Recycling construction waste in Japan

A report on construction waste recycling by Mizuho Research & Technologies

Mizuho Research & Technologies is a think tank of Mizuho Financial Group.

The following is a translation of their report posted in February 2023 titled “Need for resource recycling of construction waste (in Japan)“ 「建設廃棄物の資源循環の必要性」

According to the study by the Japanese government that this report refers, 97% of the construction waste is recycled in Japan.¹

---

Need for resource recycling of construction waste

Circular economy in the construction sector shaken by rising resource prices

Mizuho Research & Technologies, Sustainability Consulting Division 2

Aoi Minakami (水上　碧)

BACKGROUND

2022 was marked by a series of challenges that had a significant bearing on our daily lives, including Russia’s invasion of Ukraine, the outbreak of the Omicron strain of the new coronavirus, and the sharp depreciation of the yen which reached its lowest level in 32 years. In response to these domestic and international developments, the soaring construction material prices often made the news. At the end of 2022, several bids for construction work on the Osaka-Kansai Expo, to be held in 2025, had been rejected due to soaring material prices among other factors.

In addition to the current international affairs, the growing momentum for carbon neutrality in recent years has drawn attention to the need for resource security and resource autonomy, regardless of the business sector,² and the impact is particularly significant in the construction sector,³ which consumes a large amount of resources.

The shift to a ‘circular economy’ is an indispensable trend when considering resource security and resource autonomy. The circular economy is not a linear economy that leads to the conventional mass production, mass consumption and mass disposal type of economy and social pattern. It is an economy that maximizes the value of resources and products, reduces resource input and consumption, and minimizes waste generation. Since the EU set out its transition to a circular economy in 2015, there has been a global focus for a response. The transition to a circular economy will enable resources to be recycled and reduces the amount of resources needed, a move that is also important as a response to the problems caused by rising resource prices.

THE IMPORTANCE OF THE TRANSITION TO A CIRCULAR ECONOMY FOR THE CONSTRUCTION SECTOR

In Japan, the Global Warming Prevention Plan, set out in October 2021, proposed the concept of integrated improvement of the environment, economy, and society. This includes a shift to a circular economy, including the 3Rs (Reduce generation of waste, Reuse and Recycling of recyclable resources) + Renewables (biomass, use of recycled materials, etc.).

In September 2022, the Ministry of the Environment (MOE) published the "Results of the second Inspection of the Progress of the fourth Basic Plan for the Establishment of a Circular Society (Circular Economy Process Chart) Towards a Circular Society in 2050" (hereinafter referred to as the "Circular Economy Process Chart"). The Circular Economy Process Chart sets out the direction of the circular economy that should be pursued with a view to 2050. It identifies plastics, earth, stone and construction materials, among the five fields⁴ covered in the current Basic Plan for the Promotion of a Circular Society. These will continue to be treated as priority fields from the perspective of their environmental impact, waste generation and their contribution to decarbonisation. What is meant by 'earth, rocks and construction materials' is not clear. However, construction soil, concrete lumps, asphalt, and concrete lumps, cement and iron, which are often generated and used in the 'construction sector,' are considered to fall under this category.

CIRCULAR ECONOMY INITIATIVES IN THE CONSTRUCTION SECTOR

What are circular economy initiatives being implemented in the construction sector? The most distinctive feature is recycling. The construction sector consumes large amounts of resources and generates a large amount of waste. Construction waste accounts for about 20% of all industrial waste emissions, but the recycling rate is very high: it has made significant progress following the enactment of the Construction Recycling Law in 2000, rising from about 60% in the 1990s to about 97% in 2018.⁵

In addition to recycling, various other initiatives are also being implemented. For example, the reuse of existing buildings and building materials, the use of BIM/CIM⁶ to reduce resource input and waste emissions, the use of concrete made from waste, the use of timber and biomass materials such as CLT,⁷ easy dismantling designs such as using as little adhesive as possible, and the extension of the life of various initiatives are being undertaken.

However, compared to the high level of recycling, there has been little progress in initiatives that lead to reduce and reuse which have a higher priority than recycling, as well as long-life and easy-dismantle designs which are important in the circular economy. One of the main reasons for the lack of progress is because the construction sector is not based on mass production and mass consumption. Rather, it is build-to-order on a case-by-case basis. As the scope of cost benefits for the client is limited, designers and implementers are challenged to initiate reduce and reuse. Additionally, buildings need to be durable for long-term use. Who and how to guarantee the quality and environmental safety of reused materials is still unresolved, which is one example of the challenge the industry faces. And the fact that the supply chain is long involving several specialized suppliers make initiatives more difficult. Having said that, with the growing momentum for carbon neutrality, private companies in the construction sector and university researchers are now studying and implementing various initiatives, and future progress is expected.

So, are there any problems with recycling? The recycling rate of construction waste is 97%, as mentioned above, and the recycling rate of concrete and asphalt/concrete lumps, which are the most commonly discharged types of construction waste, is over 99%.⁸ The “Construction Recycling Promotion Plan 2020 - Towards recycling with an emphasis on ‘quality’” clearly states a 'shift from quantity to quality.' Given the transition to a circular economy, it is important to increase the 'quality' of recycled resources. However, the author would like highlight the following two points of concern in terms of 'quantity.'

