Abstract:
A method of accelerated remediation or bioremediation of contaminated material such as manure-contaminated material is provided comprising generating a treated contaminated material entraining air stream at a velocity sufficient for entraining the contaminated material therein. The contaminated material is entrained in the air stream and is then microenfractionated to form a microenfractionated contaminated material. Finally, the microenfractionated contaminated material is treated with a least one chemical amendment and/or one biological amendment thereby facilitating the accelerated remediation or bioremediation. The chemical amendment can comprise either a chemical oxidizing agent, a chelating agent, or a metallic reducing agent. The preferred metallic reducing agents are zero valent iron, zero valent zinc, zero valent tin, zero valent manganese and zero valent aluminum.

Description:
RELATED APPLICATION 
     This is a continuation-in-part application of U.S. Ser. No. 09/943,725, filed on Aug. 30, 2001 now U.S. Pat. No. 6,541,241 which is a continuation of U.S. Ser. No. 09/197,079, filed Nov. 20, 1998 (U.S. Pat. No. 6,306,641), which is a continuation-in-part application of U.S. Ser. No. 08/782,410, filed Jan. 14, 1997 (U.S. Pat. No. 5,854,061), which is a continuation-in-part application of U.S. Ser. No. 08/685,116, filed Jul. 23, 1996 (U.S. Pat. No. 5,824,541), which is a continuation-in-part application of U.S. Ser. No. 08/223,523, filed Apr. 5, 1994 (U.S. Pat. No. 5,593,888), which is a continuation-in-part application of U.S. Ser. No. 08/043,666, filed Apr. 6, 1993 (abandoned), which is a divisional application of U.S. Ser. No. 07/918,528, filed Jul. 21, 1992 (abandoned). 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method for the remediation of manure-contaminated material, and more particularly to a method for the remediation of manure-contaminated material treated with chemical amendments. It also relates to producing an enriched fertilizer from the remediated manure-contaminated material. 
     There are known processes for treating manure-containing soil. U.S. Pat. No. 3,939,280, for example, is directed to a process for treating poultry manure with acid, formaldehyde and urea to obtain a pathogen-free product suitable as feedstuff for ruminant animals. 
     As stated in U.S. &#39;208, poultry manure has been utilized for centuries as a soil enriching material because it contains an advantageous mixture of organic protein, inorganic nitrogen, fiber and minerals. The disposal of this material, which is collected in large quantities, poses a serious problem to the poultry industry. It is customary to remove the accumulated poultry manure periodically from under the cages and transport it to a disposal area some distance away. After drying and composting the poultry manure for a period of days or weeks, it is then used as a landfill, or it is sold as a soil builder. A major use of poultry manure at the present time is as a soil enriching agent, based on its inherent phosphorus content. 
     According to the U.S. &#39;280 invention, there is provided a process which comprises four critical steps. In step 1, to the poultry manure as collected in the poultry raising operation, there is added an amount of acid capable of adjusting the pH of the poultry manure to be less than 7.0, preferably about 5.5 to 6.0. Formaldehyde, or a substance that releases formaldehyde, such as paraformaldehyde, is added in step 2 and is mixed in the poultry manure, before or after step 1, to kill the bacteria present therein. As the third critical step in the process, there is added from about 1 to about 20 weight percent of urea, preferably about 2 to 10 weight percent, based on the weight of poultry manure, calculated as having zero percent moisture. The final critical step of the process is drying the product of step C to a condition suitable for storage, packaging and use, generally to a moisture content of less than 15 weight percent, preferably about 10.+−.5 weight percent. This final drying is conducted at a temperature below the melting point of urea, i.e., 132.degree.C. 
     U.S. Pat. No. 5,928,403 relates to treating poultry manure in the growing location with alum in an amount of from about 0.15 to about 9.25 pounds per bird raised. The alum-treated manure may also be used as an agricultural fertilizer. 
     The invention of U.S. &#39;403 is predicated on the discovery that treatment of poultry litter with the aluminum sulfate compound, alum, dramatically reduces ammonia volatilization from the litter. Results also indicate that alum, ferrous sulfate and calcium hydroxide effectively precipitate soluble phosphorus when added to litter, thereby reducing soluble phosphorus levels. Poultry litter is composed of a mixture of bedding material, manure, spilled food and feathers. 
     A need therefore exists for a method of remediation which will overcome problems associated with the above described prior art methods. 
     SUMMARY OF THE INVENTION 
     Applicants have met the above-described existing needs and have overcome the above-described prior art problems through the invention set forth herein. 
     Accordingly, a method is hereby provided for remediating manure-contaminated material. The method of the present invention comprises providing a mass of manure-contaminated material including in situ-formed bacteria and nitrogen-containing materials. The mass of manure-contaminated material is acidified to a pH of not more than about 7.0 without (a) destroying a substantial portion of said active bacteria, and/or (b) without liberating a substantial portion of said nitrogen-containing materials. Then, the acidified manure-contaminated material is particularized, preferably microenfractionated, as hereinafter described. The particularized, acidified manure-contaminated material is treated with at least one chemical amendment to form a treated particularized manure-contaminated material. Preferably, the microenfractionated, acidified manure-contaminated material is treated with at least one nutrient. 
     Preferably, acidifying of the mass of manure-contaminated material comprises neutralization. The mass of manure-contaminated material is preferably acidified with sulfuric acid and/or phosphoric acid and/or citric acid. 
     In a preferred form of this invention, the average size of the particularized, acidified manure-contaminated material is substantially reduced. Moreover, when the mass of manure-contaminated material undergoes microenfractionation, the average size of the particularized, acidified manure-contaminated material is substantially reduced as hereinafter described. Furthermore, the average surface area of the particularized, acidified manure-contaminated material is substantially increased. And, when the mass of manure-contaminated material undergoes microenfractionation, the surface area of the particularized, acidified manure-contaminated material is substantially increased as hereinafter described. 
     The amount of active bacteria, which is present in the mass of acidified manure-contaminated material, is substantially increased as compared to the amount of active bacteria which is present in said mass of manure-contaminated material. And, the amount of nitrogen-containing materials which are present in said mass of acidified manure-contaminated material as compared to the amount of nitrogen-containing materials which are present in said mass of manure-contaminated material. 
     Preferably, the chemical amendment comprises at least one nutrient. Additionally, the chemical amendment can be configured to activate the active bacteria so that subject method will proceed more expeditiously. Thus, in a preferred embodiment of this invention, the treated particularized manure-contaminated material comprises a fertilizer. 
     In one form of the invention, a method of using an apparatus is provided for the accelerated remediation of treated contaminated material. Treating of the contaminated material with at least one chemical amendment, with or without at least one biological amendment, can occur prior to, and/or during, and/or subsequent to, microenfractionating of the contaminated material. The chemical amendment can be at least one chemical reducing agent with or without at least one chemical oxidizing agent. For example, a contaminated material can be treated with at least one chemical amendment comprising a chemical reducing and/or oxidizing agent to form a treated contaminated material prior to microenfractionation of thereof. Then, an air stream is generated at a velocity sufficient for entraining the treated contaminated material therein, and the treated contaminated material is entrained in the air stream, and the treated contaminated material is microenfractionated under conditions sufficient to form a microenfractionated treated contaminated material such that subsequent accelerated remediation is provided under conditions sufficient for conducting said accelerated remediation. Alternatively, the chemical amendment(s) can be added during, or subsequent to, microenfractionating of the contaminated material. In any of the above-described methods, the accelerated remediation of the treated contaminated material can be facilitated. 
     The chemical amendment can also comprise at least one chemical reducing agent which is in the form of a liquid or a solid, preferably an aqueous solution, which is capable of acting as a chemical reducing agent for remediation or bioremediation purposes, particularly in the microenfractionation of contaminated materials of the present invention. These types of chemical amendments are particularly useful in the dehalogenation of halogenated hydrocarbons such as the difficult to remediate chlorinated hydrocarbons. 
     The chemical amendment of this invention can comprise a chemical reducing agent. Preferably, the chemical reducing agent comprises a metallic reducing agent. Preferably, the metallic reducing agent comprises a zero valent metallic compound. More preferably, the metallic reducing agent is a zero valent metallic compound comprising iron, zinc, tin, aluminum, manganese or other similar zero valent metallic compounds. Most preferably, the chemical reducing agent comprises a zero valent iron compound. 
