Construction waste management
Best practices for an environmentally optimized job site.
After completing this course, you will be able to:
- Describe waste recycling options as they pertain to construction waste management (CWM)
- Identify key elements of a CWM plan and how the CWM plan enhances the project's sustainability
- Explain the environmental benefits of contract language specific to a CWM plan
- Explain how to train and monitor the workforce for best practices in construction waste management
Construction debris accounts for more than one-fifth of the waste stream. Better construction waste management (CWM) practices can have triple-bottom-line benefits:
- Environmental: Less landfill space and less use of natural resources have a positive environmental impact.
- Financial: Less wasted material equals less wasted money.
- Social: The public appreciates efforts to reduce negative impacts on the environment.
To achieve these goals, however, all members of the Building Team must be on board with the CWM program. Achieving CWM goals requires three important actions: reduce, divert, recycle.
REDUCE According to the California 2004 Statewide Waste Characterization Study, construction and demolition (C&D) debris accounts for 22% of the waste stream. Reducing C&D debris conserves landfill space, cuts down the environmental impact of producing new materials, and can trim overall building project expenses through avoided purchase or disposal costs. Building Teams can further reduce excess on-site waste generation through better estimating.
DIVERT Raw C&D debris can be diverted and used as a resource. For example, waste concrete and masonry can be crushed on site and used for drainage base, and gypsum waste can be shredded and used as a landscaping supplement.
Materials that can be diverted include:
- Landscape and land clearing debris (green wood materials)
- Asphalt pavement
- Gravel and aggregate products
- Masonry scrap and rubble (brick, concrete masonry, stone)
- Metals: ferrous (iron, steel), nonferrous (copper, brass, aluminum)
- Clean wood (dimensional lumber, sheet goods, millwork, scrap, pallets)
- Plastics (films, containers, PVC products, polyethylene products)
- Asphalt/bituminous roofing
- Insulation materials
- Glass (untempered)
- Door and window assemblies
- Carpet and carpet pad
- Fibrous acoustic materials
- Ceiling tiles
- Plumbing fixtures and equipment
- Mechanical equipment
- Lighting fixtures and electrical components
- Cardboard packing and packaging
RECYCLE so that raw debris can be processed to create a new usable material. Metals, cardboard, and wood are the most commonly recycled C&D debris materials.
EVALUATING WASTE RECYCLING METHODS
There are three methods of waste recycling: site-separated, commingled, and hybrid. The method selected usually depends on the specific capabilities of the hauler used and the job location, as well as other factors specific to the particular construction project.
Site-separated recycling uses multiple boxes, one for each type of waste (wood, metal, cardboard, etc.) Separating construction waste on the job site provides immediate feedback to everyone on the job and can help ensure that the project’s recycling and reuse goals will be reached. Site separation helps promote a responsible atmosphere on the job site and is the best method for high diversion goals, as in LEED projects seeking 50%, 75%, or even 95% C&D diversion. It’s also easier for haulers, which could be a negotiating point to get lower box costs.
On the other hand, site separation takes up more space at the job site and requires a high level of project supervision. It can also be difficult on high-rise projects, where the number of trash chutes may be limited.
Commingled recycling uses one container for all waste. The hauler sorts everything off site. This makes it easier for field staff to manage waste on the site. It is the best option on tight sites because it usually requires the least amount of storage space.
However, commingled recycling is not available in all parts of the country. In cases where facility labor costs are greater than field labor costs, commingled recycling may cost more than site-separated recycling. There is also concern that commingled recycling may not be as effective as site-separated recycling in C&D diversion, although the statistics in its favor are improving.
Hybrid recycling combines the site-separated and commingled methods—for example, one box for concrete, one box for cardboard, wood, and metal, and one box for general non-recyclable waste.
The case can be made that hybrid recycling represents the best of both worlds. It optimizes weight vs. sorting effort. The total number of boxes can be reduced by working in phases—for example, concrete and garbage during demolition, then miscellaneous and garbage in a later phase. In general, it produces less work for sorting haulers, which could lead to lower hauling fees.
For each project, the general contractor or construction manager must assess the project requirements and site location to determine the optimal waste recycling method to use.
Ask these questions to help make this determination:
- How many waste containers do you have room for? Five, or only two? What will be their location on site?
- Will you be using a trash chute?
- Is it a high-rise site?
- Is this a high C&D diversion project? If it’s a LEED project, is your goal >=50%, >=75%, or >=95% C&D diversion?
- Will there be sufficient staff on site for the required supervision?
