- Created: Saturday, 01 August 2009 08:00
- Published: Saturday, 01 August 2009 08:00
As landfill space is lost, especially in dense areas engaged in urban renewal, it's increasingly difficult for construction contractors to dispose of construction demolition debris. For many aggregate producers, this translates into opportunity.
Contractors are desperate to get rid of construction debris, so they'll line up outside a spent quarry or pit to dispose of it. They'll pay just about any tipping fee, so long as it is less expensive and more convenient than taking it to the landfill. The aggregate producer can then sell some of it right back to the contractor, if the producer is willing to sort it, crush it and screen it. For many aggregate producers, however, it might be more tempting to accept it as a fill material for reclamation sites.
This concept, albeit brilliant, seems largely unrecognized outside of the Midwest. In and around Chicago, however, necessity has made it a reality. The city simply is running out of space to put the materials. The innovative leaders in Illinois include VCNA Prairie Aggregates, Bluff City Materials and Vulcan Construction Materials.
These companies recently gathered in Springfield under the umbrella of the Illinois Association of Aggregate Producers to discuss the pros and cons of accepting Clean Construction Demolition Debris. John Henriksen, association president, says he has seen increasing interest in the subject, which prompted the association to organize and education seminar in conjunction with its annual convention. It brought in several experts on the subject, including Annick Maenhout.
Maenhout is safety and environmental manager of VCNA Prairie Aggregates Illinois. She oversees four operations accepting CCDD for Chicagoland reclamation sites. She says contractors have an economic incentive to unload as much debris as possible. This often includes contaminated material that the Illinois Environmental Protection Agency declares unsuitable for fill material, so there is some due diligence for the parties involved.
CCDD is mostly limited to uncontaminated soil, brick, reclaimed asphalt pavement and uncontaminated concrete without protruding metal. It is up to the operator to police the front gates, and test and monitor for contaminates. Once material is discarded, it is the sole responsibility of the property owner.
ìOne of the difficulties in running this program is that the IEPA has put everything on the operator of the CCDD facility,î says Maenhout. ìAll of the liability ó all of the policing ó is on us.î
EACH INCOMING LOAD must be checked by a designated inspector, in accordance with IEPA regulations. In addition to a visual inspection, personnel also must use a calibrated instrument to test material for contamination. Most commonly this device is a Photo Ionization Detector, which measures various gases in parts per million. Testing should be performed from an elevated position, which allows the inspector to see into the trailer of the incoming vehicle. Either a catwalk or scaffold will suffice.
From the inspector's elevated position, he can visually inspect the load for obvious contaminants such as rebar, pipes or barrels. Loads also should be denied if even a faint chemical odor is present. This is often a petrochemical such as gasoline, diesel or oil. Landscaping waste is prohibited because it turns into methane during decomposition.
ìGo out there and use all of your senses,î Maenhout says. ìIf you are at all suspicious, do not take it.î
THE PID IS the inspector's extra sense. Maenhout says that no load should be accepted without consulting a calibrated device (It's the law in Illinois). It should be waved just over the load, but it should never actually touch the material because dirt can clog the sensors. For a better reach, the device may be attached to the end of a broomstick or pole. Extension rods also are available from the manufacturer. The PID is more likely to expose contaminates if the load is disturbed, so it is helpful to turn some over with a shovel or other tool. Also, warm material will register more quickly than cold material. Zero is the ideal reading, and loads (by Illinois law) must be rejected if the PID alerts to a contaminant.
However, in an urban or industrial atmosphere, it can be difficult achieving absolute zero because there's contamination even in the air we breathe. Maenhout advises performing a fresh-air calibration, and zeroing out the meter to normal conditions. Other operations have discussed documenting the consistent readings and only rejecting loads beyond those. For example, if background readings are consistently 0.2, rejections can be 0.3 or higher. Maenhout also reminds inspectors to keep the PID far away from the truck's exhaust and be conscious of any industrial chemicals in the area. She adds that the IEPA tests in parts per billion, while the average site collects readings in the millions.
IF A LOAD is rejected, there may be ill feelings from the driver or contractor, Maenhout says. Some operators at CCDD facilities have suspected contractors of burying material to smuggle waste past inspectors. Maenhout, however, says there could be a simple lack of education. Maenhout says, working in Chicago, with a large Hispanic population, there often is a language barrier among drivers. And loaders at the job site might not have a clear understanding of what constitutes CCDD. Whether the error is accidental or malicious, an aggregate operator should not hesitate to blacklist contractors that consistently deliver contaminated materials.
Maenhout emphasizes the need to inform everyone that potentially sees the material including loaders and drivers. There is a trial-and-error phase, but people learn quickly when money is at stake. She says her largest operation only rejects about one load a week, even when accepting upwards of 400 loads a day. Whereas, several loads were rejected daily when the site started in 1995.