     An activating agent can also be added to the chemical reducing agent to make the remediation with the chemical reducing agent more effective and/or efficient. Such activating agents are typically acidic activating agents, preferably organic acid acidic activating agents such as acetic acid, or inorganic acidic materials such as hydrochloric acid, phosphoric acid, or nitric acid. Other acidic activating agents may include aliphatic alpha-hydroxycarboxylic acids of the type RCHOHCOOH and the corresponding beta-hydroxycarboxylic acids RCHOHCH 2 COOH, complexing agents such as ethylenediaminetetraacetic acid (EDTA), nitrolotriacetic acid (NTA) and diethylenediamine-pentaacetic acid (DPTA) and amines, hydroxyl containing amines such as mono-, di- and triethanolamine and diamines, triamines, polyamines having complexing properties. Exemplary alpha- and beta-hydroxy carboxylic acids are glycolic acid, lactic acid, glyceric acid, α,β-dihydroxybutyric acid, α-hydroxy-butyric acid, α-hydroxy-isobutyric acid, α-hydroxy-n-valeric acid, α-hydroxy-isovaleric acid, β-hydroxy butyric acid, α-hydroxy-isobutyric acid, β-hydroxy-n-valeric acid, β-hydroxy isovaleric acid, erythronic acid, threonic acid, trihydroxy-isobutyric acid and saccharinic acids and aldonic acids, such as gluconic acid, galactoni acid, talonic acid, mannonic acid, arabonic acid, ribonic acid, xylonic acid, lyxonic acid, gulonic acid, idonic acid, altronic acid, allonic acid, ethenyl glycolic acid, and β-hydroxy-isocrotonic acid. Also useful are organic acids having two or more carboxylic groups, and no or from one to ten hydroxyle groups, such as oxalic acid, malonic acid, tartaric acid, malonic acid, tartaric acid, malic acid, and citric acid, ethyl malonic acid, succinic acid, isosuccinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, maleic acid, fumaric acid, glutaconic acid, citramalic acid, trihydroxy glutaric acid, tetrahydroxy adipic acid, dihydroxy maleic acid, mucie acud, mannosaccharic acid, idosaccharic acid, talomucie acid, tricarballylic acid, aconitic acid, and dihydroxy tartaric acid. 
     The chemical amendment can also comprise at least one chemical oxidizing agent which is in the form of a liquid or a solid, preferably an aqueous solution. Preferably, the chemical oxidizing agent can comprise a peroxide, a permanganate, a nitrate, a nitrite, a peroxydisulfate, a perchlorate, a sulfate, chlorate, a hypochlorite, an iodate, a trioxide, a peroxybenzoic acid, an oxide, an iodic acid, a nitric acid, a periodic acid, a peracetic acid, a hydantoin, a triazinetrione, a hydroxide, a percarbonate, a superoxide, an isocyanate, an isocyanic acid, a bromanate, a biiodate, a bromate, a bromate-bromide, a molybdic acid, a dichromate, a chromate, a periodate, a chlorite, an iodate, or a perborate. More preferably, the chemical amendment can comprise any one of the following: aluminum nitrate, ammonium dichromate, ammonium nitrate, ammonium peroxydisulfate, ammonium permanganate, aquaquant sulfate, ammonium perchlorate, microquant sulfate, ammonium peroxydisulfate, spectroquant nitrate, barium bromate, barium chlorate, barium nitrate, barium perchlorate, barium permanganate, barium peroxide, cadmium nitrate, 1-bromo-3chloro-5,5 dimenthylhydantoin, bismuth nitrate, calcium hypochlorite, calcium iodate, calcium nitrate, ceric ammonium nitrate, ceric sulfate, calcium chlorate, calcium chlorite, calcium hypochlorite, calcium perchlorate, calcium permanganate, calcium peroxide, cerous nitrate, chloric acid, chromium trioxide, chromium nitrate, cobalt nitrate, copper chlorate, cupric nitrate, halane (1,3, dichloro-5,5dimenthylhydandoin),3-chloroperoxybenzoic acid, cobalt nitrate, ferric nitrate, hydrogen peroxide, guanidine nitrate, iodic acid, lanthanum nitrate, lead dioxide, lead nitrate, lead oxide, lead perchlorate, lithium nitrate, lithium perchlorate, lithium hypochlorite, lithium chlorate, lithium peroxide lithium, perchlorate, magnesium bromate, magnesium chlorate, magnesium peroxide, magnesium nitrate, mercuric nitrate, mercurous nitrate, mercurous chlorate, manganese dioxide, mono-(trichloro)-tetra-(monopotassium dichloro)-penta-α-triazinetrione, magnesium perchlorate, nitric acid, nickel nitrate, mercurous nitrate, periodic acid, peracetic acid, perchloric acid solutions, Class II and III (depending upon centration), potassium peroxide, potassium superoxide, potassium biiodate, potassium bromate, potassium bromate-bromide, phosphomolybdic acid, phenylmercuric nitrate, potassium hydroxide, potassium iodate, potassium dichromate, potassium nitrate, potassium nitrite, potassium chromate, potassium dichloro-β-triazinetrione (potassium dichloroisocyanate), potassium dichromate, potassium chlorate, potassium percarbonate, potassium nitrate, potassium perchlorate, potassium periodate, potassium permanganate, potassium persulfate, silver peroxide, sodium bromate, sodium carbonate peroxide, sodium dichloro-β-triazinetrione (sodium dichloroisocyanate) silver nitrate, silver oxide, silver perchlorate, sodium chlorite, sodium chlorate, sodium nitrate, sodium iodate, sodium dichromate, sodium nitrate, sodium perborate, sodium perborate (anhydrous) sodium perchlorate, sodium percarbonate, sodium perchlorate monohydrate, sodium periodate, sodium nitrite, sodium persulfate, sodium permanganate, sodium peroxide, strontium nitrate, strontium perchlorate, strontium peroxide, thorium nitrate, trichloroisocyanic acid, zinc nitrate, thallic nitrate, uranyl nitrate, urea peroxide, yttrium nitrate, zinc bromanate, zinc chlorate, zinc permanganate, and zinc peroxide. 
     The contaminated material can comprise nitrated and/or chlorinated hydrocarbons including nitrated and/or chlorinated polycyclic materials, nitrated and/or chlorinated heterocyclic materials, and nitrated and/or chlorinated aliphatic materials. Exemplary contaminated compounds include chlorinated pesticides, TNT, and RDX. 
     Preferably, the accelerated remediation reaction is conducted aerobically or abiotically, and more preferably by an in situ abiotic process. The reaction can also be conducted methanogenically. 
     Generally, the means for generating a treated contaminated material entraining air stream at a predetermined velocity comprises an elongate drum having a longitudinal axis, first and second end portions, and a center portion. The drum is rotatable about its longitudinal axis at a predetermined rotational speed, and means extending outwardly from the drum are provided for generating the treated contaminated material entraining air stream. Preferably, the treated contaminated material entraining air stream comprises a plurality of air currents, and the air current generating means comprises a plurality of paddles extending outwardly from the cylindrical outer surface of the drum. Typically, each paddle comprises a base portion connected to the drum, and a blade portion. Each blade portion has a major surface oriented for generating at least one the air current having a sufficient velocity for entraining and transporting treated contaminated material upwardly of the rotating drum when the drum is rotated at the predetermined rotational velocity. 
     The treated contaminated material entraining air stream preferably comprises a plurality of intersecting air currents. Each of the intersecting air currents has a sufficient velocity for entraining and transporting a portion of the treated contaminated material upwardly of the air stream generating means. More specifically, the means for generating a plurality of intersecting air currents comprises a plurality of end paddles extending radially outwardly from the first and second end portions of the drum. Each end paddle can comprise a base portion connected to the drum and a blade portion. In this instance, the blade portion has a major surface oriented relative to the drum for generating an air current directed upwardly of the drum and transversely toward the center portion of the drum when the drum is rotated at the predetermined rotational speed. It also has a plurality of center paddles extending radially outwardly from the center portion of the cylindrical outer surface. Each center paddle comprises a base portion connected to the drum, and a blade portion having first and second major surfaces. The first and second major surfaces are oriented relative to the drum for generating an air current directed upwardly and rearwardly of, and transversely toward the first and second end portions of the drum respectively when the drum is rotated at the predetermined rotational speed. In use, the air currents generated by the end and center paddles intersect and combine to form the treated contaminated material entraining air stream for microenfractionating the treated contaminated material. 