- Does the field staff have previous experience on a CWM project?
- Has pricing been negotiated for each method?
- Will there be changes in the type of waste generated during the project?
Finally, when you are evaluating your waste recycling options, the GC/CM and the entire Building Team must first and foremost keep the owner’s goals and requirements in mind. However, there are other factors outside the owner’s direct control that must also be considered. For example, recycling markets can vary greatly in maturity from region to region. In some parts of the country, it can be more difficult to find haulers with the experience or capacity to deliver high recycling rates.
It is also important to remember that there are two components to the hauler’s task: the hauling itself and the accurate and timely reporting of the results.
Now that you’ve put all this effort into C&D diversion, you may ask: What happens to the recycled materials that have been salvaged? Answer: They go into the downstream market, which refers to the companies that take the recycled materials and do something with them or make something out of them. Construction waste management results in more recycled materials being available to the markets that use them. Using materials with high recycled content also may help satisfy corporate sustainable building goals and make the circle of reuse become self-perpetuating.
DEVELOPING THE CONSTRUCTION WASTE MANAGEMENT PLAN
A CWM plan must be project specific. The recycling options used on site will determine how involved with recycling on site each individual subcontractor will be as well as how much site management will be necessary. The CWM plan will reflect these needs and communicate to all subcontractors the Building Team and owner’s expectations for recycling and waste disposal.
The basic elements of a CWM plan include the following:
- Name of the individual or individuals responsible for waste prevention and management
- Actions that will be taken to reduce solid waste generation
- Description of the meetings to be held to address waste management
- Description of the specific approaches to be used in recycling and reuse
- Waste characterization, notably the estimated material types and quantities
- Name of landfill and the estimated costs, assuming no salvage or recycling
- Identification of local and regional reuse programs
- List of specific waste materials to be salvaged and recycled
- Estimated percentage of waste to be diverted by the CWM plan
- Recycling facilities to be used
- Identification of materials that cannot be recycled or reused
- Description of the means by which any materials to be recycled or salvaged will be protected from contamination
- Description of the means of collection and transportation of the recycled and salvaged materials
- Anticipated net cost or savings
The CWM plan must be developed to be project specific, including:
- The list of materials to be sorted and the method by which they will be sorted (by box, etc.)
- Signage: how containers and dumpsters will be marked
- Fines and back-charge schedule
Fines or back charges may be used as leverage with subcontractors on site. If fines or back charges are implemented, be sure to state where the money will go (e.g., general contractor recovery for additional coordination or claim language in case the project fails to reach the owner’s goal).
The plan must also describe the process that will be implemented when “contaminated” materials are spotted in dumpsters slated for recycling, and how any additional labor that may be required for sorting contaminated dumpsters (either at the site or at the hauler’s sorting facility) will be compensated.
CWM REPORTING REQUIREMENTS
CWM-specific contract language should be included in the contracts with all subcontractors. Copies of the CWM plan should be provided to all subcontractors, and it should be made clear that the CWM plan applies to all of them. Specifically, contract language should state the exact text to be used on signage and the reporting requirements, including forms to be used and due dates. Finally, contract language should specify that second-tier haulers must also comply with the CWM plan.
Contract language should also include information regarding:
- Documenting and recording every waste container that is removed from the job site
- Requiring the refuse hauler to provide a monthly report of material by weight (pounds or tonnage) that was diverted from the landfill and all recycled materials
- Maintaining monthly reports to check if recycling rates are being met
- Confirming that monthly construction waste management reports are prepared by haulers on time and reviewed for accuracy by project staff on time
- Tying payment to timely and accurate reporting
- Monitoring waste recycling and hauling on a weekly basis and updating documentation so that a running record is kept and reviewed with the Building Team on a monthly basis
- Including weight tickets from the hauler and recycler as additional supporting documentation
For LEED-registered projects, all LEED submittals, including monthly reports on waste hauling, must be collected and kept separate from general submittals at the beginning of the project. This ensures compliance with LEED requirements before work is put in place.
A weekly on-site green submittal meeting can be helpful to those subcontractors not familiar with LEED requirements. The GC or CM can lead the subcontractor through the process and ensure that the required information is obtained and its accuracy and completeness are verified.
TRAINING AND MONITORING THE WORKFORCE
Before construction begins, all subcontractors and trades should know the answers to these questions:
- What form of recycling will be used: site-separated, commingled or hybrid?
- Which boxes will be used for which type of waste?
- Will a trash chute be used?
- What documentation is required?
- What could happen if procedures or contract requirements are not followed?
