Management And Minimisation Of Materials Waste Construction Essay

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This study provides a summary of the techniques that can be currently be applied to improve the management of waste on construction sites. The study emphasises the need to prioritise waste management on construction sites. It also promotes waste avoidance before minimisation and treatment and disposal. This report consolidates learning from various initiatives that have been implemented around the world and presents it in an innovative yet practical manner for easy comprehension by construction people.

The report is intended to be an easy reference document for construction industry professionals including designers, contractors, representative organisations, statutory bodies, government departments and the waste management sector.

1 Introduction

Reducing construction site waste can reduce both the cost of raw material purchase and the cost of disposing of the waste created on site. It can also reduce wastage due to inefficiency on site e.g. source separation can reduce the amount of waste resulting from commingled disposal. It is estimated that around 80% of a homebuilder¿½s waste stream is recyclable. If planned, waste recovery for reuse and recycling can tremendously reduce the amount of waste that is destined for disposal by landfill. This can also open up secondary resource streams of building materials. Since building construction is a business, it will be to the advantage of the contractor to adopt waste management methods that reduce liability for jobsite waste.

2. Problem statement

Construction site waste contributes to the large quantities of construction wastes that are generated by the construction industry every year. It is estimated that on average construction waste constitutes 15-30% of the total amount of waste that ends up in landfill sites in many countries. At project level, the waste generated on site has been estimated to be about 10% of the materials originally purchased. Many contractors realise that many materials that are wasted on the jobsite result in two cost factors i.e. the material procurement cost and the waste disposal cost. Although the waste disposal costs of construction site waste form as little as 0.5% of the total budget of a typical home, builders realise that this cost can significantly affect their profit since builders generally operate within a tight 5% profit margin.

3. Definition

Construction site waste can be described as the non-hazardous by-product resulting from activities during new construction. It is generated during the construction process because of factors such as site preparation, material use, material damage, material non-use, excess procurement and human error. Examples include but are not limited to packaging materials, site clearance, excavation material, and building materials such as metals, gypsum, concrete, brick, insulation, wood, plastic, glass, asphalt, composites and site sweepings. Certain types of waste are not included in this definition because of their nature. These materials include hazardous substances such as asbestos and lead, liquid waste such as paint and kerosene, food waste, tyres and containers with residue.

4. Context

The construction industry contributes a significant amount to a country¿½s economy. For instance, the South African construction industry accounted for 9% of the GDP in 2009. The construction industry is however also one of the most inefficient and wasteful sectors.

Worldwide the construction and operation of the built environment has been estimated to account for:

¿½ 12-16% fresh water consumption;

¿½ 25% wood harvested;

¿½ 30-40% energy consumption;

¿½ 40% virgin materials extracted;

¿½ 20-30% greenhouse emissions;

¿½ 40% the total waste stream of countries, 15-30% of which ends up in landfill sites;

¿½ Up to 15% purchased materials at jobsite ending up as waste.

The South African construction industry has been under recession for more than two decades.

Construction related investment declined by about 50% since the late 1970. The main reason for this trend is said to be the shift from heavy infrastructure projects such as highways, dams, bridges and power stations. Other problems that were experienced during the downward trend of construction output included constraints in the capacity of materials, equipment and competence. Another issue of concern was around the performance of the construction industry i.e. output per unit input. The construction industry, throughout the world, has been found to be generally wasteful. The concept of waste in construction covers labour, materials and equipment aspects. Of particular interest to this document is the issue of material wastage. Material wastage has largely been found to be a result of avoidable practices on site.

The South African government, in partnership with the private sector and other stakeholders, has embarked on a reform process to regenerate the construction industry and improve its performance. The Construction Industry Development Board, a statutory body, was promulgated to be the driver of the national vision of construction industry development.

The Construction Industry Development Board will promote enhanced delivery performance to meet the needs of South Africans through best practice, enhance the role of industry in economic and social development through the development of standards, guidelines and regulatory instruments, and provide leadership and partnership with all stakeholders within the construction industry.

