CA2072691A1 - Waste feed system - Google Patents

Abstract

Docket No. K-1515-016 Abstract of the Disclosure A waste feed system for feeding an incinerator, kiln or storage container includes a drop chamber for receiving waste material; a primary grinder, preferably a dual auger shredder, for receiving waste material from the drop chamber to shred and blend the material; a secondary grinder, preferably a single auger shredder; and a feeding component for injecting material from the secondary grinder into the receptacle. The drop chamber includes bulk and containerized material inlets sealed by air locks, and a stabilizer for feeding stabilizing material. In a preferred embodiment, the feeding component includes a single auger which receives material from a side discharge from the secondary grinder, and the entire system is enclosed and includes mechanisms for sensing oxygen and purging the system with an inert gas, as well as a fire suppression system. The feeding component also includes a rotary gate to isolate the system from the associated receptacle.

TDL:APPLNS:ap6

Description

Dccket No. ~-.515-016 2072S91 WASTF FEED S'~STFM
Back~o~nd o. the ~ en~3n ~e present inver.rion relates tO waste feedlng systems and, more particularly, to waste teeding systems which redu~e tn_ volume of waste material prior tO injection into a receptacl~
such as an incinerator, kiln or sealed storage container.
Pollution conce~ns and restrictive laws make i~
undesirable to bury toxic or hazardous material, or dispose of such ma~erial in landfills. Burning of such material in incinerators, kilns or rotary reactors, along with treatment o~
the gaseous effluent of such burning, in becoming more acceptable. 8urning of hazardous material appears tO be the least environmentally harmful method for disposing of such material, since the complex molecules of such material often can be broken down into less harmful constituents. In any event, t~.e volume of hazardous material is reduced by burning. According ,~, incinerators have been adapted to receive hazardous and to~ic material for burning.
In order for such incineration processes to be run in an efficient manner, it is desirable to provide a mechanism for feeding different types of hazardous material in different kinds of containers to incinerators so that the material may be in~ected at a measured rate. It is also desirable to reduce the size of the hazardous material prior ~o burning to an even homogenous consistency to promote burning of the material or to

2~ facilitate its storage in containers. ~urther, i~ is desirable to feed the containers used in transporting the hazardous material to the incinerator for burning as well, thereby eliminating potentiaLly dangerous drum storage and manual drum emptylng sltuatlons.
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Docket No. K-1515-016 2072691 One ~xample o~ su~h a syst~m is disclosed in House~ 'j. a, ~atent No. 4,95~,578. T.~at sys~m c~nsis~s ~f ~n inc ne ~t~r .'~eating syste~n in ~hich con~alnerized solid waste s f~l ir.t~ d shredder whlch ~e~uces the material and co.~minutes the mate~la`
con.ainers, all o~ which falls downwar~ tû an auger reac~er which in~ects ~he shre~ded material into a r~tary kiln ~hr~ugn opening in the face of the kiln. A disadvantage with such ~
system is tha~ it utilizes a single-pass shredder whlch can~c-ensure consistent particle size, and utilizes a single au~e~
feeder which ~ay cause jamming and burn-bac~ si~uations.
Accordlngly, a need exists for an incinerator feed system in which hazardous or toxic material can be reduced co a predetermined, homogeni~ed consistency and feed into an incinerator at a ~niform rate. ~urthermore, ~here ls a need ^~
a device which can feed comminuted ha2ardous material in~o the face of an incinerator which can be offsec from the face ot the incinerator to provide clearance for other fuel feed sys.ems.

Summary of the Invention The present inYention is a waste feed systam for an 'ncinerator which can receive toxic material in either bulk or containerized form and reduce such material to a homogenous consistency of predetermined particle si2e and inject it into an incinerator or a suitable storage receptacle. The waste feed system includes a drop chamber which receives waste material, a primary shredding and blending component which receives the waste material from the drop chamber, a secondary grinding component which receives shredded material from the primary component and further reduces the size of the material, and a fee~ing componenc which receives the shredded and blended material from the secondary grinding component and injects the material into the incinerator.