The answers to these questions should be spelled out both in the CWM plan and in the contract language. Before a subcontractor begins work on site, the CWM plan should be discussed at the subcontractor orientation meeting. CWM plan requirements should be a topic of regularly scheduled toolbox talks.
Subcontractors should expect on-site leadership to aid them in implementing the CWM plan. Project site staff has the frontline responsibility to educate the workforce as well as to enforce the CWM plan. Don’t assume that all subcontractor project managers will explain the CWM requirements to their foremen or tradesmen.
Constant communication regarding waste diversion expectations will likely get trades to buy in to the CWM effort voluntarily. However, it is equally important to communicate what will happen if waste and debris diversion methods are not followed.
Recommendation: Post the rules and consequences of their violation on or near the dumpsters, where they will be seen.
Be prepared to modify the CWM plan depending on the different phases of construction and the varieties of construction waste that can be generated. Waste hauling during foundation work is greatly different from the waste that is generated at later stages of the project.
SITE SIGNAGE—AN IMPORTANT COMMUNICATION TOOL
Signage is an important component of an effective CWM program. Having clearly marked containers allows workers to know how and where materials are to be disposed.
Keep in mind that dumpsters can be big billboards for your organization. If they are unsightly, the public will draw a negative impression of your project. Instead, use signage to advertise the good your project is doing to divert C&D waste from precious landfill.
Clear, large, and easily readable signage will allow workers to follow the CWM plan.
Remember, too, that project signage may need to be translated into multiple languages to inform all workers at the project site.
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MONITORING DURING CONSTRUCTION
As the work proceeds, it is important regular site inspections to verify and document that all construction waste management measures are in place and working properly are performed. Make sure monthly construction waste management reports are prepared by haulers on time and reviewed for accuracy by project staff on time. The waste hauler should provide an inventory of the items that are being disposed of as trash.
Waste recycling and hauling should be monitored on a weekly basis and documentation should be updated so that a running record is created and reviewed with the Building Team on a monthly basis. Most important, actual performance to meet or exceed established project goals should be monitored on a frequent basis.
Construction waste management has come a long way in the last 10 years, spurred in great part by LEED. The experience thus far is that high levels of recycling—well into the 90-95% range—can be achieved without undue effort on the part of Building Team members, provided there’s a solid CWM plan in place and that it is communicated effectively to everyone on the job.
SIDEBAR: UP TO 3 LEED POINTS AVAILABLE FOR CONSTRUCTION WASTE MANAGEMENT
According to the LEED Reference Guide (2009 ed.), “The intent of MRc2 is to divert C&D debris from disposal in landfills and incineration facilities.” This can be achieved by redirecting recyclable recovered resources back to the manufacturing process and reusable materials to appropriate sites.
- To achieve one credit point, the project must recycle or salvage at least 50% of nonhazardous construction and demolition waste.
- To achieve an additional point, the project must recycle or salvage at least 75% of nonhazardous C&D waste.
- An Innovative Design credit can be achieved if 95% of nonhazardous C&D waste is diverted from landfills.
SIDEBAR: BE SURE TO MONITOR OFF-SITE RECYCLING FACILITIES
Off-site sorting facilities that claim to recycle materials should employ the following sorting techniques or their equivalent:
- Concrete and masonry - Pick lines for removing concrete and other masonry debris
- Metals - Electromagnets for ferrous metals (iron, steel); pick lines for nonferrous metals
- Paper - Pick lines for removing paper products (office paper, cardboard, etc.); air classifier for separating lightweight material
- Wood - Float tanks or pick lines
- Gypsum - Pick lines for removing drywall and other gypsum products
Facilities that claim to recycle any other materials should employ pick lines and other appropriate techniques for removing the specific materials.
Caution: It is important to inspect the waste that facilities send to landfills to make sure it contains only minimal amounts of recyclable materials.
Scott Grogan, Sustainability Engineer for Turner Construction’s Sustainable Construction Group in New York City, developed Turner’s online construction waste tracking system. Scott Bollmann, a Senior Project Engineer with Turner’s New Jersey business unit, is a USGBC Educational Reviewer, a USGBC NJ chapter member, and head of GBCI Credentialing Maintenance training for Turner’s NJ business unit. Robynn Selle is a member of the Turner Knowledge Network team. She has been a project engineer and purchasing agent on commercial construction projects, a Business Unit Training Director for Turner’s Indianapolis Business Unit and a Business Unit Green Champion. Chrisie Ambrass is an instructional designer with the Turner Knowledge Network.