Chapter One
General Introduction of Construction and Demolition Waste
Abstract
Construction and demolition (C&D) waste has become an enormous part of municipal solid wastes in recent years due to rapid urbanization and industrialization process. Traditionally, it can be processed depending on its type, source, or utilization pathways, most of which is harmless and is able to be disposed or reused without much pretreatment. The general properties, management and recycling technologies, yield estimation for C&D waste in developing and developed countries is introduced. Industrial C&D waste, which is also of a huge amount and contains pollutants or other poisonous substances, is described. A large proportion of these C&D wastes comes from industrial workshops and possesses the characteristics of both hazardous waste and common waste, reflecting in its massive production and high environmental risk. As a general principle the hazardous waste should be primarily separated and sorted before industrial C&D waste is recycled.
Keywords
Classification; Construction and demolition waste; General process; Management situation; Recycling
1.1. Definition, Source, and Classification
Construction and demolition (C&D) waste has become an enormous part of municipal solid wastes since 1990s due to rapid urbanization and industrialization process. There is not much criteria for C&D waste management in China, which have led to its explicit definition and coverage. It is traditionally recognized that C&D waste is the debris generated during the construction, renovation, and demolition of buildings, roads, and bridges, such as concrete, wood, metals, glass, and salvaged building components. “Regulations on municipal construction waste and engineering sludge (Revised version)” established by the Ministry of Construction in 2003 issued a wider definition of C&D waste in which the sludge, muck, and mud were also included.
C&D waste can be classified into five categories depending on its source: (1) Land excavation waste, which refers to the waste generated during the process of land excavation, including topsoil and deep soil. (2) Road excavation waste, which can be divided into concrete and asphalt road waste, including waste concrete block, asphalt, concrete blocks, etc. (3) Building demolition waste, including stone, concrete, sediment, wood, mortar, roofing scrap, steel, and metal, etc. (4) Construction waste, which is generated during construction and renovation projects, including discarded bricks, concrete, stone, mortar, wood, plastic, glass, etc. (5) Building materials waste, which mainly refers to the waste generated during the production process of building materials.
C&D waste can also be classified according to its recycling. Its recycling represents the recovery of useful energy and substances from construction waste through material recycling, material exchange, energy conversion, and other management or technical ways.
Except for the C&D waste derived from civilian buildings, industrial C&D waste and the subsequent hazardous substances should not be ignored. This means C&D waste can be classified into two groups: common C&D waste and hazardous C&D waste. The hazardous C&D waste contains pollutants or other poisonous substances which exceed their legal limits. A large proportion of hazardous C&D waste comes from the industrial workshops, which is namely industrial C&D waste. It possesses the characteristics of both hazardous waste and C&D waste, reflecting in its massive production and high environment risk. Strict treatment should be employed before the hazardous C&D waste is disposed or reused.
1.2. Components and Characteristics of Hazardous Industrial Construction and Demolition Waste
Common C&D waste may pose lasting harms on the environment and ecology. Sediment, rubble, and other inert construction waste do not seem to cause much adverse environmental impact due to their inertness. But various kinds of organic acid will be emitted if they are piled without any pretreatment. The resultant leachate can also contain heavy metals that will contaminate the underground water, soil, and air.
C&D waste mentioned in this book varies from ordinary waste in its industrialized source and hazardous characteristics that occupy a large proportion of industrial C&D waste as discussed earlier. The main pollutants can be classified as heavy metals and persistent organic pollutants. Industrial C&D waste like lead-based paint, fluorescent lamps, asphalt (pavement and roof), wood preservative, and asbestos are all hazardous C&D waste, mainly from the chemical industry (electroplating factory), metallurgy (zinc smelting plants), light industry, and pesticide enterprises. The complex contamination may result from equipment maintenance and leakage, pipeline leak, as well as flotation agents, catalysts, preservatives, and other pollutants.
In chemical, metallurgy, thermal, light and other industrial enterprises, heavy metals, sulfates, organic matter (such as polycyclic aromatic hydrocarbons), and other toxic substances inevitably leak and spill on the wall or ground in the process lines, in which the contaminants will be leached by rain and thus transferred to the surrounding soil and water environment. Knowledge and executive management of industrial C&D waste are lacking in most countries nowadays, resulting in the ineffective disposal and regulation, which has largely retarded the sustainable development.
