Seasonal Variation on Combustible Set-outs under

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Seasonal Variation on Combustible Set-outs under
Door-to-door Collection Method with
Pay-as-you-throw system
Shinya Suzuki, Ayako Tachifuji, Yasushi
Matsufuji Department of Civil Engineering,
Fukuoka University 8-19-1 Nanakuma, Johnan-ku,
Fukuoka, 814-0180 Japan E-mail
ssuzuki_at_fukuoka-u.ac.jp
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions1-1
Background in Japan

• Increasing number of municipalities
• begun charge for waste collection
• - in many cases, Pay-as-you-throw system
• - by using specific waste bag

- in order to realize waste minimization
effectively
Specific waste bag
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions1-2
Objective
For better management on waste collection, To
clarify characteristics on waste set-outs -
set-out frequency, - number of waste bag, -
capacity of waste bag, - weight of waste bag
- under door-to-door collection method - with
pay-as-you-throw system
In previous our study, - most households
decided to use only 1 kind of waste bag - from
long time experience - tended to keep from
setting out waste bag - for adjustment of
amount of waste in bag - additional survey in
summer season
But, seasonal variation still remained to be
clarified
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions2-1 Solid
Waste Management Fukuoka city, Japan
Fukuoka city, 8th largest city, 1.4 million
people, - for MSW, pay-as-you-throw system,
since Oct. 2005. 1) Combustibles, 2)
Incombustibles, 3) recyclables Glasses and
PET bottles, 4) Bulky waste
Combustibles - average unit amount of waste 0.6
(kg/person/day) (90 of MSW) - 10 reduction
occurred by introducing pay-as-you-throw
system - Households can buy any capacity they
like - collected twice a week in night time
under door-to-door collection method
- 15 litters (15 yen/bag), 30 litters (30
yen/bag), 45 litters (45 yen/bag )
One district in Fukuoka city was selected for
survey of combustible waste - 1,664 peoples -
673 households - 9,800 people/km2 Typical
residential area in Japan.
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions2-2
Analytical Methods
50 sample households - with a variety of
household size - used specified waste collection
point
Actual measurement survey on amount of waste -
to clarify actual status on waste set-outs
- on Mar. 7th 2006, Mar. 10th, Mar. 14th, Mar.
17th, continuously in spring - on Aug. 26th
2008, Aug. 29th, Sep. 2nd, Sep. 5th, continuously
in summer - enabled us to confirm retention time
in each waste bag
In summer season, many households set out garden
waste with usual combustible waste generated
from daily activities, - such households have
been excluded from this analysis.
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-1-1)
Actual Status on Waste Set-out Pattern
6 CATEGORIES confirmed for waste set-outs in
summer season - more than 2bags? 1 bag? - 45 L?
30 or 15 L?

• CATEGORY 3) was not confirmed in spring season.
• changed capacity of waste bag
• to avoid long storage of waste
• to keep from bad smell

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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-1-2)
Difference of Waste Set-out Pattern
In summer season, households tended to set
out, - more frequently, more than 2 bags, with
smaller capacities of waste bag - Percentage of
30 or 15 L of waste bag was much higher
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-1) Unit
Amount of Waste in each CATEGORY
To clarify relationships between waste set-out
pattern and amount of waste,
Distribution of unit amount of waste changed -
in some CATEGORIES
C-4) 1.0 2.0 (kg/household/day) - in spring
season 1.0 1.5 (kg/household/day) - in summer
season C-3) near 1.5 (kg/household/day) - in
summer season
Coverage of each unit amount of waste - very
narrow
C-1) 45 L gt2 bags
C-6) 30 or 15 L 1 bag
C-4) 45 L 1 bag
C-2) 2 kinds gt2 bags
C-5) 2 kinds 1 bag
C-3) 30 or 15 L gt2 bags
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-2)
Seasonal Change of Waste Set-outs
Capacity 45 L
Relationships between number and capacity of
waste bag
Spring
Larger amount of waste
Summer

• In spring season,
• Households who have a large amount of waste
• - tend to use larger capacity of waste bag
• - tend to use 45 L and set out 1 bag every time

Capacity 30 or 15 L
More than 2 bags
VARIABLE ZONE

• In summer season,
• Some households changed capacity of waste bag

1 bag
Variable zone was formed only around border line
of more than 2 bags or 1 bag every time
Smaller amount of waste
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-3)
Impact on Profile of Waste Set-outs
Spring

• Seasonal change of waste set-outs occurred only
  for limited households
• - 1.0 1.5 (kg/household/day)
• - as stated before
• 1.5 2.0 (kg/household/day)
• - set out more than 2 kinds of waste bag

Summer
Seasonal change - very small - negligible
We should take care of annual change of waste
amount
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-3-1)
Annual change?
C-4)
C-2)
C-3)
Amount of waste still continued to decrease
gradually - distribution of unit amount of waste
will change year after year - drastic change of
waste set-outs will occur in near future?
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions4-1
Conclusions
Seasonal variation on waste set-outs Actual
condition survey in one district in Fukuoka city,
Japan
Seasonal variation really existed - in summer
season, households tend to set out - more
frequently, more than 2 bags, with smaller
capacities - to avoid long storage of waste
- to keep from bad smell
But households who used smaller capacities of
waste bag were restricted - between 1.0 - 2.0
(kg/household/day)
So, this seasonal change of waste set-outs -
very small - negligible
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions4-2
Conclusions

• But, we should take care of annual change of
  waste amount
• Amount of waste still continued to decrease
  gradually
• - by introducing pay-as-you-throw system,
• Coverage of each unit amount of waste
• - very small

Perhaps drastic change of waste set-outs will
occur in near future?
We should check such change in summer season! -
easier for us to find change of waste set-outs
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Thank you very much for your attention !