     In a preferred embodiment, the treated contaminated material entraining air stream comprises a vortex-type air stream which transports the entrained treated contaminated material in a generally circular path. In this case, the end and center paddles can extend radially outwardly from the drum so that they are arranged in a plurality of helical longitudinal row. Also, the drum can further comprise first and second transition portions disposed between the center portion and the first and second end portions respectively. The first and second transition portions of the drums having a plurality of end paddles and a plurality of center paddles extending radially outwardly therefrom. 
     In another form of the invention, a method of accelerated remediation of treated contaminated material is provided. This method comprises the steps of (a) treating the treated contaminated material with chemical biological amendments for facilitating accelerated remediation thereof, (b) providing an entraining air stream having a sufficient velocity for entraining the treated contaminated material therein, (c) entraining the treated contaminated material in the air stream, (d) microenfractionating the treated contaminated material, and (e) discharging the microenfractionated treated contaminated material from the air stream so that the treated contaminated material will be acceleratedly remediated. The microenfractionating step preferably comprises homogenization and aeration of the treated contaminated material. The entraining air stream preferably comprises providing an entraining air stream including a plurality of upwardly and transversely flowing, intersecting air currents, and more preferably comprises a vortex-like entraining air stream. Typically, the step of providing an entraining air stream includes the step of rotating a drum assembly at a rotational speed sufficient for generating the entraining air stream. The drum assembly can include means for generating this plurality of intersecting air currents when the drum assembly is rotated. 
     In one preferred method, the treated contaminated material is contaminated with a hydrocarbon material, and the accelerated remediation of the treated contaminated material comprises accelerated chain scission of the hydrocarbon material. In another case, when the treated contaminated material is contaminated with hydrocarbon material, the accelerated remediation, typically employing chemical reduction. If the hydrocarbon contaminant is halogenated, a halogen will also be produced. A further instance is where the treated contaminated material is contaminated with hydrocarbon material, and the accelerated remediation comprises reduction of the total hydrocarbon material in the treated contaminated material. 
     In general, at least about 70%, preferably at least about 80%, more preferably at least about 90%, and most preferably at least about 95% of the accelerated remediation of the treated contaminated material is completed within 150 days, preferably within 120 days, more preferably within 90 days, and most preferably within 60 days. Moreover, the volume of treated contaminated material which is acceleratedly remediately treated by the method of the present invention is generally at least about 1500 cubic yards, preferably at least about 2000 cubic yards more preferably at least about 2500 cubic yards, most preferably at least about 3000 cubic yards, per day per apparatus. This is particularly significant in the case of chlorinated contaminates since most prior art systems cannot remediate these compounds even after years of trying to treat same. 
     The method of the subject invention produces high surface area treated contaminated microenfractionated material. The surface area of the treated contaminated non-microenfractionated material can be increased, after the microenfractionating step, as compared to the surface area of the treated contaminated non-microenfractionated material, by a factor of at least about 1×10 6 , preferably at least about 2×10 6 , more preferably at least about 3.5×10 6 , and most preferably at least about 5×10 6 . More specifically, the subject method can further include the step of discharging the microenfractionated treated contaminated material from the air stream and redistributing it throughout a soil matrix. In this manner, the surface area of the microenfractionated treated contaminated material is substantially increased. This is especially important when dealing with clay type soils. 
     Most prior art remediation processes cannot be conducted at ambient temperatures below 10 degrees C. However, when the method of the subject invention is employed, the aforementioned high degree of accelerated remediation can be maintained at an average ambient temperature which is not more than about 10 degrees C., preferably not more than about 7 degrees C., more preferably not more than about 3 degrees C., and most preferably not more than about 1 degree C. 
     One reason why the accelerated remediation of this invention can be conducted at the low ambient temperature conditions described in the preceding paragraph herein, is that the subject reaction is generates a more substantial amount of exothermic heat than known prior art remediation processes. Thus, the accelerated remediation is preferably conducted at an exothermic temperature measured within the contaminated material of at least about 5 degrees, and more preferably at least about 10 degrees, higher than an average ambient air temperatures of from about zero up to about 10 degrees C. 
     As for the treatment of the contaminated material with the chemical amendments, it is preferred that they are dispersed throughout the redistributed microenfractionated treated contaminated material thereby facilitating accelerated remediation. 
     Other preferred embodiments of the subject method include (a) locating an impervious undercover below the treated contaminated material prior to the microenfractionating step thereby preventing the chemical amendments from leaching into soil underlying the treated contaminated material, and (b) a cover over the microenfractionated treated contaminated material, the cover allowing substantial solar radiation to pass therethrough and into the microenfractionated treated contaminated material, thereby facilitating the accelerated remediation and preventing moisture from soaking the microenfractionated treated contaminated material and to prevent moisture evaporation from the microenfractionated treated contaminated material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of the preferred apparatus for use in the present invention. 
     FIG. 1A shows a front view of an alternative embodiment of the present invention. 
     FIG. 1B schematically depicts an exemplary flow tank system  225 . 
     FIG. 2 is a rear view of the apparatus of FIG.  1 . 
     FIG. 2A shows a rear view of an alternative embodiment of the present invention. 
     FIG. 3 is a left side view of the apparatus of FIG.  1 . 
     FIG. 3A is a left side view of another embodiment of the apparatus according to the present invention. 
     FIG. 4 is a right side view of the apparatus of FIG.  1 . 
     FIG. 4A is a left side view of the apparatus according to the present invention as shown in FIGS. 1A and 2A. 
     FIG. 4B is an enlarged view of the pivoting rear wheel assembly in its extended position. 
     FIG. 5 is a top view of the apparatus of FIG.  1 . 
     FIG. 5A is a top view of an alternative embodiment of an apparatus according to the present invention. 
     FIG. 6 is a top view of the apparatus of FIG. 1 configured for being driven sideways. 
     FIG. 7 is a front view of the apparatus of FIG. 1 configured for being towed sideways. 
     FIG. 7A is a front view of an apparatus shown in FIGS. 1A and 2A configured for being transported by towing. 
     FIG. 7B is an enlarged view of the drum shaft bearing assembly. 
     FIG. 8 is a right side cross-sectional view of the drum and paddle assembly according to the first embodiment of the present invention. 
     FIG. 8A is a right side cross-sectional view of the drum and paddle assembly according to a second embodiment of the present invention. 
     FIG. 9 is an enlarged sectional view of the center portion of the drum and paddle assembly, showing the counter-rotating vortex-like airstreams generated when the assembly is rotated. 
     FIG. 9A is bottom view of an alternate drum and paddle assembly. 
     FIG. 10 is a top view of a right side paddle according to the first embodiment of the present invention. 
     FIG. 10A is a top view of a right side paddle according to the second embodiment of the present invention. 
     FIG. 11 is a top view of a center paddle according to the first embodiment of the present invention. 
     FIG. 11A is a top view of a center paddle according to the first embodiment of the second invention. 
     FIG. 12 is a top view of a left side paddle according to the first embodiment of the present invention. 
     FIG. 12A is a top view of a left side paddle according to the first embodiment of the second invention. 
     FIG. 13 is a side view of a right side paddle showing the shear pin feature, and showing the released paddle in phantom according to the first embodiment of the present invention. 
     FIG. 13A is a side view of a right side paddle showing the shear pin feature, and showing the released paddle in phantom according to the first embodiment of the second invention. 
     FIG. 13B is a enlarged fragmentary view of a paddle showing a cutting edge  72  formed on the leading edge of a paddle body  74 . 
     FIG. 14 is a front perspective view of a contaminated material according to the present invention, having the drapes removed to expose the chamber and drum assembly. 
     FIG. 15 is a top view of windrows formed in the treated contaminated material prior to microenfractionation. 
