History of municipal solid waste composting in Tokyo(Operational challenges and transitional improvements)

Bureau of Environment
Tokyo Metropolitan
Government

2015/1/31

1Concept ⇒ Composting municipal
waste(Composting garbage in urban areas)

Composting raw materials
Livestock waste
Agricultural waste
Sewage sludge

Concept

Municipal waste(garbage)・Food scraps (bread, rice, vegetables, fish, meat, fruit, etc.)
・Cooking scraps (vegetable scraps, fish bones, etc.)
・Tea and coffee grounds

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Contents
1. Brief history of municipal waste composting technologies in Japan
2. Composting research and changes in processing for municipal waste inurban Tokyo

3. Examples of odor problems caused by private compost processing
facilities in urban areas
4. Problem resolutions needed to further municipal waste compost
processing (Example)
5. Considerations in planning municipal waste compost processing facilities

6. Conclusion
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1. Brief history of municipal waste composting
technologies in JapanFirst era of composting

Second era of composting○Supply of cheap chemicalfertilizer○Decrease in demand forcompost products due to negativechanges in garbage○Recovery of decline in soil fertility
due to heavy use of chemicalfertilizers○Review of organic farming andorganic pesticides

Compostingregains
popularity
1938
Kobe
Composting
experiments
begin

1950s
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Composting
facilities start
operationnationwide
(30)

1960s

Composting
facilities
begin closing
one after thenextnationwide

Value ofcomposting is
recognized
again

1970s

1980s

Current of as 201276 governmentowned facilities

Since the 1990s
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2. COMPOSTING RESEARCH AND CHANGES IN PROCESSING FORMUNICIPAL WASTE IN URBAN TOKYO1978〇 Social shift toward organic
farming〇 Sudden increase in need formunicipal waste composting
due to the effects of the oilcrisis

1933
Aerationtankfermenter11/dayTest facility operation: 1 t/day(Tokyo Metropolitan CleansingLab)
1957-1961
Garbagefermentation
composting
equipment

1959-1961
Human waste
composting
equipment

37 t/day

50 t/day1950s
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Compostingregains
popularity

Second era of compostingFirst era of composting

1985
CompostCenter1993
CompostCenter

50 t/dayOperation

Ceasedoperation

1961-1966
Dano highspeedfermentation
composting
facility
30 t/day

1960s

1970s

1980s

Since the 1990s
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First era of composting (Tokyo)(1930-1960)

1. From 1933: Operation of compost business using an aeration tank fermenter (11 t/day) starts.
A) High expectations that this would prove a powerful alternative to manure relying on humanwaste, which was problematic at the time.
B) Technical challenges included transitioning from natural fermentation to high speed
composting
2. From 1957: Garbage fermentation composting equipment ( 37 t/day)A) Manual sorting and separation process becomes necessary due to glass and plastics in garbage.
B) Operations ceased in 1961 due deterioration of the working environment and increases instorage costs due to fluctuations in seasonal demand and expiration dates of products.
3. From 1959: Human waste composting equipment (50 t/day)
Quality compost could be achieved due to the fermentation inhibition caused by adding humanwaste ultimately resulting in ceasing of operations in 1961.

4. From 1961: Dano high speed fermentation composting facility (30 t/day)A) Various problems surfaces including fluctuations in product demand and increased storage
costs.
B) The change in collection method from garbage to mixed waste led to significant decreases inoperation efficiency and the plant ceasing operations in 1966.

*Part of the reason farmers chose not to use compost was due to the foreign matter
content
in the compost.
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First era of composting

Garbage fermentation composting equipment (1957-1961)

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First era of composting
System diagram of garbage fermentation composting equipment (rotary fermentation tank)(1957-1961)

1. Transport conveyor 2. Sieve turning 3. Manual sorting conveyor 4. Magnetic sorting machine
5. First crusher 6. First conveyor 7. Storage tank 8. Second conveyor 9. Digester 10. Third Conveyor
11. Rotary dryer 12. Second crusher 13. Combustion furnace
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First era of composting
Human waste composting equipment Image of garbage sorting(1959-1961)

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First era of composting

Dano high speed fermentation composting facility
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The Dano system includes a rotary kiln functioning as a fermentation tankwith blades installed on the inside walls. The drum rotates between 0.1 to
1.0 rpm and is suitable for waste with low pigment and moisture content.