The first point is that the supply-demand balance of recycled materials may become imbalanced in the future. Concrete and asphalt concrete lumps, which are the most common type of construction waste generated, are currently recycled mostly as construction aggregate and reused as roadbed material and other civil engineering materials.⁹ With fewer roads expected to be built in the future, the concentrated use of recycled materials could lead to an imbalance between supply and demand, which could make recycling itself impossible. For more information on this point, please refer to the report "Future construction waste resource recycling - the need to strengthen initiatives for debris recycling," which will be published at a later date.

Secondly, the non-compliance with environmental standards, specifically the tightening of standards for hexavalent chromium in the Soil Contamination Countermeasures Law, may make it difficult for recycled materials to be used. For hexavalent chromium, following the establishment of the tolerable daily intake level by the Food Safety Commission of the Cabinet Office in September 2018, the environmental standard for water quality in tap water (from April 2020) and for water pollution in public waters and groundwater (from April 2022) were both strengthened from 0.05 mg/L to 0.02 mg/L.¹⁰ The tightening of the environmental standards for water pollution may impact the standards for soil. The MOE's "Direction for Setting Environmental Standards for Soil Pollution" states that "it is considered necessary to set soil environmental standards with conditions that satisfy these various standards for water quality."¹¹ In fact, after the environmental standards for water quality were strengthened, the Soil Contamination Countermeasures Law matched the standards for cadmium and trichloroethylene. Furthermore, cadmium and trichloroethylene have also been restricted to the same standard in the Soil Contamination Countermeasures Law after the water quality environmental standards were strengthened. Therefore, it is quite possible that the standard for hexavalent chromium in the Soil Contamination Countermeasures Law will be revised from the current 0.05 mg/L to 0.02 mg/L in the future. If this happens, recycled aggregates and other materials recycled with current technology cannot meet the new standards and they will become difficult to use. As a result, construction recycling, which has made steady progress and has entered an era of 'quality' rather than 'quantity', may once again hit a major wall in terms of 'quantity.'

LOOKING AHEAD

Because of its high resource consumption and waste generation, circular economy initiatives in the construction sector are important. However, the construction sector is also an industry with a long supply chain involving a variety of specialist suppliers, making it difficult for individual companies to address any of these issues alone. At a time when the concern on rising cost of resources is high, it is desirable to promote initiatives through inter-company cooperation and public-private partnerships, including dynamic and static cooperation.

There are also future concerns about the quantity of recycling, which has been considered less of a challenge. The issues of 'quantity' and 'quality' are two sides of the same coin, and by improving 'quality' it is possible to resolve the above-mentioned concerns in terms of 'quantity.' Therefore, it is important to enhance 'quality' while taking into account that there are also concerns in terms of 'quantity,' and comprehensive policy and technological development that considers the balance between quality and quantity is necessary. In this regard, the Water Environment and Soil Pesticides Sub-Committee of the Central Environment Council also commented that 'in recycling, it may be necessary to consider resource recycling and environmental conservation of soil and groundwater as well,¹² and future cross-sectoral discussions are expected.

1. Ministry of Land, Infrastructure, Transport and Tourism (MLIT), “Construction Recycling Promotion Plan 2020 - Towards recycling with an emphasis on ‘quality’”　（「建設リサイクル推進計画2020〜「質」を重視するリサイクルへ〜」の策定について）（https://www.mlit.go.jp/report/press/sogo03_hh_000247.html）

2. For example, since October 2022, the Ministry of Economy, Trade and Industry (METI) has held a Study Group on “Designing a Growth-oriented Resource-autonomous Economy,” which is currently studying a comprehensive policy package to establish a growth-oriented resource-autonomous economy.

3. For example, "Construction and the built environment in the circular economy: A comprehensive literature review" points out that the construction sector consumes 65% of total construction aggregates, 20% of metal materials, and is involved in 60 % of raw materials globally.

4. (i) plastics, (ii) biomass, (iii) metals such as base metals and rare metals, (iv) earth, stone, and construction materials, (v) new products and materials as a result of global warming measures.

5. MLIT, “Construction Recycling Promotion Plan 2020 - Towards recycling with an emphasis on ‘quality’”　（「建設リサイクル推進計画2020〜「質」を重視するリサイクルへ〜」の策定について）（https://www.mlit.go.jp/report/press/sogo03_hh_000247.html）

6. BIM/CIM refers to Building/ Construction Information Modeling, Management

7. CLT stands for Cross Laminated Timber. The government has established a 'Liaison Conference of Relevant Ministries and Agencies for Promoting the Use of CLTs' and other government-wide initiatives are underway to promote their use.

8. MLIT, “Construction Recycling Promotion Plan 2020 - Towards recycling with an emphasis on ‘quality’”　（「建設リサイクル推進計画2020〜「質」を重視するリサイクルへ〜」の策定について）（https://www.mlit.go.jp/report/press/sogo03_hh_000247.html）

9. MLIT, “Survey of Construction By-Products.”

10. MOE press release, "Revision of Environmental Standards for Water Pollution (Notice)" and "Environmental Standards for Water Pollution (7 October 2021, Ministry of the Environment Notice No. 62)".

11. Water Quality Protection Bureau, Environment Agency (now MOE), "Direction for setting environmental standards for soil pollution (Report of the Soil Environmental Preservation Problem Study Group)" (April 1991), p. 8: "3. (3) Existing findings that can be applied in setting environmental standards for soil contamination (a) Effects on water purification and groundwater recharge functions.

12. Main opinions at the 3rd meeting of “the Water Environment and Soil Pesticides Subcommittee of the Central Environment Council and main requirements for 2023", Document 4-1.