Construction site waste management and minimisation, as presented in this document, has a great opportunity to contribute to construction industry performance improvement as well as solve waste management problems caused by the construction sector. This can be achieved through:

¿½ Waste prevention during the design and procurement stages

¿½ Demand management during construction (waste handling)

¿½ Source control (reduction at the point of generation)

¿½ Waste planning (prioritising waste management on site) and

¿½ Using recycled content materials and products.

5. Trends in construction site waste management and minimisation

In recent years, the construction industry has realised not only the need to be environmentally responsible but also the benefits of green construction. There is an on-going campaign to encourage life cycle assessment and costing. There is also a drive to quantify the environmental costs of construction in order to internalise the externalities of construction related activities. Many countries have embarked on programs that promote efficiency in construction in terms of labour, equipment and material use. Much effort has been dedicated to developing strategies that focus on construction site waste prevention, reduction, reuse and recycling. In addition, governments have increasingly introduced legislative and incentive instruments that make it more difficult to continue with wasteful jobsite practices. Of particular importance is the documentation of best practices that demonstrate the economic advantage of alternative waste management options for construction sites.

It has been realised that the client is the main driver of waste prevention and green buildings. This is because firstly the client can specify what he/she is prepared to pay or not pay for. Secondly, since the client is likely to be the end user of the building upon completion, details of its performance will be key considerations to him/her. However, in some occasions the client is either unaware or unable to use this ability. This can be because the client does not have a high level of environmental awareness or the designer has no experience with green building to help the client make the correct decisions. Designers can play a significant role in green construction, particularly in waste management in this case by designing buildings for waste reduction through doing more with less and by designing buildings to allow for building, component and material reuse and recycling at the building¿½s end of life. However, this can only work if the contractor and his crew firstly understand the designs and secondly have the necessary training and commitment to ensure success. Many developed countries have realised the need to modify tendering, contracting and construction site processes in order to ensure that waste prevention and management are prioritised on site.

6. Waste specifications for construction sites

Designers are beginning to experience increasing demand from the client for measures to reduce wastage on the jobsite and ensure environmental buildings. This demand is a result of three factors viz. a need to cut down on jobsite costs, a need for environmental responsibility and a need to comply with local waste reduction goals. One way to ensure that waste management is given priority on construction sites is through the introduction of waste specifications. Waste specifications can be prepared by designers for inclusion in tender documents. These specifications can be written in model specification language to address waste avoidance and minimisation on construction sites. The specifications need to emphasise that the project is looking for alternative waste management techniques to conventional collection and disposal by landfill. The specifications also need to address the following areas:

¿½ Waste reduction techniques in construction;

¿½ Reuse of construction waste material on site;

¿½ Recovery of construction waste material from site for resale and use elsewhere;

¿½ Return of unused construction material to vendors for credit; and

¿½ Recycling of construction waste.

Specifications for waste management can also be incorporated into broader specifications for green construction. Such an approach can ensure that the construction process addresses the question of sustainability not only in terms of waste management but also in terms of issues such as the energy performance of the building, indoor air quality and the use of green materials.

In terms of waste management, specifications can be written to address waste avoidance and waste minimisation. Waste avoidance concentrates on the activities that determine whether waste will be created in the first place while waste minimisation concentrates on those activities that determine how much of waste that will go to landfill sites.

Typical actions that can be incorporated into specifications include:

¿½ Compliance with innovative designs;

¿½ Reduced packaging requirements;

¿½ Material return arrangements;

¿½ Waste management plans;

¿½ On site reuse; and

¿½ Use of local recyclers.

Waste specifications are not designed just to make the lives of contractors difficult. On the contrary, they can present an opportunity for contractors to benefit from secondary markets.

7. Contract language for construction site waste

Designers can go a step further and use the power of a contract document to make sure that waste management gets priority on site. Being a legal and binding document, a contract stipulates required actions and also outlines possible punitive measures in the event of breach of contract. The project contract can be used to:

¿½ Ensure compliance with project plans and goals;

¿½ Ensure participation of the whole project team;

¿½ Delegate responsibility; and

¿½ Distribute liability between the general contractor and his sub-contractors.