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First era of composting (Tokyo)

Transitions in municipal waste composting operations in Tokyo due to changes
in garbage collection systems

1. 1930s: Smoke pollution emitted from incineration plants. Waste isseparated into kitchen waste and trash.

2. 1940s: A policy was developed to incinerate trash while converting
kitchen waste into feed and fertilizer.
All kitchen waste could not be converted into feed and fertilizer and so thisportion was disposed of in landfills.
3. Composting became more complex due to the mixed waste collections
and kitchen waste containing plastic containers resulting in a need todevelop sorting technologies.

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First era of composting (Decline in 1965)

Key factors and circumstances behind the decline of the first era ofcompostingAdvancements in the petrochemical industry led to the supply of inexpensive
chemical fertilizer.
The quality of compost products declined due to deterioration in the quality of
raw materials as plastics were developed and produced in large quantities
becoming mixed with garbage.
The decline in product quality led to a decline in demand, which created a vicious
cycle and decreased production.

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Second era of composting (from 1970)

Compostingregains
popularity

Factors and circumstances behind the resurgence of composting
research and operation① Soaring oil prices caused anewed awareness in effective use of resources andthe need to promote recycling.
② The effect of organic fertilizer was reviewed in light of allegedly harmful
pesticides.
③ Decreases in soil fertility as a result of using chemical fertilizers resulted inrenewed appreciation of and increased interest in organic fertilizers.

④ Development of fermentation tanks and secondary equipment (crushing andsortingequipment) as well as development of various operational
processes was advancing.

* 1981: Tokyo established the "Basic Policy for Municipal Waste Composting Facilities".
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Second era of composting (Tokyo)

Tokyo Metropolitan Cleansing Lab
Composting Experimentation and Research (from 1977)
 1977-1978: Indoor experimentation and research Municipal waste fermentation experiment;
Primary fermentation, aerobic fermentation, initial temperature of 35 °C,
5-6 days
Secondary fermentation Fermented for approximately 30 days

From 1978: Construction of compost laboratory research center (1 t/day) Conditions study on stable aerobic fermentation, municipal waste,moisture content from 40-60%
 Research into bag-tearing equipment
 Soil improvement effects
 Deodorization experiment performed on compost Study on compost demand and marketability assuming efficient andeconomical composting facilities were in place.
 From 1985: Support for the constructed compost center (50 t/day)
 Empirical studies on deodorization technologies using bark compost
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Second era of composting (Tokyo)

Tokyo Metropolitan Cleansing Lab
Composting Experimentation and Research (from 1977)
System diagram of research laboratory producing 1 t/day

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Second era of composting (Tokyo)

1985: Construction of Tokyo Compost Center Facility scale (processing capacity): 50 t/day Compost production capacity: 5 t/day
 Process method: High speed composting method
 Bag-tearing equipment: 1 hydraulic scissors type machine (10 t/h) Fermentation tank: 3 rectangular box tanks
 Deodorization equipment: Acid/alkaline washing and activated carbon filtering Construction cost: Approximately 730 million yen

Site features: Adjacent to an incineration plant which enabled use of power
generated by the incineration plant and easy offloading of remaining waste after
sorting processes.

This center ceased operations in 1994 to make room for the construction of a new incineration plant.

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Second era of composting (Tokyo)

System diagram of the Tokyo Compost Center (50 t/day)

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Second era of composting (Tokyo)

Tokyo Compost Center Performance Statistics 1985-1994

Performance Statistics
 Characteristics of received garbage
in 1989
1. Flammable materials
88.8%
・Paper
36.5%
・Kitchen waste
33%
・Textiles 4.4%

 Compost production in 1989
1. Received garbage 13,801 t/year
2. Amount converted into compost 3060 t/year
3. Compost conversion ratio 22.2%
4. Residual amount 10,741 t/year
5. Residual ratio 77.8%

・Lumber, grass, etc.

