ISWM, Japanese Style

Feb. 21, 2013

Up until four decades ago, waste management practices in Japan looked very similar to those found in the US. However, in the 1970s, new legislation driven by the scarcity of landfill space pushed Japan to seek such solutions as waste-to-energy. Beginning in the 1990s, growing environmental awareness and stricter laws like the 3Rs policy brought the country to the forefront of the waste management industry. One of the greatest enabling factors for this transformation was a cultural and industrial commitment to excellence.

This attitude towards waste is shown in every facet of the waste management infrastructure. The overarching philosophy is a view that minimizing environmental impact is a duty of the people and the government. As a result, individual communities have taken responsibility for their own waste-facilities are smaller scale, with community interface as a high priority. There is also a large degree of cooperation between different facilities in order to save resources. Finally, the end products produced by facilities are held to an extremely high standard of quality and safety.

Similar to California’s Integrated Waste Management Hierarchy, Japan instituted a “3 Rs” policy to try and reduce waste. Included as part of the “Reduce, Reuse, Recycle” plan was the idea that energy recovery is a way of utilizing waste-thermal recovery of energy is an inextricable part of recycling to the Japanese.

To observe this firsthand, the UCLA Recycling & Municipal Solid Waste Management Advisory Board sent a group of representatives to Japan in September 2012. A weeklong flurry of tours took us as far south as Fukuyama and as far north as the disaster area of Ishinomaki. The purpose of the tour was to determine the best management practices case studies that are to be incorporated into the solid waste management engineering curriculum.

The Management Infrastructure
Waste management truly begins with the homes and businesses of Japan. Participation in segregation at the generator level is extensive, with contamination kept to an absolute minimum, allowing for facilities to have good quality feedstock for recovery of materials.

Reduction and recycling are the highest priorities for waste management, fitting in with a total philosophy of conservation of resources and minimization of waste.

The high level of active citizen participation in source-separated recycling programs creates benefits for the overall waste management infrastructure in the form of “socially processed” recycled materials and waste-to-energy feedstock with very low levels of contamination.

For example, at the Mizue Recycling Plant, PET bottles are recycled. Manufacturers in Japan have almost universally adopted a standard for PET bottles, including mandating that every bottle be clear.

As a result, labels are often large, covering the entire bottle to mimic a colored plastic. But once the labels are removed, the incoming bottles are uniform. Once shredded and washed, pieces of caps are separated from the bottles by a density method, and the final clear flake is recycled.

Also at Mizue, home appliances are accepted for recycling. Because of the variety and complexity of appliances being recycled, they are hand-disassembled by staff. Again, thanks to manufacturer cooperation, this process is made as painless as possible. While older machines may pose some difficulty, newer appliances are easily broken down with few tools required.

Photo: WTE
Waste-derived fuel pellets

After recyclables have been removed from the wastestream, almost all of Japan’s waste goes through a waste-to-energy process. While landfilling waste and capturing the gas for energy is a solution in the US, the environmental effects have rendered them all but obsolete in Japan. Landfill gas, while some of it is captured, will still manage to escape, contributing to odors and carbon in the atmosphere. Thermal treatment allows for more direct control over the process that creates synthesis gas or energy, giving modern incinerators and gasifiers far lower emissions than landfills.

One such facility is the Kanazawa waste-to-energy plant. The facility uses a stoker incinerator to power a turbine for energy recovery. Due to its proximity to a wastewater treatment facility, resources are shared between the two easily and cheaply. The incinerator uses reclaimed water for cleaning and cooling, and also accepts the digester gas generated by the wastewater treatment. Energy from the furnace is sent back to the wastewater facility. The dewatered sludge is then converted to energy in the digester tank within the facility.

What makes the Kanazawa facility unique among others with similar technology is its devotion to community outreach. In addition to the stoker incinerator, the Kanazawa facility provides heat and electricity to a nearby community pool that includes a tea room and cafeteria. The incinerator itself is surrounded by clean, windowed hallways that allow for easy tours with school children and adults. As a result, patrons of the amenities are constantly aware of the ins and outs of the waste management process, which encourages participation.

As part of the community interaction, Kanazawa developed a series of educational materials designed for local households and schools. For example, one such pamphlet includes a cheerful trash cartoon mascot, designed as a trash bag with a belt tied round its middle, encouraging families to reduce their waste. Also inside the pamphlet is a chart showing how to separate waste properly so the facility receives the proper feedstock.

