Japan; Utilization of food wastes for urban peri-urban agriculture in Japan

8/3/2019 Japan; Utilization of food wastes for urban peri-urban agriculture in Japan

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Utilization of Food Wastes for Urban/Peri-Urban

Agriculture in Japan

GEN ISHOKA


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Utilization of Food Wastes For Urban/Peri-Urban

Agriculture In Japan

Gen ISHOKA

ABSTRACT

Large amount of municipal/industrial wastes is discharged in Japan and

critical state of final disposal site emerged. Japanese government shifted the policy to

establish a "Sound Material-Cycle Society" and "Reduce, Reuse, Recycle" of waste is

requested. Under such circumstances, reuse and recycle of food waste is requested in

agriculture. Utilization of fertilizers and feeds made of food waste and utilization of

the effluent of methane fermentation of food waste can contribute, but there are many

constraints to hamper recycle especially for the garbage from household.

Keywords: municipal waste, garbage, compost, feed, effluent, methane fermentation

INTRODUCTION

Japanese society and government used to give highest priority to advancing

its economic development. This policy enhanced mass production, mass consumption

and mass disposal. As a result, amount of discharged waste increased year by year and

waste disposal site said to be full in several years. This situation led Japanese

government shift their policy to turn Japanese society more environmentally sound,

and "Fundamental Law for Establishing a Sound Material-Cycle Society" was enacted

in 2000. Several laws concerning recycling, such as "Food Waste Recycling Law,"

were enacted and enforced subsequently. Then started "3Rs" policy, "3Rs" means"Reduce, Reuse, Recycle", in order to create a sustainable society: one that has

balance between the environment and the economy. Under such circumstances, reuse

and recycle of food waste is requested in agriculture, as most of the food waste is

agricultural origin. Generation of food waste is more in urban area than rural area.

Thus urban/peri-urban agriculture should contribute more in reuse and recycle of food

waste.


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STATE OF DISCHARGE OF SOLID WASTES AND RECYCLING

OF FOOD WASTE IN JAPAN

State of discharge of municipal/industrial solid waste

Solid wastes are classified into two categories in Japan: municipal and

industrial. The disposal of municipal wastes is the responsibility of the municipalities.

The disposal of industrial wastes is the responsibility of the entities that generate the

wastes.

In FY 2003, the amount of discharged municipal solid waste was 51.61

million tons in total and 1.106 kg/capita per day. These figures have not changed

much in 15 years (Fig.1). Household waste was 34.66 million tons (67.2%) and

business waste was 16.95 million tons (32.8%).

Method for final disposal is landfill in Japan. Direct landfill is 1.86 million

tons (3.6%) and landfill after reduction by intermediate treatment (e.g. incineration) is

6.59 million tons (12.8%). Amount of landfill decreased gradually from 1994-2003,

largely due to decreasing volume of direct landfill (Fig. 2).


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2 4 6 8 100

5

10

15direct landfilllandfill aftertreatment

'94 '95 '96 '97 '98 '99 '00 '01 '02 '03 FY

millionton

s

Fig. 2. Amount of final disposal (municipal waste) in Japan,FY 1994 - 2003

Source: Ministry of the Environment

2 4 6 8 100

50

100

150

200

'94 '95 '96 '97 '98 '99 '00 '01 '02 '03 FY

millioncubic

meters

Fig. 3. Remaining capacity and lifetime of final disposal site(municipal waste) in Japan, FY 1994 - 2003

remaining capacityremaining lifetime

0

5

10

15

20

years


Remaining capacity of final disposal sites for municipal solid waste is 137.08

million cubic meters and remaining lifetime is 13.2 years. The remaining capacity

decreased steadily in these several years but the remaining lifetime increased slightly

(Fig.3), as the amount of landfill decreased (Fig. 2).