1.3. Estimation of Construction and Demolition Waste Production
In general the C&D waste production is added by construction, demolition, and renovation waste amount. The detailed estimation methods are introduced below.
1. The production of construction waste can be estimated in three ways. (1) Calculation based on the construction area. Commonly, 30 m2 construction waste is generated within a 1000 m2 construction area. For brick and frame structure, 500–600 t construction waste is generated in a 10,000 m2 construction area. (2) Calculation based on the material consumption. Commonly, it is reasonable to estimate the production amount of C&D waste according to the material consumption. C&D waste proportion of the materials consumed is listed in Table 1.1 (3) Calculation based on the urban population output ratio. Related statistics show that the reasonable output ratio is 100 kg C&D waste production for each person annually.
2. The demolition waste of old buildings. No exact statistics is available due to the relatively complex characteristic of such waste. It can be estimated using the empirical coefficient method and the construction budget estimation method. (1) Empirical coefficient method. According to the Japanese residential completion report in 1999, 1.86 t of demolition waste is generated per square meter of demolition area. In China, the value is 1.35. The coefficient is usually affected by a variety of factors. (2) Construction budget estimation method. This method is generally used as a reference model due to the uncertainty of construction materials characteristics.
Table 1.1
Proportion of Construction and Demolition Waste in Total Materials Consumed
| Main Components of C&D Waste | Proportion of the Materials Consumed (%) |
| Brick | 3–12 |
| Mortar | 5–15 |
| Concrete | 1–4 |
| Pile head | 5–15 |
| Roof material | 3–8 |
| Steel | 2–8 |
| Wood | 5–10 |
3. Renovation waste. Since the public buildings involve large construction area and complex renovation process, as well as multiple material usage, which are different from residential building, these two kinds of buildings should be separated in the estimate of C&D waste production. According to the renovation waste generation standard of Luoyang, China, for building area of more than 160 m2 the renovation waste can be calculated as 0.15 t/m2, otherwise, it is 0.1 t/m2.
Besides, another C&D waste yield estimation model is based on five different engineering projects, including building construction projects, road and municipal construction projects, material production projects, demolition projects, and renovation projects. Estimation formula and waste yield coefficients are listed in Table 1.2.
1.4. Management Situation of Construction and Demolition Waste in China and Developing Countries
With the economic development and industrial restructuring, a number of real estate projects have been established and developed in China since 1990s. Meanwhile, there are many industrial plants either being removed or converted, thereby generating a huge amount of C&D waste. The [2011] No. 2919 paper issued by National Development and Reform Commission (NDRC) published the “‘12th five-year’ guidance of comprehensive resources utilization” and the “bulk solid waste utilization plan,” in which the ten key demonstration projects were defined, including the construction waste projects. Several megatons of C&D waste recycling bases and equipment manufacturing projects were to be established. Forty million tons of annual utilization capacity was expected to increase. The comprehensive utilization ratio of municipal C&D waste was tentatively expected to rise to 50%.
Unfortunately the planned recycling projects for C&D waste have not been well implemented, and most projects were actually cut or terminated due to the lack of collection system and relatively high cost compared with the primary sources. The main existing management problems that have led to the ineffective disposal and reuse of C&D waste in China are listed below.
1. Deficient standards and regulations
Compared with developed countries, relevant regulations and standards started late in China, the existing regulations are more limited in their coverage and with blind spots in management. Many regulations published such as “Law of the People's Republic of China on the prevention and control of environmental pollution by solid waste” and “Rules for the implementation of the administration regulations of city appearance and environment sanitation” have put forward specific demands for the dumping, transportation, transit, backfilling, consumptive use, and other disposal activities of C&D waste. However, the pollution control for industrial C&D waste and its management is not involved. No relevant regulations and technologies are available.