     FIG. 16 is a side view of windrows formed in the treated contaminated material prior to microenfractionation. 
     FIG. 17 is a perspective view of an alternative embodiment of the invention. 
     FIG. 18 is a front elevational view of a drum showing an alternative paddle arrangement wherein paddles in adjacent rows are offset. 
     FIG. 19 is a partial side view of an apparatus showing the drum drive motor mounted on a torque plate. 
     FIG. 20 is a sectional view along line A—A in FIG.  19 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the ex-situ method of this invention, the soil should be removed from the contaminated site and placed in windrows on top of durable liner which acts as an underliner in the subject accelerated remediation process. This underliner substantially prevents undesirable materials present in the ex-situ soil from leaching into the surrounding uncontaminated soil prior to the completion of the remediation process. It has been determined that a woven polyolefin fabric of the type exemplified by NOVA-THENE® RB616-6HD, manufactured by Polymer International (N.S.) Inc., of Truco Nova Scotia, Canada, is one of the most durable liners available for this purpose. One reason is that it will remain intact during the microenfractionation of the treated contaminated material by the hereinafter-described subject apparatus. 
     After the liner has been laid down in a pile (on as smooth a surface as possible), a layer of sand is applied over the liner. Windrows are typically spaced 6-8 feet apart. The windrows should be no wider than 14 feet and no higher than 6 feet. The above-described liner is extended out 4 feet past edge of pile with a berm of about eight inches to allow the microenfractionating equipment to straddle the pile. All rocks, chunks of concrete larger than two inches and other debris should be removed from contaminated soil prior to microenfractionation. Once the contaminated dirt has been windrowed, treatment with the chemical amendments can commence. 
     Soil Analysis Prior to Starting Treatment 
     First, the soil is analyzed for contaminant, and a full agricultural analysis is done. The testing for total petroleum hydrocarbons is not in itself an easy task. The type and quantity of contaminant must be accurately revealed. The contaminant reduction requirements must also be known. In addition, a series of soil tests must be undertaken. These tests include, but are not limited to, the following: 
     1. Total Petroleum Hydrocarbon Levels: The amount and nature of the hydrocarbon contaminants in the soil must be first determined. These include BTEX, PCP, PAH, PCB and the like.(EPA Test Nos. 418.1, 8015, 8020, 8270, etc.) 
     2. Standard ⅓ Bar Moisture Retention: The test will ascertain the quantity of water this soil will retain when placed under ⅓ bar vacuum. This is a standardized test to determine the saturation point of the soil with water. Knowing this will assist in determining the quantity of moisture that can be reasonably utilized during soil treatment. 
     3. pH: This test will determine if the soil is acidic, basic or neutral. Acidic pH is best for chemical oxidation degradation. If the soil is too basic (i.e. pH 8.0 or above), soil amendments will be necessary to make the soil pH more acidic. 
     4. Standard Buffer Capacity: This test will determine how much acid or base can be introduced into the soil before a pH change occurs. This information is useful because soil amendments can alter pH as can biological metabolyte materials produced during the biological treatment of petroleum hydrocarbon contaminated soil. 
     5. Standard Electrical Conductivity: Bacteria require a certain amount of electrical conductivity to survive and metabolize nutrients. If there is too little electrical conductivity or too much, the biological system can be inhibited or destroyed. Again, soil amendments can alter electrical conductivity if it becomes necessary. 
     6. Standard Sodium Absorption Ratio (SAR): This test determines an estimate of the exchangeable sodium percentage of what a soil is, or what it is likely to become if the water that comprises the sample water is in that soil for long periods of time. The SAR has a good correlation to the exchangeable sodium percentage and is easier to calculate exactly (or to estimate from a few simple analysis) than is exchangeable sodium. 
     percentage. If the SAR exceeds 13, the biological system will be greatly impaired. 
     The purpose for the test is to determine if too much salt in the soil will inhibit biological activity by having sodium ions occupy a high proportion of exchange sites in the soil causing high pH and low water permeability. If this situation occurs, biological activity will slow or cease. Note that the use of inorganic nutrients can promote high salt content in soil due to the salt nature of inorganic nutrients. Organic based nutrients do not cause this to happen because they are not salt based. 
     7. Standard Organic Matter: Organic matter is required for any biological system to function properly. The organic matter can be a media of bacteria, it can supply nutrients in some cases, and it can be an indicator of biological activity. Knowing the organic matter level can help determine if additional organic matter is needed for soils treatment. 
     8. Standard Micro-Nutrient Profile of the Soil: In addition to macro-nutrients, a micro-nutrient profile of the soil is very useful. Macro-nutrients are elements such as sulfur, copper, iron, zinc, boron, manganese, sodium, magnesium and calcium. All of these elements are necessary for microbial growth in very small quantities. If one or more of these nutrients are absent or unavailable, bacterial activity is inhibited. Conversely, if one or more micro-nutrients is excessive, this can also be inhibitory on bacterial growth. This must be known. The soil type of the contaminated soil must be ascertained, i.e. percentage of sand, silt, or clay. Each soil type must be treated differently. For instance, straight sand may not be capable of retaining moisture; clay or fine silt may require the addition of sand to assist in breaking the soil platelets apart, so that oxygen is not excluded from the system. 
     9. Redox Potential: This is a measure of the potential for a soil to oxidize or reduce introduced materials. More specifically, in soils, the redox potential determines the oxidation-reduction equilibrium as measured analytically using an electrode (usually a platinum electrode). This electrode potential will yield the oxidation states of iron and manganese in the soil as well as the sulfate/sulfide ratio, the nitrate activity, and other elements or compounds actively receiving or releasing electrons. The redox potential value is useful in estimating the quantities of oxidative and/or reductive chemicals required for remedial activity. 
     10. Contaminants: This includes the contaminant materials which typically pollute the soil including pesticides, insecticides, herbicides, dioxins, PAH compounds, and chlorinated hydrocarbons. 
     Ex-Situ Soil Treatment 
     Ex-situ treatment is the removal of contaminated material to a second site, and the remediation of thereof at that second site. In providing the second site, a berm is made typically from soil, straw or concrete ecology blocks. The width and length is dependent on the area available for use in remediation. First, the area contained by the berm is smoothed. It is then covered with the above-described underliner in order to create an impermeable barrier between the contaminated soil and the uncontaminated soil. Next, the underliner is covered with 2-4 inches of fine sand or pea gravel. Then, the windrows of contaminated soil 14 ft. wide and 6 ft. tall are laid out. Space must be left at sides and ends of berm for maneuvering the microenfractionating equipment. Finally, the entire windrow layout is covered with a translucent outdoor material which permits solar radiation to pass therethrough. The preferred material for this purpose is Loretex 1212 UV (clear), manufactured by Chave &amp; Earley, Inc. of New York City, N.Y., a woven polyethylene substrate coated with polyethylene which is manufactured by The Loretex Corporation. 
     Treatment of Contaminated Materials 
     The soil is prepared by first adjusting the pH. In general, the soil pH is maintained in an acidic to neutral environment. Therefore, the pH of soil is preferably adjusted to between about 4.0 and 7.0, more preferably between about 4.5 and 6.5, and most preferably about 5.0, and is then treated with the chemical amendments. 
     Treatment Cell Construction 
     The treatment cell design of choice is a windrow configuration with the soil pile dimensions. For example, a windrow configuration conforming to 14 feet wide at the base, 5 feet wide at the top and a height of no more than 6.5 feet. Windrow length is limited only to available space at a given job site. The windrow should be placed on a level, smooth, firm surface. An underliner must be used and must be a continuous piece for surrounding environment protection. The edges of the underliner must be bermed 8″ to 10″ to prevent any leachate that may be produced during treatment form escaping. The berm material may vary, but a ridge of sand under the underliner and completely surrounding the contaminated soil works very well. Typically, when using this treatment method, no leachate collection basin has been necessary. By using sand or a similar textured material, the underliner covering the bermed section can be driven on by the microenfracting apparatus without damage to the underliner. 