14.9%

2. Plastics 8.5%
・Plastic 8.4%
・Rubber & leather

0.1%

3. Non-flammable materials 2.7%
・Metals 0.8%
・Glass 1.7%
・Soil and pottery
0.1％・Other
0.1％

6. Compost production 288 t/year
7. Compost production ratio 2.1%

 Compost product characteristics in 1989
1. Foreign substances: 0.4-0.8% (specifications are 1% or less)
2. Moisture content: 27.7-29.4% (specifications are 30% or less)
3. Fertilizer components
C/N ratio: 11.0
Nitrogen (T-N)
3.5%
Phosphate (T-P305) 1.6%
Potassium (K20) 0.9%

Material balance: Receives 50 t/day of municipal waste, produces 2 t/day of compostAverage product cost: 300 yen/kg (maintenance and management costs of 140 million yen/year)
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Tokyo Compost Center Issues 1985-1994
Issues 1/2
Decreased compost production
 The compost center requires 30 days of fermentation to produce compost after sorting
received municipal waste to extract kitchen waste.
 The facility was designed to produce 5 tons of compost for every 50 tons of waste
received daily.
 However, actual compost production was less than design goals at 2-3 tons.
 Key factors include single-person and elderly households switching from containercollection to disposing waste in bags, increases in hard paper products such as cardboard
as well as non-flammable materials, and decreases in operation efficiency due toblockages and malfunctions in machinery.
 To counter these issues, attempts were made to use waste from restaurants in busy
sections of the city to more easily extract kitchen waste, but waste from these sources
also included a significantly high proportion of bottles, cans, styrofoam, and so on. Using
kitchen waste from hotels, however, resulted in an improvement to 3 tons.
 Collecting waste suitable for compost was an ongoing problem.
Insufficient facility performance Mechanical sorting equipment was not able to sufficiently remove unsuitable materials
such as plastics which resulted in unsuitable materials being included in thefermentation tank inhibiting the fermentation process.
 There was no equipment for adjusting moisture content. Waste with high moisture
2015/1/31 content had to be drained in the fermentation tank. (Suitable moisture content is 30%) 19

Issues 1/2
 Root rot in compost productInitial compost product was produced in the shape of a rose. This resulted in being one of
the causes of root rot, and so the product was changed into pellets resulting in sloweracting material and eliminating root rot.
Insufficient deodorizing equipment to deal with the many types of odors produced
 Deodorizing improvements were made such as removing moisture from postfermentation air containing a high odor concentration level and reusing this moisturefor fermentation of more compost.
 The facility was equipped with chemical cleaning deodorizing machinery using acid andalkaline substances. These chemical agents were successful in eliminating odors
produced by compounds but were not effective in dealing with complex odors from thefermentation of many different types of waste. Active carbon deodorization equipment
was added to the facility, but the capacity of this equipment was not enough to meetdemands.
Concern over heavy metal content
Initially there was concern over cadmium, mercury in batteries, and other harmful
substances, but fertilizer product was produced in compliance with the Fertilizers
Regulation Act and always better than the standards.
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3. Examples of odor problems caused by private compost
processing facilities in urban areas
Private composting facilities
・Processing capacity of 80 tons/day
・Facilities composting garbage from food factories, restaurants, school cafeterias, etc.

Odor problems arose in the areas surrounding the processing facilities. Local governments continue toprovide guidance and instruction on improving this situation.

Causes and solutions to odor problems

Main causes of odor Moisture content management is not properly conducted before the fermentation
process.
 Aeration and other air supply capacity is not sufficient resulting in anaerobic
fermentation.
 Deodorizing equipment capacity is not in line with processing capacity.
 There is no expert in fermentation and resulting odors on staff.

Improvements and mitigations
 Improvements in moisture content management to maintain proper balance
between secondary materials (sawdust and such) and raw materials.
 Improvements in air supply and stirrer equipment. Research into and improvementsof deodorizing methods and equipment.
 Review of processing capacity and amount of raw materials received. Improvements
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in process flow.