Table 1.2
Estimation Formula and Waste Yield Coefficients of Different Engineering Projects
| Types | Estimation Formula | Waste Yield Coefficients | |
| Building construction | Main construction waste amount = Construction area × waste yield coefficient | 0.05 t/m2 | Brick and concrete |
| 0.03 t/m2 | Concrete | ||
| Foundation excavation construction waste amount = (excavation − backfill) × waste yield coefficient | 1.6 t/m3 | ||
| Road and municipal construction | Waste amount = (excavation − backfill) × waste yield coefficient | 1.6 t/m3 | |
| Material production | Material production waste amount = total mass of materials × waste yield coefficient | 0.02 | |
| Demolition | House demolition waste amount = demolition area × waste yield coefficient | 0.8 t/m2 | Brick and wood |
| 0.9 t/m2 | Brick and concrete | ||
| 1 t/m2 | Concrete | ||
| 0.2 t/m2 | Steel | ||
| Structure demolition waste amount = demolition volume × waste yield coefficient | 1.9 t/m3 | ||
| Renovation | Public architectural demolition waste amount = total cost × waste yield coefficient | 2 t/10,000 Yuan | Office building |
| 3 t/10,000 Yuan | Commercial building | ||
| Residential building demolition waste amount = building area × waste yield coefficient | 0.1 t/m2 | Less than 160 m2 | |
| 0.15 t/m2 | More than 160 m2 | ||
2. Unreasonable supervision mode and unclear management responsibilities
The national Solid Waste and Chemicals Management Center and 31 province-level solid waste management centers have been set. But C&D waste is not involved. On the macro level the collection, transportation, disposal, and utilization of C&D waste are managed by the local construction and urban management departments. However, the contaminated C&D waste has not been effectively supervised and regulated by the environmental protection department. As a result the hazardous waste mixed in C&D waste is sent into regular disposal and reuse systems, which will cause severe environmental pollution with the migration of pollutants.
3. Inadequate understanding of environmental risks and lack of control measures
Organic matters and heavy metals in contaminated C&D waste are migrated into soil and aquatic systems with rain and will cause harm to the aquatic organisms and human health. Therefore a comprehensive and systematic inventory of contaminated C&D waste pollutants by industry, pollution control and generation list are necessary to be established for the setting and amendment of pollution control standards and regulations by the relevant departments.
1.5. Current Development of Construction and Demolition Waste Worldwide
Utilization ratio of C&D waste in the EU exceeds 50% while that in South Korea and Japan reaches 97%. A lot of work in the circular economic legislation has been established, including a series of laws, regulations, and policies in the reuse, recycling, and reduction of C&D waste. These laws, regulations, and policies have made it clear the responsibilities and obligations related to the main responsibility in the treatment of C&D waste and have even made the plan targets of the recovery, promoting its minimization and recycling. Relevant legal and regulatory systems of C&D waste worldwide are shown in Tables 1.3 and 1.4.
Table 1.3
Relevant Laws and Regulations Worldwide for Construction and Demolition Waste
| Countries | Laws and Regulations | Main Contents |
| Germany | “Regulation on the disposal of commercial wastes and certain building and demolition wastes,” “Act on Promoting Closed Substance Cycle Waste Management and Ensuring Environmentally Compatible Waste Disposal,” etc. | The waste generators or owners are obliged to recycle and reuse, and it should be preferential treatment of waste. Classification is necessary. |
| Britain | “Sustainable development in the construction industry,” “Waste Strategy,” etc. | Zero landfill of C&D waste is targeted till 2020. |
| United States | “The Superfund law,” “Solid waste disposal,” etc. | Source reduction should be carried out in some manufacturing companies. Some other regulations are also put forward. |
| Japan | “Waste Management Act,” “Law for Promotion of utilization of recycled resources,” “Construction material recycling law,” etc. | Responsibility on classified demolition and reuse is clearly regulated. Recycling of concrete and other C&D waste and their treatment methods are also ruled. |
| Singapore | “The Singapore green Plan 2012,” etc. | Waste reduction is included in the criteria system. C&D waste recycling is included in the Green Mark certification. |
Table 1.4
Relevant Regulatory Systems Worldwide for Construction and Demolition Waste
| Countries | Regulatory Systems | Main Contents |
| Germany | Charge system | Charge for the storage of untreated C&D waste. Fine for the random dumping of C&D waste |
| Britain | Tax system | Tax on dumping, landfilling, and incineration of C&D waste |
| United States | Advocacy by government while self-regulation by enterprises | Based on government-led control methods, improved by the market stimulus policies. The mode of advocacy by government while self-regulation by enterprises is to be established. |
