Waste minimising and recycle in construction
| ✅ Paper Type: Free Essay | ✅ Subject: Education |
| ✅ Wordcount: 4244 words | ✅ Published: 1st Jan 2015 |
INTRODUCTION:
The construction industry has a major impact on the environment, both in terms of the resources it consumes and the waste it produces. The construction industry is responsible for producing a whole variety of different wastes, the amount and type of which depends on factors such as the stage of construction, type of construction work and practices on site.
The construction industry generates a large amount of waste every year. As construction professionals we should follow a hierarchical approach to waste management by aiming primarily to reduce the amount of waste produced then aim to reuse and recycle any waste that is produced. Whilst the trend is to reject the traditional methods of waste disposal in favour of sustainable waste strategies, the majority of the construction industry has placed waste reduction at the bottom of research agendas because of complexities over reuse and recycling. Construction waste has a significant impact on the environment and more emphasis must be put on reducing waste production and increasing recycling and reuse.
WASTE
“Sustainable waste management means using material resources efficiently; to cut down on the amount of waste we produce, and where waste is produced, dealing with it in a way that actively contributes to the economic, social and environmental goals of sustainable development.”[1]
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SOURCES OF WASTE
CLIENT ROLE:
The client plays an important role in the reduction of waste. This is for a reason that when the client changes his requirements at a stage when construction has already began, the materials which are already being used would be wasted as they no longer will be used in the new design.
IMPORTANCE OF SKILLED LABOUR:
The use of skilled labours means that good techniques will be used and hopefully fewer mistakes will occur during the construction phase. A mistake could lead to the need for replacement of materials. Thereby increasing the amount of waste generated.
LOGISTICS OF MATERIALS:
The logistics of materials to the site can also play a part in reducing the waste; this is for a number of reasons. Packaging of material will create waste. Therefore, if a method is generated to reduce the amount of packaging then the waste will be reduced.
AFFECTS OF TRANSPORTATION OF MATERIALS:
Waste will also be generated due to the transportation of the product. While transporting, goods can be damaged due to the vehicular movements if proper care is not taken and hence get wasted. Delivering goods in large quantities could generate problems at the site as more storage may be required which may need temporary structures or heating to keep the products in the right conditions, this adding to the amount of waste generated.
MANUFACTURING DEFECTS:
During manufacturing, the manufacturer produces only a specific size, but the client may require a slightly different size, therefore the material is trimmed down on site. This creates a large amount of wastage. Also a poor manufacturer may produce a number of low quality products that can’t be used.
SITE MANAGEMENT:
Site management could also be a factor that courses waste. Time management and storage of material on site could course waste if the site management is not as good as it should be. If materials are not used within a limited time period or if when they are not stored properly, its properties might change and therefore may not be suitable for the project. An example of this is if concrete arrives on site and is forced to wait for the site to be ready, then the concrete might start to set and therefore can’t be used.
TYPES OF WASTE
There are two main types of waste in the construction industry, this include solid waste (which may be recycled or taken to landfill) or gasses waste which may be a pollutant.
Gaseous waste will be generated from a number of different sources. In the construction process a large amount of plant and heavy machinery will be used. Most of this machinery will be driven by diesel engines which will generate exhaust gases, these gases will be a waste product generated in the contraction process. Waste gasses can also indirectly be generated due to the construction industry, gasses may be produced in the fabrication and manufacturing of different products that are used.
Solid waste can also be split into sections, waste that can be recycled or re-used and waste which will be put into landfill. There are a large number of different waste products that could be generated from the construction industries such as, timber, metals, concrete and more serious waste, which may be harder to recycle and reuse. These wastes include plastics, plaster boards and asbestos.
How much Waste does the Construction Industry Produce?
Construction and demolition (C&D) waste includes brick, concrete, hardcore, subsoil and topsoil, but it can also contain quantities of timber, metal, plastics and occasionally special (hazardous) waste materials. Wastes occur from the construction, repair, maintenance and demolition of buildings and structures.