4. Problem resolutions needed to further municipal waste compost
processing (Example)
1. Selection of municipal waste, which typically contains unsuitable materials

 Characteristics of municipal waste (garbage)
 Moisture content is too high.
 Requires grinding, dehydration, and moisture adjustment (additives).
 Additives used as needed include rice straw, grain, and sawdust.
 Purchasing additives raises costs and sometimes negatively impacts financials.
 Possibility to contain unsuitable materials
 Garbage raw material may contain heavy metals such as copper, lead, zinc,and mercury.
 May contain small pieces of plastic and glass.
 Garbage could contain salt used in cooking.

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2. Reduction of residual material and the associated improvement in production
The amount of residual material varies depending on the collection method and type of waste discarded. Thissignificantly affects the compost production ratio.

○ Selection of garbage suitable for compost○ Use efficient collection methods
Households
Food and beverage
storesConvenience stores

Type ofgarbage

Sorting
Sourceseparation

Restaurants

Ferment
ation

Production

Assembly, improvement, and development ofsorting equipment suitable for different types
and characteristics of garbage
Residualmaterial○Production efficiency decreases as
residual material increases

2015/1/31○ Large amounts of residual material
increases costs for processing such as crushingand incineration, which negatively affects
financials.

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3. Quality control of the product Municipal waste compost characteristics
1. Degree of maturity 2. Fertilizer components 3. Hazardous components
4. Residue (glass, plastics, etc.)

 Degree of safety when using municipal waste compost for soil and crops
1. Does not rapidly decompose after use.
2. Does not cause nitrogen starvation.
3. Does not contain growth inhibitors over defined standards.
4. Does not contain hazardous substances over defined standards.
5. Does not contain plant pathogens and weed seeds.
 Municipal waste compost ⇒ Special fertilizer (Fertilizers Regulation Act) Product quality labeling (certificate of component analysis)
 Concentration levels of nitrogen, phosphate, and potassium Carbon-nitrogen ratio (C/N ratio) Moisture content and others
 Hazardous substance regulations
 Arsenic, cadmium, mercury, lead, hexavalent chromium, organic phosphorous, cyan, and
PCB
 Registration with government agencies
 Registration as a special fertilizer
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4. Ensuring demand and demanded amounts
 Two aspects of processing facilities
 The facility is both a waste processing facility and a facility producing a commercial
product.
 If it were purely a production facility, actual production would be based on demand.
As a waste processing facility, however, it is expected to constantly accept waste.
 Ensuring stable demand Contracting with farmers capable of sustained use.
 Setting of prices that promote stable demand and development of suitable supply
systems.
 Disclosure of components and effect on soil improvement. Provide guidance on
proper use.
 Balanced demand ⇒ Compost granulation ⇒ Primary storage
 Farmer demand of compost changes in accordance with the season (much higher infall and spring).
 Develop demand with other types customers besides farmers such as golf courses andother grounds.
 Temporary storage locations and equipment needed for periods of decreased demand.
 Granulating rose-shaped compost improves both usability and storability
 Ensuring usability in farms and avoiding nitrogen starvation
 Granulating compost improves its slow-acting properties, improves usability, and2015/1/31
avoids nitrogen starvation.

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5. Deodorizing Efforts
 Odor produced from composting facilities
 Hot multi-component gas that includes carbon dioxide as wells as sulfur compounds such as ammonia,
ethanol, methanol, acetone, and methyl sulfide.
 Insufficient fermentation causes organic acids producing odor.
 Deodorizing systems
 Combination of methods including water washing, chemical cleaning using acids and alkalines, activatedcarbon adsorption, soil adsorption, and compost adsorption.
 Water washing and chemical washing using acids and alkalines is particularly effective with large amounts
that have low concentration levels of odor.
 Soil adsorption and compost adsorption is a low-cost method, but blockages may be a concern.
 Direct combustion method decomposes odor at high temperatures and thus is effective, but the cost ishigh.
 Activated carbon adsorption is not effective on ammonia. The adsorption effect is reduced by theadhesion of water.
 Reducing highly concentrated odors
 Removing moisture from post-fermentation air in a mist separator and reusing air in the fermentation tank
improves the deodorizing effect.
 Air at the top of the fermentation tank with low odor concentrations is sent to the deodorizing equipment.