     After the underliner structure and windows are set up, the soil amendments—pH modifiers and chemical reductants—may be added. The method for dispersion of soil amendment is via broadcast spraying by the H&amp;H Eco Systems spray unit or equivalent, or it is injected directly into microenfractionating chamber of the Microenfractionator™ during the course of its operation. 
     A one piece top cover made from Loretex 1212 UV material is very resistant to damage from solar radiation. This material also transmits the maximum amount of solar radiation to the contaminated soil, thus assisting with elevated soil temperatures to assist the chemical reductive reaction. This property is very useful in promoting chemical activity during periods of low ambient air temperature. 
     Microenfractionation 
     Soil microenfractionation is one of the most critical aspects of soil remediation, such as chemical oxidative and/or reductive treatment of contaminated materials in general, and more particularly petroleum hydrocarbon contaminated soils. In the case of most petroleum hydrocarbon contaminated soil, for example, it is very unevenly contaminated or fractious in nature. The hydrocarbons will frequently form “globs” of contamination of high concentration in the soil. These “globs” repel water as well as maintaining a high enough concentration of petroleum hydrocarbon to inhibit complete chemical oxidation and/or reduction except at the contamination interface. The contamination interface will generally provide conditions favorable for chemical reaction with both available oxidants and/or reductants and relatively low hydrocarbon concentrations. The oxidative and/or reductive degradation rate is thus controlled by the active surface area of the hydrocarbon contaminant. 
     One conclusion that could be discerned from this is that, if the surface area of the hydrocarbon contaminant was increased, the rate of chemical oxidative and/or reductive reactivity would also increase. The apparatus used for that purpose in the subject invention very actively disperses the hydrocarbon contaminant throughout the soil matrix. The apparatus, known as the H &amp; H Microenfractionator, is manufactured by Frontier Manufacturing Company and is capable of increasing surface area by a factor of at least about 1×10 6  with one two-way mixing pass. This same mixing action can disperse all of the soil amendments in the same manner. No other soil mixing machine currently in use is capable of this type of mixing. The H &amp; H Microenfractionator does not just “mix” the soil; it literally homogenizes and aerates it. With this corresponding increase in surface area, the remediation degradation rate, in this case oxidative and/or reductive remediation degradation rate, will increase by several thousand times. This process is defined, for purposes of this invention, as “microenfractionation”. 
     After all additions are added, then the microenfractionation step can take place. For example, after application of pH modifiers and chemicals using a spray system such as the HH System 1000 sprayer, then an apparatus, such as the H &amp; H Microenfractionator, can start its work. In order to achieve the maximum effect, the microenfractionating apparatus preferably must be passed through the soil matrix at least twice. The most efficient method is for the machine to pass through the soil in one direction, then, turn on its axis and pass through the soil in the opposite direction. This way the soil displacement (longitudinally) is essentially negated. 
     Stirring intervals for the contaminated soil will depend on the rate of remediation activity. If all of the treatment specifications are adhered to, a very rapid remediation rate will ensue. Additional/more frequent chemical requirements may be necessary depending on the soil analysis/testing done as the project progresses. 
     In the past, machines such rototillers, trackhoes, discs, and the like were used in remediation to “stir” contaminated soil. In the case of trackhoes, for example, this procedure was extremely time consuming, frequently taking all day to stir 500 cu. yards of soil. This factor alone greatly limited the economics of attempting a large remediation site. The soil handling would probably be cost prohibitive. While this method did a much better job of stirring than rototillers, it still did not address the stirring problem completely. Ideally the soil should be very thoroughly mixed with the soil amendments. The track hoe did not totally address this. It was also too costly as well as inadequate in aerating the soil. Extensive research was done to find soil mixing equipment that would adequately address all of the requirements for efficient biodegradation of hydrocarbons. A variety of rototillers, track hoe attachments, pug mills, batch mixers and shakers were researched. While some of the machines identified had merit, daily mixing volumes were limited. Also, all of the machines were inadequate in aeration. 
     The H &amp; H Microenfractionator can mix remediation chemicals such as pH modifiers, chemical oxidants and/or reductants, other amendments with contaminated soil to form a treated microenfractionated material. Hydrocarbons will rarely contaminate soils in a uniform manner due to causes ranging from varying soil permeability to the water insoluble nature of hydrocarbons. Reducing the normally fractious nature of hydrocarbon contamination in soils is a task that this apparatus can accomplish very effectively. The mixing action simultaneously mixes the remediation chemicals and any other soil amendments with the hydrocarbon contaminated soil. This action brings the remediation chemicals and any soil amendments into direct contact with the contaminated soil to allow the most efficient remediation system. The HH System 614 also aerates the soil very thoroughly to keep the soil in an oxidated rather than a reduced state. It is also much faster—it can “microenfractionate” 500 cubic yards of soil per hour rather than “stir” the 1000 cubic yards per day that the track hoe is capable of doing. 
     Referring now to FIGS. 1 and 2, a microenfractionating apparatus for use in the present invention is shown generally at  10 . A second embodiment is shown in FIGS. 1A and 2A which differs in detail as described below. 
     The apparatus  10  includes frame  12  which is assembled from ladder-type left, right, and top subframes,  12   a ,  12   b  and  12   c  respectively. Frame  12  is supported at its front end by left and right drive wheels  14  and  16 , and at the rear by left and right caster wheels  18  and  19 . Each wheel mounted on an axle which is journaled into a supporting frame assembly  40 . Each rear caster wheel is mounted into its respective frame assembly  40  by a vertical shaft journaled into frame assembly  40  as shown in FIG.  3 . Each rear caster wheel may be locked into a transverse position by locking pin assembly  19  when desired as described below. Each frame assembly  40  includes an upright member  42  slidably received within a complementary vertical sleeve  44  of a mounting assembly  46 . Frame assembly  40  may thereby be raised or lowered relative to the ground on upright member  42  by actuation of hydraulic cylinder  43 , allowing the ground clearance of apparatus  10  to be raised or lowered during operation as more fully described below. Mounting bracket  46  is in turn pivotally mounted on frame  12  at brackets  48 , allowing each frame assembly  40  and wheel to be pivoted by actuation of hydraulic cylinder  45  for different modes of operation as described below. 
     A spray system  200 , as depicted in FIGS. 1 and 3A, is provided for discharging chemical amendments and/or biological amendments into the air stream generated by the apparatus  10  which contains the microenfractionated contaminated material. In this way, the contaminated material can be treated with the chemical amendments and/or biological amendments thereby facilitating said accelerated remediation. The spray system  200  comprises a transversely-extending flow pipe  214 , which extends across the front of the apparatus  10 , beyond the transverse extent of the apparatus  10 . Vented ball valves  220 , including quick-connect fittings, are connected at each end of pipe  214 . A hose  275  (not shown) from a tank  240  (shown in FIG. 1B) containing chemical and/or biological amendments can be attached to either or both of the valves  220  for introducing the amendment(s) into the pipe  214 , and then into the flow pipe  212  and nozzle  210  (see FIG.  3 A). 
     Connected to the midpoint of flow pipe  214  is one end of a shorter flow pipe  212 . Flow pipe  212  extends rearwardly at a right angle to the flow pipe  214 . The other end of the flow pipe  214  is joined to a spray nozzle  210  which discharges a spray  250  of chemical amendments and/or biological amendments into the air stream generated by the apparatus  10 . 
     One or more trailers (not shown) can be attached to the rear of apparatus  10 . Each trailer has a flow tank system  225  mounted thereon for transferring the chemical amendment and/or biological amendment to the flow pipes  214  and  212 , and in turn to the spray nozzle  210 . An exemplary flow tank system  225 , shown schematically in FIG. 1B, comprises a holding tank  240  for storing the chemical amendment and/or biological amendment. In order to transfer the chemical amendment and/or biological amendment to the spray nozzle  210  from holding tank  240 , a pump  230  moves the amendment(s) from tank  240  (see arrows A), through flow pipes  245 ,  255 , and  265 , and then through hose  275  to valve  220 , and onto spray nozzle  210 . Hose  275  is connected to valve  220  by a quick connect fitting. Pump  230  can also transfer chemical amendment and/or biological amendment from pump  230  back to holding tank  240  (see arrows B). The path of chemical amendment and/or biological amendment from pipe  245  to pipe  255  is limited by vented check valve  260 . The path of chemical amendment and/or biological amendment from pipe  265  to hose  275  is limited by vented check valve  265 . Finally, the path of chemical amendment and/or biological amendment from pipe  265  to pipe  285  is limited by vented check valve  280 . 
