C&D Recycling is critical throughout the U.S., but its importance becomes amplified in geographies where space is at a premium. One such location is on the Hawaiian island of Maui.
Although it has long been a pressing issue in Maui, the need to preserve landfill space became even more pronounced in 2016 when the only C&D landfill on the island closed, leaving companies without a permitted location to take excess inert materials.
Realizing the need for a solution, Pete Sullivan opened Kihei, Hawaii-based Hawaii Materials Recycling (HMR) in 2018 to help recycle concrete, asphalt, rock, dirt and clean sand. Sullivan, who has also served as the owner of PB Sullivan Construction since he established the company in 1994, says opening a C&D recycling facility focused on inert waste was a natural extension of his construction company’s operations.
After Maui's only C&D landfill closed in 2016, Pete Sullivan saw an opportunity to expand on the crushing and screening work his construction company, PB Sullivan Construction, had been offering since 2006. Presently, HMR processes concrete, asphalt, rock, dirt and clean sand into a number of different products.
“We have been crushing and screening rock, concrete and asphalt on job sites to support our construction company since 2006,” he says. “In 2016, the only C&D landfill on the island closed and there was no other permitted place to take materials. Quite often, there is a surplus of excavated rock or dirt on a job site. Ideally, you would take this material to another job site that requires the material, however, that is not always available, so it was a natural progression to open the facility.”
Although the need was clear, getting permission to open the recycling site, which sits on 10 acres HMR leases from landowner Haleakala Ranch, did come with its own set of challenges, Sullivan says.
He says HMR had to wait a year to get an initial permit to operate crushers on-site and about three years to get the special use permit from the county of Maui to use agricultural land for a recycling facility as well as three years to get a solid waste permit from the state’s department of health. He says to help facilitate the permitting process, HMR utilized a team of environmental, traffic, solid waste, civil engineering and land planning consultants, without whom “this process could have been much more painful,” according to Sullivan.
Getting the green light
Once HMR was able to procure the necessary permits, operations commenced in April 2018.
Sullivan says that in addition to his own construction company, other construction and demolition contractors, trucking companies and waste management providers are HMR’s biggest customers. These customers drop off C&D materials to the facility, with some leaving loaded with the company’s recycled materials to use on job sites. Additionally, the site is open to homeowners who come in for topsoil, wall rock and other products.
To process the 108,690 tons of material the facility received in 2019, HMR employs two fulltime employees and brings in several more when needed to help with crushing operations. Sullivan says the company also employs a range of different specialized recycling equipment to meet its needs.
“We use equipment from our construction company, and we favor Caterpillar,” he says. “We load the crushers with either a 330, 336, 345 or 349 Caterpillar excavator. A 972 Caterpillar wheel loader supports the crushing operation and loads outgoing trucks. As for the crushing and screening, a typical setup begins with a Komatsu 550 as our primary jaw crusher, which feeds a Powerscreen 1800 two-deck scalping screen. Then, material goes into a Pegson 1300 cone crusher that feeds into a Powerscreen 2100 three-deck screen that recirculates back to the cone and also feeds MGL or Edge stacking conveyors for stockpiling.”
Saving money and the environment
According to Sullivan, being able to recycle C&D materials on Maui has contributed to significant cost savings on the island.
“The cost of concrete here starts at about $150 per cubic yard. We continue to recycle this concrete and turn it into aggregate base course and a fine material used with mortar for masonry work. We also divert previously landfilled or fugitively dumped dirt, rock and asphalt,” he says. “Years ago, we were told by the Maui Department of Environmental Management that the cost to create landfill space was about $77 per cubic yard, so for every cubic yard that we can divert from landfill, we like to think that we are saving the people of this island that money.”
According to Sullivan, an average truckload of 25 tons with rock and dirt pieces larger than three inches can be dropped off at the facility for a tip fee of about $125. At the landfill, that would cost $1,875, he says. Beyond the tip fee savings, Sullivan says that the company’s customers appreciate that HMR is conveniently located in the growing area of South Maui, which has helped contractors save money through reduced trucking costs.
“Our tipping fees are so much lower than at the municipal landfill, we’ve heard people say, ‘[Using HMR] is a no-brainer,’” Sullivan says. “People find it amazing that we do what we do without being a landfill or quarry. … Since our opening, we have diverted from the landfill and from fugitive dumping in gulches and elsewhere and supported construction projects with around 200,000 tons of recycled materials. This value can be expanded into lessened trucking costs and by having trucks loaded both inbound and outbound from the facility, which saves on road wear, lessens traffic and reduces fuel consumption and emissions.”
