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Debra, this question was asked on our MSWlf list serve in 2005 and here are the responses: One of the landfills in Minnesota has proposed to use shredded construction and demolition debris as an alternative daily cover. In order to respond to this request, I am trying to gather some information on the use of ground construction and demolition debris used as alternative daily cover at lined landfills in other states. Are there any states that have allowed shredded construction and demolition debris to be used as an alternative daily cover? If yes, what restrictions were placed on the use of this material as an alternative daily cover? What types of restrictions were placed on its contents? What types of experiences did you have? If it has been proposed and was not authorized, what were some of your reasons for not approving this use? Thanks in advance for your assistance. 2-4-05 Geoffrey D. Strack, Graduate Engineer 2 Minnesota Pollution Control Agency Municipal Division Solid Waste Section (651) 296-7716 (phone) (651) 282-6247 (fax) Indiana allows the following construction/demolition material: rocks, bricks, concrete and road demolition material to be used as ADC. The standards for ADC are set in 329 IAC 10-20-14.1 I'm including a web side link: http://www.in.gov/legislative/iac/T03290/A00100.PDF Other materials than those listed in our regulations can be approved on a case by case basis. I don't recall that we have approved in the past mixed construction/demolition waste as ADC that would include dry wall. Mr. Strack: Be careful in approving this use as to the proportion of wallboard in the daily cover. We had one landfill I am aware of provisionally approved for this in Virginia. The gypsum contains calcium sulfate, and anaerobic bacteria produce hydrogen sulfide from it, when it is wet and other food is present. The concentrations were high enough that the HazMat team controlled access to the site for a time, and an EPA OSC came to investigate. It was a very difficult problem to resolve, using FML cover, negative pressure gas capture, and flaring. Citizens' suit followed. This has been some years ago now (1996-1997). There was a study done on a captive landfill associated with a gypsum wallboard manufacturer in the northwest, but I do not have it now. Geoffrey, In Florida C&D recycling has been growing steadily over the last 8 years or so and one of the recovered materials from these C&D recycling operations has been the fines or Arecovered screen material@ (RSM) is the term we use. While not being shredded C&D, the RSM is what falls out of the screening/picking lines and is soil-like in nature. We have approved RSM as alternative daily cover at lined landfills. Some other uses have been approved based on a characterization of the RSM and comparison with specific criteria. The protocol for characterizing RSM and the criteria for reuse is included in a guidance document entitled AGuidelines for the Management of Recovered Screen Material from C&D Recycling Facilities in Florida@ which is posted on our website at http://www.dep.state.fl.us/waste/categories/solid_waste/pages/beneficialuse.htm . In Maryland we did an extensive study about 10 years ago when one of our auto shredders wanted to branch out into this. They even patented it under the trade name Recovermat. We had them add the material to the shredder in accordance with different formulas of "heavy" vs. "light" fraction of C&D (heavy = concrete, bricks, drywall, etc., while light = wood, packaging, plastic, etc.), determined by eye. They also had a lab do visual classification of the product for awhile, checking for asbestos and the rough percentages of flammable vs. non-flammable particles, although after awhile we found it really didn't make much difference to the performance so we just let them grind up what cam down the shoot, and they could use it for cover as long as it met some minimum standards for non-flammable constituency. In brief, we found that: - it is generally adequate for most uses of cover - keeps the litter down, stops birds and vermin from feeding, compacts nicely, etc. - it is however porous - it readily lets rain in, and odor (and landfill gas) out. - due to the potential for fire, and to improve it's performance in other ways, we require that a layer of intermediate cover, in this state 1' of soil that is put over the waste after the completion of each lift, be placed on more frequently, like every week or two depending on the amount of waste the using landfill gets (a bigger landfill is weekly, smaller biweekly). - Use of the material at several landfills indicated that it generally performs acceptably. HOWEVER, we did have a problem at two sites with a link to the formation of hydrogen sulfide odors. One, in particular, had a very nasty problem that developed. What happened was this - they are a site located in the Coastal Plan that has extremely clay-rich soil for daily cover. Unfortunately, in the rain the stuff gets really slippery, so in addition to using the shredded C&D for daily cover, they were putting some down as temporary access roads inside the cell, to give better vehicular traction. They did this for a couple of years, no problem. Then, a month or two after they received 12.5" of rain in 24 hours during a tropical storm (live shots of the flooding of Northeast, Md., which the landfill is just east of, made CNN) we started getting complaints about a strong sulfury odor from the town. It got worse - I personally measured over 100 PPM H2S at belt level downwind of a couple of methane vents, before they put flares on 'em. (I couldn't smell anything at all for 6 months after that little adventure). What had happened was that the water soaked into the fill, and then perched on top of layers of that nice clayey cover - in the layer of gypsum-containing shredded C&D. Since it had soaked thru a layer of trash and was now leachate, you had exactly the right conditions needed to manufacture hydrogen sulfide from gypsum - calcium sulfate, lots of water, organic carbon, and an anaerobic atmosphere. They fixed it with really good cover and an awful lot of flares. The problem occurred at one or two of the other sites that used it too, but not nearly so noticeably and it was quickly suppressed. - So, what we do is, we still approve the stuff, but we do it with conditions, and a warning that this can happen - and that they will be required to jump on the odor problem if it develops. - The one landfill quit using it but a few still do. We do have ongoing slight odor problems at a couple of those sites, but I think it is more related to the porosity of the cover than the H2S content - the odors we are getting now are more a classic garbage smell than the pronounced sulfur odor we had before. (After awhile it's just like wine-tasting: "Ah, let's see...not too sweet, yet not too dry...a subtle piquancy of sludge, with the heady flavor of petroleum-contaminated soil...some crisp tannins from the wood and cardboard...just a touch of industrial solvents and undertones of incinerator ash...This is from Baltimore City garbage, buried about August, 1983, before the fall rains..."). - I note that some (Massachusetts?) have banned gypsum from their landfills, and it may be of interest to those in wet climates to consider minimizing wallboard and plaster content in a C&D-derived ADCM. We are not at that point, however. If you need more on this please give me a call. Kansas has not received any requests to use shredded C&D waste as alternative daily cover material. This could be because soil is readily available at most landfills, and other alternative cover materials (tarps, low-level contaminated soil, spray-on slurry) are probably more cost-effective than shredding C&D waste. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "GreenYes" group. To post to this group, send email to GreenYes@no.address To unsubscribe from this group, send email to GreenYes-unsubscribe@no.address For more options, visit this group at http://groups.google.com/group/GreenYes -~----------~----~----~----~------~----~------~--~--- |
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