| Japan | Whole process management | Whole process management is carried out in the generation, collection, disposal, and recycling of C&D waste |
| Singapore | Tax management, franchising, acceptance inspection, etc. | Levy a landfill tax on C&D waste. Franchise license is issued for C&D waste treatment business. Disposal of C&D waste is included in the criteria index of the project. |
1.5.1. United States
C&D waste is divided into three categories in the United States. Firstly, inert or nonhazardous waste, secondly, hazardous wastes, and thirdly, waste containing dangerous ingredients. Most of C&D waste is harmless, which belongs to the first category. According to “The Resource Conservation and Recovery Act, RCRA,” this kind of waste is not under the jurisdiction of the EPA, while it is managed by the state or local government. However, the second category, hazardous C&D waste, of which its generation, storage, transport, and disposal is under EPA regulation. Since most waste in the C&D waste landfill is inert the federal government does not require that those landfills should be equipped with the same environmental protection measures as municipal solid waste landfills. Research shows that regulations of C&D waste in different states are not consistent, antiseepage landfill is required in 23 states, groundwater monitoring is demanded in 27 states, while laws about the C&D waste recycling have been established in 17 states.
The Resource Conservation and Recovery Act, RCRA was published in the United States early in 1967, generator status is determined on a monthly basis, most C&D waste is considered nonhazardous solid wastes. The federal Hazardous and Solid Waste Amendments (HSWA) are the 1984 amendments to RCRA that focus on waste reduction and phasing out land disposal of hazardous waste as well as corrective action for its releases. Conditionally exempt small quantity generators (CESQG) is defined as those generated 100 kg or less per month of hazardous waste, or 1 kg or less per month of acutely hazardous waste. CESQG waste can be disposed of in solid waste landfills (40 CFR Parts 258). If C&D debris is sent to municipal solid waste landfills or landfills that accept CESQG waste, those landfills must still meet federal regulations set forth in RCRA, Subtitle D.
According to statistics the annual C&D waste generation in the United States is about 325 million tons, accounting for 25–40% of the total waste, most of which eventually enter the municipal waste landfill or C&D waste landfill. Governments are also actively exploring ways to reduce the land occupation by increasing the recycling rate of C&D waste. In California, for example, the government has made the minimum recovery requirements of the construction companies. In Florida, C&D waste is separated through manual sorting; the remaining residue is then landfilled.
1.5.2. European Union
There is a comprehensive and detailed classification and coding of C&D waste in EU, in which it is divided into eight categories. (1) Concrete, bricks, tiles, and ceramics (1701). (2) Wood, glass, and plastic (1702). (3) Bitumen, tar, and asphalt (1703). (4) Metal and alloy (1704). (5) Soil (including excavated soil from contaminated sites), stones, and dredging waste (1705). (6) Insulation materials and asbestos-containing construction materials (1706). (7) Gypsum building materials (1708). (8) Other C&D waste (1709), including those containing mercury, PCB, and other hazardous materials. The different types of wastes in the list are fully defined by the six-digit code for the waste and the respective two-digit and four-digit chapter headings.
Waste Framework Directive, WFD, 2008 sets the basic concepts and definitions related to waste management, such as definitions of waste, recycling, and recovery. It includes a new recycling and recovery target to be achieved by 2020: 70% preparing for reuse, recycling, and other recovery of C&D waste.
Overall the European C&D waste management policies and standards can mainly be divided into five categories. (1) The waste policy framework, a national policy with “Waste Framework Directive” as its basis. (2) The provisions of the landfill, for example, the restrictions on landfills in Flanders (Belgium) effectively improved the recycling rate of C&D waste. (3) C&D waste policy. A C&D waste implementation plan was exerted in Flanders in 1995. As a country with the earliest C&D waste policies the recovery rate of C&D waste in Belgium already reached 85% in 2000. (4) Standards for recycled products. In addition to national mandatory standards, there are also some recommended industry standards such as the C&D waste recycled products quality assurance guideline issued by the German Federal Building Materials Recycling Association. (5) Standards for the places where C&D waste is generated, mainly for the management in building construction sites and demolition processes. There are two parts about the regulations of the C&D waste in the standards set by German Sustainable Building Council.