Beyond helping protect landfill space and lessen trucking costs, HMR works to keep as green of a footprint as possible.
Sullivan says that HMR’s location, which sits in close proximity to waterways that lead to the ocean, presents some challenges, but that the company has been able to manage runoff with site grading and a retention basin.
The company has also been able to leverage its neighbor, the Maui County Wastewater Reclamation Facility, to use reclaimed water for dust suppression, which helps cut down on water waste.
“The R-1 water from the wastewater reclamation facility supplies us with all of the water that we need for dust suppression at a lesser rate than potable water. We were fortunate to have an R-1 watermain running adjacent to our site and were able to install a 2-inch meter with minimal costs. … Being located next to the wastewater facility has actually been a plus because of the stigma attached to these types of facilities—I believe that our facility represents the highest and best use of this land,” Sullivan says.
In addition to using recycled wastewater, the company also relies on solar power to help minimize its energy footprint. HMR employs the power of photovoltaic panels to help power its operations. Sullivan says the scale and scale house office currently are 100 percent powered by solar panels, with a generator for backup if necessary.
While HMR’s sustainability focus has made sense from a financial standpoint, Sullivan says the ability to preserve Maui’s natural resources is what’s most important.
“If we looked at a yard of concrete that weighs about 2.2 tons, and you think about the materials it takes to make up that yard of concrete, I don’t care what form it’s in, it should never go in the landfill,” Sullivan said in a recent release. “So, if we can avoid that and we can process it here, we’re creating less of a scar on the island.”
Sullivan says that the average truckload of 25 tons with rock and dirt pieces larger than three inches can be dropped off for a tip fee of about $125. At the landfill, this would cost $1,875.
Work in progress
As HMR is only coming up on its second anniversary of operations, there is a lot of room to grow, according to Sullivan.
Because the company is located next to a wastewater treatment facility, the organization is currently looking at ways to recycle organics and sewer sludge. Additionally, HMR presently only recycles the metals that are embedded in the concrete it receives since its solid waste permit is specific in allowing only for inert materials. However, Sullivan says HMR is currently communicating with the state’s department of health about modifying the organization’s permit to include the ability to recycle metals.
Sullivan says that contractors, trucking companies, and waste management providers are HMR's biggest customers.
Although it’s still early days for formal C&D recycling in Maui, Sullivan says that being able to offer a more mindful way of managing materials is one of the core reasons he got into the business.
“I believe that we are fortunate to live here, and that the opportunities that are created in this environment and community have greatly benefitted us as a company, so we think we should reciprocate in any way that we can. We work to supply the community with superior service and pricing for tipping fees and outgoing products that is well below what is offered through the standard means.”
The author is the editor of Construction & Demolition Recycling magazine and can be reached at aredling@gie.net.
Pioneering a solution for C&D fines
Features - C&D Fines
Pioneer Aggregates is working to find an outlet for C&D fines as fill material under Pennsylvania’s Beneficial Use program.
Finding an end market for construction and demolition (C&D) fines continues to pose a challenge for recyclers as increased scrutiny and questions surrounding the material’s environmental impact arise. Fines, which are generated during the processing of C&D debris, consist primarily of soil, wood, concrete, drywall, rock and other miscellaneous material particles.
According to the Construction and Demolition Recycling Association (CDRA), the most common market for C&D fines is for use as alternative daily cover (ADC) in landfill applications, which helps conserve virgin soil. Fines with a high soil concentration can also be used as clean structural fill, whereas fines consisting of concrete, brick and denser material can be used as structural fill.
While exploring the potential for these materials to be used as fill under Pennsylvania’s Beneficial Use program, the Laflin, Pennsylvania-based aggregate supplier, Pioneer Aggregates, began looking into the possible application of C&D fines.
The Beneficial Use program, which encourages the environmentally sound use of municipal and residual waste, provides guidance on permitting and compliance monitoring for beneficial use facilities. Past permits issued in the state for construction materials have allowed processed construction waste, including gypsum, soil, stone, brick, concrete block and more, to be used as a soil additive and for concrete or asphalt mixtures. With this program in place, Pioneer President Mark Popple saw an opportunity for putting the fines his company was generating to good use while simultaneously avoiding having to landfill the material.
FINDING A USE
In 2016, Popple approached the Pennsylvania Department of Environmental Protection (DEP) to discuss using a mixture of C&D fines with Portland cement, called “re-crete,” as fill material to reclaim a portion of Simpson Stone Quarry, a non-active coal mining quarry in Lackawanna County, Pennsylvania.