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Total amount of discharged industrial waste is approximately 412 million

tons, this figure has not changed much in 15 years (Fig. 4). Three major sources

accounted for more than 60%, i.e. electricity, gas, heat and water supply (92.25

million tons, 22.4%), agriculture (90.59 million tons, 22.0%) and construction (75.01

million tons, 18.2%). Sludge accounted for 46.3% (190.38 million tons), followed by

excrement of animals (88.98 million tons, 21.6%) and debris (59.25 million tons,

14.4%).

48.9% (201 million tons) of industrial waste is recycled and 43.7% (180

million tons) undergoes reduction. Final disposal is 30 million tons (7.4%). Amount

of final disposal decreased steadily in these 10 years (Fig. 4). Highest recycle ratio is

scored by excrement of animal, 93.8%, and most of them turned into livestock waste

compost.

Remaining capacity of final disposal sites for industrial solid waste is 184.18

million cubic meters and remaining lifetime is 6.1 years. The remaining capacity

decreased steadily in these several years but the remaining lifetime increased slightly

(Fig.5), as the amount of landfill decreased (Fig. 4).

2 4 6 8 10 12 140

100

200

300

400

500

'90 '92 '94 '96 '98 '00 '02 FY

milliontons

Fig. 4. Amount of industrial waste in Japan, FY 1990 - 2003


total volumefinal disposal


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2 4 6 8 100

50

100

150

200

'95 '96 '97 '98 '99 '00 '01 '02 '03 FY

millioncubicmete

rs

Fig. 5. Remaining capacity and lifetime of final disposal site(industrial waste) in Japan, FY 1995 - 2003

remaining capacityremaining lifetime

0

5

10

15

20

years


State of food waste recycle

Other than commonly used livestock waste compost, waste that can be

applied to agriculture is food waste. It includes garbage of household and waste from

food related business, i.e. food manufacturing, food distribution, food sales and

restaurant/catering. Only the waste from food manufacturing is categorized into

industrial waste, others are categorized into municipal wastes.

Discharge from food related business is 11.358 million tons in FY 2004 and

the amount recycled is 5.793 million tons. Total amount have not changed much since

2000, but the recycling rate gradually increased and it exceeded 50% in FY 2004

(Fig. 6).


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2 40

5

10

15total volumerecycled volume

'04'00 '01 '02 '03 FY

millionto

ns

Fig. 6. Amount of food waste in Japan, FY 2000 - 2004Source: The Ministry of Agriculture, Forestry and Fisheries

Table 1 shows amount of food waste and recycling type of each food related

business. Food manufacturing is most in amount and highest in recycling rate. As

business scale turns smaller, recycling rate decreases.

One important constituent of food waste not listed in Table 1 is garbage from

household. Estimated volume of the garbage is about 10 million tons in FY 2003. The

amount is gradually decreasing, but still it is as much as total discharge from food

related business (Fig. 7). More important is the recycling rate. In FY 2002, only 1.8%

of garbage from household said to be recycled, contrary to the food waste of business

origin in municipal waste, 24%.

Table 1. State of Food Waste Recycling

total volume

(million tons) (million tons) (%) fertilizer feedmethane

fermentation

fat/fat

product others

manufacturing 4.898 3.80 78 46 35 0 3 16

wholesales 0.751 0.40 53 28 38 0 1 33

retail 2.604 0.82 32 30 36 0 7 27

restaurant/catering 3.194 0.77 25 22 20 1 6 51

total 11.358 5.79 51 39 33 0 4 24

recycled volume type of recycle (%)


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2 40

10

20

30

40

'03'99 '00 '01 '02 FY

milliontons/

%

Fig. 7. Amount of waste and garbage from householdin Japan, FY 1999 - 2003


total volume from householdestimated percentage ofgarbageestimated volume of garbage

UTILIZATION OF RECYCLED FOOD WASTE IN JAPAN

Among the types of recycle listed in Table 1, fertilizer, feed and effluent of

methane fermentation can be utilized for agriculture. Over all, separation of the

materials not suitable for farmland application, such as plastics and pull-tabs, is the

largest problem, especially for the wastes from household and restaurant/catering.