Kanazawa’s stoker technology accepts waste directly without additional processing. As an alternative, some facilities preprocess mixed waste to produce a more uniform refuse derived fuel (RDF) to thermally treat for energy recovery. Fukuyama is home to the largest densified RDF pellet production and gasification plants in Japan. As a regional facility, the gasifier accepts fuel both from the connected-by-conveyor RDF plant next door as well as other RDF pellet production facilities from local surrounding communities in the region.

While gasifiers naturally can accept a variety of waste compositions, to achieve the maximum efficiency a specific quality of RDF is used. Early in the RDF production process, a crucial drying process ensures extremely low moisture content in the RDF, from 5% to 8% by weight.

By using a gasifier instead of a different technology like the stoker-powered Kanazawa plant, Fukuyama represents a push towards cleaner waste management. The gasifier design emits a much lower amount of dioxins compared with other waste-to-energy options. While it is possible to meet regulations with a stoker furnace (as evidenced by facilities like Kanazawa), Fukuyama’s gasifier prides itself on far exceeding expectations.

Another benefit of gasification is that bottom ash is slagged and continuously removed as part of the process. After it is granulated, the slag is separated into a metallic and glassy slag. The metallic portion can be recycled, and the glassy slag, because of the consistency of the process, can be used as a construction material. As a result, the only product from the gasifier that goes to landfill is the treated fly ash, less than 5% by weight; this gives the gasifier the largest volume reduction out of all the current technologies in Japan.

As a regional facility, the Fukuyama gasifier is able to benefit from economy of scale. However, the actual gasifier is only the last step in the process-RDF production plays a role as well. Manufacturing the RDF in other areas represents an almost transfer-station-like step. Spread-out communities each have an RDF plant, which can separate out certain inerts before creating RDF pellets to be shipped to the large facility at Fukuyama. Unlike a transfer station though, there can be a large reduction in weight and volume from waste to RDF. This makes the process overall more efficient, since only the densified RDF fuel pellets need to be transported to the gasifier.

Finally, Japan also collects and recycles foodwaste. In cooperation with restaurants, homes, and some industry, local plants like the Chiba biogas facility can exist. The Chiba facility produces biogas that is then utilized together with other recycled gas in a nearby powerplant. Other technologies for foodwaste do exist; there are facilities that convert clean, source-separated foodwaste into animal feed.

Earthquake, Tsunami Cleanup
In day-to-day life, the Japanese waste management system functions amazingly enough by any measure. However, it was truly tested by the disastrous tsunami in March 2011. Centered in the Sendai region of Northern Japan, the Tohoku earthquake and tsunami caused damages upwards of $10 billion US. In the aftermath, the local government gave a contract to a general contractor who then formed a joint venture to assist in the cleanup effort of the massive amount of disaster debris. After the contracts were settled, work began quickly in September 2011. In the port city of Ishinomaki, Miyagi Prefecture, a large area was cleared and a massive, two-part, makeshift disposal facility was constructed.

At Ishinomaki, a new priority arose: speed. More than anything, it was important to remove the building debris so that rebuilding and normal life could resume for the affected residents. The majority of the waste at the disaster site resembles C&D waste. Due to the lack of space in Japan, landfilling is not an option-instead, incineration was the process of choice. Because of the focus on speed, there was no time or space allotted for energy recovery from these processes, however.

For mixed wastes, the first step is to remove all personal belongings, after which it goes through a simple screening sort that provides three separation stages. Oversized wastes pass through hand-picking lines and magnetic separators to remove inerts and easily identified materials for recovery. Of the 4,000 total tons of materials processed each day, approximately 2,000 tons are combustible, of which 1,500 tons are then transported  to an adjacent area where three stoker furnaces and two kilns complete the incineration process. The remaining 500 tons are shipped to another prefecture for incinereation.

Depending on the quality, wood materials will either be recycled or taken through a partial shredding before being sent to thermal treatment. Concrete debris is simply crushed for construction material.

A total of five of these lines feed into three stoker furnaces and two rotary kiln incinerators. In the interest of speed, the rotary kilns were reused from a cement factory to cut construction time. The fly ash from these incinerators is packaged into bags, which are then landfilled. Most of the bottom ash can be recycled as construction material. The disaster debris planning, coordination, and mobilization effort is remarkable. The JFE rotary kilns, for example, were designed, constructed, and in full operation within six months. Each line and incinerator represents a capacity of approximately 300 tons per day, for a total of 1,500 tons per day.