According to Eurostat data, C&D waste generation reached 819 million tons in the European Union in 2012, accounting for about 25–30% of the total waste, of which the average recovery rate was 25%. The recovery rate is above 80% in Netherlands, Belgium, Germany, and Denmark, while that is less than 5% in Spain, Portugal, and Greece, which is related to the management situation in each country. In Germany the most common method of waste management is called “controlled demolition”. Plans should be developed before demolition, which must include the concept of controlled demolition and waste recycling, treatment, etc. Contaminated materials must be removed first, and then the useful parts such as doors and windows, heating systems, etc. Sorting system was added in the demolition site (in accordance with brick, concrete, wood, etc.).
1.5.3. Japan
C&D waste in Japan is classified into concrete blocks, wood, asphalt, building sludge, and mixed building waste. Among these, the mixed waste refers to the bricks, paper, wood, plastics, plasterboard, glass, metals, etc., which are discharged during the construction projects. C&D waste is treated by specialized enterprise, including rough and fine sorting, first large wood chunks and packaging cartons are manually sorted, and then other waste is further subdivided by mechanical assembly line. The nonrecyclable residues are either landfilled or incinerated according to their flammability.
Emissions of C&D waste in Japan are about 80 million tons, and the resource utilization exceeded 75% in 2000. It is a large decrease compared with the 100 million tons of emission in 1990s. The progress in waste minimization and resource is closely related to the encouragement in source reduction and recycling. In addition the research and applied technology also play an active role. The source reduction is focused and applied in the project planning and design phase, by developing, manufacturing, and widely using the building materials in which the generation of scraps could be controlled. In C&D waste recycling the waste concrete is manufactured into renewable gravel, recycled concretes, and recycled graded gravel, etc. through the crushing, screening, cleaning, and particle size adjustment process, which can be used for road paving. The wood chips made of waste wood can be used as wood panels, raw material for compost, and fuel. The building sludge is used for backfilling after being pressed and stabilized.
1.6. General Processes of Disposal and Recycling for Construction and Demolition Waste
The term C&D waste treatment encompasses all alternatives that facilitate transport, storage, reuse, or final disposal processes. Traditional disposal and recycling are the two pathways of C&D waste treatment nowadays, including backfilling, stacking, landfilling, sea reclamation, and road pavement. No sorting or source separation is needed, and very coarse and simple crushing process can meet the requirements of these ways of disposal. Recycling commonly includes the manufacturing of various products which aims at turning C&D waste to regenerated resources. An overview of various alternatives for treatment and disposal is presented in Fig. 1.1.
General process for disposal and recycling of C&D waste includes pretreatment, crushing and sorting, classified storage, and deep processing, a typical flow sheet of these process is demonstrated in Figs. 1.2–1.5.
The C&D waste coming out of the feeder is sent into the jaw crusher for primarily crushing. Generally particle size is controlled less than 80 mm to meet the requirement of the iron removal and sorting. The iron remover and manual sorting platform aim at separating reinforcement bars or large blocks.
The C&D waste is then sent into the impact crusher for secondary crushing. The secondary crushing operation is then combined with the vibrating screen aiming at the fine crushing of waste and dividing them into different scales. Wind sorting machines are used to separate the light materials such as plastic and wood.
The materials in classified storage section are semifinished products which are divided into several classes (usually four: 0–5 mm, 5–15 mm, 15–22 mm, and 22–31.5 mm). The function of storage warehouse is to continuously feed for the combined grinding and load for sale of semifinished products.
The materials with a high quality have already been sorted and removed of mud, impurities, and iron. They are first transported into the roll press for tertiary crushing and grinded to particles. The ground materials are classified into several classes (usually three: 0–0.08 mm, 0.08–0.16 mm, and 0.16–2.36 mm) and are collected in the tanks respectively.
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