Building materials

Ecological characteristics of the used

Recently, to characterize the construction process, the term “life cycle of a construction object” (LCSO) is increasingly used, which is understood as a chronologically expressed sequence of stages (stages) of its creation and disposal.

The allocation of the sequence of stages of the ZhTsSO is due to the fact that the international ISO standards, which are beginning to be introduced in our country, provide for the creation of mandatory operational control over the promotion of construction products throughout the life cycle of a construction object - from design to disposal (ISO 14040 standard). Assessment of environmental conditions upon exposure life cycle object on environment set out in ISO 14042.

The expediency of identifying individual stages of the LCSO can be illustrated by the example of one of the components of this cycle - the production of building materials. According to foreign experts, the assessment of the life cycle of building materials should include an environmental impact assessment on the environment of the very process of extracting natural raw materials used for the production of building material, an assessment of the environmental safety of its production, an assessment of the composition and properties of the building material, as well as the possibility of its processing and reuse. use in the disposal of the object.

Environmental support of the life cycle of building materials at individual stages allows us to assess not only the intensity of their negative impact on the environment natural environment(pollution, waste generation, consumption of natural resources, etc.), but also to more accurately establish energy costs at each stage.

The impact of the construction production of the reinforced concrete plant on the atmospheric air. The construction of a reinforced concrete plant has a significant negative impact on the air basin in the form of pollution with harmful gas and dust emissions and various aerodynamic disturbances.

The production of building materials and building structures makes the most significant contribution to air pollution. Suffice it to say that the global cement industry annually emits more than a million tons of nitrogen oxide emissions and a huge amount of CO 2 , significantly worsening the state of natural ecosystems.

A significant emission of dust in industrial premises is observed in the manufacture of building materials such as cement, concrete, silicate products, as well as reinforced concrete, wood and metal building structures. Ancillary industries actively emit dust, for example, warehouses with finished cement products. Polydisperse dust containing up to 20% SiO 2 is released both during loading and unloading operations and during transportation of finished products.

The dust content of the air in the premises during the production of the most important binder material - cement reaches 100120 mg/m 3 (with the dust content of the surrounding technosphere -1.7-1.9 mg/m 3). Active sources of dust and gases in cement plants are handling devices, drying drums, ball mills and especially clinker rotary kilns.

In addition to dust, emissions of toxic gases, heavy metals, radionuclides and other harmful substances lead to a significant deterioration of the sanitary and environmental situation near existing construction industry enterprises.

No less dangerous is the ecological situation that develops in the workshops of the reinforced concrete plant during the production of non-standard metal structures (dust of metals and their scales, welding aerosols, carbon dioxide, manganese and other harmful substances).

During the production of cement, the air is polluted within a radius of up to 3 km or more. The surroundings of cement plants often turn into lifeless yellowish-gray spaces. In the area of ​​action of the largest cement production in Europe - JSC "Maltsevsky Portlandcement" with an annual emission of pollution up to 90 thousand tons, extensive areas of damage and drying out of the most valuable pine plantations were noted.

The development of deposits of non-metallic building materials is accompanied by air pollution with gas and dust emissions from the operation of quarry equipment and machines (bulldozers, conveyors, excavators, dump trucks, etc.).

Particularly large emissions of organic and inorganic dust occur during open-pit mining and explosive extraction of minerals. A cloud of dust can extend for many kilometers; settling on the soil, dust pollutes it and reduces fertility.

No less pollution of the atmosphere is created during the transportation of mined bulk mineral raw materials transported in open wagons and in car bodies. In these cases, tens of thousands of tons of natural building materials are blown out.

Dust in the atmosphere can play not only a negative, but also a positive role. Without dust particles, there would be no clouds or fogs. However, a large amount of dust reduces the total radiation, which leads to a decrease in the amount solar energy, and this adversely affects biotic communities. And, of course, one should not forget about the toxicity of many types of dust, their ability to be carriers of pathogenic bacteria, etc.

However, the most radical measure to protect the air basin from pollution should be considered the greening of technological processes and, first of all, the creation of closed technological cycles, low-waste and waste-free technologies that exclude harmful pollutants from entering the atmosphere.

Unfortunately, the current level of development of the greening of technological processes, the introduction of closed technological cycles, etc. insufficient to completely prevent emissions of toxic substances into the atmosphere. Therefore, at the enterprises of the construction industry, various methods of cleaning exhaust gases are widely used, however, from the point of view of the future, dust and gas cleaning devices have no prospects.