Various actions can be implemented on site to ensure that the issues highlighted above are achieved. Compliance with project goals and participation can for instance be achieved by giving clear instructions to all team members on what is expected of them, inserting penalty clauses for non-compliance and by offering incentives for achieving targets. Site waste management is generally effective if there is an individual with overall responsibility. A general contractor or waste management specialist can be appointed to manage the waste management portfolio, delegate responsibility to relevant people and ensure commitment and accountability. Finally, it may be beneficial to distribute liability among sub-contractors for their specific wastes rather than have the general contractor being responsible. Such an approach will encourage sub-contractors to be responsible and more efficient since they will have a stake in the resulting gains or losses due to their waste practice.

8. Waste Avoidance

8.1 Definition

Waste avoidance refers to activities that focus on ensuring that waste is not created to begin with. It is by far the most economical approach to dealing with waste compared to minimisation and disposal. Increasingly, international debate is beginning to question the whole notion of waste. One such debate is the perception that waste is a man-made creation that does not have to exist. It is a creation that has for long been accepted to be a cost of development. Research by resource efficiency protagonists such as Young reveals that consumption and production have over the years, resulted in increased quantities of generated waste. It then follows that human action has the ability to eliminate waste and transcend to waste avoidance if there is awareness, commitment, accountability and liability.

8.2 Waste prevention

Waste prevention looks at the site practice that can determine whether or not waste will be created prior to or during construction site activity. As the saying goes, the best way to manage waste is not to create it at all. The biggest opportunity to impact on waste generation through prevention principles is at: Design through design for waste reduction i.e. doing more with less, and design with consideration for reuse and recycling at the end of life of a structure. Operations through clear communication of designs to the project team to avoid unnecessary waste through errorS. Procurement through the engagement of suppliers to encourage a reduction in packaging waste, the use of reusable containers and through take backs.

8.3 Demand management

Waste demand management concentrates on site practices that rely on the human element.

Many jobsite waste problems are a result of avoidable practices. Some of the key human interfaces that can avoid waste generation include: Material delivery care when loading, transporting and offloading materials. Material storage safe storage, covered storage where necessary and storage away from jobsite activities. Material use doing more with less, material storage for reuse elsewhere. Project team communication, commitment from staff, training and reduced human error. Buying recycled reduced demand of virgin material production, redirection of waste to extended use applications.

8.4 Waste reduction

Waste reduction concentrates on site practices that determine the amount of generated waste that will ultimately be disposed by landfill. If some amount of waste is inevitably generated on site, the next opportunity is to reduce the amount of waste destined for landfill to an absolute minimum. This is best achieved through source control as the waste is being generated on site. This requires 100% contribution from the generators. Source control is achieved through: Separation at source selective and separate disposal of generated waste for reuse, recycling and garbage disposal. On-site reuse closure of materials flow loop internally on site instead of externally in the waste stream.

9. Waste management plan

9.1 Definition

A waste management plan is described as a construction project related plan that gives provisions for the prevention, separation, salvage, reuse, recycling and disposal of jobsite waste. The goal of a waste management plan is to cut down on the amount of jobsite waste destined for landfill to an absolute minimum. A waste management plan encourages resource efficiency and helps internalise the environmental externalities related to building construction. A waste management plan presents an opportunity for a building owner and his team to demonstrate responsibility toward the environment by using a green approach to construction. Furthermore, the plan helps the building contractor identify opportunities from waste rather than to have to deal with it as a daily problem on site. Most importantly, a waste management plan encourages the client team to demand, help develop and comply with waste reduction targets for the project and also serves as a guideline for the contractor¿½s waste management activities on site.