“Pioneer held extensive discussions with the DEP over several years to determine the best approach to demonstrate the viability of using this mixture in non-coal mine quarry reclamation,” says Mark McClellan, environmental consultant for Pioneer. “The DEP determined that since the mixture had not been used for this purpose in [Pennsylvania], it would require Pioneer to apply for a Demonstration Project permit under the Solid Waste Management Act, with strict requirements and monitoring for a limited period of time under controlled conditions.”
On Sept. 21, 2017, Pioneer received the Municipal Waste Demonstration Permit from the DEP, which allows the quarry to receive up to 1,000 tons of C&D fines per day. Pioneer’s responsibilities, as detailed in the permit, include creating quarterly reports to the DEP that provide chemical analysis of the fines and re-crete, surface water monitoring data, and other information. To ensure everything is within DEP limits on materials such as copper, lead and mercury, the company is expected to collect and analyze samples of fines every 6,000 tons used or at least once per month.
“Pennsylvania has over 250,000 acres of abandoned coal and non-coal mine sites with no responsible party and limited funds to address the environmental and health risk posed by these sites,” says McClellan. “The successful use of this mixture and other waste materials presents the opportunity to reclaim these sites, eliminate the environmental risks and bring them back to productive use.”
Prior to producing the fine mixture, Pioneer must first source their C&D fines from permitted processing facilities and submit the material to the DEP for chemical testing. Once the fines are accepted, they are transported to the quarry site to be mixed with Portland cement and water through a pugmill system. After the material is placed in the designated portion of the quarry, Pioneer will continually perform on-site testing, stormwater monitoring and leachate testing to ensure the material meets concentration limits and shows no adverse impacts to groundwater or surface water.
MEETING THE REQUIREMENTS
In many locations, C&D fines have not been widely recycled outside of landfill applications due to concerns over trace contaminants. In a 2018 study by the CDRA, researchers addressed these risks by assessing 14 samples from 12 C&D facilities in the U.S. The study analyzed the chemical and physical properties of the fines, as well as direct exposure and leachability when beneficially reused.
One of the main chemicals of potential concern in C&D fines is polycyclic aromatic hydrocarbons (PAHs), which naturally occur in coal, crude oil and gasoline. The study found concentrations among the different samples vary considerably, with half of the samples close to or above Florida’s commercial/industrial risk threshold (0.7 mg/kg) and four samples exceeding New York’s residential risk threshold (1 mg/kg).
In terms of heavy metals, arsenic and lead were two warranting the most concern in the study. Nine samples had concentrations above the EPA’s regional screening levels (RSLs) commercial risk threshold for arsenic. Arsenic concentrations existed at levels above the lowest risk threshold in all samples, with only one sample exhibiting arsenic slightly above Florida’s commercial/industrial risk threshold (12 mg/kg).
The controversy over trace chemicals in C&D fines has led some state regulatory agencies to require routine testing and compliance with risk-based regulatory thresholds. According to a Pennsylvania general permit for construction waste, the processed material cannot exceed the state’s chemical limitations on arsenic, copper, mercury, lead and more, as well as nitrogen, organic nitrogen and ammonium if used for land application.
FUTURE APPLICATIONS
Pioneer’s permit expires on June 12, 2020, when the company must submit a final report to the DEP documenting the results of all testing and monitoring data. Pioneer reports that the data so far indicates the project is successful and these materials can be placed directly into the environment as fill in a manner that is protective of public health and the environment.
“C&D processing facilities will potentially have a long-term alternative to disposal [for fines] and can see their byproducts put to productive use in reclaiming disturbed properties,” McClellan says.
If the DEP deems the project successful, the department can issue a statewide Beneficial Use permit, which would allow the C&D fines mixture to be used for similar fill applications across Pennsylvania. According to Pioneer, the mixture could be used as construction fill to reclaim abandoned mines, restore disturbed properties and remediate other contaminated sites.
“The Pioneer project offers an opportunity to these processing facilities to reuse the C&D fines, avoid disposal costs and, ultimately, provide an environmental benefit,” says McClellan.
The author is the assistant editor of Construction & Demolition Recycling magazine and can be reached at hrischar@gie.net.
The importance of materials recovery coordination in construction & demolition
Features - Industry Outlook
For C&D materials recycling to become the norm, the way the industry looks at building and demolition needs to be reexamined.