The task of architectural and planning solutions also includes the environmentally appropriate mutual placement of emission sources and populated areas, taking into account the direction of the winds.

The impact of the construction production of the precast concrete plant on water resources. Modern construction has a multifaceted negative impact on both the underground and, in particular, the surface hydrosphere.

The water shell of the Earth's surface is a necessary and extremely sensitive component of the natural environment to pollution and other types of anthropogenic impact. Like other types of ecosystems, water ecological system has corresponding limits of anthropogenic impact, the excess of which can cause disruption of relationships within ecosystems and irreversible phenomena in the biosphere.

There are the following main types of construction impact on aquatic ecosystems:

1) intensive water consumption, up to the depletion of water resources;

2) pollution and clogging of surface water bodies sewage and construction waste

H) changes in the water regime of rivers (silting, etc.) during the construction of various facilities.

Construction is a major consumer of utility and drinking water, and mainly technical water. Huge amounts of water are used for the preparation of concrete and cement mortars, for cooling engines, aggregates and other technological installations, for washing construction machines and mechanisms, for heat supply, for hydraulic testing of structures, for the domestic needs of the builders themselves, etc.

One of the most water-intensive industries in the industry includes factories for reinforced concrete products and structures, cement plants, enterprises producing gypsum and ceramic products, wet cement, etc. For example, steaming reinforced concrete and concrete structures consumes 500-800 kg of steam per 1 m 3 products.

A significant amount of water is consumed by operating ready-mixed concrete plants. In European countries, water is used not only for mixing concrete, but also in large volumes for washing drums of concrete mixers, mixing equipment, wheels of concrete trucks, not only at the end of the shift, but also during the day.

It follows from the above data that huge volumes of construction production (for example, in Europe alone there are currently more than 10 thousand ready-mixed concrete plants) also require a significant amount of water.

The environmentally dangerous depletion of water resources under conditions of their unreasonable exploitation can lead to the depletion of water reserves. Water depletion is understood as an unacceptable reduction in their reserves within a certain territory or a decrease in the minimum allowable surface runoff. Both lead to unfavorable environmental consequences, violate the established ecological ties in the human-biosphere system.

Construction can be a serious factor in the pollution of the surface hydrosphere. First of all, this occurs when wastewater from construction industry enterprises is discharged into water bodies in an untreated (or insufficiently purified) form.

At the plant for the production of racks of contact networks, water is used as a solvent, absorber, coolant, coolant, etc. The volume of wastewater is determined by such factors as the capacity of the enterprise, the features of the production technology, the type of product and material, etc.

The composition of wastewater from construction industry enterprises is quite complex - it is a heterogeneous mixture of various impurities of mineral and organic origin, including hydroxides of a number of metals, various toxic compounds, hydrocarbons (oils, fuel oil, etc.), etc.

Surface water bodies and rivers are complex ecosystems that are very sensitive to anthropogenic impacts. When untreated wastewater is discharged, it changes chemical composition, mineralization increases, the active reaction of the environment changes, new toxic substances appear, etc. Physical properties (color, smell, taste, etc.) deteriorate sharply. Reservoirs pass into the category of polluted and bring a significant dissonance and functioning of the natural system.

The ecological state of the surface hydrosphere is also disturbed by changes in the hydrological regime of rivers caused by the construction of underwater and other hydraulic structures, the development of coastal quarries of building materials, which is manifested in the reshaping of banks, deepening of the channel, etc.

The construction production of the precast concrete plant can have a negative impact on the underground hydrosphere in various ways. Firstly, it often significantly pollutes groundwater with its waste, secondly, it depletes their water resources, and, thirdly, it creates conditions for the development of unfavorable geological processes (flooding, karst, etc.).

The main sources of groundwater pollution associated with construction are sewage from construction industry enterprises, polluted runoff from construction sites and temporary storage of building materials, as well as leachate from construction and household waste dumps. Pollutants infiltrate through the soil aeration zone and enter underground aquifers.

Ground and surface waters are protected from the negative impact of construction through a set of measures aimed at preventing (preventive measures), limiting and eliminating the consequences of their pollution, clogging and depletion.