9.2 Elements of a waste management plan

Project planning is very important because it allows the opportunity to define a problem, assess possible solutions, proceed to implement the final option and make provision for evaluation at the end. It is unthinkable to commence a construction project without going through this process. For the same reason, waste management on construction sites should be planned before construction activities begin (in order to avoid dealing with waste as a problem). A waste management plan does not have to be complicated; in fact it need not even be a long document. It simply needs to be concise, comprehensive and practical for easy interpretation and implementation on site. A good waste management plan will contain the following components:

¿½ Goals;

¿½ Waste audit;

¿½ Waste disposal options;

¿½ Waste handling requirements;

¿½ Transportation requirements; and an

¿½ Economic assessment.

9.3 Setting goals

Before conducting any detailed planning for waste management on site, the client team should make a commitment to waste prevention and waste redirection from landfill to reuse and recycling applications. This should be followed by realistic quantitative targets for waste reduction4. Realistic targets can be based on previous projects of similar nature, targets set by environmental rating systems that reward waste reduction with credit points and financial considerations (advised by market conditions).

9.4 Waste Audit

For the contractor to be able to determine the best approach to deal with jobsite waste, he needs to collect information relating to the waste that will be generated on site. This information will be useful for waste planning. Such information is generally required before the waste is actually generated on site although on site waste audits can also be conducted to capture useful information for future projects and to update waste estimates for the current project.

A waste stream analysis will determine the types and quantities of waste that will be generated in the project. The analysis will also determine the stages of construction where specific wastes will be generated. There are two methods of conducting a waste stream analysis. The first involves collecting actual data from project sites to determine the types of materials being discarded. The second uses information from previous projects. Both methods characterise wastes that are generated on the jobsite, and can help identify suitable waste reduction options. Collecting data from the jobsite during construction can take several forms. Information can be extracted from purchase records, waste bin inspections and detailed waste analyses of selected sample waste bins. Secondary analysis from previous experience on the other hand includes extracting waste generation rates, using purchase records and using waste disposal records for similar projects. In cases where information is not readily available, other sources that can be used for quantity estimates include engineering estimates, and typical waste composition figures for construction sites.

A waste assessment will use the information collected in the waste analysis to determine the site-specific waste characteristics. The assessment will help characterise waste by type, amount, and method of generation and time of generation. It will also identify the construction activities that generate large quantities of waste. This information will inform the contractor on which waste reduction options he needs to focus his efforts. Waste analysis and assessment information can be captured in a simple spread sheet. It can be arranged in a manner that will easily show the types of envisaged waste materials, the expected quantities, recyclability, activity and time of generation, and a possible recycling option.

9.5 Waste disposal options

Having assessed all the waste that will be generated on site, it is now possible to explore the various end-scenarios. It is useful to have knowledge of the types of materials that are reusable and recyclable, the conditions of acceptance in the respective markets, secondary market conditions in your area and the location and types of waste disposal sites.

Reusable materials

- Some materials can be accepted for reuse applications if they satisfy certain criteria. e.g. Dimensions, level of contamination and quality.

- Typical places to approach with reusable materials include suppliers, secondary material outlets and renovators.

- If available, obtain a published list of locally accepted reusable materials.

- Reusable waste can be sold at a site sale or auction.

- Useful waste material can also be donated to charity organisation.

Recyclable materials

- Find a list of which materials are recycled in the locality of the project.

- Locate the companies that recycle these waste materials.

- Useful sources of such information include registers of recyclers, waste material exchanges and waste information systems that are either administered by government waste departments or by research institutions that specialise in waste management.

- Sometimes unconventional methods of searching for information may yield the best results, particularly for the not so popular recyclable materials such as insulation material and carpet padding.

- Establish market prices for specific waste materials.

Unwanted waste

- Accept that site activity will inevitably still generate a certain amount of unusable and unwanted waste that is good only for disposal by landfill.

- Find out what types of waste disposal sites are there, i.e. municipal waste sites, construction waste sites, garden and construction waste sites etc.

- Determine the requirements for acceptance e.g. commingled or clean separated waste.

- Determine the location and distance to these sites.

- Determine the tipping fees charged by each.

Hazardous waste

- Find out about all the relevant local regulations relating to the handling and disposal of hazardous waste.

- Find local hazardous waste removal contractors.

- Determine the location and distance to the designated hazardous waste disposal sites.