Buildings are incredibly resource and material intensive, accounting for more than one-third of global resource consumption and 11 percent of global emissions stemming from their construction, renovation and demolition, not accounting for operations. Moreover, most of these building materials are lost to the landfill when buildings and interior spaces are renovated or demolished. According to the U.S. Environmental Protection Agency (EPA), demolition activities alone accounted for more than 90 percent of the estimated 569 million tons of construction and demolition (C&D) waste generated in the U.S. in 2017. This was more than twice the amount of municipal solid waste (MSW) that the EPA estimated was generated in the same year. And this type of waste generation has been growing, quickly, ever since the EPA first estimated C&D waste generation at 136 million tons in 1996.
Certainly, not all C&D waste is attributable to buildings: by weight, most is generated from roads, bridges and other infrastructure in the form of asphalt, concrete and other aggregates. The EPA calculates that buildings themselves are estimated to account for just 32 percent of C&D waste by weight, but this category is more problematic than others because of the types of materials it generates. Much of the road, bridge and other infrastructure-related waste is primarily comprised of asphalt (which boasts an impressive recycling rate of 99.7 percent) and concrete and other bulk aggregates, which have an 85 percent recycling rate. The materials in buildings and their interior spaces, however, often fall into the mixed C&D category, which achieves a significantly lower recycling rate of only 37.6 percent, according to the Construction and Demolition Recycling Association (CDRA). Mixed C&D recycling, therefore, is an industry sector that poses significant opportunity for growth.
With so many mixed building materials headed to the landfill, the U.S. does itself a disservice in allowing these valuable resources and their associated embodied carbon and energy to leak from the country’s resource and economic system.
So, why has the recycling rate of these materials remained so low in comparison to asphalt and concrete? The issues are multifaceted and span the value chain, including manufacturers, designers and architects, construction contractors, materials processors, and the public policy officials and waste managers in local and state governments. Building a better solution will require us to use systems thinking principles and shift our perspective from the linear to the circular.
C&D waste from a designer’s point of view
I spent the first part of my career in the architecture and design industry. I always did my best to deliver design solutions that met my clients’ needs while also being sustainable. But there were often many competing demands and numerous variables to consider, including functionality, aesthetics, materiality, availability, sustainability and cost. And apart from the select manufacturers that have developed internal recycling programs for the products they produce, designing for reusability and recyclability was not a readily discussed topic. From the architect’s perspective, commingling the C&D waste for collection and hauling off-site was the construction contractor’s responsibility. Sometimes, if the contractors were pursuing Leadership in Energy and Environmental Design (LEED) certification, the construction contractor would need to ensure that at least 50 percent, or sometimes 75 percent, of materials were diverted from waste. Where this material went after that, or how it was processed, was anyone’s guess.
By and large, the design community has not had to think about what happens to building materials after they leave a building site as waste. LEED, launched in 2000, has evolved over time and grown from one certification standard to a suite of certification options. LEED remains the most popular certification option in the U.S., but there are now other competing building standards including Green Globes, which advertises itself as a more flexible competitor to LEED, and the Building Research Establishment Environmental Assessment Method (BREEAM), an international standard that evaluates the whole lifecycle of the built environment. But here’s the challenge: As far as building materials are concerned, these standards have historically focused primarily on the impact of the materials on indoor air quality and, to a lesser extent, the sustainable sourcing and manufacturing of materials. With few exceptions, less attention has been paid to products’ full lifecycle impacts, including end of life management.
For example, prior to LEED version 4 (which was not fully phased in until late 2016), commercial construction projects could achieve a maximum of only two possible, non-mandatory points related to C&D waste: one point for achieving 50 percent waste diversion and the other for achieving 75 percent waste diversion. LEED version 4, now updated to LEED version 4.1, maintains these same essential waste diversion benchmarks and also gives more options to incentivize material reuse and products being taken back by the manufacturer via extended producer responsibility (EPR). It also made mandatory the development of a C&D waste management plan for these projects but requires few specifics within the plan beyond identifying five material streams to be targeted for diversion. There is still no incentive to achieve more than 75 percent waste diversion, and a given project does not necessarily need to achieve this level of diversion to attain LEED certification at any level based on the other points earned.