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Docke~ No. K-~Cl5-016 rn a preferred embodiment, che prlmar~ grLr.ding comDonent includes a dual auger shredder ~.avlng a pair o~
opposing, counter-rotatlng, tapere~ augers mcur,ce~ Ln a con~,ur~
3rindlng chamber haviny ad~usta~le doors n che ~3~^m wr;i xn al`_w ~ rea~ence ~imC of the ma~eria~ n ~he rha~er ~o ~e selectively varied, there~y contr~llir.g ~:A5 UltlmacC ?ar'_l-_e size of the material leaving the chamber. The sec~ndary component preferably is a single tapered ~uger shredder whl n 1, mounted within a contoured grinding chamber posltioned dirc-r y below the bottom doors of the primary grinding chamber to rerel~~
the waste material therefrom. The secondary grinding char~er further reduces the ma~erial received from the primary chamber and the single auger disLharges the mater al through ~ side opening in the secondary grinding chamber.
The feeding component preterabl-/ includes a single auger mounted within a conical housing which receives the side discharge of material from the secondary ~rinding componen~ and injects the material into the incinerator. Also in the prerer-_~
e.~bodiment, the auger screw of the feeding component is or enrC~
at a right angLe to the auger shredder of the secondary ccmponer.r so that the entire system may be offset from the face of the incinerator, thereby providing clearance on the incinera~or tace for additional fuel devices.
Also in the preferred er~odiment, the drop chamber inclu~es an air-lock and conveyor system so that containeri2ed waste, which may be in steel drums, can be deposited into the ;~ drop chamber to be ground and shredded without the release of - toxic material to the atmosphere. In addition, the drop chamber includes an air lock which accepts bulk was~e from a skip loader.
The drop chamber also includes a screw conveyor for feeding stabilizing material, such as cement, to the waste material.
Further, the entire system is enclosed to prevent the escape of toxic fumes or liquids, and includes oxygen sensing and ~ .

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Gocket NG. ~-1515-0'0 2072691 inert gas purging syste~s ~ re~uce the llkelihood of a flr~ o-explosion during the srln~ing and ahredding operation. The enclosed system also includ^s fire su~ressivn mechanisms event a fire does occur ln the sys~em. The incineraror ~ee~ r~
compcnent lncludes a rotary gate which lS posi~ioned dswnatr-a or ~he reeding auger screw ~o pr.even~ burn-back of materiai ~r~
the incinerator. The invention also in-ludes a computer c~r.~r~
which senses the resistance encountered by the grinding elêm-n.;a and can vary the particle SiZê of material in the primary grinding component by selectively positioning the bottom ~v~a ^
the primary grinding component ~:o allow material to drop into ~^.e secondary grinding component.
Accordingly, it is an object of th~ present inventi~n ~_ provide a waste reed system which is capable oi handling boch 1~ bulk and drums or other containers of hazardous waste material, reducing the material to a consistent particle size and feeding the material into an incinerator; a waste feed system in which waste is reduced in size in an environment which is closed o-from the atmosphere ~o reduce contamination; a waste feed sysc-m which can be positioned in an offset location from the face or ar.
incinerator to provide clearance for other fuel feeding devicesi a waste feed system which includes oxygen purge and fire suppression systems to insure that waste material is reduced in size in an environment where explosions and fire are minimized; a ; 25 waste feed system in which burn-back from the incinerator is prevented; and a waste feed system in which waste material can ~e continuously fed into a waste reducing means for feeding into an incinerator with a minimum of jamming.
Other objects and advantages of the present invention will be apparent from the following description, the accompanyin3 drawings and the appended claims.
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2072~1 Docke~ No. K-LS15-016 Brie~ Descri~tion o~ ~.e ~r~wlnq Fig. I is a schematic side ele~/ational v;ew Ot a waste f,,-d syâtem incorpcra~ing the present inventioni ~ . ' is a de~aiL of t:he â-~S'e~ OL~ sn3wi~ ~ee S air lock and drop cnamber mechanism;
Fig. 3 is a de~ail o~ the a ~ r lock and dr~p c~amb_r mechanism of Fig. 1 showing ~he air Lock ~oor f~r t~.e bu~k r-_~
stabilization feeder;
Fig. 4 is a detail of the sys~em of Fig. 1 showing rr,~
discharge doors of the primary grinding component in a closed configuration;
Fig. S is a detail plan view or ~he System GC ~i9. ;, showing the injector component in section adjacent to an incinerator;
l, . Fig. 6 is schematic block diagram of the inputs and outputs to the programmable logic controller of the system of Fig. 1: and Fig. 7 is a schematic block diagram of the sensors ct the system of Fig. 1.
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As shown in ~ig~ 1 and schematically in Fig. 7, the ;~ waste feed system of the present invention, generally designated lO, is used to feed hazardous or toxic material to a rotary reactor such as an incinerator 12. The system includes a drop chamber 14, a primary grinding component 16, posicioned below the drop chamber, a secondary or base grinding component 18, ~ positioned beLow the primary grinding component, and a reeding or ; ; injector component 20 which interconnects the system 10 with the incinerator lZ. The system also includes a horizontal conveyor 22 ad~acent to a~n air lock chamber 29 which is connected to ~he ::: : :