- Determine the tipping fees charged by each.

9.6 Waste handling requirements

In order to have efficient waste management on the jobsite, consideration should be given to how the waste will be handled to maximise recovery. Since the most effective waste reduction strategy is source control, 100% participation from the construction crew is important. Before the crew can participate, it is important that they are made aware of the waste plan, they need to be trained on waste handling methods and they need to be involved in the process. The project team needs to appoint an individual that will be responsible for the overall waste management activity. This can be the general contractor or a waste management specialist. This individual can appoint and train one or two waste management leaders that will be responsible for the day-to-day running of jobsite waste activities and feedback to the waste manager. Some of the actions the waste team will have to take include the following:

- Decide on whether to implement a time based. Waste recycling system at the job face or dedicate .a recycling centre on site.

- In case of the former, plan the system and determine container sizes, number and location and coordinate details of container collection.

- In case of the latter, design and layout the recycling centres on site.

- Determine security, staff and facility requirements for the recycling centre.

- Clearly mark all items in the recycling centre to avoid confusion, contamination and abuse.

- Plan for the collection of waste from the job face to the recycling centre.

- Ensure adequate and sufficient containers to allow for effective waste separation, storage, collection and transport to the recycling centre and to the final destination.

- Train the labour crew to distinguish between reusable and recyclable materials, how to avoid contamination and where to store reusable, recyclables and unwanted waste.

- Co-ordinate waste collection to avoid the collection of half-empty or overflowing containers.

9.7 Transportation requirements

Consider options available to collect and transport reusable, recyclable and unwanted waste away from the construction site. There are four basic methods that can be used , namely:

¿½ Commercial hauling - This method involves contracting with waste or recycling service providers to place collection containers on-site, collect and transport the full containers to waste or recycling facilities. This strategy works well on projects where large quantities of materials are generated, such as on demolition sites, big housing projects and on commercial projects. Some recyclers offer smaller waste containers or containers with several compartments for small-scale projects such as home improvements.

¿½ Self-hauling - This method is often preferred for residential construction and remodelling. Recyclable materials are collected on-site in piles or temporary containers and taken to recycling facilities using the contractor¿½s own vehicles. This method is effective for materials generated in small quantities.

Clean-up services - A construction clean-up service that offers waste removal and recycling services all in one. The clean-up crew comes on-site and picks up recyclables and garbage that are collected in piles or containers. The materials are then taken to the most appropriate recycling or disposal facility. Such services can offer job-site recycling consultations as well.

¿½ Commingled recycling. The last option in the order of preference, commingled recycling programs collect containers of mixed recyclables or mixed garbage and recyclables, and separates them at material recovery facilities. This option is convenient for cramped sites, but the cost saving is limited (high pre-recycling costs) and recycling rates may be lower than for other options.

When assessing the above options, contact the service providers in your area and request details on the sizes of their containers, and their rental and collection cost estimates.

10. Conclusion

There has been increasing pressure to come up with processes that reduce wastage on the jobsite and ensure the yield of environmental buildings. This demand is a result of factors such as a need to reduce the cost of construction, a need to demonstrate environmental responsibility and a need to comply with strict local waste legislation and goals. Governments and construction industries around the world have responded by introducing innovations such as:

¿½ Construction site waste specifications;

¿½ Model contract waste management language;

¿½ Construction site waste avoidance strategies;

¿½ Construction waste management plans; and

¿½ Buying and using recycled content materials and products.

Improving construction site waste management can contribute to the overall improvement of the performance of the construction industry. It will also bring us a step closer to achieving sustainability in construction. The benefits of construction site waste management include:

¿½ The reduction of the generation of avoidable waste on site.

¿½ Preventing site waste from entering the national waste stream and redirecting potential waste from landfills to reuse and recycling applications.

¿½ A reduction in construction waste transportation and disposal costs.

¿½ Reduced material procurement costs as a result of reduced site wastage and the use of on-site secondary materials.

¿½ Protection of the contractor¿½s (already narrow) profit margin.

¿½ Improvement of site efficiency and performance.