I do believe the LEED system has good intentions, however, it also has its weaknesses. LEED’s weaknesses have not gone unnoticed by others in the industry, particularly others who seek higher levels of sustainability standards and compliance. Since its release in 2006, the Living Building Challenge (LBC) has sought to achieve environmental restoration through the built environment by producing more energy than is consumed for given projects, treating water on-site and using healthy building materials. LBC’s version 4.0 standards for waste are rigorous. These standards seek to achieve “net positive waste,” both by diverting 80-100 percent of all waste and by reusing materials that would otherwise become waste. Its waste management plan, which is referred to as a “materials conservation management plan,” must address the entire project lifecycle from design through end of life. The other LBC requirements are no less rigorous, and consequently, its strength is also its weakness: Only 24 buildings in the world have achieved ”Certified Living” status for meeting these benchmarks.
Two other certification programs deserve mention here: TRUE Zero Waste (an acronym for Total Resource Use and Efficiency) administered by Green Business Certification Inc., and Underwriters Laboratories’ (UL) Environmental Claim Validation Procedure 2799 for Zero Waste to Landfill. The TRUE program focuses on holistic organizational change to minimize waste and is ongoing over an organization’s life. The UL certification is used to demonstrate landfill diversion rates of 90 percent or higher, commonly from facility operations such as manufacturing, although it can also be used to certify time-limited events such as concerts and conventions or even construction, demolition and renovation projects. While these programs are unique in that they are exclusively focused on waste, the scope of these programs—TRUE encompassing the organization as a whole and UL focusing on operations only— makes them unlikely to become the program of choice for most architecture and design projects.
This leaves LEED as the industry’s de facto certification option. On top of LEED’s general lack of emphasis on C&D waste mitigation and management, the responsibility for achieving these goals is effectively placed on the construction contractor to procure a service provider and produce the correct documentation to meet the LEED standard requirements. What’s more, there is no consideration in LEED or its directly competing standards for designing for the ease of reuse or recyclability. Frankly, the design industry just isn’t thinking about what will happen at the end of material life. And if the design industry isn’t thinking about it, and isn’t asking manufacturers to create products that cater to these needs, the result is a vast disconnect between how and what we are putting into our buildings and the ability to reuse or recycle these items at the end of their initial lives.
HildaWeges | Adobe Stock
Our role in the waste & recycling industry
Stakeholders in the waste and recycling industry, whether it be consultants, processors or public officials and program managers, have a duty to communicate how the C&D recycling process works. This is not limited to outreach to the design industry.
GBB is currently working with a client as its C&D materials recovery coordinator to help achieve a goal of zero C&D waste during renovation projects. At the start of one project, the need for these services was particularly evident during an early visit to a construction site. It became clear that the construction contractor wanted to help the client meet its goal, but was unaware of what was and was not recyclable, how the materials were processed and what the contracting team could do to ensure recyclability. It appeared as though the construction contractor was dependent on someone else later resolving the issue of recycling. In fact, in the years since LEED was introduced, the responsibility has indeed fallen on the C&D recycling service provider to document materials and diversion percentages on reports that are submitted to the contractor, who submits the reports to the design team, who then submits the documentation package to the certification body. At every level, there is a disconnect from the next. This is not a best management practice.
Logistics can also be challenging for construction contractors. A well-run C&D recycling facility with a relatively automated processing system may not have much trouble achieving 50 or even 75 percent waste diversion, depending on the incoming material stream. But achieving more diversion than 75 percent can be challenging, especially considering some of the specialized building materials that have been developed in the past few decades. Because of this, there is a growing demand for C&D facilities to update and expand processing capabilities to include materials that some may consider difficult to handle. If a C&D recycling facility is not equipped to handle such specialty materials, the contractor must devise a way to manage multiple material waste streams at the construction or demolition site, which may be space or cost prohibitive and require a higher level of training to all crew members.
Salvaging materials
We have a responsibility to communicate and collaborate across the value chain, as well as to challenge ourselves to keep improving and innovating. This includes, at the policy and public program management level, how we communicate about C&D waste. In direct opposition to how it is commonly referred to, C&D “waste” is actually a valuable resource that should be recovered and not placed in landfills. Rather than speak in terms of C&D waste management, which implies that we are burdensomely managing something of little to no value, we should speak in terms of C&D materials recovery, which better represents the reality that we must recover these valuable resources to the greatest extent possible. A similar difference exists between the words “demolition” and “deconstruction,” which are two fundamentally different activities. Demolition implies destruction such that the components of a building will be rendered unusable for any purpose and can only be recycled or landfilled. Deconstruction, on the other hand, involves dismantling a building with the goal of maximizing the salvageability and reuse of its components. This is a paradigm shift that starts simply with how we talk about the idea of waste.
