***Q. You use the terms hazardous waste landfill and TSDS…are these the same thing?
A. A TSDS may do things other than own and operate a land fill. It may recycle waste, incinerate it, and pump it into wells (uggg Not a good idea, but still legal in some cases.) or just be authorized to store it for a while a new facility is being built. An industrial operation that generates HW can get part of its site designated as a TSDS, if they can persuade the EPA it is a legitimate operation, not a ruse to avoid proper disposal of the waste.

*** Q. Don't all MSW's end up with hazardous waste dumped in them? (at a minimum from household sources?). Don't virtually all MSW's leak into the surrounding soil/ groundwater?
A. Yes, more yes, and more uggg. New landfills are always lined. Liners must meet rigid specifications and the seams are tested. In a multi-acre site, however, it's a safe bet it will leak somewhere, and that is where leachate will flow. Old landfills were not lined and those operating, which is most of them, are not lined. They leak some HW but more yukk. If they are capped with clay and properly graded to deflect most of the rainwater, the leakage is minimized. Also, groundwater itself can degrade many wastes and which are diluted in any case. Finally, most landfills have monitoring wells at their property lines to verify that they are not poisoning people with wells downgradient.

***Q. As I read about the hazardous waste landfills, I had the thought that some States might to gain money by build up a landfill (in a desert or so) and accept HW from other densely populated States.
A. Yes, typically the poorer states are more amenable to them. Also, poorer locations within the states - the locals want the jobs. Indeed, that is where the landfills are. Today there is the concept of "environmental justice," whereby the children of rich people and college professors go to the state and federal governments and say, "Hey, you would not put that mess in your backyard, why do you put in the backyard of some disadvantaged person?" That's still where it will go, if it goes anywhere, but it's a longer, costlier fight to put it there.

***Q,Related to landfill siting, what do you mean with "Air Quality"?
A In the old days, landfills smelled badly and often caught fire and burned. So there was a definite air pollution issues. Well-managed landfills are much better today, but still smell, so the prevailing wind needs to be taken into account. Hazardous waste landfills need special attention due to the possibility of a sudden large release of toxic chemicals into the air, either from the landfill or from a delivery of materials.

**Are listed wastes by definition untreatable? I'm guessing that if they could be changed into something benign they would be and there would be no use for their listing except that not everyone will follow the rules and some will get spilled somewhere.

Q. Good point. If the waste is treated as part of the process , it may never become a waste . It's only when it leave the process , i.e., is put in barrels or such, that it becomes a waste . Once it is a waste , and it is a listed wast e, it remains such forever. Now, if it is practical to treat a waste so that all the hazardous constituents are removed, it may be possible for the generator to appeal to the EPA to get the waste “ de-listed .” This must go through the regulation making process – public notice and comment.

**I always thought the FNSB Landfill was just a municipal solid waste landfill, but they do accept some quantities of hazardous waste there. For example when I worked at a laboratory in town we had all sorts of strange jugs of mixed up chemicals. The landfill would accept this in limited quantity once a month. Also the company I work for now is allowed a certain amount of hazardous materials once a month. What makes that possible, is it just the permitting, or the remoteness of Fairbanks so there is no where else for it to go? There are the battery bins at the transfer sites, and I've seen plenty of strange drums dropped off at those sites too.
A. The borough accepts the hazardous waste at the landfill, but does not put it into the landfill – just keeps it there until they have a shipment and then sends it out. There are many exceptions to RCRA, besides the conditionally exempt small generators. Households are one exception. And there are “universal wastes” that are in between. So the borough collects all that stuff, including the batteries, on the theory that if they did not, it would just wind up in the landfill anyway. Now at some point the borough becomes a “TSDS” because of the mass of stuff they accumulate, so they must get the permits for that.

**Q. When you say -- you must treat the waste to below the TSHW, who is "you"? The producer of the waste, or the TSDS?
A. The generator is always, always, ultimately responsible for the HW, under RCRA. The work of treating / storing the waste is also the responsibility of the TSDS facility, i.e., both the generator and TSDS can be held accountable for any problems. In addition, if the waste was not treated properly, the TSDS could loose their EPA certification.

** Q. Your anecdote about the old landfill you dug up in Texas was interesting. Why is there such a lack of degradation in landfills? Wouldn't it be simple to speed up degradation (possibly utilizing some of the techniques we've been seeing on the clu-in site such as adding oxygen to enhance microbial activity?
A. See answer above. You would need to add water to hasten degradation. Also, as long as there is space in the landfill, it is not worth their while to try to reduce volume.

