introduction of compact compost toilet as a disaster
TRANSCRIPT
Introduction of Compact Compost Toilet as a Disaster Preparedness to Detached Housing in Japan
Yoshiki Higuchi
Department of Living Design, Nippon Institute of Technology
Mr.Yadoben
Evacuation Center Introduction
Even if the house is not collapsed, if the toilet becomes unusable due to water cut-off etc., you have to ・・・・
Housing
The most important thing is to stock disaster toilets at home and increase the proportion of ”Home Evacuation”.
The main problem leads to deterioration in public health.
Decision of home evacuation after the introduction of a compost toilet
Introduction
セカンドトイレがあれば、家でトイレができる!!
さらに、避難所のトイレ利用者数も軽減できる!!
Disaster occurred
The house collapsed.
To evacuation center
Water Supply cutoff at home.
An evacuation
order was issued
Stay at home during a
disaster
(home evacuation)
Yes
No
No
Yes
Yes
No
No
Yes
Stay at home during a
disaster
(home evacuation)
To evacuation center
There is a compost toilet at
home
Composting toilet as a second toilet of the housing
Flush toilet
Composting toilet
Introduction
Flush toilet
Flush toilet
Flush toilets are convenient for everyday life. Compost toilet are convenient in case of disasters.
+
↓ Home Evacuation!
Procedure of the research Introduction
STEP1. Questionnaire survey on disaster toilet stockpiling ratio Whether a disaster toilet was stocked at home for detached houses was
investigated.
STEP2. Continuous usable days of compost toilet How much compost tank capacity would be needed when stockpiling a compost
toilet as a disaster toilet in a detached house was examined.
STEP3 Proposal of compost toilet for home evacuation at the time of
disaster The compost toilet for home evacuation at the time of a disaster was developed.
2. Questionnaire survey on disaster toilet stockpiling ratio
2.1. Questionnaire outline
Satte City, Saitama Prefecture
Total number of detached houses:
14,930
5200 questionnaires were distributed
2822 questionnaires were collected
54.3%
18.9%
2. Questionnaire survey on disaster toilet stockpiling ratio
2.2 Questionnaire result
2257
1772
1576
1013
946
777
668
610
542
446
345
255
71
0 400 800 1200 1600 2000 2400
Water and gas supply outage
Toilet can not be used
Fire and spread of fire at home
Failure to contact with family / friends
Fall of furniture
Physical fitness and behavioral power at evacuation
Communication of information
Stockpile
Difficult evacuation from the inside of the house to the outside
A neighboring relationship
Unknown evacuation location and evacuation route
Dangerous goods blown up
Others
n=2,778
(Total respondents)
63.8%
Number of people
Water, Gas supply and Electricity outage
Toilet can’t be used
Fire at home
Failure to contact with family
Fall of furniture
Physical fitness and mental strength
Communication of information
Lack of stockpiling
Difficult evacuation outside the house
Neighboring relationship
Unknown evacuation location and evacuation route
Dangerous goods blowing up
Others
Multiple answers allowed
What will you be troubled with in the event of a disaster?
2.2 Questionnaire result
What do you think you need as disaster prevention measures?
2292
1432
815
700
623
406
355
340
286
0 400 800 1200 1600 2000 2400
Stockpiling of daily necessities
Stockpiling of emergency toilet
Information transmission system
Power supply
Maintenance of evacuation centers
Private power generation
Disaster prevention map
Rainwater storage facility
Others
n=2,718
(Total respondents)
52.7%
Number of people
Multiple answers allowed
2.2 Questionnaire result
What do you have prepared in the event of a disaster?