To incentivize this paradigm shift through innovation and increased recycling, some jurisdictions have taken inspiration from the various sustainability certification programs and made C&D waste management plans and diversion minimums the standard requirement—not the option. This could be accomplished by making these requirements a building code minimum, a condition of permitting or a means for building owners and builders to avoid citations or fines, such as CALGreen’s green building standards code, which requires that all construction projects divert at least 65 percent of waste and either submit a waste management plan or use the services of a company that can provide verifiable diversion documentation. Some local jurisdictions have even higher diversion minimums. Policy could also be written to require proof of recycling in order to receive a conditionally refundable deposit, as is the case in the cities of San Jose and Santa Monica, California.
To meet a similar end, policy could revolve around certain C&D materials prohibited in landfills, such as metals, gypsum board, clean wood, concrete and stone, and the requirement that all C&D materials pass through a recycling facility prior to landfilling, as in King County, Washington. Other types of financial disincentives to wasting materials exist, such as through landfill taxes or fees. For example, North Carolina taxes both MSW and C&D landfills and taxes MSW and C&D transferred to states for out-of-state disposal. Landfill requirements for C&D materials are not as stringent as for MSW, often leading to lower construction and management costs, and therefore, lower tipping fees that do not necessary serve to incentivize the diversion of C&D waste.
Hoda Bogdan | Adobe Stock
Technology to move from recycling to upcycling
Recycling C&D materials at high rates today is possible, but the industry needs to ensure it is continuing to make strategic investments in its infrastructure. Similar to municipal MRFs, there is not one prototypical C&D recycling facility that can serve as a model for all others. All facilities are different and have differing considerations for future investment, but investment is key to keeping these facilities operating at maximum efficiency. C&D recycling facilities should be receptive to feedback from the customers and communities they serve to ensure they meet evolving needs. By weight, most of today’s mixed C&D materials can already be diverted from waste, either for recycling or beneficial reuse, at a well-equipped C&D recycling facility. There are many reasons why this may not occur, as discussed previously, but the industry should not let insufficient equipment be one of them.
As building information modeling (BIM) technology has continued to develop and mature over the past decade, the architectural and design industry can document exactly what materials go into a building as part of its construction plans, down to the manufacturer, material type, shape, size and color. This could be an additional tool used and required for building permit submission as we plan for the future of building de- and re-construction. This is the concept of buildings as material banks. Indeed, buildings are rich stores of materials, whose embodied energy, carbon and economic value should not be lost due to a lack of planning, communication and collaboration. Certainly, recycling is better than landfilling, but better yet is upcycling to create something of higher value.
One of the biggest barriers to building material reuse is the unknown (i.e., not knowing exactly what materials may be available, what its structural properties are, and its current condition). Ascertaining this information requires time and money, ultimately disincentivizing material reuse and conservation. Today’s technology helps remove this barrier. If we document today the components of a given building project, we can better understand how to salvage and reuse these components in the future. If we could reach a tipping point of having enough projects planned in this manner, we would have a critical mass for the creation of a materials exchange, where materials from buildings are aggregated for sale to the reuse market. Implementation of such an idea may be years away, but it is possible now.
C&D materials recovery gives back so much. These processes create more jobs than landfilling the same materials, lengthen the life of our landfills, save our limited natural resources and preserve the embodied energy and carbon that was required to mine or harvest virgin resources and produce the building materials in the first place. Thanks to advances in BIM technology, we can know all the construction materials that go into a building, and in turn, anticipate its materials for recovery at the end of its useful life. And through proper C&D materials recovery coordination, we can work together to make connections and foster collaboration across the value chain, communicate to bridge the disconnects where they exist between actors, and create a system that works hard to preserve the value of materials by keeping these products circulating within, instead of leaking out of, our economy.
Features - Operations Focus | Air Quality Monitoring
With new in-cab air quality standards in the works, managers can stay ahead of the curve by implementing air cleaning systems into their existing equipment.
Based on estimates from the U.S. Department of Labor’s Occupational Information Network, more than half of construction production occupations are exposed to contaminants like pollutants, gases, dust or odors at least once a week.
Thanks to advancing technologies and relatively new standards from the U.S. Occupational Safety and Health Administration (OSHA), industry consciousness over silica exposure has grown in recent years. But that’s just the tip of the iceberg as it relates to air quality for construction, demolition and recycling operators, says Jeff Moredock, the executive vice president for Sy-Klone International, an air cleaning equipment manufacturer based in Jacksonville, Florida.