Separation machine is installed in some facilities, but separation at the source, for

example kitchen and table, is necessary. It requires consciousness from all of us.

Another problem is offensive odor and pathogen, which compels immediate

treatment. Variation in volume and constituent also restricts utilization. As it is

difficult to control these issues on waste from household, recycle and reuse is limited.

Fertilizers

Wide variety of garbage processing machine is sold in Japan. For household

use, which handles 1 to 3 kg at one time, price is above $300 and many municipalities

set subvention for purchasing. For business use, capacity varies from 10kg to more

than 500kg and so is the price, usually more than $10000. Type of treatment is

dehydration and or fermentation. Fig. 8 shows crude fat content of processed

garbage from school-provided lunch in Mie Prefecture. Even the treatment type is


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fermentation, a lot of crude fat remains, meaning these garbage processing machine

cannot complete fermentation. Application of immature compost may cause severe

damage to plant growth. It is not advisable to use this kind of treated garbage directly

to agriculture.

2 4 6 8 10 12 14 16 18 200

5

10

15fermentationdehydration

%

Fig. 8. Amount of crude fat in processed garbageSource: Mie Prefecture Science and Technology Promotion Center

One solution for this issue is nitrogen addition. Tokyo University of

Agriculture operates garbage dehydration and pelletization facility which can add urea

into the pellet (Goto I. 2005). Additional nitrogen from urea avoid nitrogen deficiency

in soil (Fig. 9). It is not only nitrogen deficiency that causes damage, but even after 5

years of application (N-P2O5-K2O = 4-1-1, 1t/10a), no damage has observed. Salt

content is 0.8-2.1% and it is not harmful as far as using outside of greenhouse. The

facility produces 70kg of fertilizer from 500kg of garbage from restaurant in the

university, schools and supermarket nearby. Their plan was utilization in the farmland

of the district, about 140 ha, but could not be achieved. What hampers utilization is

the impression that it is made of "garbage", despite it is rather "clean" biologically as

it becomes about 90C during the dehydration process. Collaboration work with some

comprehensive farmer to prove harmless is necessary.


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Another solution is secondary treatment to complete fermentation. There are

several compost plants for garbage or dehydrated garbage. Some of the compost

plants for livestock waste accept garbage. Garbage contains high amount of fat,

protein and starch. These constituents are easily decomposed by microorganisms and

the decomposition process requires oxygen. This means regular mixing and aeration is

necessary and it takes longer period to complete fermentation.

Even after complete fermentation, the impression of "garbage originated" and

worries about salinity hampers utilization. Some of the franchise chains of restaurant,

convenience store resolve this issue by promising to purchase agricultural products

using the compost from the franchise chain.

Feeds

It is necessary to take extreme care on sanitary and quality when one turns

food waste into feed of livestock. Waste from food manufacturing industries, such as

crumbs of bread, residues of alcoholic fermentation and juice, is easier to control

quality, quantity and purity, therefore they are widely used. Waste from the other type

of food related business is also possible to turn into feed if separation of trash is

achieved.

In City of Sapporo, Hokkaido, garbage from food manufacturing factory,

supermarket, hotel, school, hospital and restaurant is collected by a public corporation

and a company processes and sells as a material of mixed feed. Garbage from

household is not included.


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In City of Nagaoka, Niigata, NPO conducts recycle of garbage from

school-provided lunch to livestock production in the district. The system is highly

dependent on participants, i.e. kitchen staffs of school and livestock farmers, and

volunteers who transport garbage from school to farmer. Kitchen staffs are

responsible for separation and farmers are responsible for manufacturing feed by

fermentation. An important point at the separation is feed for bovine cannot contain

meat and fish.