24591951
17821670
16051503
13261294
1224121312121212
107610491022979
885860846846
766706703
654648627
586574571
526478
432426410
339296
217
0 500 1000 1500 2000 2500
Flashlight
Portable radio
Food
Vinyl bag
Cigarette lighter,Matchstick
Candle
Towel
Scissors
Knife · Can opener
Wet tissue
Gum tape
Toothbrushing tool
Bandage
Sneakers
Antiseptic solution
Raincoat
Whistle
Simple toilet
Others
n=2,822
(Total respondents)
12%
Flashlight Drinking water
Portable radio Work gloves
Food Spare battery
Vinyl bag mask
Cigarette lighter,Matchbox Adhesive plaster
Candle Tissue paper
Towel Saran wrap
Scissors Leisure sheet
Knife · Can opener Writing utensils
Wet tissue Underwear
Duct tape Outer wear Dental tool
Balm Bandage
Paper/Plastic dishware Sneakers
Heating pads Antiseptic solution
Rope Raincoat Tweezers
Whistle Cotton
Simple toilet Helmet Others
Multiple answers allowed
Here
12%
2257
1772
1576
1013
946
777
668
610
542
446
345
255
71
0 400 800 1200 1600 2000 2400
Water and gas supply outage
Toilet can not be used
Fire and spread of fire at home
Failure to contact with family / friends
Fall of furniture
Physical fitness and behavioral power at evacuation
Communication of information
Stockpile
Difficult evacuation from the inside of the house to the outside
A neighboring relationship
Unknown evacuation location and evacuation route
Dangerous goods blown up
Others
n=2,778
(Total respondents)
63.8%
Number of people
Water, Gas supply and Electricity outage
Toilet can’t be used
Fire at home
Failure to contact with family
Fall of furniture
Physical fitness and mental strength
Communication of information
Lack of stockpiling
Difficult evacuation outside the house
Neighboring relationship
Unknown evacuation location and
evacuation route
Dangerous goods blowing up
Others
24591951
17821670
16051503
13261294
1224121312121212
107610491022979
885860846846
766706703
654648627
586574571
526478
432426410
339296
217
0 500 1000 1500 2000 2500
Flashlight
Portable radio
Food
Vinyl bag
Cigarette lighter,Matchstick
Candle
Towel
Scissors
Knife · Can opener
Wet tissue
Gum tape
Toothbrushing tool
Bandage
Sneakers
Antiseptic solution
Raincoat
Whistle
Simple toilet
Others
n=2,822
(Total respondents)
12%
Flashlight Drinking water
Portable radio Work gloves
Food Spare battery
Vinyl bag mask
Cigarette lighter,Matchbox Adhesive plaster
Candle Tissue paper
Towel Saran wrap
Scissors Leisure sheet
Knife · Can opener Writing utensils
Wet tissue Underwear
Duct tape Outer wear Dental tool
Balm Bandage
Paper/Plastic dishware Sneakers
Heating pads Antiseptic solution
Rope Raincoat Tweezers
Whistle Cotton
Simple toilet Helmet Others
What will you be troubled with in the event of a disaster?
What do you have prepared
in the event of a disaster?
There are many people who are concerned about toilet
in the event of a disaster too. However, the proportion
of preparing toilets at home was very low.
3. Continuous usable days of compost toilet
3.1 Outline of experiment
3. Continuous usable days of compost toilet
Large size compost toilets are ・・・・
→ expensive.
→ involve construction work for installation.
It is not realistic to install it. It is realistic for preparation of disasters.
How many days can be used the toilet ?
Assuming that a disaster actually occurred, the continuous usable days of the compact
compost toilet was verified by subject experiments.
3.1 Outline of experiment
3. Continuous usable days of compost toilet
Estimated number of days for water restoration :
About 1Month
3.1 Outline of experiment
A family of four people
⇒ ⇒
When does the capacity of the compost tank
reach the limit ?
3. Continuous usable days of compost toilet
Excrete feces 2 to 4 times a day
Period, site and type of toilet
3. Continuous usable days of compost toilet
Table1. Period, site and type of toilet
Period Summer 7/1 to 8/5 Winter 11/7 to 12/18 Site Compost toilet experiment building of Nippon Institute of Technology (Japan)
Compost Toilet
Compact non-electrified compost toilet (Capacity:35Liters) (Fig.1)
This toilet uses “Separate Bowl” to collect feces and urine separately(Fig.2).
Fig.1 Compost toilet[4] Fig.2 Separate bowl[4]
Measurement items
3. Continuous usable days of compost toilet
Room temperature of the toilet [℃] Measured at 10 minute intervals
External air temprature [℃] Measured at 10 minute intervals
Temperature inside the compost tank [℃] Measured at 10 minute intervals
Moisture content inside the compost tank [%] Measured once a week
Weight of the compost tank [kg] Measured once a week
Odor and Comfortability Filled out the questionnaire at the time of use
Questionnaire items
3. Continuous usable days of compost toilet
Table3. Questionnaire items
Fecal excretion
amount [g]
Weight difference before and after excretion
Note) Urine is done before the experiment
Hardness of feces Constipation (Bristol Stool Form Scale : 1 ,2) , Normal (Bristol Stool Form Scale : 3 to 5)
Diarrhea (Bristol Stool Form Scale : 6 to 7)
Odor Comfortability
5. Intense odor
4. Strong odor
3. Easily perceptible odor
2. slight odor
1. Very slightly perceptible odor
0. Odorless
-4. Extremely uncomfortable
-3. Very uncomfortable
-2. Uncomfortable
-1. A bit uncomfortable
0. It is neither comfortable nor uncomfortable
1. A bit comfortable
2. Comfortable
3. Very comfortable
4. Extremely comfortable
Both Filled out at the time of entering the toilet and opening the toilet lid
0
200
400
600
800
1000
1200
1400
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.1
07
.11
7.1
27
.13
7.1
47
.15
7.1
67
.17
7.1
87
.19
7.2
07
.21
7.2
27
.23
7.2
47
.25
7.2
67
.27
7.2
87
.29
7.3
07
.31
8.1
8.2
8.3
8.4
8.5
Summer period
0
200
400
600
800
1000
1200
1400
11.7
11.8
11.9
11.1
01
1.1
11
1.1
21
1.1
31
1.1
41
1.1
51
1.1
61
1.1
71
1.1
81
1.1
91
1.2
01
1.2
11
1.2
21
1.2
31
1.2
41
1.2
51
1.2
61
1.2
71
1.2
81
1.2
91
1.3
01
2.1
12.2
12.3
12.4
12.5
12.6
12.7
12.8
12.9
12.1
01
2.1
11
2.1
21
2.1
31
2.1
41
2.1
51
2.1
61
2.1
71
2.1
8
g ※ Color coding indicates the number of people used per day.