With Moredock serving as the international project lead for the International Standards Organization (ISO), a new standard of in-cab air quality is on the horizon that could help improve both machine and operator well-being and performance.
But even before that standard comes into play, managers can take steps to ensure their operators have optimal air quality while they work.
Problems with air quality
According to Moredock, in-cab air quality is primarily dependent on four different factors: temperature, humidity, carbon dioxide (CO2) concentration levels and dust particle levels.
Temperature and humidity are easily controlled by most HVAC systems. CO2 and dust, however, are not as simple to address.
Some HVAC systems only recirculate the air inside the cab and some, known as fresh air systems, draw air from outside the cab. Either configuration can present significant air quality problems when operating in high dust concentrations, as one recirculates stale air while the other draws dust into the cab.
“There are issues when you talk about recycling facilities or construction environments, particularly when they're not exposed to the atmosphere—in other words, they're inside of a building. When you're running equipment inside of a building and you don't know how much ventilation you're getting, you can have higher concentrations of all of the different types of particles because you're in there moving things around, crushing, abrading, grinding, whatever you're doing, and you're creating all this dust,” Moredock says. “If the ventilation system, the air intakes, then filtration system cannot remove those particles from the air, they will suck them into the cab. The result of that is you increase the concentration levels of these particulates inside the cab, and the air quality goes from good to not good.”
Dust in the cab can be problematic for both the machine and the operator.
When outside particulates get sucked into the cab, they clog the HVAC system and degrade its function.
But even more problematic is the particulates’ effects on operator health. Dust can contain a variety of contaminants, including silica and asbestos, which can be harmful to operators, especially with long-term exposure.
If the HVAC system is not recirculating air, CO2 also starts to build up in the cab. Moredock says CO2 exposure can also create health problems that may be more immediate, especially with the use of diesel-powered machines. More CO2 equals less oxygen in the cab, which can impair cognitive function and decision-making. It also causes the air to feel stifling, which may result in operators opening a window and exposing themselves to even more contaminants.
Regulations currently exist to quantify safe levels of contamination. OSHA’s recent silica regulations lowered the permissible exposure limit (PEL) to 50 micrograms per meter cubed averaged over an 8-hour day. Similarly, ISO 16000 has established that the CO2 concentration for medium indoor air quality is 800 parts per million (ppm).
Moredock, however, says there is a difference between indoor air quality in a typical building and in-cab air quality in a working environment.
“What we found is the 800 ppm was a good mark for buildings, but … you also have ambient CO2, which is what your CO2 level is just walking around outside, and then you have the CO2 level inside the cab with a guy breathing it,” he says. “What we're really concerned about is the difference between those two and making sure that that difference is not substantial.”
Setting standards
The discrepancy in current standards is part of the reason why Moredock is working to create a new framework for assessing air quality.
Moredock is the international project lead for developing ISO 23875, an air quality control systems and air quality performance testing standard for operator enclosures.
“As it relates to standards that directly address air quality, there are very few. In fact, the one that we're writing is the first one that's been written on an international basis that addresses air quality in an operator cab and provides awareness of this as a problem,” Moredock says.
The standard will establish a testing methodology for evaluating the cab’s performance upon manufacturing, as well as methodology for the cab’s ongoing maintenance. Moredock says the standard will be applicable across the entire supply chain, from original equipment manufacturers (OEMs) to industrial hygienists.
“ISO 23875 is unique because of its emphasis on new and retrofit cab air quality system performance. It applies equally to those who design new equipment and those who retrofit used equipment in the field,” Moredock says. “Improving air quality cannot be the sole responsibility of any one group. As the machine passes through its life cycle, it must be continuously maintained and performance tested to validate its proper function.”
Finding solutions
Moredock says he hopes the standard is in place by 2021 at the latest. But until then, there are solutions managers can put in place to maintain good in-cab air quality for their operators.
Keeping the cab well-sealed is an important component. But according to Moredock, keeping fresh air recirculating in the cab is key.
“Fresh air [is important] for two reasons. It dilutes the amount of CO2 that's in the cab by mixing it with ambient air, which has lower levels of CO2, so we're diluting the CO2 in the cab. Then, it performs another function. It puts the cab into a positive pressurization state, which means that we have air coming in through a control source, and then this air must look for a place to get out of the cab,” Moredock explains.
Fresh air, however, can be difficult to come by when in an enclosed working environment.
Moredock says high-efficiency filters can filter air coming into the cab through the HVAC system, controlling the airflow in and out of the cab to minimize CO2 and dust buildup.