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DGC ket No. ~ 5-016 2 0 7 2 6 9 ~

drop chamber 14 and ncludes a t~anspcrt conveyor. Con~eyor '~
is used ~o convey containerized materials, such as a a pallet or steel drums o~ hazardous ma~erlal 26, co the drop chamber 14.
As shown in Flgs. 1, 2, 3 and 7, the drG? chamber !4 n~ ca a ~-~ran~ular housing ~3 havin~ e~plosi~^ d~o~s 3C
mount~ ln an upper surface, a fire suppression system 3' -onsisting of tanks o~ a fire suppressan~ chemical, connected r_ discharge int~ housing ~8, an oxy~en monitoring system 34, an~. 3 safety relief valve 36 to purge the chamber in the event ne~r gas pressure exceeds a predetermined limir. An infeed chu~e 3 is connected to the drop chamber 14 and is sealed fr~m the atmosphere by an outer, horizontal, sliding air lock door 40, ar.d rrom the drop chamber 14 by an inner vertical door 41.
Similarly, air lock 24 includes outer and inner l~ vertically sliding air lock doors 42, 44, an explosion relier door 46 in the upper surface and a safety relief valve 48 for purging an excess of inert gas. The air lock 24, drop chamber housing 28 and chùte 38 each include inert gas regulators 50 connected to sources 51 of inerting as. Air lock 24 and chute also include oxygen monitors 34 and fire suppression systems 3~.
A skip hoist, generally designated 52, is connected eo the chute 38 and includes a motor 54 mounted on a vertically extending track 56 which supports a bucke~ loader 58. The buckec loader 58 is pulled to the top of the track 56 by the motor 54 t~
2S dump its contents into the chute 38.
As shown in Fig. 3, the system 10 preferably includes a ~; screw conveyor 59 which is connected to the drop chamber 14 and is sealable therefrom by an air lock (not shown). conveyor 53 is used to convey bulking or stabilizing agents, such as lime cement, to the material to be ground, shredded and blended by t~e system 10.
The primary component 16 includes a dua! auger shredder having a pair of reverse-oriented tapered augers 60 positioned ~ 6-: ~
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withln a grinding chamber 62 contoured to the shape of tne auger., and including a pair of adjustable discharge doors 64 in the botrom of the chamber. This apparatus is disclose~ in grea~er derail in U.S. ~atent Nos. 4,938,426 and 4,993,649, the -~ Oa'~reS -f ~hich are lncorpor~ted herein by rersren~e. T~.c secondary cGmponent 16 includes an open top which ~ommunicates directly with the drop chamber 14. The primary ~rinding cr,am~er includes oxygen monitors 34 and is connected to a source o. Ln-r~
gas 51.
Directly beneath the primary component 16 is the secondary component 18, ~hich includes a single tapered auge~ 66 mounted within a grinding chamber 68 shaped ~o the contour of tne auger 66. The design details o the singLe auger 66 and grlnd chamber 68 are disclose~ in grea~er de~ail in U.S. ~atent NOâ.
4,253,615 and 4,951,884, the disclosures of which are incorporated herein by reference. Secondary component 18 includes oxygen monitoring and inert gas systems 34, 51, respectively.
As shown in Fig. 5, the auger 66 of the secondary component 18 projects into an extrusion tube 70. The extrusion tube 70 is connected to the housing 72 of the feeding component 0 and provides a side discharge for chamber 68. The feeding component 20 includes a single tapered screw 74 and extends sidewardly relative to the extrusion tube 70 into the face 76 of the incinerator 12. The screw 74 is rotatably mounted within a injector tube 78. The injector tube 78 includes a non-tapered : section 79 having a rotary gate 80, which can be actuated to open and close the section 79 between the incinerator face 76 and ~: auger 74. The details of the design of the rotary gate 80 are disclosed in U.S. eatent Application Serial Number 07/632,766 filed December 21, 1990, and of ~he feeding component 20 in U.S.
atent No. 4,915,308 the disclosures of which are incorporated herein by reference.