** Q. Are landfills in smaller communities subject to the same regulatory criteria as those in larger communities? I know there is a provision for hazardous waste generation (small scale generator, etc.), but is there a scale factor for landfills as well? I'm ultimately curious about the composition of a typical landfill in a small community.
A. Landfills are closely regulated by a permit system. The size of the landfill is closely monitored, usually by sections or "cells." There are different requirements for different sizes of landfills. Rural Alaska is covered with "unpermitted" landfills. The village dumps it trash somewhere and never gets a permit. Since the village is often not incorporated, who is the DEC to sue to get the village to comply with the regulations and get a permit? And if they get a grant and hire a consultant to design the landfill and get a permit, who will see to it that the permit is followed?

** Q. This was interesting module. I found land fill description interesting but I wonder whether hazardous waste are most of the time stabilized or not before closing and covering it with soil and vegetation cover. Does stabilizing process still continue after covering it?
A. Stabilizing usually means treating the chemicals so that they are less liquid and reactive. Liquid HW must be combined with some substance and made solid. This is often an absorbent material. It may be cement or a cement-like material. If it were a reactive substance (perhaps explosive) it must be chemically treated or dispersed so it is no longer explosive, etc. Beyond those generalizations, it all depends on the particular waste, and the HW landfill's permit will establish those treatment standards. You would expect the material not to change much after it is placed in the landfill, so the stabilizing process will not continue.

*Q. I have been curious about this for some time. For instance, in the lab I would generate (among other things) spent tissue fixatives which were a mixture of formaldehyde, gluteraldehyde, and buffers. The waste was picked up by risk management. Then what? I expected that they created the manifest and paid to have it shipped off ...somewhere? I haven't completely finished the reading for this module so maybe I will find my answer as I continue reading.
A. They ship it to a TSDS facility. If the waste is below the landban numbers and is solid or can be made solid, and those kinds of waste often do, they can be put in a special lined HW landfill without too much fuss.

*Q. In my paper Pesticides in fertilizer I describe the usage of toxic waste products in a recycling technique to produce fertilizers, which are supposed to improve the agricultural harvest. However, in many cases farmers have no information about the percentage of different fertilizer components. Thus, the effect of fertilizer on plants and humans cannot be analyzed on a high scientific level. Moreover, lot of other different factors influence fertilizer pathways: humidity, temperature, porosity of the ground, availability of the groundwater etc.
My question is: What improvements in this topic can be done to assess the effect of fertilizers correctly?
A. Good question. If you are dealing with human health effects, you first need to know which chemicals are humans exposed to? That is, the chemicals in the fertilizer and perhaps their end products after chemical changes. Next you need to know the concentrations to which humans will be exposed. You might predict this via a model or measure it in the location of the human receptors. This is a topic in our Environmental Risk Assessment course.

*Q. My paper involves the question of computers and possible leaching of heavy metals from the improper disposal of them. The EPA does not regulate this disposal for households. It does regulate for businesses. Anyway, I am trying to visualize what actually happens to these monitors, keyboards and computers. Do you know if garbage collectors would actually pick them up if I were to leave them on or near the dumpster? Or do you have any idea about consequences or responsibilities associated with the improper disposal within a garbage dumpster. It seems the garbage trucks crush the trash from the dumpster. Is the waste just assumed to be ok because it is in a residential area?
A. Households are not regulated by RCRA. Some states do regulate household trash, but obviously it is very hard to enforce. Although scavengers might pick out some computers, most will go to the landfill and be crushed and compacted. The HW issue would revolve about the concept of the TCLP. That is, during the presumed leaching process, would significant levels of the toxic chemicals in the computer leach out and presumably find its way to the ground water? If it does, for example older fluorescent light bulbs, ni-cad batteries, or perhaps computers, there are HW issues. EPA tries to regulate these less toxic but omnipresent wastes with what is known as the "universal waste rule." The requirements, especially paperwork, are less stringent, presumably to encourage compliance. You probably need to review the universal waste rules as part of your paper.

Q. What type of wastes are typically put into hazardous waste landfills? Is there one particular item or category that dominates in these HW landfills?
A. Excellent question. I don't know. I will try to find out.