Moredock adds that filter pre-cleaners are an important component to help tackle especially dusty environments even before those particles hit the HVAC filter, which prevents clogging. “In the absence of this, you're a victim of whatever dust is outside and how much is there, [and] that relates to how quickly that's going to cause a failure on your air conditioning system,” Moredock says.
The National Institute for Occupational Safety and Health (NIOSH) recently published its 2019 Dust Control Handbook for Industrial Minerals Mining and Processing, where it concludes that the most effective cabin filtration and pressurization systems are integrated directly into the HVAC system. Although the handbook pertains to the mining industry, Moredock says the recommendations included are pertinent to all industries.
The handbook’s recommended HVAC components to maintain high air quality include:
A pre-cleaner that uses high-efficiency filtration to collect and divert a majority of particles before they reach the filter.
A high-efficiency filter that captures 95 percent or more of toxic respirable particles from the 0.3 to 10 micrograms per meter cubed range. Moredock says while many favor HEPA filters, MERV 16 filters are cheaper, longer lasting and typically enough to do the job.
A high-efficiency MERV 16 minimum recirculating air unit to filter fresh air as it cycles through the cabin.
A cabin pressure monitor that can alert operators if pressure dips below a set level.
A CO2 monitor with real-time readings.
Unidirectional airflow to ensure a steady supply of fresh air.
With new standards coming up the pipeline, fleet managers can get ahead of the curve by requesting new machines conform with ISO 23875 from the factory and adjusting old machines to create cleaner air in the interim.
The author is the assistant editor for Construction & Demolition Recycling and can be reached at tcottom@gie.net.
How Lindner’s shredding technology is helping conserve landfill space
With landfill space at a premium and community opposition making it more difficult to expand existing sites, municipalities across the country are increasingly looking for solutions to maximize their landfill density through the use of equipment.
While compactors may help condense material after it has been tipped on-site, high-capacity shredders allow municipalities a more proactive solution for reducing waste volumes.
In April, Bill Raper, general manager of the Gresham, South Carolina-based Sandlands Landfill, and Mike Bessant, assistant executive director at South Carolina’s Horry County Solid Waste Authority, got to see one of these solutions in action for themselves as Lindner Recyclingtech demonstrated its Urraco 95 DK mobile twin-shaft shredder at the Sandlands Landfill.
Raper and Bessant, along with a contingent of other parties, were interested in seeing how the Urraco 95 DK could potentially help extend a landfill’s life by preshredding incoming mixed C&D material. With this in mind, Service and Test Lab Manager Jake Dennis pitted the Urraco 95 DK against both an 80- and 120-ton pile of wood waste, green waste and light C&D materials to see how it would fare in a real-world scenario—the goal being to shred the materials at a rate of 80-plus tons per hour.
Powered by its robust 770-horsepower engine, the Urraco 95 DK’s slow-speed twin-shaft cutting system featuring fully welded crushers, rippers and scrapers made short work of the on-site debris.
According to Dennis, the 80-ton pile was processed in less than an hour and the 120-ton pile was shredded in 90 minutes with a resulting throughput size at 90 percent of 8 to 12 inches.
“The Urraco is really well suited to C&D material,” Dennis says. “We ran the machine with our specially designed C&D shafts and it quickly processed all of the various material that was fed into it. During the run, the machine was only working at 40 to 60 percent power, which leads to good operating efficiency. The output size also exceeded expectations for the application we demonstrated. In all, it was quite a success.”
Measuring the results
Following the demonstration, Raper and the operators at the Sandlands Landfill wanted to gauge for themselves how effective the Urraco was at condensing the materials within the landfill. After performing an independent airspace density test, Raper reported a 40-percent increase in density achieved in areas where the incoming material was preshredded by the Urraco versus the areas where only a landfill compactor was used to condense the material. Through data obtained by the airspace density test, Raper also found they could extend the useful life of its compactor with about 50 percent fewer passes when dealing with preshredded material from the Urraco.
“This test really proved the versatility and capability of our Urraco-series machines,” Rob Vogel, a Lindner Urraco representative, says. “Not only did it flawlessly perform the test, it also provided results that add tremendous value to the landfill. Obviously, the increase in density was the goal of the demonstration, but it also allows a landfill owner to consider investing in a smaller, less expensive compactor or even a track loader that costs less to operate per hour, which just adds to the value of the Urraco.”
To learn more about the Urraco 95 DK mobile twin-shaft shredder from Lindner Recyclingtech, call 1-800-235-1391 or visit https://www.lindner.com/