     In certain cases the chemical amendments and/or biological amendments have detrimental effect on the materials of construction of the apparatus  10 . In these instances it is advisable to use a material of construction for the apparatus  10  such as stainless steel and thereby avoid these detrimental effects. 
     An alternative design for the wheel frame assemblies  40  is shown in FIGS. 4A and 4B. Note that in the alternative frame assembly design for drive wheels  14  and  16 , frame assembly  40  does not pivot, but rather is moved rearward by hydraulic cylinder  45  and raised up by hydraulic cylinder  43  to its stowed position. 
     As best seen by reference to FIG. 5, frame  12  includes upper deck  32  on which are mounted fuel tank  34 , operator&#39;s cab  36 , hydraulic oil tank  37 , engine  38 , and hydraulic pumps  40 ,  42  and  44 . As readily appreciated by those skilled in the art, suitable auxiliary equipment for operation of the engine and drive components in dusty environments is also provided, such as rotating self-cleaning screen  41  of the cooling system of engine  38 . Power for the operation of apparatus  10  is provided by hydraulic pumps  40 ,  42  and  44 , which are driven by engine  38 , preferably a 460 hp diesel engine such as Model 3406, manufactured by Caterpillar. Each hydraulic pump  40   a  and  40   b  delivers pressurized hydraulic fluid to each of drum assembly drive motors  48   a  and  48   b  to reversibly drive rotating drum and paddle assembly  22  from each end. Hydraulic pumps  42   a  and  42   b  deliver pressurized hydraulic fluid to left and right drive motors  50  and  52  respectively. Pump  44   a  delivers pressurized fluid to hydraulic cylinders  43  for raising and lowering frame  12 , while pump  44   b  provides pressurized fluid for operating hydraulic cylinders  45 , and hydraulic cylinder  54  for raising and lowering tail section  31 . Left and right drive motors  50  and  52  are separately controllable by the operator for steering and for driving left and right drive wheels  14  and  16  respectively through an appropriate drive assembly of a suitable design as could be readily determined by one skilled in the art. 
     In the preferred embodiment, a planetary gear assembly, Model No. W-2 as manufactured by Fairfield is used on each the left side and right side drive wheel and motor assembly. The left side planetary drive assembly differs from that of the right side only in that it is rendered free wheeling for reasons described below by operation of an external T-handle. Apparatus  10  is steerable and driveable forwardly, rearwardly, and sideways as described below by virtue of the fact that each drive wheel is driveable forwardly and rearwardly independently of the other by appropriate hydraulic controls of standard design and well-known to those skilled in the art. Each hydraulic pump  40   a  and  40   b  delivers pressurized hydraulic fluid to each of drum assembly drive motors  48   a  and  48   b  to reversibly drive rotating drum and paddle assembly  22  from each end. 
     In an alternative four-wheel drive embodiment (FIG.  5 A), left and right castor wheels  18  and  20  are replaced by left and right rear drive wheels  15   a  and  15   b  and respective hydraulic drive motors  51  and  53 . Corresponding controls as described above with reference to the two-wheel drive embodiment are provided to allow the operator to control the speed and direction of each of the four driven wheels. 
     While the present invention is not intended to be defined or limited by reference to any specific dimensions, in both prior art apparatus and the present invention there is an efficiency of operation resulting from incorporation of a relatively long drum assembly, 17 feet or more for example. Accordingly, the overall width of the apparatus will be even greater than the drum length, while the overall length of the frame of the apparatus is preferably no greater than 8′ 6″. The overall width of the prior art apparatus prevents them from being driven through standard fence gates between adjacent fields, and requires that they be transported over public roads by truck and trailers designed for transporting heavy equipment. The present invention overcomes these limitations and cost disadvantages of the prior art apparatus by providing an apparatus which may be driven sideways under its own power through standard fence gates or over public roads for short distances, and which may be towed for longer distances over public roads when necessary. The means of configuring the present invention for so doing will now be described by reference to FIG. 5 where it can be seen that each wheel is mounted on a frame assembly  40  which is movable between a first position for accommodating forward and rearward travel of apparatus  10  during normal operation, and a second transverse position for accommodating towing or sideways travel of the apparatus. Each frame assembly  40  is moved between the first and second positions by a dedicated hydraulic cylinder  45 , which is controlled by means of appropriate controls (not shown) from operator&#39;s cab  36 . 
     Referring now to FIGS. 1 through 14, drum assembly  22  is mounted transversely within chamber  24 . Chamber  24  is an open-ended housing consisting of a top wall  26 , left and right side walls  28  and  30 , and tail section  31  (FIG.  5 ). Front opening  25  is partially shrouded as shown in FIG. 1 by front drapes  33   a-c . In the preferred embodiment, screened openings  23  are provided in left and right side walls  28  and  30  ahead of drum  56  to permit additional air to be drawn into chamber  24  during operation. (FIG.  3 A). Tail section  31 , essentially a rearwardly extending projection of chamber  24 , extends rearwardly from rear opening  27 . Tail section  31  may be described as a generally planar frame having rearwardly and inwardly extending side members pivotally attached to frame  12  at one end, and to lateral member at their outer ends. Drapes  39  are hung from each side member and the lateral member as best seen in FIG.  2 . The drapes may be made from any suitable material. 
     In the present embodiment, they are fabricated from grade 2 SBR in the form of ½″ thick conveyor belt material. Tail section  31  is pivotable by hydraulic cylinder  54  between a lowered operational position and a raised stowed position for use during transport of the apparatus. Rear drapes  35  are hung from each side and the rear of tail section  31  and from angled frame members defining rear opening  27  as shown. Chamber  24  serves to contain direct the air streams and contaminated material during operation of apparatus  10 , and to reform the contaminated material into a windrow after mixing and aerating as more fully described below. 
     Drum assembly  22  is journaled at opposite ends in left and right subframes  12   a  and  12   b . Hydraulic motors  48   a  and  48   b  are mounted on left and right subframes  12   a  and  12   b , and reversibly drive drum assembly  22  by means of shafts  49   a  and  49   b  when supplied with pressurized hydraulic fluid from hydraulic pumps  40   a  and  40   b  as described above. 
     Alternatively, motors  48   a  and  49   b  are each mounted on a torque plate  120  (FIGS. 19,  20 ), which has notched corners as best seen in FIG.  19 . Torque plate is fitted into a corresponding opening  121  in frame  12 . Rubber plates  122  are fitted into the notched corners between the torque plate and frame  12  to provide cushioning. As the motor is activated, torque plate  120  rotates in response to the reaction torque generated thereby. In addition, this mounting arrangement accommodates a certain amount of radial and axial movement of the drum relative to the frame. 
     Drum assembly  22  includes drum  56 , a hollow cylinder having closed ends, onto which are welded shafts  57   a  and  57   b  (not shown). Shafts  57   a  and  57   b  are journaled into frame  12 , and driveably connected with drum assembly drive motors  48  as described above. Each of shafts  57   a  and  57   b  are journaled into its respective subframe by means of a four bolt flange-type tapered roller bearing  91  such as Model FB 900 manufactured by Browning Company. Each bearing  91  is fitted into a corresponding hole in left and right subframes  12   a  and  12   b . A split ring collar  92  is fitted into circumferential recesses  96  on each of shafts  57   a  and  57   b , and bears against the protruding rotating race  94  of the tapered roller bearing to counteract spreading forces exerted on subframes  12   a  and  12   b . Drum  56  thereby functions as a tension member in frame  12  counteracting spreading forces represented in FIG. 7A by force arrows  102   a  and  102   b . This novel use of drum  56  as a tension member saves the weight of additional structural members which would otherwise be required to counteract spreading forces on subframes  12   a  and  12   b , and allows a lower overall height which further accommodates towing the apparatus  10  on public highways. 