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Docket No. K-'Si5-016 In the Freferr~d embodimen~, the ~edi~g _omponen~ 0 ;~
oriented such t~at the auger 74 exrends at a righ~ angl~ t~ ~ne auger 65 of the secondar~ component 13, 50 ~hat ~ne system : J -3':
be positione to one side of the face 76 c~ the l~cinerac~r 1 , as ~nJwn in ~igs. 1 and 5.
As shown in Fig. 6, the encire syst~m !0 s ~erated r~
a programmable logic con~roller 82, whlch receiv,s ln~rma~or ~rom sen~crs LGcated in the drop cha~ber 14, primary grin~ g component 16, se-ondary grinding compGnent 13 and ~eedin~
component 20. Such sensors include a material proximity senso-84 for the staging conveyor 22 (~ig. 1~, open and closed posir~on sensors 86 for the air lock outer door 42, open and closed position sensors 88 for the air lock inner door 44, material pro:cimity sensors 90 for the air lock and oxygen sensors 34 fJr ~he air lock and drop chamber 14.
With respect to the primary grinding -omponent 16, the programmable logic controller 32 receives input from sensors connected to the hydraulic system which drives the hydraulic motors (not shown) that rotate the dual augers 60 of the primary grinding component. These sensors 92 detect hydraulic motor rotation, hydraulic system pressure, hydraulic fluid level, hydraulic fluid temperature, main pump condition and hydraulic filter condition. Sensors 94 detect the electric motor amperage of the motor (not shown) driving the hydraulic pump of the auger.
Sensors 96 detect the temperature of the bearings (not shown) supporting the augers 60, and t~le rate of lu~ricant fLow.
Sensors 98 detect the position of the material discharge doors 54 of the primary grinding component.
With respect ~o the secondary grinding component 18, the programmable logic controller 82 receives input from sensors 100 connected to the hydraulic system for the secondary grinding component. This includes sensors that detect the hydraulic motor rota~ion, hydraulic system pressure, hydraulic fluid level, ; :~

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Docket Nc. ~-1515-~16 hydraulic fluid tempera~ure, ma1n ~ump condition and h-JdrauL:
filter condition. Sensor 10~ de~ects the electric motor amperage of the motor driving the hydraulic system of the secGndary grinding component 18. Sensors 104 detect the temperature ,f ~,e suppor~ bearings (no~ shown) for the auger screw 66, t~.e rate _-lubricant f low and the level of lubrican~ fluid. SensGrs ~4 ~see also Fig. 7) detect the level of oxygen in the grindin~ cham_c~
68 or the secondary grinding component 18.
Similarly, the programmable logic controller 82 recel~ea input from sensors connect~d to the feeding component 20.
Sensors 106 detect the rotation of the hydraulic motor drivin~
the auger screw 74 (Fig. 5), the hydraulic system pressure, ~.e hydraulic fluid level, the hydraulic fluid temperature, the main pump condition, and the hydraulic fiLter condition. Sensors 103 detect the amperage of the electric motor driving the hydraulic motor for the auger screw 74, sensors 110 detect the bearing temperature and lubricant flow, and sensors 112 ~etect whether the isolation door 80 is in an open or closed corfiguration.
The programmable logic controller 82 also receives lr.p~
from sensors 106 connected at the infeed conduit 79 (Fig. 5) of the kiln 76, sensors 108 connected to the air lock 24 (Fig. 1) and sensors 110 connected with the fire suppression systems 3~.
These sensors 106-110 signaL the controLler 82 to shut the sys~em down should an overload condition occur at the kiln 79, a fire occur anywhere in the system 10, or the air lock become inoperative.
The controller 82 actuates control valves 112 that control the ~ischarge doors 64, control valves 114 for ~he inner and outer air lock doors 44, 42, pump strokers 116 ror the dual ~; 30 augers 60 ~also controlling auger speed and direction), the pump stroker 118 for the secondary grlnding component (also auger speed and~direction), stroker 120 for the feeding component auger (controlling speed and direction) and the directional control ~ 9 , : .