There are several progressive examples like this, but the number is still

limited due to the difficulties on controlling quality, quantity and purity. Feed made of

garbage is high in fat. It makes fat in pork softer and degrades quality. Farmers have

to recognize the quality of the feed and control it by mixing with the other kind of

feed. For about purity, relationship between waste producer and consumer affects.

Successful case tend to have producer and consumer known each other. In such case,

producers try their best to meet consumer's demand.

Methane fermentation

Methane fermentation, which produces methane from livestock waste or

garbage by anaerobic digestion, produces effluent as by-product. In many cases, the

effluent is treated as sewage. This means separation of solids, denitrification or

dilution to meet water quality standard is operated with extra cost. The effluent

contains 0.2-0.5% nitrogen, 0.2-0.4% potassium and 0.1-0.2% phosphate. Although it

is dilute, still agricultural use is possible.

The main constraint for agricultural use is that the effluent is liquid. This

means some method for transport is necessary. Solid material content is usually less

than 10% but it is difficult to transport with ditch or pipe. In order to apply 10kg of

nitrogen in 10a, the amount of the effluent with 0.2% nitrogen is 5 tons. Only with the

vehicle with huge tank can manage.

Another constraint is offensive odor. Although it smells far better than slurry

or rotten garbage, it is not acceptable to spread large amount of the effluent onto the

top of soil, especially in the urban area. It can be avoided with injection into soil or

immediate covering with soil, which requires special apparatus. One good utilization

method is spreading into paddy with water. Dilution of the effluent reduces offensive

odor.


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In Japan, interest in organic agricultural products grows more and more these

days. Farmers can apply livestock waste compost as basal dressing, there was no good

organic fertilizer for top dressing. The effluent of methane fermentation would be

useful. It is difficult to meet the criteria of Japanese Agricultural Standard for Organic

Agricultural Product, but it is suitable to meet the demand for "Specially Grown

Agricultural products", which requires reduction of chemical fertilizers and pesticides

by 50%.

Methane fermentation is operated at 35C or 55C. Temperature is lower than

composting or dehydrating and pathogen may not die out. Carbonate and alkali said to

eliminate E.coli form dairy cattle manure (Diez-Gonzalez et.al. 2000), precise

condition to eliminate is not confirmed. The effluent of methane fermentation is

usually pH 7.5-8.0 and contains high amount of carbonate (100-200mM). More study

on this topic is needed.

Methane fermentation plant of large scale costs several million dollars to

build and several hundred thousand dollars to operate. But it does not cost much to

keep the minimum requirement, anaerobic condition. In Ogawa town, Saitama, NPO

made small scale facility of strong plastic sheet and compressed panel, which costs

about $14000 (Fig. 10). Garbage is collected from household in exchange of local

currency. The effluent is applied to paddy and vegetables, which can be purchased

with the local currency.

Fig. 10. Methane fermentation plant of NPO Foodo, Ogawa Town


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REFERENCES

Diez-Gonzalez F., Jarvis G.N., Adamovich D.A., Russell J.B. 2000. Use of carbonate

and alkali to eliminate Escherichia coli from dairy cattle manure.

ENVIRONMENTAL SCIENCE & TECHNOLOGY 34 (7): 1275-1279

Development of high quality composting system using garbage treated materials.

2005. Report for Research project for utilizing advanced technologies in

agriculture, forestry and fisheries. (in Japanese)

Goto I. The trial of community-based garbage recycling in Setagaya-ku Tokyo. 2005.

SOIL MICROORGANISMS 59 (2): 111-115 (in Japanese)

State of Discharge and Treatment of Industrial Waste in FY 2003. 2005. Ministry of

the Environment, JAPAN

State of Discharge and Treatment of Municipal Solid Waste in FY 2003. 2005.

Ministry of the Environment, JAPAN

State of Recycling of Cyclical Food Resources. 2005. The Ministry of Agriculture,

Forestry and Fisheries, JAPAN

Japan; Utilization of food wastes for urban peri-urban agriculture in Japan

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