     Turning now to FIGS. 8-12, a plurality of left and right paddles  58  and  60  respectively, and center paddles  62  are mounted on the outer cylindrical surface of drum  56  as shown. In one embodiment, the paddles are arranged in four evenly spaced helical rows along the length of the drum, each row traversing 90° about the drum from one end to the other. In a second embodiment shown in FIG. 9A, the paddles are arranged in four “V-shaped” rows. The V-shaped rows of paddles serve to eliminate transverse steering torque on the apparatus which may be experienced with the use of helical rows where one end of the paddle row engages the contaminated material prior to the other. The V-shaped rows are oriented so that the paddles at each end of a row engage the contaminated material simultaneously, eliminating any steering effect resulting from paddles on one end of the drum engaging the contaminated material before the other. Additionally, the paddles of each V-shaped row are offset from those of adjacent rows to minimize bypassing of contaminated material past the drum. In one embodiment, the paddles in each row are spaced at 12″ intervals. The corresponding paddles of adjacent rows are offset 3″ from one another. Offsetting of the paddles in this manner promotes complete mixing and aeration since the contaminated material at every point along the entire length of drum  56  is directly in the path of at least one paddle. 
     It should be readily understood that more or less rows of paddles and different arrangements of paddles may be used. It is preferred however that left and right paddles  58  and  60  are mounted generally to the left and right of the center point of the drum respectively, while center paddles  62  are mounted along a central portion of the drum. Center paddles  62  may also be interspersed with the left and right paddles along transition portions of the drum as shown in FIG.  9 . Minor variations in the number and arrangement of center paddles interspersed with left and right paddles are possible in accordance to the present invention. 
     Each paddle has a base section  64  by which it is pivotally attached to bracket  66 , which in turn is welded to drum  56  as shown in detail in FIG.  13 . Each paddle is additionally secured in position by a shear pin  68  inserted into hole  70 . Shear pin  68  serves to release the paddle to pivot rearwardly if impacted by a solid object during rotation of drum assembly  22 . A deflector plate  71  is attached at a rearward angle to a forward edge of bracket  66 . 
     In a further embodiment of the present invention, each paddle has a base section  64  by which it is attached to bracket  66 , which in turn is welded to drum  56  (see FIGS. 8A,  10 A- 13 A and  13 B). Each paddle is attached by two bolts  68  inserted into holes  70 . Bolts  68  are designed to shear and release the paddle base section  64  if the paddle encounters an obstruction that would cause damage to the drum assembly  22  during drum rotation. Bracket  66  includes a deflector section extending forward of the paddle base attachment point as a rearward angle therefrom. 
     Each paddle includes a cutting edge  72  formed on the leading edge of paddle body  74 . Extending transversely from the trailing edge of left and right paddles  58  and  60  is a single paddle portion  76  extending inwardly toward the longitudinal center of drum  56 . Center paddles  62  each have a pair of opposed paddle portions  78  extending outwardly toward opposite ends of drum  56 . The paddle portions are preferably disposed at an angle slightly less than perpendicular relative to the paddle body. In a second embodiment (FIGS. 17,  18 ), one or more of the paddles include first and second slots  110 ,  111  in place of bolt holes. Slots  110  and  111  are preferably oriented perpendicular to one another, although other orientations are possible. The mounting assembly for paddle  56  includes bracket  112 , plates  114  and nut and bolt assemblies  116  and  118 . Bracket  112  is welded onto drum  56 . Plate  114  is bolted to bracket  112  by bolts  116 . Paddle  56  is mounted by sliding slot  110  onto bolt  116 , sliding slot  112  onto bolt  118 , then tightening bolts  116  and  118  to clamp paddle  56  into the assembly. Use of this mounting assembly permits paddles  56  to be quickly and easily replaced by merely loosening bolts  116  and  118 , then tipping the paddle forward and sliding it out of the bracket assembly. A new paddle is then fitted in reverse order. 
     Each paddle portion  76  serves to generate an air stream directed upwardly of the drum and in the direction of the free end of the paddle when the drum is rotated in a direction such that the paddle travels upwardly and then rearwardly in its circular path around the drum. Stated slightly differently, the normal direction of rotation of the drum assembly is in the opposite direction of wheel rotation when the apparatus is being driven forward. 
     Having described the construction of the preferred embodiment, its operation will now be explained. The primary function of apparatus  10  is to shred, mix and aerate solid contaminated material. While a wide range of materials can be accommodated, the preferred embodiment is particularly suited to the contaminant of relatively light agricultural wastes such as straw and grass. Referring now to FIGS. 4 and 6, to configure the apparatus for being driven sideways, each hydraulic cylinder  43  is activated to lower frame  12  onto the ground and to raise each wheel several inches above the ground. Tail section  31  is retracted to its raised stowed position by hydraulic cylinder  54 . Each frame assembly  40  is pivoted to its transverse position as shown in FIG. 6; left and right drive wheels  14  and  16  are thereby aligned transversely, as are left and right rear caster wheels. Left drive wheel  14  is then drivably disengaged from left drive motor  50  by pushing T-handle  78  inward to disengage the planetary gear drive as discussed above. Each hydraulic cylinder  43  is then activated to lower each wheel and raise frame  12  above the ground. 
     Apparatus  10  is now configured for being driven sideways. It is propelled in this configuration by right drive wheel  16 , now facing in the direction of “forward travel”, which by virtue of being fitted with flexible hydraulic supply and return lines is operable in the transverse position. Steering is accomplished by operation of hydraulic cylinder  45  to “swing” right drive wheel  16  slightly as required to adjust the direction of travel. After arriving at the desired location, the apparatus  10  is reconfigured to its contaminated mode by reversing the foregoing procedure. 
     If it is necessary to transport the apparatus a greater distance, other transporting configurations are provided which allow the apparatus to be flat-towed by a truck. Referring to FIGS. 3 and 4, each wheel is raised above the ground, pivoted to its transverse position, and the wheels lowered, raising frame  12  above the ground. Left drive wheel  14  is driveably disengaged as before, and left rear castor is locked against castoring action by pin assembly  19 . As best seen in FIG. 7, a pair of auxiliary towing wheel assemblies&#39;  80   a  and  80   b  are then mounted on the right side of frame  12  by being inserted into channels  82   a  and  82   b , and yokes  84   a  and  84   b  respectively, and secured therein by locking pins  86 . Auxiliary towing wheel assemblies  80   a  and  80   b  are additionally secured by lateral link  86 , which is pinned into bracket  88  and frame  12  as shown. Right side drive wheel  16  and right rear castor  20  are then raised to lower the right side of frame  12  onto towing wheel assemblies  80   a  and  80   b . As shown in FIG. 2, fifth-wheel assembly  90  is an articulated, hinged frame assembly which is normally stored in a retracted position, and which is extended and locked into position as shown in FIG. 7 for being hooked to a truck (not shown) for towing apparatus  10 . Fifth-wheel assembly  90  may be raised and lowered by any suitable winch assembly  92  (FIG.  6 ). An alternative fifth-wheel design is shown in FIG. 7A where rather than a separate towing wheel assemblies, an integral rear towing wheel assembly  81  is provided which can be raised into and lowered from its retracted position (FIG. 7A) by operation of hydraulic cylinder  83  without being detached from frame  12 . Apparatus  10  thus configured may be conveniently towed over public roads with considerably less expenditure of time, effort and expense when compared to prior art apparatus. Towing the apparatus is further accommodated by the novel frame design of the present invention as shown in the figures. Drum  56  serves as a tension member interconnecting vertical subframes  12   a  and  12   b  as discussed above. The use of drum  56  as a tension member in frame  12  eliminates the need for additional structural members to resist spreading forces exerted on subframes  12   a  and  12   b  during operation and towing. Frame  12  can therefore be designed with a lower overall height to accommodate passage beneath lower bridges and overpasses. Upon arriving at its destination, towing wheel assemblies  80   a  and  80   b  are removed and apparatus is reconfigured for operation by reversing the above procedure. In the alternative embodiment, wheel assembly  81  is retracted by operation of hydraulic cylinder  83 . 
