1. -Investigating the Bottom Line
The Diaper Dilemma
-Investigating the Bottom Line
Mike Ritchie

2. Where should nappies go?
Wkly
Food
and Green
Fortnightly residual
Fortnightly recycling
Problematic streams such as nappies.

3. The problem Fortnightly collected nappies = complaints Odour Hygiene
Arose out of LMCC 3 bin discussions
Study support from:
LMCC
OEH
Kimberly Clark
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

4. The options Garbage weekly Garbage fortnightly
Garbage optional weekly collection
Green bin weekly loose (composted; see trial)
Green bin weekly Red bag
Dedicated nappy collection bin
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

5. Nappies… Comprise 3-5% of MSW
Are highly engineered, comprising up to 15 different layers
Contain a super absorbent polymer (SAP)
Excellent moisture holding properties
(Kimberly-Clark send waste SAP from manufacturing plant to a local composter)
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

6. Nappies… Are 37% fluff (wood pulp) 63% plastic
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

7. Option 4 required a Composting trial
Aim:
Determine whether
Composting regular disposable nappies with food and green waste is possible, and if so
The cost premium (on top of regular organics processing)
Whether composters would be prepared to do it
Partners
Trial Soilco
Shoalhaven City Council’s Nowra Waste Depot
with nappies provided by GRL
Methodology approved by EPA
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

8. Trial methodology Commercial scale trial Open windrow
Composition of LMCC organics bin
40 t of green waste, 17 t of food waste and 2.3 t of nappies
Shredded through a slow speed shredder
Blended
Composted, turned weekly
Final product:
Screened to 4 fractions: <8mm, 8-15mm, 15-30mm, >30mm
Tested against new AS4454 standards
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

9. Before 2.3 tonnes of nappies
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

10. Immediately after shredding
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.
Nappies opened, exposing plastics, wood pulp and powder like SAP

11. Two weeks into the trial
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

12. Screening (after 12 weeks)
Fraction
Weight of fraction
Tonnes %
<8mm
30.9
71%
8-15mm
6.35
14%
15-30mm
4.65
11%
>30mm
1.7 4%
Total
43.6
100%
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

13. Results
Pathogens
AS4454 standards achieved for pathogens (E. coli, faecal coliforms and salmonella)
Physical contamination
<8mm (71%) fraction met AS4454 standards for plastic content
Problematic streams such as nappies.

14. Cost drivers of the compost output
Screening : wind sifter may reduce non conforming product from 29% to 15% (i.e. reducing contamination of 8-15mm fraction to AS4454 standards)
Worst case scenario (for green waste processing):
Average process cost: $60 / t
Additional disposal costs: 30% of incoming material landfilled @ $200 / t
10,000 t received = $600,000
3,000 t landfilled = $600,000
Price premium = $60
New gate fee applied to all incoming organics = $120
This is supported by industry feedback as a $60/t premium to receive nappies.
Applied on ALL input tonnes.
Problematic streams such as nappies.

15. Option 5 - Composters removing red bags
For a 20,000 tpa facility:
2 pickers = $160,000
Premium = $8 per tonne + disposal
Problematic streams such as nappies.

16. What does the compost industry think?
Before
Both composting and red bag very unpopular
Contamination
Devaluing product
Pathogens
After
Still very unpopular
More interest in red bag option
although concerns around contamination
sending the wrong signal to residents – if nappies are accepted, what else?
processors sensitive to contamination disposal costs
Problematic streams such as nappies.

17. Scenario 1 – windrow composting
Assumptions
Weekly garbage – double the collection (only) costs
Fortnightly garbage – no change
Optional weekly garbage = $5.20 /hh/lift
Windrow composting With nappies: = $120/t, conformance = 70%
Red bag: gate fee = $68/t, conformance = 100%
Dedicated collection = $5.20 /hh
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

18. Scenario 2 – tunnel composting
Assumptions
Weekly garbage – double the collection (only) costs
Fortnightly garbage – no change
Optional weekly garbage = $5.20 /hh
Tunnel composting with nappies: = $110/t, conformance = 90%
Red bag: gate fee = $68/t, conformance = 100%
Dedicated collection = $5.20 /hh
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

19. Conclusions so far 360 L 240 L Weekly garbage - everywhere
Expensive and unnecessary
Fortnightly garbage – base case
Not always the cheapest option.
Does not solve political problem
Optional Weekly garbage
Always more expensive than red bag and is more expensive than tunnels
Loose in Green bin
Complicated for current windrow composters; $60 premium
If use EfW on residuals that would save big $
Red Bag in Green bin
Always the cheapest option – avoiding landfill costs and no new collection costs
AS4454
Creates options for further reprocessing
But difficult to educate on
Composters don’t like it – what if the bag splits open?
Dedicated nappy service
Generally more expensive than options 4 and 5
Possibly unpopular due to drawing attention to houses with incontinence waste
240 L
360 L

20. Conclusion 360 L Red Bag in weekly service Cheapest
If you have tunnels the Red Bag doesn’t save money BUT it does give you options for reprocessing as compost or something else
Solves the politics of odour
Delivers the best resource recovery outcomes
Next best
Optional weekly garbage
Next cheapest but more expensive than base case and Red Bag
Current system and infrastructure
Fixes composters concerns
No stigma of putting out an incontinence bin
But doesn’t provide resource recovery options
240 L
360 L

21. MRA Consulting

22. Options assessment 1 Cost (x$10m) Option 1 2 3 4 5 6 Collection1 2 3 4 5 6
Collection
Nappies
$0.0
$0.4
Organics
$3.4
Garbage
$6.0
$3.0
Total
$9.4
$6.4
$6.7
Processing
$0.2
$1.4
$3.1
$1.5
$7.6
$7.3
$9.0
$10.4
$8.8
$9.2
Combined
$0.5
$4.8
$6.5
$4.9
$13.6
$10.6
$10.9
$10.3
$18.4
$15.4
$15.7
$16.7
$15.2
$15.9
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.

23. Options assessment 2 Cost (x$10m) Option 1 2 3 4 5 6 Collection1 2 3 4 5 6
Collection
Nappies
$0.0
$0.4
Organics
$3.4
Garbage
$6.0
$3.0
Total
$9.4
$6.4
$6.7
Processing
$0.2
$3.1
$3.3
$7.6
$7.3
$10.7
$10.6
$10.9
Combined
$0.5
$6.5
$13.6
$10.3
$20.1
$17.1
$17.4
$16.9
$17.0
$17.6
Research is needed to determine the reason why recyclables end up in garbage bin. E.g.:
Bin constrains
Don’t care to recycle
Etc
During audits, need to record whether recycling bin was full and cross check to see if the corresponding garbage bin contained recyclables.