The Construction Industry Research and Information Association (CIRIA) have reported that an estimated 72.5 million tonnes of construction and demolition waste are produced annually. This is around 17.5 % of the total waste produced in the U.K. Furthermore, 13 million tonnes of construction materials are delivered to sites in the U.K. and thrown away unused every year. This is not sustainable.[3]
EFFECTS OF CONSTRUCTION WASTE ON THE ENVIRONMENT
The two main types of waste generated by the construction industry are solid wastes and gaseous wastes. Liquid wastes may also be generated during construction processes, such as cleaning, but the effect of such wastes is minimal and generally local to a particular site. Gaseous waste is a sub-product from the use of machinery in the construction process, transportation of materials and from the production of construction materials. This type of waste is emitted to the air and has inherent effects on air quality. Solid waste can be generated from demolition and excavation or may be unused material from the construction process. Some solid waste may be recycled or reused however the majority is put into landfill sites, because of this the overarching target of the UK government’s strategy for sustainable construction is to reduce the amount of construction waste to landfill by 50% by 20121. Solid waste therefore adopts the associated effects on the environment that landfill has.
Of the solid waste that is put into landfill the majority comes from the demolition of existing structures and the excavation of material to allow construction, however a relatively small proportion consists of unused materials generated from amongst others, design change, lack of skilled workforce, site untidiness, poor quality materials and manufacture and lack of product information and knowledge. Unused materials will not only contribute to the environmental effects of landfill but will have indirect environmental effects due to transportation, production and packaging. The main environmental effects of waste due to demolition and excavation are emissions from transportation and primarily issues with landfill.
Landfills are widely considered to have adverse effects on the surrounding environment and public health. The main types of environmental impacts caused by landfill sites are alteration to surrounding landscape, visual intrusion, degradation of air quality, pollution of ground water and degradation of soil quality. The construction industry makes a considerable contribution as it makes up a large proportion of the total waste assigned to landfill in the UK.
Landfill sites generally occupy a large area required for waste disposal itself as well as associated facilities and enough area to minimise the effects on surrounding groundwater and soil quality. Additionally in some cases excavation and movement of material is required to create an area which is suitable for the disposal of waste. Thus, the surrounding landscape is adversely affected. The location of a landfill site is often sensibly chosen so to minimise the effects it has on the surrounding environment, however it may be impossible to locate it so that it is entirely invisible to the public and the negative visual impact a landfill site will have on a community cannot be avoided. Gaseous emissions from a landfill site come from the transportation of waste, use of machinery and more importantly the anaerobic digestion of organic matter producing methane. Generation of gas in a landfill site is one of the largest sources of methane emissions to the atmosphere; methane having a much greater global warming effect than carbon dioxide as well as being harmful to humans. Landfill sites therefore have a negative effect on air quality and public health. The precipitation that falls on a landfill coupled with the disposal of liquid wastes results in the extraction of water soluble compounds and particulate material, such as cement, dust and asbestos. Although nowadays measures are generally taken to water-proof a landfill site resulting solutions and mixtures will almost certainly end up in surrounding groundwater and soil. Thus, a degradation of groundwater and soil quality occurs.
Gaseous wastes are a by-product of any development but have increased severity in large scale developments which require a large amount of material and associated transportation, use of a greater amount and varying machinery and occur over a longer timescale. Transportation of materials will usually be by road, rail or occasionally by sea. In any case the method of transportation will produce gaseous emissions that will have an overall global warming effect and reduce the air quality locally and regionally. An increased local reduction in air quality occurs in areas around large developments with longer construction times due to the prolonged constant use of machinery in the same area. The production of construction materials also has a significant effect on air quality due to emissions of particularly damaging waste products from industrial plants.
WASTE MINIMISATION:
Definition of waste minimisation:
“The reduction of waste at source, by understanding and changing processes to reduce and prevent waste. This is also known as process or resource efficiency. Waste minimisation includes the substitution of less environmentally harmful materials in the production process.”[4]
Designing out waste at the initial stages of the construction process provides the greatest opportunities for waste minimisation. The best way to manage waste, particularly hazardous waste, is to manage the process so that there is no waste to manage. This is definitely not easy, but the whole aim is that when a similar thought occurs, waste can be minimised if not eliminated.
Benefits of Waste Minimisation:
* Increase resource efficiency
* Reduce costs
* Improve environmental performance
* Demonstrate best practice
* Ensure compliance with legal obligations
* Reduce disposal to landfill
* economic incentives
* social advantages
* internal business benefits
* external business benefits
Waste minimisation contributes to the increase efficiency in the utilisation of resources.