To protect the hydrosphere from pollution, the following protective measures are envisaged:

· reducing the volume of wastewater discharged by construction industry enterprises through the development of low-waste and waste-free technologies, the introduction of closed-loop water supply systems;

· forced treatment of industrial waste water. According to the Water Code of the Republic of Belarus during the construction and operation of any facilities, including construction facilities and construction industry enterprises, the discharge of wastewater into water bodies without treatment is prohibited;

· Allocation on any water body (river, pools, lake, etc.) of a water protection zone with a width of 0.1 to 1.5 km or more. Within the water protection zones, any construction, plowing of land, dumping of garbage and production waste, etc. is prohibited. The water protection zone is marked with a special sign.

The impact of the construction production of the precast concrete plant on the soil. The lithosphere, more precisely, its upper part, is exposed to the greatest negative impact during construction work in comparison with other natural spheres.

The construction of the concrete goods plant activates in the near-surface zone earth's crust the most dangerous geological processes - landslides, flooding, karst, subsidence, etc.; pollutes, litters and litters the soil cover and soil massifs; alienates huge areas of the most valuable lands, while sharply reducing the area of ​​natural ecosystems.

Soil is an invaluable, practically non-renewable natural resource, the most important biological adsorbent and pollution neutralizer. At the same time, the soil is subjected to a very strong anthropogenic impact, since it is the first lithospheric layer from the earth's surface. It manifests itself in pollution and littering, "sealing", the development of erosion processes, alienation (withdrawal), etc.

In the process of construction activities, soils are easily polluted with garbage, cement, sewage, oil products, and toxic substances. The main sources of pollution: construction waste landfills, gas and smoke emissions, building materials at the time of their transportation and storage, without complying with technical requirements, flushing of polluted water from the construction site, etc.

Near construction industry enterprises (cement, asphalt concrete plants, etc.), soils can be intensively polluted from above as a result of gas and dust emissions. Toxicants accumulating in the soil will pose a danger to populations of any organisms, including humans, for a long time.

The soil cover of agroecosystems is irreversibly disturbed during the alienation of land for the construction of industrial facilities, cities, towns, for laying roads, pipelines, communication lines, during the open mining of deposits of natural building materials, etc. The greatest environmental damage during construction is caused to the environment precisely by the fact that for the construction of facilities, access roads, significant land areas are allocated for permanent and temporary use. According to the UN, more than 300,000 hectares of arable land are irretrievably lost every year during the construction of cities and roads in the world. Of course, these losses are inevitable, but they must be reduced to a minimum.

The soil, like all land in general, is protected by law. Builders are obliged to efficiently and rationally use the soil cover, to prevent its unauthorized removal, damage, pollution, clogging and depletion.

test

Impact of the construction industry on the environment

The construction industry is a complex multifaceted complex that has a powerful impact on the natural environment, dramatically changing natural biogeocenoses, creating a specific habitat for humans.

The construction industry is a whole system of production activities and includes the following components.

1. Extraction of building materials and raw materials for their production.

This component of the construction industry leads to the destruction of natural biogeocenoses, radically changes natural landscapes, changes water regime natural reservoirs (rivers, lakes, etc.), pollutes the atmosphere, hydrosphere and lithosphere of the regions where mining operations are carried out, large areas are alienated from natural areas of nature, quarries, dumps, and overburden wastes appear.

2. Processing of primary raw materials, obtaining building materials and their components (cement, concrete, brick, ceramics, various building structures). This part of the construction industry leads to pollution of the air basin with dust, gases, hydrosphere and lithosphere with liquid and solid waste.

3. The production of the construction work itself, in which industrial and civil buildings are erected. In this case, alienation of new territories occurs, a strong change in the old territories of settlements, pollution of the lithosphere with construction waste, solid and liquid waste. Due to the operation of various construction machines, the environment is polluted with hazardous gaseous and liquid wastes typical for vehicles.

4. A component of the construction industry associated with the technical operation of industrial and civil buildings. In these buildings, industrial and domestic activities of people are carried out, which determines the specifics of the impact of this component on the natural environment. During the operation of buildings, repair construction work is carried out, the impact of which on the environment is similar to that during capital construction, excluding some stages (zero cycle, construction of auxiliary communications, etc.).

It should be noted that for the degree of impact of works carried out in the construction industry, the design stage is important, because environmentally competent design allows you to reduce the load on the natural environment.

