CA2050777A1

CA2050777A1 - Vertical cell method and system for waste storage and energy recovery

Info

Publication number: CA2050777A1
Application number: CA002050777A
Authority: CA
Inventors: James S. Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-09-06
Filing date: 1991-09-06
Publication date: 1993-03-07

Abstract

ABSTRACT OF THE DISCLOSURE

Vertical cells are constructed for landfills by excavating a deep narrow hole. The hole can be excavated below the water table lined with an impervious liner and used for storage of waste. Solid organic waste can be anaerobically fermented to methane and compost. The methane is collected by a central core shaft and perforated sleeve from the cell. When the methane has all been generated the compost formed from the fermented waste is dug out for use.
All waste storage is below grade. Air, soil, and water pollution and contamination are eliminated.

Description

2~3077~

VERTICAL CELL METHOD AND SYST~M
FOR WASTE S~ORAGE AND ENERGY RECOVERY

This invention relates to a method o~ construction of municipal sanitary landfills. In particular it relates to the Vertical Cell System, which is designed to comply with current environmenta7 laws and regulations, such as those existing in Canada and the United States.

Although the invention will be described and referred to primarily as it relates to Vertical Cell System in munlcipal sanitary landfills, it will be understood that the principles of this invention are equally applicable to related waste systems and accordin~ly, it will be understood that the invention is not limited to such Vertical Cell System.

BACKCROUND AND PRIOR ART

The human race has generated increasin0 volumes oE
waste per capita since prehistory. Archeology ls mainly excavation of waste dumps. The earliest known set-tlements are buried in their own was-te.

The current generation of waste, leaving a~ide hazardou~, toxic, radioactive and industrial waste, pollution and other effects, is already well pa~t the crlsis level. A major problem i~ disposal of solid waste at the municipal level. This solid waste includes residential, institutional, com~erclal and industrial solid waste.

The major component of waste in North America is residential solid waste. At present municipal solid waste tsolid waste directly disposed of by municipal authorities) is mostly residential solid waste.

The volume of residential solid waste has grown with increasing population, increasing urbanization, and .. ., .:

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increasing consumption. The answer to solid waste disposal has been municipal waste disposal sites evolving into sanitary landEills. At present residential solid waste is being generated at a level approximating 1 ton (2,000 lbs, 0.9 tonnes) per capita, annually, in North America, or approximately 2 cubic meters, ~70 cubic feet~. In most urban environments ~olid waste disposal is already a major problem.

Elsewhere even though solid waste production is less per capita, the population is ~enerally denæerr consequently municipal solid waste disposal i~ similarly a major problem.

The growth of world populatio~ and urbanization, (estimated to reach 10 billion and 50~ of population, respectively by 2050) will exacerbate the solid waste disposal problem. The inevitable proliferation of conurbations of 5 million plus, will propel it lnto crisis.
Conurbatlons o~ such size have already lost control o~ their solid waste disposal.

Even were su~iclent land available ~or sanitary landPills, which is not the case, even in relatively unpopulated North America, there are already environmental problems, which are inevitably escalating to environmental crisis.

In conventional current landEill, the 80il iS
excavated, typically to a lesser depth than ~he permanent yround water table. A compacted layer or stratum of 50il forms the bot~om o~ the land~ill, which is covered with a impermeable plastic liner, or geomembrane, to prevent contaminated leachates escaping into the ground water.
Every form o~ solid waste is then deposited to a compacted "lift" -typically 6 to 10 feet deep ~2 to 3 meters), forming a horizontal cell. A shallow stratum of compacted soil, typically 1 to 3 feet deep ~30 to 90 cm) is -then deposited on the waste materials and the process repeated. The .
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, ~ ~ a ~ r~ rl r~,1 . .
resultlng mass of landfill generally rises above ori~inal ~round level, in ~ome cases up to 150 feet ~45 meters) high, forming a "mountain" oE waste. Some of these are gigantic, the ~resh Kills site adjacent New York City, being large enough to be visible from the Moon. There are numsrous similar mountains of waste throughout North America.

LANDFILL PRIOR ART

In practice the landfills are ~ource~ of pollution and contamination. Older land~ills may not have an impermeable ~; liner, and their leachates contaminate the soil and ground wa~er. Newer landfills are not supposed ~o allow leachates to escape throu~h the liner, but it is ncarly always ruptured to some extent by hydrostatic pressure, man made events or natural phenomena. This allows leachate to contaminate the ground water to an increasing degree. The air i8 contam~nated downwind of the landfills for considerable distances, similarly neiyhborin~ soil and water are contaminated, by alrborne and waterborne waste, sur~ace runoff and subsurface groundwater migration. A land~ill in u~e is oEten lnfested with birds, rodents and litter.
Besides this the landfill site itself i~ contaminated Por at least several decades, and generates quantities o~
fermentation gas mainly methane. Sometimes landfills have caught fire and burnt for years. As the contents of landfills are unknown it is dl~ficult to take counter measure~ to prevent pollution and contamination of the local environment. It is also difPicult to predict the long term effects of such contamination and pollution. Consequently the interim use o~ ~ormer landfill ~ites is restricted to parks, recreation areas, etc.