It also helps in reduction of cost of overall project, when the expenditure over the waste is reduced; thereby the cost of project also reduces.
Waste Minimisation understandsenvironmental improvementssuch as ameliorated pollution control, development of environmentally friendly products
Waste Minimisation ensureslegal compliancewith European Directives, UK Legislation and Regulations.
Waste minimisation will considerably reduce the disposal to landfill, thereby reducing the landfill tax.
Waste Minimisation haseconomic incentivessuch as diluted trade waste costs and better efficiency. It is important that any industry regards in implementing the waste minimisation initiatives because the introduction of the landfill tax means that waste disposal costs are set to increase in the future.
Waste Minimisation hassocial benefitsas the recycling and reuse methods allow employment and economic opportunities for local charities, voluntary groups, the community sector and businesses that can reuse or recycle materials.
Waste Minimisation hasinternal business benefitsby promoting a cultural change within any industry by nurturing environmental awareness. It also provides an opportunity for staff training and qualifications as well as improved employee motivation.
Waste Minimisation hasexternal business benefitsby managing a variety of your businesses stakeholder relationships. Industry’s investors, customers, the general public, the regulator, companies within your supply chain and contractors may require evidence of good environmental performance or look for a ‘green’ image. [5]
How to achieve the benefits:
Waste minimisation demands action on three fronts:
1. People:
Many reductions in waste can be accomplished through improved housekeeping. It is crucial that employees are aware of the issues related to waste and are motivated and trained to prevent it.
2. Methodology:
A systematic approach to measurement and control foregrounds deficiencies and problems, alters targets to be set and maintains levels of efficiency.
3. Technology:
Capital investment in new technology can enhance productivity and decrease waste generation, giving very short paybacks.
METHODS OF WASTE MINIMISATION
The process of waste minimisation through ‘Designing out Waste’ is still at the early stage of development. Many barriers and opportunities exist in developing waste minimisation strategies in design. If this process is considered in the early stages of construction activities, there are opportunities for it to exist.
The waste hierarchy (see figure 1) establishes waste reduction as one of the highest priorities for addressing the increasing volumes of waste. The target for any waste reduction strategy must be to focus on opportunities from the outset, at the earliest stages of design. Many barriers and opportunities exist in developing a strategy of waste reduction in design.
Opportunities for waste minimisation exist in four construction areas:
1. Project Planning
2. Pre-Construction
3. Off-Site Activities
4. On-Site Activities
PROJECT PLANNING:
During project planning phase, it is essential that waste management strategy is made for better profit margins. Focus on elimination of waste is the prime factor. Communicating strategies with client, developer, designer, builder, project manager, contractors and suppliers is very important. Analysis on waste reduction plan should be done.
PRE CONSTRUCTION:
This stage involves three areas where waste reduction is possible.
* Designing: proper and accurate dimensions, proposing standard material sizes, building for deconstruction (can be easily reused if future modifications occur with ease and minimum wastage) and operational waste reduction.
* Estimating: over estimation of required materials leads to wastage.
* Purchasing: Buying environmental friendly items, using procurement policy as specifying manufacturers and suppliers your exact requirements reduces the amount of waste.
OFF-SITE ACTIVITIES:
· Prefabrication: By prefabricating frames and trusses, timber waste can be decreased to an extent.
ON-SITE ACTIVITIES:
* Delivery and storage of materials.
* Packaging
* Separation of materials.
* Safe disposal of unavoidable waste.
WASTE MINIMISATION STRATEGIES
Managing and monitoring the different waste streams on a construction site requires a detailed waste minimisation strategy. This needs careful planning throughout the design, build and occupancy phases, to ensure its success, effectiveness and compliance with building regulations.
There are three basic strategies for dealing with waste: reduce, reuse and recycle. Waste prevention is the ideal, and this can be addressed first by identifying possible waste streams early on in the build process, and then designing for their minimisation. Using standard sizes for building components (windows, doors etc.) can prevent future waste, as can design for deconstruction, using recyclable components. It has been estimated that over ordering accounts for 13 million tonnes of new building materials being thrown out every year. Better communication between building professionals to ensure exact calculations of required materials are made can mean that this waste is prevented. Just-in-time delivery strategies can further reduce waste created by improper storage and weather damage.