Anthropogenic human impacts on the environment

The need for energy is one of the basic human needs. Energy is needed both for the normal activity of modern human society, and for the simple physical existence of each person ...

Impact of subsoil use on the environment

In the process of developing oil and gas fields, the soil is polluted with oil, oil products, high-mineral sewage ...

The impact of sectors of the national economy on the environment

Energy is one of the sources of adverse effects on the environment and humans. It affects the atmosphere (oxygen consumption, emissions of gases, moisture and particulate matter), the hydrosphere (water consumption...

The impact of productive forces on the environment

After analyzing the main aspects and indicators economic development, we can proceed to consider the content of the concept of "environment". In the most general sense, the environment is a collection of physical, chemical ...

Circulation of matter and energy in nature

The agricultural industry is the basis of the life of human society, as it gives a person something without which life is impossible - food and clothing (or rather, raw materials for the production of clothing) ...

Measures to reduce the toxicity of automobile engines

Oil as a source of environmental pollution

Application of pesticides

Pesticides are the only pollutant that is deliberately introduced into the environment by man. The use of pesticides allows you to get stable crops and limit the spread of infections ...

Problems of noise pollution in the urban ecosystem

In addition to the fact that noise pollution negatively affects humans, it also negatively affects the environment. Noise pollution is the sonic scourge of our time, apparently...

Calculation and forecasting of the state of the environment

As the pace of technological progress accelerates, the impact of human economic activity on nature becomes more and more destructive. At present, it is already commensurate with the action of natural factors ...

Reducing the environmental impact of a plastics recycling facility

In the production of polyvinyl chloride, its processing into products, the operation of products and the incineration of waste, toxic compounds are released that are dangerous to human health. For the reason that...

State and problems of the transport complex of the Republic of Kazakhstan

Motor transport leads to the formation of solid waste, air and soil pollution, littering of large areas, vibration, electromagnetic radiation...

Comparative analysis gas and aerosol emissions from nuclear power plants and VVER and RBMK

Influence of radionuclides on vegetation. Living organisms have different radioresistance, i.e. resistant to ionizing radiation...

Transport and environment

Environmental problems caused by road transport can be divided into three main groups: local, regional and global...

Transport and environment

The impacts that the transport industry has on the environment can be divided into three groups: traffic factors, highway factors and structural factors...

Introduction

Chapter I. Features of air pollution by construction industry enterprises

1.1 Impact of dust on human health

1.2 Impact of dust emissions on the environment

1.3. Regulation of the content of harmful substances in the air and in the air of industrial premises

1.4 The main directions and prospects for combating air pollution by enterprises page

the heating industry

Chapter 2. Classification of methods for determining the concentration of dust

Chapter 3

3.1 Dedusting workshops for the production of fibreboard (Fibreboard) and wood products

3.1.1 Production technology and sources of dust-steam-gas formation

3.1.2 Localization of harmful emissions in certain areas of fiberboard production

3.2 Dedusting and gas cleaning in roofing factories

3.2.1 Chemical gas purification methods used in roofing and thermal insulation factories

3.2.2 Characteristics of dust and gas emissions in the production of roofing and heat-insulating materials

3.2.3 Purification of gases from hydrocarbons, phenol and odorizing components

3.3 Dedusting of gases in the production of ceramic products

Chapter 4

4.1 Technological measures to reduce dust formation

4.1.1 Vibrational disintegration is a universal technology for material processing

4.2 Main types of modern dust collectors AAAAAAAAAAAAAAAAAAAAAAAAAAA

Conclusion

Literature

Introduction

The production of building materials are complex technological processes associated with the transformation of raw materials into different states and with different physical and mechanical properties, as well as using a variety of complexity of technological equipment and auxiliary mechanisms. In many cases, these processes are accompanied by the release large quantities polydisperse dust, harmful gases and other contaminants.

Increased dust emission is observed in the production of concrete mix: in the mixing section - up to five maximum allowable concentrations (MAC), in the over-bunker room 1.5-2, in the dosing section of the working mixture 3-4 MPC.

The production of cement, lime, dolomite, inert materials is accompanied in some areas by especially abundant dust emission, exceeding the MPC by 5-10. and in some cases up to several tens and even hundreds of times.