 Aerobic fermentation
 Improve air supply capacity of aeration and other equipment to prevent anaerobic fermentation andmaintain aerobic fermentation capability.
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Reference 1/2

Performance of Municipal Waste Compost ProductApplication testing continually conducted at the Tokyo Metropolitan Agricultural ResearchCenter (1985-1994)

 Includes 1-3% each of nitrogen, phosphoric acid, and potassium
 Organic fertilizer with soil improving effect (special fertilizer incompliance with the Fertilizers Regulation Act) Compost testing areas showed a yield increase of 255 overareas treated with chemical fertilizer and a yield increase ofover 10% over areas treated with cow manure.
 Largely used for Chinese cabbage, cabbage, and fruits.
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Reference 2/2
Municipal Waste Composting Technologies

 Fermentation tank
 Rotary kiln fermentation tank
 Multi-stage fermentation tank
 Sorting and crushing machine Silo fermentation tank
 Bottle fermentation tank

 Sorting equipment

 Deodorizing equipment
 Chemical cleansing equipment
 Soil deodorizing equipment
 Compost deodorizing equipment
 Activated carbon deodorizing
equipment Combustion deodorizing
equipment Vibrating sieve machine Trommel Sorting and crushing machine Zigzag wind sorting machine Screen sorting machine Rotary spike sorting machine Inclined belt conveyor sorting
machine Specific gravity difference sorter
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5. Considerations in planning municipal waste compost processing facilities
To proceed with the planning of compost processing facilities:
Goal: Formation of a recycling-oriented society, efforts to recycle resources and contribute to global warming
initiatives.


Governmental factors in reducing or abolishing the municipal waste (garbage) composting business• Difficulty in continually producing high-quality compost due to improper sorting of raw materials
and garbage.
• Necessity and related cost of additives (sawdust and such) to adjust moisture content of garbage
with high moisture content.
• Difficulty in ensuring long-term and stable customers due to fluctuations in compost
marketability that peaks in the spring and fall.
• Significantly high operation costs in comparison with incineration and other processing facilities.
• Difficulty in maintaining operations in dense residential areas due to insufficient deodorizing
systems.

Key resolution factors

Improve
Overcome

 Ensure high quality raw materials necessary to manufacture compost
Requires guidance on sorting garbage, a sorting system/process, and promotion and public awareness/education initiatives.
・Improved collection devices (biodegradable plastic bags, specialized containers, etc.)
・Management of collection locations (door-to-door collection, station collection, etc.)
・Economic motivation such as making the disposal of garbage free and the disposal of combustible waste requiring a fee.
 Ensuring long-term compost users, verification of the effect of usage on farms, widespread publicity
 Ensuring aerobic fermentation via sufficient air supply to fermentation tanks, suitable selection/combination of sorting
equipment depending on type of waste
 Selection and combination of deodorizing equipment suitable for the types of odors present and the regional environment
Direct combustion equipment often times cannot be installed, which requires proper maintenance and management of a
combination of equipment such as cleansing equipment and soil deodorizing equipment.
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Summarizing the recycling of municipal waste (garbage)

 Municipal household waste (garbage)○ Government facility (recycling facility)
・Composting facility
・Methane fermentation facility
・Livestock feed facility○ Garbage composting at households and small businesses
・Compost containers
・Small business composting equipment○ Private facilities
・Composting facility
・Methane fermentation facility
・Livestock feed facility

 Restaurants, cafeterias, food and beverage stores, etc.
Commercial waste (garbage)

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Initiatives to promote garbage composting in households and small business

Local government initiatives
 Compost containers for household use Local governments provide subsidies
 Many local governments in the Tama region, which has many natural areas
 Used mainly to ferment and provide fertilizer for ones own land.

 Commercial garbage processing machines (compact and motorized)
 Some local governments provide subsidies
 Compact, electric devices capable of around 1 t/day* This initiative is not actively promoted in the 23 Wards of Tokyo.
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6. Conclusion
 Composting technologies are already established.
 Operating a stable composting business requires the collection
and selection of raw materials appropriate with the scale of the
facility and ensuring long-term and stable customers.
 The key to success in composting is the securement of suitableand quality raw materials, crushing and sorting equipment
appropriate for the types of garbage collected, improvementand development of aerobic fermentation technologies, andsufficient deodorizing measures.

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