Once waste has been produced, the best method of managing it is through reuse either on the existing site, or a nearby site. Many materials can be usefully reclaimed, and even sold to offset the costs of a building project. Recycling materials is the final option for managing waste. Materials that can be reused or recycled need to be identified early on the build process, and segregated for easy storage, collection and transfer. For the strategy to be effective, links also need to be established with local recycling and reuse facilities and contractors. [6]
OCCUPANCY WASTE
Sustainable building practice goes one step further than conventional practice, by designing for waste minimisation in the operation of the building, through grey water recycling, composting toilets, on site food composting and off-site recycling facilities, thus helping to reduce residential waste. [7]
LEGISLATIVE ASPECTS OF WASTE MANAGEMENT:
LANDFILL TAX
The landfill tax aims to encourage waste producers to produce less waste, recover more value from waste, through recycling or composting, and to use more environmentally friendly methods of waste disposal. The tax applies to active and inert waste, disposed of at a licensed landfill site.
The aims of the landfill tax are:
* To promote the ‘polluter pays’ principle, by increasing the price of landfill to better reflect its environmental costs;
* To promote a more sustainable approach to waste management in which less waste is produced and more is recovered or recycled.
There are two rates of tax. Inactive waste is subject to the lower rate at £2 per tonne. Active waste is subject to £15 per tonne, rising at £3 per tonne per year from 2005/06 towards a long-term rate of £35 per tonne.
Her Majesty’s Customs and Excise has updated its General Note on the Landfill Tax. The guidance replaces the previous version (February 2000) to include the changes to the tax liability of materials re-used on landfill sites; permits issued under regulations under section 2 of the Pollution Prevention and Control Act (1999) that authorise deposits or disposals in, or on the land; the changes to the liability to pay landfill tax and changes to the Landfill Tax Credit Scheme.
The Landfill Tax Regulations have been clarified following a legal challenge brought by a waste management company last year. [8]
SITE WASTE MANAGEMENT PLANS (SWMPS)
Site Waste Management Plans (SWMPs) are an important tool for construction companies and their clients, of all sizes, to improve their environmental performance, meet regulatory controls and reduce rising costs of disposing of waste. This document sets out the basic structure of SWMPs and how companies can best use them to improve and manage their operations at all stages of site activity. It includes useful checklists and other guidance to help ensure the Plan is a practical tool.
Note that it is not essential for there to be a separate SWMP document for your site – the guidance given here can equally well be included in a Waste Management Section of an overall Site Environmental Management Plan.[9]
THE PURPOSE OF SWMPS:
SWMPs aim to address two key issues:
1. Improving materials resource efficiency, by promoting the economic use of construction materials and methods so that waste is minimised and any waste that is produced can be re-used, recycled or recovered in other ways before disposal options are explored; and
2. Reducing fly-tipping, by restricting the opportunities available for the illegal disposal of waste by ensuring compliance with existing legal controls and providing a full audit trail of any waste that is removed from the construction site. Although it is a legal requirement to write and implement a SWMP, the greatest cost savings are likely to be achieved as a result of the consideration of materials resource efficiency which will be a necessary part of the preparation, before the SWMP is drafted. [10]
WASTE AS A VALUABLE RESOURCE
Effective waste management can reduce building and operating costs, enhance the reputation of the building industry, and also generate new revenue streams through developing recycling and reclaiming markets. Reducing construction waste also saves landfill space, conserves valuable natural resources, saves energy and creates less pollution by reducing transportation and manufacturing processes, with a mitigating effect on climate change.
CONCLUSION:
According to the ODPM waste survey (2001), the C&D industry in Wales produces around 5.02 million tonnes of waste per year; this is around 30% of all controlled waste arising in Wales. Given the scale of the construction industry in Wales and the quantity of waste produced, it has great potential to lead the way in waste minimisation, re-use and recycling.[11]
Waste minimisation is now an instituted business practice for many organisations and a number of industries have enforced waste reduction programmes. Reducing waste is a key to a cleaner world and more competitive industry.
It would not be fair to conclude that building services should undergo revolutionary redesign or standardisation just to reduce wastes in construction. However, the reduction of waste, in terms of materials or time is beneficial to all because a reduction in cost will result in better systems within the same budget.
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