The potential value associated with all such waste hills depends entirely on how they are managed.

Traditional MSW management for the last 75 years called for burying the wastes and covering them with dirt until the landfill site could hold no more, eventually forming a large hill at full capacity. Some 25 years ago enterprising waste-to-energy companies started a new management approach by generating electricity from MSW. This was accomplished by burning the MSW to create heat. The heat was used to produce high pressure steam. The steam in turn powered a steam turbine electric generator. The resulting waste-to-energy plants are commonly referred to as mass burn MSW waste-to-energy facilities.

During the last 15 years marketplace efforts have been made to prevent the continuing discharge of methane gas from landfills. Methane gas is the most detrimental greenhouse gas, perhaps 20 times as harmful to the environment as carbon dioxide gas. By burning the methane in a gas powered electric generator the gas is converted into carbon dioxide gas as electricity is produced.

Next generation waste management may be significantly improved by using different technology to better manage solid wastes. The next generation technology calls for the anaerobic digestion of MSW that produces biogas in the same manner that landfills produce biogas. Municipalities are quite familiar with anaerobic digestion technology since some 10,000 already own and operate anaerobic digesters and have been doing so for the last 75 years. The biogas can be beneficially used by generating electricity in the same manner that landfills are converting methane gas to electricity. This method of waste management, however, is easily capable of producing over twice as much electricity as mass burn MSW facilities are able to accomplish by using improved anaerobic digestion technology.

There are now over 100 MSW-to-energy plants in operation in 31 states throughout the United States. These plants incinerate about 15% of the total trash generated or about 105,000 tons per day. On a consolidated basis, these plants generate approximately 2,769 megawatts of electricity. The investment in capital facilities totals more than $10 billion. These MSW-to-energy (also called biomass-to-energy) plants represent extremely inefficient conversion of Btus (British Thermal Units) to electricity. The total electricity generated can be converted into equivalent Btus by multiplying the total kWh by 3,414. 2,769MW x 1000 kW/MW x 24h x 3,414Btu/kWh = 226,880,784,000 Btus. The total 105,000 tons of trash per day is equivalent to 105,000 x 2,000 lbs/ton = 210,000,000 lbs/day. Dividing the total Btus/day by the lbs of trash/day results in an average Btu/lb of trash or 226,880,784,000 divided by 210,000,000 = 1,080 Btu/lb average. Since MSW has a rather well known Btu value of about 4,750 Btu/lb, the total system conversion efficiency of existing MSW-to-energy is 1,080 divided by 4,750 x 100% = 22.7%. According to the US Department of Energy, biomass-to-electricity through pyrolysis technology (same as mass burn MSW facilities) exhibits an efficiency of approximately 20%. These dismal efficiencies of dry processing are, for the most part, attributable to the inherent high moisture content of biomass.

Anaerobic digestion technology is a wet rather than dry process. Moisture is a process requirement rather than an operational detriment. The ability of anaerobic digestion to convert Btus into electricity may be theoretically determined as follows: MSW has an average organic content of about 70%. 70% of 210,000,000 lbs/day = 147,000,000 lbs/day. Of this amount, approximately 75% are volatile solids or 0.75 x 147,000,000 = 110,250,000 lbs/day. The new and improved OAT(™) process of anaerobic digestion produces about 12 cubic feet of methane/lb volatile solids. The total methane produced at 99% volatile solids to methane efficiency is found by 110,250,000 x 12 x 0.99 = 1,309,770,000 cubic feet/day.

The next step is to convert the methane into electricity. The hourly methane production is found by dividing the daily production by 24 or 1,323,000,000/24 = 54,573,750 CFH (cubic feet per hour). This figure divided by about 12 equals the kW sized gas generator that would convert the total methane into electricity or 54,573,750/12 = 4,548,000 kW. kW/1000 = MW or 4,548,000/1000 = 4,548 MW or 1.64 times as much as existing MSW-to-energy mass burn technology. This establishes a greatly improved biomass-to-electricity efficiency to 36%. By adding combined cycle generation, the efficiency increases above 50% or more than twice as much electricity than existing state-of-the-art mass burn MSW facilities. Combined cycle refers to the practice of using the waste heat from a power generation device to produce steam. The steam, in turn, is beneficially used to produce additional electricity through the use of a steam turbine generator. Steam generation is the only method of making electricity in existing mass burn MSW facilities. The splendid improvements in generation efficiency can be accomplished by applying common scientific principles to existing and fully established well known technologies. New technology doesn’t have to be created. Existing technologies must be used in a different manner than before. It’s that simple.

The use of new and improved anaerobic digestion technology to manage MSW is therefore far more effective than existing waste management practices in terms of total marketplace value produced. A bit of gold from a pile of trash one might conclude.

Coal provides nearly 50% of the electrical generating fuel in the United States and similar percentages apply around the world. Coal is more abundant than oil, if fact, coal reserves are far more abundant than oil reserves. There is enough coal on the earth to supply all the current energy requirements of the entire planet for hundreds of years. Coal is many times more abundant than the reserves of all other fossil fuels combined.

In the normal mining of coal its overburden must first be removed. The resulting piles of overburden materials become waste coal. They are called "culm" piles in the eastern Pennsylvania anthracite coal region and "gob" or "boney" piles in the bitiminous coal mining regions of western Pennsylvania, West Virginia, and elsewhere.