The undersize material from the screens is mostly dirt and soil. However, due to contamination with things like plastics, in its received state it is unusable. As a result, the undersize fraction is processed to remove contaminates from the soil, and then the soil is further processed through a soil washer. The final washed soil is then used as construction material.

An important part of the recovery effort was directed at the people affected. The initial plan called for hiring 1,250 local people who had been affected by the tsunami, but because of increased efficiencies and reduction of waste generation, the total number of workers was reduced to 800, of whom half are from the local area.

Planning for disaster debris management is an integral part of emergency preparedness. The overall estimated cost of the cleanup and disaster debris management (6.8 million metric tons of debris and an additional 2.0 million cubic meters of tsunami sediment) for this natural disaster is approximately $250 billion. The estimated cost for Ishinomaki alone is $2.4 billion

Heading Home
The most impressive thing about Japanese waste management has been the mindset and attitude. The homogeneity of society and culture has allowed for a uniquely unified outlook on waste management as a necessary responsibility of the people and their government. Economics play a backseat role compared to minimizing environmental impact, and producing the best product, whether it is a recycled plastic fork, or a refuse-derived fuel pellet.

Importantly, cooperation between government, businesses, and waste management facilities has allowed for the growth of markers for products made from waste-recycled materials, energy, treated water, construction materials from slag, and more.

These long-term, green goals were the drivers for innovation. However, enough time has passed for the economic drivers to pay off after the initial investment. Japan has established a functioning, viable system that thrives on cooperation and community.

While Japan represents an excellent example of waste management, the process of adapting its technologies and policies in the states is a task that requires alteration and innovation. Perhaps the easiest technology to transfer to the US would be a biogas facility. Biogas generation via anaerobic digestion is an accepted technology that is well-liked due to its clean biological nature. Also, foodwaste is an easily separable material at the generator level, requiring minimal effort from restaurants and food facilities.

On the other hand, thermal treatments like incinerators have a somewhat negative connotation in the states. It must be stressed that the stoker process produces far less in the way of greenhouse and dioxin emissions than does a comparable landfill, with a gasification plant being even cleaner. Also, a gasification process greatly reduces the amount of waste that goes to landfill, while producing slag that is useful as a construction material.

Producing a refuse-derived fuel is also an excellent option. An RDF allows for a more consistent output of both power and slag content from a gasifier. While as a general trend, Japan maintains small community thermal treatment plants, the RDF process has allowed them to achieve a lot of the same benefits of smaller facilities while gaining economy of scale with a large regional facility to process the RDF.

According to Wayne Tsuda (City of Los Angeles, Local Enforcement Agency, director), one of the UCLA Engineering Extension Advisory Board Members, “I was particularly impressed with the JFE Engineering Fukuyama RDF plant, as it seems the most applicable to assist small cities to produce energy from wastes in the USA. Having regional energy-producing facilities using RDF from many local manufacturing centers offers environmentally sound, economic options to small to medium sized cities.”

Existing infrastructure in the US resembles this regional approach more than the smaller community ideology, which would make an RDF system a better fit. Local RDF production facilities can essentially act as transfer stations and MRFs at once, while providing a consistent RDF feedstock for a regional gasifier. The smaller RDF facilities, due to their community size, will be ideal for implementing greater interaction with the public. Increased education of the issues surrounding waste management is a key advantage the Japanese system holds over the US.

Japan’s problem of conserving land has led that country to focus highly on extending the lifetime of its landfills. Landfill space in the US is still relatively abundant, but similar policies must be considered as we look to the future. While practices such as the Japanese excavation of landfills for thermal treatment and regional RDF gasifiers may seem to be far away in the United States, these practices-which provide the benefit of much cleaner emissions while reducing the burden on landfills-today have already been commercially proven and in operation for many years in Japan.

Countries like Japan have been propelled ahead of the United States in the waste management field by their unique cultural and environmental pressures, while innovation at home has been stifled by a lack of aggressive policies. To catch up and clean up our own practices, the US must look to Japan as an inspiration more than an example, to develop policies and projects that fit our own needs and culture.

About the Author

Jason Tseng

Writer Jason Tseng is a project manager with E. Tseng and Associates in Los Angeles, California.