US Patent 2,164,536 is~ued Jul. 4, 1939, to McCarthy, teaches methods of landfill and reclamation of water front land. Trenches are dug filled with solid waste and eovered ; with excavated 90il and topsoil. The trench may be excavated at one side, while being ~illed with solld waste ' .

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2~7 7 1 at the other.

US Patent 3, 835, 652 issued Sept . 17, 1974, to Hignite, teaches drllling vertical cylindrical holes separated by undisturbed firm soil to a depth approaching the water table. Waste is deposited to partially ~ill each hole, compacted and the process repeated until each hole is fill~d to near ground level, when it is then ~illed with soil which is further compacted. A casing is not required. As temporary casing i5 not used this method, is restricted to shallow depths and ideal 50il c~ndltions. Dimen~ions are not given, but it is stated 8 or 10 feet (2.4 to 3 m) diameter holes, spaced 2 feet (0.6 m) apart are drilled, this is highly impractical as this interval is too small to provide protection for completed holes ~rom thoae being drllled. The depth is mentioned as up to 50 feet ~15 m), which would nearly always penetrate exist:lny water tables.
This is impossible under current regulations, as the system does not employ any ~orm of .environmental protectlon (for instance geomembranes). Additionally the estimated volume of waste dispo~al 44,000 cubic yards~acre (83,000 cubic meters/ha), compares most unfavorably with ~tandard land~ill waste capacity of 100,000 cubic meters~acre (247,000 cubic meters/ha). Hignite's system would therefore not only be environmentally unacceptable, but more expensive than conventional landfill in -terms of land uæe.

US Patent 4,0~6,355, i~sued May 31, 19~7, to Johnson et al., teaches a method ~or testing and monitoring gas produced ln sanitary landfills. Production holes and probe holes are drilled into the landfill and static gas prqssure mea~ured, the probes are preferably at different depths.
Gas is pumped from one well at an empirically selected rate until probe pressure stabilizes. ~as is then withdrawn at rates maintaining positive gas pressure within the land~ill.

US Patent 4,323,367 issued Apr. 6, 1932 to Ghosh, teaohes a method o~ generating methane from organic wastes, ~ ~3~ ~ 7 i including cellulosics (newspaper and paper). Organic waste is placed in a specific lined and sealed landfill receptacle and rapidly fermented (90% of po-tential within 5 years~ to produce methane by introduction of activated anaerobic culture.

US Patent 4,469,176 issued Sep. ~, 1984 to ~ison et al., teaches an improved method of gas r~covery from landfills, using two sealed trenches around a collecting point. Both trenches even pressure, the inner may be used for secondary collection. The outer i~ used a~ ~ pressure measuring device.

Canadian Patent 1,188,525, issued June 11, 1985 to Matich et al,, teaches a store for toxlc or radioactive waste in an open pit, extending below the water table. A
filter layer surrounds the waste itself surrounded by a pervious layer which can be drained or dewatered by tunnel and sha~t. Water flowing throuyh the waste is alleged not to reach the grollnd water.

US Patent 4,705,429 issued Nov. 10, 1987 to Natale, teaches a variation on landfill, where the excavation is an asbe~tos mine site, and the waste is asbestos waste. Layers of asbestos waste are covered with non-contaminant material, preferably soil, tailings or du~t supressant.

Canadian Patent 1,25~,702, issued May 9, 1989 to Sagefors, teaches a store for radioactive waste this comprises a rock container for the waste surrounded by am elastoplastic deformable material preferably bentonite.

US Patent 4,877,353 issued Oct. 31, 1989 to Wisotsky, Sr., teaches a method of driving a pile containing hazardou~
waste into geologically stahle seabed using a form of pile driver.

US Patent 5,000,617 issued Mar. 19, 1991 to Eggert et .
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2~3 ~

al., teaches a store for environmentally toxic substances.
An array of vertîcal storage boreholes are dri~en up to 300 metres into rock ad~acent a syncline, to store toxic or nuclear waste. A sealed top cover i5 providedj peripheral and bottom drainage are provided by boreholes and tunnel~ or by crushed rock forming walls and floor around the store.

US Patent 5,000,618 issued Mar. 19, 1991 to Greenley., teaches a method of preventing clogginc7 of geotextiles and geonets. The landfill liner (geomembrane) has a drainage system Igeonet) to drain leachate from the landfill for removal, the geonet is covered by a layer (geot~xtile) which allows llquid flow but prevents solids from clogging the geonet. Microbial growth in the nutrient rich leachate tends to clog ~eotextlle and reduce geonet flow.
Antimicrobial blocks are built into the geotextile to prevent microbial growth.