During the technological process of silicate brick production, increased dust emission is observed at workplaces in the mixture preparation rooms from 2 to 20, in the molding shop from 2 to 5 MPC.

In the production of ceramics and clay bricks, the highest dust emission exceeding the MPC in clay warehouses is 1.5-2.5, sand 5-7. in the mixture preparation shop 12-15, and in the chamotte grinding department, the dust content reaches 30-32 MPC. At the loading and unloading area, the dust content is 2-3 times higher than allowable concentrations. The main dust emission in the production of mineral wool boards at the preparation site of the nozzle in places exceeds sanitary standards by 40-70, at the furnace site - by 10-20, the formation of mineral wool - by 5-10 times. At the site of mechanical processing of fiberboards, the concentration of dust exceeds the MPC by 1.3-1.6 times.

When sawing, milling, sanding wood, the workplace air is polluted with polydisperse wood dust, the concentration of which exceeds sanitary standards by 1.5-3 times, sometimes up to 5-10 times.

Reinforcing shops for the production of non-standard metal structures are characterized by dust of metals and their scales, welding aerosols of carbon dioxide and manganese.

The enterprises of the industry annually emit more than 4 million tons of harmful substances into the atmospheric air, including about 2.4 million tons, or 58% of solid inorganic dust. Its excess emission is 1.41 million tons, and the excess of the standard for gaseous harmful substances is 722 thousand tons.

Dust and gas emissions from the production of building materials contain 85 harmful dust components, and many of them, having no smell and color, immediately manifest themselves. The dust of the industrial technosphere is the cause of various diseases of personnel, wear and tear of technological equipment and auxiliary mechanisms, a decrease in product quality and production profitability.

These dust emissions, which are very toxic in themselves, under the influence of sunlight and with the participation of ozone, can form new, even more toxic compounds. At the same time, atmospheric turbulence and wind do not have time to remove dust emissions from the air basin of enterprises, which are growing due to the intensification of production.

The problems of creating a waste-free technology and introducing the latest dust-collecting complexes at existing enterprises for the production of building materials have not yet been resolved. Traditionally operating wet dust collection systems are extremely energy intensive, require the organization of a sludge management, exclude the disposal of trapped dust and do not always provide maximum permissible emissions (MAE).

Therefore, the development and analysis of the scientific foundations of energy-saving dry dust collection are of particular importance.

ChapterI. Features of air pollution by construction industry enterprises (building material) and its impact on health

1.1 Impact of dust on human health

In scientific terminology, solid or liquid particles suspended in the air are called aerosols or aerodisperse systems. The precipitated solid phase of the aerosol is commonly referred to as the airgel. For simplicity of presentation, we will call both aerosols and aerogels dust, and, if necessary, clarify the use of terms. Industrial dust is the smallest solid particles released during crushing, grinding and mechanical processing. various materials, loading and unloading of bulk cargo, etc., as well as those formed during the condensation of certain vapors.

The dust generated at the enterprises of the construction industry is very diverse in terms of properties, chemical and disperse composition. dust particles various substances have different effects on the human body and are divided into two groups. The first group includes dusts of toxic (toxic) substances that are dangerous for the body as a whole, the second group includes dusts that are harmful to the respiratory system, i.e. predominantly fibrogenic. According to the degree of impact on the body, harmful substances are divided into four hazard classes: 1) extremely dangerous; 2) highly dangerous; 3) moderately hazardous; and 4) low-hazardous.

In connection with the development of chemistry and the use of chemicals in the production of building materials in last years increased the amount of harmful substances contained in the dust. For example, when processing wood, not only wood, but also toxic dust of substances with which the wood is impregnated is released. Sanding and polishing dust may contain particles of abrasive material and toxic substances - hardened polyester and nitrocellulose varnishes. Toxic chemicals, such as formaldehyde, also contain the dust generated during particle board processing. Continuous inhalation of formaldehyde can lead to chronic poisoning.

Generally construction production has a negative impact on natural complexes. In areas of construction, especially industrial, there is high level air, water, soil pollution. This happens at all stages of construction: during design and survey work, during the construction of roads and quarries, directly during work at the construction site.

The main sources of pollution during construction work are: drilling and blasting, construction of pits and trenches, the use of a hydraulic method of excavation, deforestation and shrubs, burning the soil with fires, quarrying, damage to the soil layer and washout of pollution from the construction site, the formation of construction waste dumps, emissions vehicles and other mechanisms operating in the construction zone.

