds, would be even less for on-line analysis
1,800 ft/hr for detection of 1-ft board (2 s)
3,600 ft/hr for detection of 1-ft board (1 s)
Detection of CCA for Model 400 is possible at 1 inch distance with a plastic shield

22. LIBS Based on creation of microplasma by the use of a high-power laser
A signal from emitted light transmitted to a detector

23. LIBS Instruments Detectors Laser Continuum Minilite ($50,000)
More sensitive
Monitors one element at a time
Ocean Optics ($2,000)
Not as sensitive
Monitors more than one element at a time
Laser

24. LIBS Instruments
Flash lamp replacement cost of ~ $1,000 (replacement every 3 to 6 months)
No licensing required

25. LIBS Results
Elements with higher wavelength more sensitive to analysis
Chromium (425 nm): detected
Copper (327nm and 324 nm): detected, smaller signal
Arsenic (200 nm): not detected
Chromium best indicator metal

26. LIBS Results Shortest analysis time 1/5 of a second (200 ms)
4,500 ft/hr for detection of 1-ft board
Spacing detector and wood being analyzed could be 12 “

27. Lens Mirror Laser Detector Fiber-optic Cable Air Air-Tight Box
Glass
Window
Detector
Fiber-optic Cable
Air
Air-Tight Box
Puff of Air
Laser Beam
To PC
Up to 12”
Conveyor Belt

29. Questions?