The Susquehanna River is the nation’s sixteenth largest river and is the largest river lying entirely in the United States that flows into the Atlantic Ocean. The Susquehanna and its tributaries drain 27,510 square miles spread over parts of the states of Maryland, New York, and Pennsylvania. The river meanders 444 miles from its origin at Otsego Lake near Cooperstown, New York until it empties into the Chesapeake Bay at Havre de Grace, Maryland. The Susquehanna contributes one-half of the freshwater flow to the Bay. Acid mine drainage occurs in several tributaries to the Susquehanna.

Acid mine waste pollution is caused by the physical and chemical weathering of a very common mineral. The main culprit seems to be iron pyrite, a mineral as "fool’s gold". The level of acidity and the concentration of heavy metal pollutants in the mine drainage can be directly correlated to the amount of pyrite in the area around the mine. Physical weathering of the pyrite is essential to reduce the grain size of the mineral. The early miners inadvertently accelerated this process by grinding up the ore and dumping the overburden in the mine tailings piles.

Raw coal may be sold as mined or may be processed in a beneficiation/washing plant to remove noncombustible materials (up to 45% reduction in ash content) and inorganic sulfur (up to 25% reduction). Coal beneficiation is achieved with wet physical processes such as gravity separation and dissolved air flotation. Beneficiation produces two waste streams: fine materials that are discharged as a slurry to a tailings impoundment, and coarse materials (typically greater than 0.5 millimeters in size).

Whether gob/culm piles or tailings ponds the chemistry of acid mine drainage remains the same namely the chemical oxidation of pyrite described in the following reactions:

Iron II ions and acidic hydrogen ions are released into the waters that runoff from the mine drainage tunnels or tailings piles. Iron II ions are oxidized to form iron III ions as shown in the following reaction:

The iron III ions now hydrolyze in water to form iron III hydroxide. This process releases even more hydrogen ions into the aquatic environment and continues to reduce the pH. The iron III hydroxide formed in this reaction is called “yellow boy”, a yellowish-orange precipitate that turns the acidic runoff in the streams to an orange or red color and covers the stream bed with a slimy coating. Aquatic life that dwells on the bottom channel of the stream is soon killed off. Equation 3 describes this reaction:

If we were to look at the net effect of equations 1-3, we would find that the pyrite is oxidized releasing acidic hydrogen ions into the water and coating the stream bed with "yellow boy". The sum of equations 1-3 is shown in the following reaction:
 

Complex systems in nature such as mine tailings piles and mine draining tunnels cannot be described by just a few equations. Other chemical reactions are occurring as shown in equation 5. In addition, sulfides of copper, zinc, cadmium, lead and arsenic will undergo similar geochemical reactions resulting in the contribution of toxic metal ions into mine waste water. Other factors such as the presence of acidic tolerant bacteria (ex. Thiobacillus ferroxidans) can also speed up the process of sulfide oxidation.

There are thousands of gob and culm piles, tailings ponds, and associated discharge streams that continue to inflict environmental damage. Remediation efforts to date have consisted of revegetation. Revegetation does little to stop acid mine drainage damage as every rainfall event continues to add to the acid mine drainage volume through waste coal percolation.

Nationally, waste coal has an average of 60% of the BTU value (British Thermal Units, a unit of energy) of normal coals. It can take up to twice as much waste coal to produce the same amount of electricity. This means that, in most places, waste coal burners can only be economically built where huge volumes of waste coal exist. It would cost too much to truck far-away low-BTU fuel to a centralized burner. Consequently, even if waste coal burning were a clean solution, it wouldn't deal with the problem of more isolated waste coal piles. Burning waste coal doesn't make the waste go away. If 100 tons of waste coal are burned, 85 tons will remain as waste coal ash.

Since far more mercury and other toxic contaminants enter a waste coal burner to produce a given amount of electricity, these high levels of toxic contaminants have to come out somewhere. Toxic metals cannot be destroyed by burning them. To the extent that they are captured in pollution controls (protecting the air), they are then concentrated in the highly toxic ash that ultimately threatens the groundwater wherever this ash is dumped. Waste coal burners have cleaner air emissions than antiquated coal plants due to their better pollution controls, but this only means that the ash is far more toxic, since the highly toxic particulates captured in pollution control equipment end up in the ash. The industry claims that 99.8% of the mercury in the fuel is captured and ends up in their ash.

Waste coal ash is dumped in communities not far from the waste coal burners, threatening the groundwater with leaching lead, mercury and other poisons. Power plant waste is allowed to be dumped without the basic protections (landfill liners) that are required for dumping household trash. When burning any solid fuel, the resulting ash has a higher surface area than the raw, unburned material. The dangers of toxic leaching from ash can be expected to be greater than from the unburned waste coal. The industry claims that by injecting limestone into the ash, the ash becomes impervious to leaching. However, this has not been proven and it seems likely that the alkaline affects of the lime would afford only temporary protection, especially since the region where most of the waste coal burners are (Pennsylvania, West Virginia) suffers from the nation's worst acid rain that would tend to deplete the effects of lime addition.

The waste coal burning industry's own data shows that waste coal ash does in fact leach metals into groundwater, despite their public assertions to the contrary. Ashes at 2 of 12 facilities studied in Pennsylvania were shown to contain levels of arsenic higher than the maximum allowable concentration set forth for land application of sewage sludge. Of 221 samples of leachate from waste coal ash at the ash dumps, lead contamination in 23 samples (10.4%) exceeded a level 10 times higher than EPA's maximum contaminant level (MCL) for drinking water. Six samples exceeded this "10 times the drinking water standard" level for cadmium, as did single samples for chromium and selenium. In short, the chemistry of acid mine drainage from gob/culm piles and tailings ponds remains the same for waste coal ash.

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