     Prior art apparatus have proven generally unsatisfactory for processing such contaminated material due to their inability to effect adequate aeration of the materials to ensure aerobic conditions throughout the material, and due to their inability to effect adequate removal of excess moisture from the material when required. To this end, the present invention provides a novel drum and paddle assembly  22 , which is, rotated at high speed in a direction opposite to that of prior art apparatus. In addition to directly impacting the contaminated material for shredding it, the rotating drum assembly  22  also draws air from ahead of the apparatus into chamber  24  and generates a high-speed stream of air in chamber  24 . The high-speed air stream entrains the relatively light materials and circulates them in overlapping, counter-rotating circular patterns within chamber  24  for thoroughly aerating and mixing them. The entrained materials are suspended and circulated in the air streams, and then redeposited in a windrow to the rear of the rotating drum. As a further advantage, after mixing and aerating the contaminated materials as described, the present invention redeposits the materials in a relatively tall, more squared-off windrow having a higher volume of materials per unit of surface area than known apparatus. 
     To begin a contaminated operation, engine  38  is started, and drum drive motors  48   a  and  48   b  are engaged to counter-rotate drum assembly  22 , preferably at approximately 550 RPMs. apparatus  10  is now raised or lowered to a desired ground clearance by activation of hydraulic cylinders  43 . By so doing, apparatus  10  can be adjusted to process more or less material. This unique ability of the present invention allows for a more efficient operation by permitting greater volumes of material to be formed into a single windrow and processed in a single pass, resulting in more efficient use of the available ground area, and less processing time for a given amount of material. The height adjusting ability is additionally useful in that as the process partially decomposes the windrow of material, the volume of material decreases. The present invention allows the operator to readily adjust for the volume decrease without any decrease in the effective-ness of mixing and aeration. 
     Having selected the appropriate height, the operator now drives apparatus  10  forward to engage the contaminated material. As the apparatus engages and proceeds along the windrow, the contaminated material is mixed and aerated by the action of the counter-rotating drum assembly. We define counter-rotation to mean rotation in a counterclockwise direction when viewed from the right end of the drum assembly, or stated slightly differently, in the opposite direction of rotation of forward rolling drive wheels  14  and  16 . Counter-rotating drum assembly draws air into chamber  24  from ahead of the apparatus in the form of an upwardly and rearwardly directed air stream ahead of the drum assembly, providing significant advantages as will be further explained. As apparatus  10  approaches, the upwardly flowing air stream first engages the windrow ahead of the drum assembly and entrains a portion of the material which travels in the air stream and which does not directly engage the counter-rotating drum assembly. Counter-rotating drum assembly  22  then engages the remaining material which is deflected by deflector plate  71  toward cutting edge  72 , where the material is shredded, and then entrained in the air stream. While the precise amounts of material shredded in each pass of the apparatus are not known with certainty, in the processing of grass straw, for example,  3 - 4  passes through the contaminated material will normally produce a thoroughly shredded contaminated material. 
     Under certain operating conditions, particularly when processing heavier materials, drum  30  can be slowed and even stalled. Owing to the hydraulic coupling between the drum and engine, stalling of the drum can stall the engine as well. In the preferred embodiment, this problem is addressed by monitoring the engine speed to detect slowing of the drum, and reducing power to the drive wheels when slowing of the drum is detected. Reducing power to the drive wheels slows the forward progress of the apparatus through the windrow, thereby reducing the load on the drum and allowing it to resume its normal operating speed. In the preferred embodiment, the power to the drive wheels is first reduced by to 50% or normal, and if after no more than a few seconds the drum has not resumed its normal operating speed, further reducing power to the drive wheels to 30% of normal. Once the drum has resumed normal operating speed, the power to the drive wheels is increased to its normal level. In order to avoid lurching and resultant damage to the drive mechanism, applicants have found that the power to the drive wheels must be resumed gradually rather than all at once. 
     Reducing and increasing the power to the drive wheels in response to changes in the drum speed is achieved by means of electrical control of the hydraulic pumps which provide pressurized hydraulic fluid to the left and right drive wheel hydraulic motors  42   a  and  42   b  respectively. A schematic diagram of the control system is shown in FIG. 16. A manually operated speed controller is provided for each of the two drive wheels. During normal operation, speed controllers  104   a  and  104   b  electrically control the output of hydraulic pumps  40   a  and  40   b  responsive to movement of the speed controllers by the operator. When drum  30  (not shown in FIG. 16) slows, a corresponding slowing of alternator  102  triggers a signal to controller  100 , a Sundstrand Model MCH22BL1844. In response, controller  100  reduces the voltage applied to speed controllers  104   a  and  104   b  by 50%, which reduces the power to left and right drive wheel hydraulic motors  50   a  and  50   b  respectively by a corresponding amount. If within two seconds drum  30  has not resumed its normal operating speed, controller  100  further reduces the voltage to speed controllers  104   a  and  104   b  to 30% of normal. Typically, reduction of power to the drive wheels to 30% of normal has been sufficient to overcome all but the most severe stalling conditions. 
     Once drum  30  has resumed its normal operating speed, controller  100  restores normal voltage to speed controllers  104   a  and  104   b  and normal operation is resumed. Generally, the control system as described is so responsive that it is necessary to resume normal power to the drive wheels gradually in order to avoid lurching of the apparatus and damage to the drive train. To that end, once the drum has resumed normal operating speed controller  100  increases the voltage to speed controllers  104   a  and  104   b  gradually over several seconds. 
     The entrained contaminated material is propelled upwardly and rearwardly in a pair of generally rotating vortex-like airstreams. The end paddles generate air currents directed upwardly of the drum and transversely toward the center portion of the drum, while the center paddles generate an air current directed upwardly and rearwardly of, and transversely toward the ends of the drum when the drum is rotated. 
     The air currents generated by the end and center paddles intersect and combine to form the vortex-like, compost entraining air stream for mixing and aerating the windrow of contaminated material. 
     The airstreams overlap at their inner portions, providing repeated exchange of entrained material therebetween. As the air streams begin to lose their velocity, the contaminated material begins to drop out of the air stream and is redeposited into a windrow. 
     The airstreams are generated according to the preferred embodiment by the left, right and center paddles previously described. As best seen in FIGS. 9 and 14, each row of paddles according to the present invention includes a group of paddles having paddle portions  76  facing toward opposite ends of the drum. As the drum is rotated, each paddle portion  76  draws air into chamber  24  and generates a series of airstreams flowing in the direction of the drum rotation and laterally outwardly toward the end of the drum. The series of airstreams generated by the two group of similarly oriented paddle portions  76  combine to form oppositely rotating airstreams spiraling rearwardly within chamber  24  and intersect. The interspersing of paddles having opposite facing paddle portions  76  near the center of the drum creates a region in which the oppositely rotating airstreams overlap. In the overlapping region, contaminated material is continuously exchanged between the airstreams, providing more thorough mixing of the contaminated materials than has heretofore been possible. The relatively light materials remain entrained in the airstreams for a relatively long time, until the air stream slows sufficiently to cause the material to fall from the airstream. In this way, the contaminated material is afforded an extended contact time for aeration and drying. As the airstreams spiral rearward, they exit chamber  24  through rear opening  27  and rear tail portion  31 . Rear drapes  35  serve to limit the rearward travel of the airstreams and any entrained or thrown contaminated materials. Applicants have discovered that the mixing and aerating effectiveness of the present invention is significantly enhanced by the use of tail section  31 , which apparently serves to promote the formation and rearward extension of the rotating airstreams, extending the contact time between the air and contaminated materials. The ability of the present invention to provide extended, interstitial aeration of relatively light contaminated materials has not been possible with prior art apparatus, and represents a significant advance in the art. 
     A further benefit of the present invention over prior art apparatus is related to the large volume of fresh air, which is continually drawn into chamber  24  and into intimate contact with the contaminated material. This feature is also of significant benefit when contaminated heavier materials which may not be readily entrained in the airstream, and which are mixed primarily by being thrown upwardly and rearwardly due to contact with paddle portions  76 . Even so, with the large amount of air drawn into chamber  24  in the form of high-speed air streams, these heavier materials are contacted with significantly more air under more effective aerating conditions than is possible with known apparatus. 
     Having illustrated and described the principles of my invention in a preferred embodiment thereof, it should be readily apparent to those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles. I claim all modifications coming within the spirit and scope of the accompanying claims.