Prevention and Recycling of Clean Drywall Waste - Shouhai Yu, University of Alberta, Edmonton

1. Prevention and Recycling of
Clean Drywall Waste
Shouhai Yu
Project Manager, EWMCE
Postdoc Fellow, University of Alberta
Banff, Canada
April 20th , 2010

2. Acknowledgement
• This project was financially supported by:
– Alberta Advanced Education &Technology
– Alberta Environment
– Alberta Agriculture Food and Rural Development
– City of Edmonton
– Alberta Research Council
– University of Alberta
– Clark Builders
– Kasian Architecture Interior Design and Planning Ltd.
– A&L Canada Laboratories Inc.
– Edmonton Waste Management Centre of Excellence

3. Management options
• Landfill
– Consume space
– H2S gas generation
• Incineration
– SO2 gas generation
• Reuse
– ½ sheet or larger
• Recycle

4. Objectives
• To develop a systematic lifecycle
approach for Alberta’s construction
industry to reduce the amount of drywall
waste generated and land‐filled

5. Outline
• Phase I
– Drywall Waste Prevention
• Phase II
– Drywall Recycling through Composting
• Phase III
– Use of Composted Drywall as a Soil
Amendment to Reclaim Disturbed Sites
• Summary

6. Phase I (March 2007 – March 2008)
Drywall Waste Prevention
Dr. Mohamed Al-Hussein

7. Waste identification
Start
Explode Wall Blocks General Procedure:
(Polyfaces))
Waste Identification
Potential Reduction
Identify wall
types Exterior Wall
Sort Continuous Identify Doors, Identify Special cases
Interior Wall Walls and Windows, Connections for doors/windows and
add boundaries and Discontinuities connections
Extrude Structural and
Vary UCS for Create Panels
Extrude Walls Start/End non-structural members
each wall from walls
(Studs, Sills, etc)
Split 3d
Create Shop Drawings Optimization Model Final Cutting List
Model by Floors
End

8. 3D modelling
• Exporting from ArchiCAD to AutoCAD

9. Shop drawings
• Floor plan • 3D Model

11. Cutting list
Valid Combinations
Takeoff List
3*C + 2*L = 96”
Waste (S8) = 0”

12. Mathematical optimization
• Analysis Method: Linear Programming
waste
N
• Objective function F(x): min xpsp
p 1
• Constraint equations:
[ x1 , x2 , x3 ,, x N ] LN 9 [100,8,9,85,4,2,2,4,2]T

13. Results
Waste : 0.58%

14. Results of phase I
• Best Management & Practices (BMP)
Guide
• Current results showed that up front
design innovations could affect use of
material in the construction phase
• Software developed is being used by a
local construction company

15. Phase II (March 2007 – July 2008)
Drywall Recycling through
Composting

16. Drywall recycling
• Gypsum wallboard manufacture
• Fertilizer Manufacture
• On Site Land Application
• Off Site Land Application (farmer’s field)
Feb 26, 2008 COMPOSTING MATTERS! 16

17. Apply to soil directly
• Benefits:
– Increases available calcium & sulfur
– Reduces sodium uptake
– Loosens clay soils and allows water & air to
circulate
• Concerns: long term effect
– Exchangeable soil K , Mg
– Chemical compounds

18. Benefits of composting
• Help to keep nitrogen
• Absorb odor compounds
• Increases Cation Exchange Capacity
– Binds Contaminants
– Degrades Compounds

19. Drywall collection

20. Collection management

21. Drywall grinding

22. Drywalls for experiment

23. Drywall mixing (ERS)

24. Mixture (ERS)

25. Turning (ERS)

26. Drywall mixing (EWMC)

27. After turning (EWMC)

28. Processes @ ERS
16% 0%
Coarse

29. Processes @ EWMC
0% 18%
Powder
15% 30%
Coarse Coarse

30. Phase III (July – December 2008)
Use of Composted Drywall as a Soil
Amendment to Reclaim Disturbed Sites
Dr. Anne Naeth

31. Experiment design
• Three soil types
– Agricultural Soil
– Reclamation of Urban Soil
– Reclamation of Mine Tailings
• Three revegetation species
– Vivar barley
– Adanac slender wheatgrass
– rocky mountain fescue

32. Greenhouse experiment

33. Compost addition: barley biomass

34. Preliminary results indicated
• Drywall compost has no significant
detrimental effects to plant establishment or
growth.
• Compost improved tailings sand as a medium
for plant establishment and growth for each
of the plant species.
• Biosolids with 15 % coarse drywall applied at
50 Mg ha-1 provided favourable results for
density and germination across the three soil
types.

35. Summary
• Drywall reduction from construction site is
practical
• Addition of drywall does not inhibit
composting, might help it.
• Compost improved tailings sand as a
medium for plant establishment and
growth