Construction production in the regions wildlife, has a detrimental effect on animal world. The habitats of many species are being disturbed, which leads to a reduction in their numbers. Animals are forced to leave their habitual habitats, migrate to other areas, often less favorable for survival.

The impact of construction production on the environment can be direct and indirect. For example, directly in the course of construction work, the destruction of ecosystems on the territory of the construction site, pollution of soils, surface and groundwater with construction waste. Indirect pollution occurs, for example, through the choice of building materials and their use. Thus, negative impacts on the natural environment already occur during the extraction of raw materials for building materials, their production, transportation, etc.

AT tab. 3.2 an example of an environmental assessment of some types of construction work is presented and the main types of negative impacts and measures to minimize them are given.

The main preventive measures for negative effects are usually worked out in the sections of the project on labor protection and environmental protection. In Moscow, there is experience in the environmentally sound organization of a construction site in the historical part of the city. For example, as seen in the above photo (Fig. 3.1), a noise barrier was built over the entire height of the residential building for the period of construction.

Rice. 3.1. Example environmental solution for the protection of a residential building from noise loads during the construction of a new building

At the same time, the organization of disposal of construction waste is being worked out extremely poorly. Let us consider the experience accumulated on this problem abroad.

Table 3.2
Some negative impacts on the environment during various types of construction work and measures to minimize and prevent them

Types of jobs	Main types of impacts (environmental problems)	Preventive measures to reduce stress
Construction site organization	Formation of construction waste and departure of polluted vehicles; surface runoff pollution; soil erosion; landscape change, etc.	Equipping exits from the construction site with points for washing the wheels of vehicles; installation of storage bins or organization of a special site for collecting garbage, transportation of garbage using closed trays; removal of garbage and excess soil to the places specified by the Customer. Organization of industrial and domestic wastewater treatment; prevention of "outflow" of underground waters during drilling operations and their pollution during works on artificial fixation of weak soils. Protection against erosion during the release of water from the construction site; organization of cutting and storage of the soil layer; correct layout of temporary roads and access roads. Replanting and fencing of preserved trees; ensuring the exclusion of wildlife from the construction site, etc.
Transport, loading and unloading operations, operation of compressors, jackhammers and other construction equipment	Pollution of atmospheric air, soil, groundwater, noise pollution, etc.	Equipment for vehicles transporting bulk cargo with removable awnings. Providing places for loading and unloading of dust-like materials (cement, lime, gypsum) with dust-collecting devices. Provision of noise barriers for construction equipment locations (during construction near residential buildings, etc.)
Welding, insulation, roofing and finishing works	Emissions into the environment of harmful substances (gases, dust, etc.)	Organization of proper storage and transportation of flammable and hazardous materials (gas cylinders, bituminous materials, solvents, paints, varnishes, glass and slag wool), etc.
Stone and concrete work	Waste generation and the possibility of air pollution Vibration and noise loads	Processing of natural stones in specially designated places on the construction site; provision of work sites with dust-collecting devices. The use of vibration devices that meet standards, as well as vibration and noise protection devices, etc.

To prevent the formation of construction waste dumps, an ecological concept of waste disposal at construction sites in the city, based on the principles of "sustainable construction", has been proposed today. It provides a system of alternative options for processing construction waste. Sorting waste at the construction site promotes its reuse. Recycling saves materials and reduces total waste. In this case, preference is given to the option when the material is reused without significant processing. This option is especially relevant for the reconstruction, restoration and demolition of buildings. For new construction, this option is less preferable. The second option involves the processing of sorted waste, the so-called "recycling" (« recycling»). The main disadvantage of this option is the need for additional energy, transport costs, etc. In addition, the process of recycling waste into new materials can release harmful substances. The third option is the incineration of waste building materials, such as wood, synthetic materials, etc., which, after sorting, is more preferable than taking the waste to a landfill. When burned, heat energy is released that can be used. The “landfill” option, which has huge environmental burdens due to the above alternative options practically avoidable.

AT tab. 3.3 an example of an environmental assessment is given options use of the most common construction waste. An appropriate assessment of environmental loads in points for various processing options is given (the higher the score, the higher the load). Options with high scores must be avoided.

Table 3.3
Environmental assessment of options for the use of construction wastematerials