2~726~1 Docket No. ~ 5-016 valves 122 ~or ~he staglng conveyor 2~ and conveyo~ in the a -lock 24. Further, the con~roller 82 can store specific se~uen~*s Gr operation for the primary and second~r~ ~eeding componen~ :6, 18, which prescribe specific numbers of auger screw rotat.Gns 1^.
for~ard and reverse directions. With respec~ to ~he dual auger of the primary grinding component 16, the eoncroL~er 82 also includes progralns for rotating the augers ln alternately r~r~a-~and reverse directions so that t:he auger sc~ews can rota~e ir.
unison or counter-rotate as neecled.
The operation or the system is as fol lows .
Containerized waste material is placed on the infeed staging conveyor 22 and the conveyor act:uated to bring the material to the air lock 24. The inner air lock door.44 is closed and the outer air lock door 42 opens to accept the material. The infeed 1~ conveyor deposits the containerized material on the air lock conveyor which conveys it to the interior of the air lock. The outer air lock door 42 closes and the nitrogen purge 51 system :s actuated to drive off ambient air until the oxygen sensors 34 detect that the oxygen level is below a predetermined value.
At that time, the inner air lock door 44 opens and the air lock conveyor conveys the containerized material 26 to the drop chamber 14 where it falls downwardly into the grinding chamber 62 of the primary component 16. At this time, the drop doors 64 or the primary component 16 are closed and the augers 60 are actuated to simultaneously grind and shred the conta~neriz-d material. The energy requirements measured in terms of motor amperage, hydraulic pressure and rotational speed, are read by the controller 82 and these energy requirements gradually decrease to a steady-sta~e Yalue. At that point, ~he materia!
has been sufficiently blended and reduced in size to be permlt~ed to drop to the secondary or base component 18.
The bottom door 64 opens, allowing the material to dr-?
into the grinding chamber 68 of the secondary component 18, whe e :

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Docket No. K-1515-016 2072~91 i~ is acted upon by auger 66 to be reduced further and, simultaneously, char~ed ir.to the feeding component 20. T~.e ~eeding component 20 mon1tors, b~ way ~f reading the hydrauii-motor amperage, hydraulic pressure and rate o~ r~tation or the sc-ew ~4 of the feeding componenc 20, and the e~ntroller /aries t~e speed of rotation of the auger 66 so tha~ material is ~2 from the grinding chamber 68 at a suffioienr rate to deve!3p plug of materia! in the conduit 70.
The feeding componen~ 20, in turn, is actuated c~ ~ne controller 82 to respond to the fuel requirements of the k ln 13.
While the controller 82 is not directly connected to tne kiln 12, or the control mechanism for the kiln, ic does r~ceive a ~igna' from the kiln control system (not shown) indicating fuel requirements as determined by the temperature within ~he kiln.
Accordingly, the heat or fuel requirements of the kiln determine the speed of operation of the feeding component 20 which, in turn, determines the feed rate of the secondary component 18.
The secondary component 18 operates to take macer1al from the grinding chamber 62 of the primary component 16 and further reduce material while simultaneously conveying it ~0 the feeding component 20. This can occur while the primary _omponen_ 16 is reducing and grinding a subsequent load of material.
Further, the controller is programmed such that the drop doors o4 are never opened at the same time as the air lock inner doors 44, 25 so that it is not possible for the material to drop through the primary grinding component 16 without being reduced and shredded by the augers 60 of that component.
The process is the same for bulk materials loaded by the skip loader 52. Such materials are dumped into the hopper 58 which is conveyed to the top of the~track 56 and dumped into the chute 38 through the open outer air lock door 40. The outer air lock door 40 is closed, the oxygen purged to a predetermined below-ambient levels and the inner air lock door 41 opened to ~:

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; , ~' Docke~ ~o. K-i515-016 2~7~6~1 allow the mater!al to fall int~ the grinding chamber 62 o .~e primary grinding component 16.
If necessar~, the s~rew 5~ is ~c~uated ~o convey a s.abilizing macerial or oulking agent lw~ _h may ~e ceme~-, i .-,~
or -:~ ash) to the material in order to scak up ~r stabi' ze llqu!d or slurr~ materials so that the~ may be fe~ ~3 the incinerator kiln 12 at dn even rate.
In the preferred embodiment o~ ~he inventLon, the se-~~
74 o~ the feeding component 20 is substan~iall~ smaller ie.
diameter than the screw 66 of the secondary compcnent 18.
Further, the grinding chamber 78 of the feeding component 2~ is prererably smaller in volume than the grinding cha~ber 63 or t-~e secondary component 18. This size dirferentiation minimizes ~-e amount of equipment that rnust be positioned dirertly in rront o~
the ~iln face 76 and the smaller feeding screw 7~ ~an in~e~r r-e finel~ reduced material at a faster rate to the ki'n 12.
In rhe event of a fire wi~hin the system IG, or a potential "burn-back" o~ material from the kiln 12, cne ro-ar/
door 8~ is actuated by the controller 82 t~ isolate the s-~s~em from the kiln.
While the form of apparatus hereindescribed cons~1tu~_s a preferred embodiment of the invention, it is to be unders~ood that the invention is not limited to this form or apparatus an~
tha~ other forms of apparatus may be employed wi~hout deDar,ir.
29 from ~he scope of the invention.

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Claims (16)

Docket No. K-1515-016

1. A waste feed system comprising:
drop chamber means for receiving waste material;
primary means for receiving waste material from said drop chamber and shredding and blending said waste material;
secondary means for receiving said waste material from said primary means and further shredding said waste material to reduce size of material; and feeding means for receiving said waste material from said secondary means and pumping said material into a receptacle.

2. The system of claim/wherein said drop chamber means, primary means, secondary means and feeding means are connected to form an enclosed pathway whereby toxic fumes, dust and liquids from material therein are prevented from escaping to the ambient.

3. The system of claim or further comprising means for purging said enclosed pathway with an inert gas whereby likelihood of combustion of waste material in said pathway is reduced.

4. The system of claim 1 further comprising air lock means associated with said drop chamber means for closing an input portion of said drop chamber.

5. The system of claim 1 wherein said secondary means includes an auger shredder having a substantially sideward discharge, and said feeding means receives material from said sideward discharge.

6. The system of claim 5 wherein said feeding means includes auger means for feeding waste material into incinerator means, said auger means being oriented substantially perpendicular to said auger shredder.

Docket No. K-1515-016

7. The system of claim 6 wherein said secondary means is positioned substantially vertically beneath said primary means.

3. The system of claim 7 wherein said primary means includes adjustable discharge doors in a bottom floor thereof, said doors being positionable between a closed configuration, wherein material is retained within said primary reasons for blending size reduction, and selectably spaced open configurations, whereby material within said primary means is reduced in size until falling between said open doors to said secondary chamber.

9. The system of claim 1 wherein said primary means is positioned substantially beneath said drop chamber means.

10. The system of claim 1 further comprising conveyor means for transporting waste material to said drop chamber means.

11. The system of claim 10 wherein said conveyor means include air lock means, connected to said drop chamber means, for preventing escape of toxic material as said containerized waste is transported to said drop chamber means.

12. The system of claim 1 further comprising skip loading means for dumping bulk material into said drop chamber means.

13. The system of claim 12 wherein said drop chamber means includes gate means for opening and closing said drop chamber to receive bulk material from said skip loading means.

14. The system of claim 6 wherein said feeding means includes rotary gate means, downstream of said auger means, for sealing said system from said incinerator means to prevent a burn-back situation.

Docket No. K-1515-016

15. The system of claim 6 wherein said auger means is of smaller diameter than said auger shredder of said secondary means.

16. The system of claim 1 further comprising means for adding stabilization material to said drop chamber means.