When loads are rejected, the IEPA requires that a CCDD Load Rejection Form be submitted within 24 hours. This allows the agency to better track where the contaminated load is being discarded. It also is recommended that samples of the material be collected and photos or video of the rejected load be recorded. If possible, a reading from a second PID or similar device should be taken. However, even if there is no obvious or measurable contaminant present, there is no requirement to accept any load, Maenhout says.
IN ADDITION TO routine inspections, IEPA requires that incoming loads be subjected to daily random inspections. Prairie uses a random-number generator to select trucks. Other companies have picked a certain time of day to inspect. During such inspections, the vehicle must be followed to the approved dumping ground. Dumped material is then spread out to visually check for contaminants, as well as conduct a thorough screening with a calibrated device. These results also must be documented on the ticket, in a log or on the inspection form, says Chad R. Taylor, general counsel for Thelen Sand & Gravel, Antioch, Ill. Also, any discovered contaminants must be reloaded and disposed of properly by the contractor.
To further prevent the hassles associated with the discovery of contaminants, it is advisable (although not mandatory) to inspect the work site before making any formal agreement with a contractor. If the site is located on a former gas station, it's probably not going to yield CCDD. It's also smart to look at neighboring properties. Consulting firms such as EDR Inc. and First Search can help. These independent consulting firms can provide an environmental history of most locations and determine what contaminant could potentially be unearthed during construction or demolition.
Another major obstacle, Maenhout says, is inclement weather. Rainy days can halt the process, as roads turn to mud. Reclamation sites usually are mined out, so there is little material left to maintain roads. This is partly remedied by applying material salvaged from incoming CCDD.
Where resources are scarce, salvaging material from incoming loads can be appealing. However, it must be sorted. This task may require additional equipment such as a portable screen, and stockpiles may consume valuable space. IEPA also imposes a time limit for storage. Concrete can be stored for four years, but everything else including wood, rebar and soil must be used within a year. This includes selling it back to contractors.
As the world continues to embrace a greener, more sustainable culture, operations will further embrace tactics to cut waste. CCDD facilities are yet another example that this changing culture also can be a profitable one, even in states with comprehensive regulations such as Illinois.
Photo Ionization Detectors, more commonly referred to as PIDs, measure volatile compounds such as benzene or various petrochemicals. According to Pat Maloney of J & M Instrument Co., a sample is introduced into an ionization chamber and exposed to an ultraviolet lamp. The photons of the ultraviolet light then excite the sample, and ions are attracted to a collecting electrode. The collection results in an increased current that is proportional to the concentration of the compound.
The hand-held varieties used by members of the aggregate industry that accept Clean Construction Demolition Debris typically calculate compounds in parts per million. Although the Environmental Protection Agency typically relies on PIDs measuring compounds in parts per billion. The PIDs most common to this industry include the MiniRAE 2000 and MSA's Sirius. An average unit runs about $2,000. These are the most cost-effective devices, comparing to an X-ray fluorescence analyzer for $35,000 or a flame ionization detector for much more.
These devices merely need to be held over the sample to produce a reading within seconds. PIDs currently are the most efficient means for measuring volatile compounds, but they are not perfect. Humidity in the air can create up to a 30% decrease in the accuracy by interrupting the flow of light from the UV lamp. Maloney says to be wary of manufacturers that claim moisture immunity or compensation.
Maloney argues that PIDs should only be calibrated to an isobutylene canister to create a true zero reading, and personnel should consistently document readings to find a rejection threshold.
ìThey start moving that zero, and the background ambient moves around depending on which way the wind is blowing,î Maloney says. ìThey now have shifted a known baseline that you can reliably relate to. How do you document that? Ö I like known baselines that I can cross reference and check.î
The PID should be tested at least daily, possibly more as weather conditions change, as both rain and sunlight can impact readings. Maloney recommends performing a bump test to check if the meter is functioning. A bump test involves applying a cylinder of gas with a known concentration to the unit to compare with the reading. Another test can be performed simply by cupping the hand around the end of a PID to see if the humidity reading can be driven up. However, these tests should not be used as a substitute for an isobutylene calibration, which should be performed monthly.
You should expect to replace the lamps and sensors every 12 to 18 months. It is industry specific, Maloney says. A sensor averages $160 and a lamp $200. Replacements should be kept handy. Manufacturers suggest that cleaning the sensors by immersion into in an anhydrous methanol and letting it air dry, but Maloney says he has not seen this work effectively. Although, he says cleaning the lamp with the same chemical is very effective. But this should only be attempted with a solution provided by the manufacturers. Maloney also says to avoid touching the lamp with bare hands because the oils will ionize.