Daily average fecal excretion amount:
426g/day
Daily average fecal excretion amount:
351g/day
※ Color coding indicates the number of people used per day.
Winter period
g
3.2 Experimental result
Fecal excretion amount to compost tank
155.5g/use
Winter
Before
After
⇓
Summer
⇓
Before
After
3.2 Experimental result
Situation in the compost tank before and after the experiment
The amount of feces in the
compost tank did not increase
much.
The feces in the compost tank
increased and the capacity limit of the
tank was approaching.
0
2
4
6
8
10
12
14
16
18
Summer WinterTotal fecal excretionRemaining amount of feces
[kg]
Degradation
and
evaporation
of moisture
82.7%
60.7
%
Amount of decomposition or evaporation in summer and winter
3.2 Experimental result
Decomposition
0
10
20
30
40
50
60
-20 0 20 40 60
External air temperature oC
Summer
Winter
R2=0.5221
Inte
rnal
Tem
per
atu
re o
f th
e ta
nk
oC
Internal temperature of the tank and external air temperature 51.2℃(MAX)
※ Effect of rice bran
5.7℃(≒External air temperature)
23.4℃(≒ External air temperature)
53.3℃( MAX)
3.2 Experimental result
Declaration of odor 3.2 Experimental result
3% 3%
12% 7%
20%13%
31%
28%
31%
41%
2%17%
0%
20%
40%
60%
80%
100%
Summer Winter
0:Odorless
1:Very slightly perceptible
odor2:slight odor
3:Easily perceptible odor
4:Strong odor
5:Intense odor
N=87 N=109
0
10
20
30
40
50
Sta
rt
1w
eek
late
r
2w
eek
s
late
r
3w
eek
s
late
r
4w
eek
s
late
r
5w
eek
s
late
r
6w
eek
s
late
r
7w
eek
s
late
r
8w
eek
s
late
r
9w
eek
s
late
r
10w
eek
s
late
r
11w
eek
s
late
r
12w
eek
s
late
r
13w
eek
s
late
r
14w
eek
s
late
r
15w
eek
s
late
r
Summer Winter
[Litter]
Estimated number of days
for water restoration
Capacity limit line
3.2 Experimental result
Progress of feces capacity in the composting tank
About 6 weeks
About 11 weeks
[Liter]
Simple estimation formula of the number of days that the compost toilet can be used continuously
y = z・x・k
3.2 Experimental result
y: Fecal volume in the compost tank [g]
z: The amount of feces per excretion [g/use] (155.5) x: Number of fecal excretions [use]
k:Season coefficient [-] (0.17 in summer and 0.39 in
winter) Applicable condition: (1) Fecal excretion of the day is limited to 4 times. (2) The range of external air temperature in Japan.
4. Proposal of compost toilet for home evacuation at the time of a disaster
4.1 Production outline of homemade compost toilet
Making with easily available materials
Low Cost
Able to make it on your own
Composting performance equivalent to or higher than that of
commercial products
45-liter garbage can, Only one piece of plywood,
PVC pipe and etc.
Use worn-out duvet feathers or blankets as
insulation
Double skin structure
4.1 Production outline of homemade compost toilet
Comparison of costs
Commercial compost
toilet Simple Toilet (50 times)
Homemade compost toilet
(Prototype)
About 210,000 yen[4] 4,980 yen/set →29,800 yen/month About 28,374 yen
1/7
≒
5. Conclusion
Continuous usable days 11 weeks (in summer)
6 weeks (in winter)
Estimated number of days for water restoration
About 1Month
y = z・x・k
Made with easily available materials Low Cost Able to make it on your own Composting performance equivalent to or higher than commercial compost toilet
I hope that the stockpiling rate of disaster toilets will
increase in Japan and households that can evacuate at
home will increase.
Thank you for your attention Mr.Yadoben
The End