HOI,E DRILLINC; PRIOR ART
Hole drilling technoloyy varles with hole dlameter, depth, soil conditions and equipment used.

Small holes may be excavated to virtually any depth, by rotating tricone bits attached to a hollow pipe driven by a kelly bar from the surface. Simultaneously clrilllng mud is pumped down the pipe to carry away the drilled taillng~, well known in the oil well art. Typically this technology applies to holes o~ 6 to 10 inch (15 to 25 cm) dlameter, ~ometimes 12 inch ~30 cm) diameter.

Alternatively smaller holes may be excavated by augers, these are typlcally continuous single flight augers, with a singl2 cutting edge. More rarely double flight augers with a double cutting edge may be used. Such augers typically vary in diameter from 4 inch to 30 inch (10 to 75 cm), exceptionally upward to 36 inch ~90 cm), more rarely to 4 inch ( 120 cm). Holes as deep as 30 to 50 feet (9 to 15 m?

7~
,, may be exca~ated using a series of ~oined augers havlng five or six flights apiece, under ideal soil conditions (cohesive clay). The system is limi-ted by the large torque that must be applied, caused by the frictional weight of the soil being excavated and the weight of soil to be remove~. For example a 48 inch (1.2 m) diameter hole, 50 feet ~15 m) deep contains approximately 50 short tons (~5 tonnes~ of soil, which is way beyond the usual limits of this technolo~y.
Typically available standard drill rigs up to 50,000 foot -pounds torque also effectively limit the practical application of this technolog~, which is widely known.

Larger holes require di~ferent technology. It is a special~zed field in construction and drilling engineering, which is not widely publicized in the literature, b*cause each site re~uires differerlt equipment. The general principles are known to manu~acturers, distributors, and desi~ners of the equlpment. Conventional equipment available for thls work is capable Oe produciny up to 20 300,000 ~oot-pounds o~ torqu~. The augers used are individually deslgned to suit speci~lc applicable soil conditions, as a result there are ~ubstantial diPferences ~etween individual augers.

Larger holes up to about 8 foot (2.45 m) are dr:llled in a single operation in normal soil conditions usiny a heavy duty double flight auger with a double cutting edge, approximately 5 to 6 ~eet ~1.5 to 1.~ m) long. The hole is drilled to depth up to 150 feet ~46 m) through coheslve soils, lncluding clay, silted clay, glacial till, mudstone and shale, and similar soil, as those skilled in the ar-t would be aware. The auger is drilled lt's length down into the soil, then is withdrawn from the hole and the tailings removed. The process is repeated until depth is reached. A
single ~light cutting single edge auger is less efficient for thls purpose, as the single edge produces eccentric torque on one side, causing the hole to drift off true vertical. The double edge double flight auger produces , 2~J~7~7 uniform and vertical drilling. For this reason alone it is doubt~ul that Hignite in t1S Patent 3,835,652 is operable.
Certainly 8 to 10 foot ~2.4 to 3 m) diameter hole~ could not be excavated or spaced 2 ~eet (0.6 m) apart, successfully by the techniques taught by Flignite.

Hol~s rom 8 to 30 foot (2.45 to 9.15 m~ diameter are excavated in a two stage operation. First a small bore, typically 6 foot ~1. a m) hole is excavated in normal ~oil conditions using a heavy duty double cutting edge double flight auger, approximately 5 to 6 feet (1.8 to 2.45 m) long. The hole is drilled to depth up to 195 feet (60 m), through cohesive soils. The auger is drilled its length down into the soil, then auger ancl tailings are withdrawn, and the tailings removed, the process is repeated until depth is reached.

The second stage consists of u5ing the ~mall bore hole to guide a cu~tom designed heavy duty double Pli~ht double cutting edge auger. The auyer has a bottom cylinder Pormln~
a guide or pilot, which e:lt~ into the small bore ho.le, the cutting edyes extend outward ~rom the pilot to the planned diameter o~ the hole. This auger i5 typically 5 to 6 feet (1.5 to 1.8 m) long. This cuts the hole to the required diameter and depth in auger length increments.

An alternative auger ~ystem may be used in the configuration oP a drilling bucket having a single or double cutting edge fixed in a slot to the otherwi~e closed bucket botto~, which may be hinged.

The excavatio~ may also under some but not all conditions be completed within a co~er dam o~ driven sheet piling ~ or other types of shoring up to about 100 feet (30 m~ deep. A crane operated hammer grab is continuously dropped from the surface to fill it with eY.cavated material, which is hoisted to the surface and removed. The final configuration of the excavation at the sur~ace controls the ~ ~30 7 7 ~

shape of the shaft.

Cohesive soils are ideal conditions. Frequently the drilling is undertaken in areas o~ rock (igneous rock such as granite, harder shales, limestone, or sandstone for example~. In this case a core barrel of the desired diameter o~ the flnal hole, typically 3 -to 30 Eoot (0.9 to 9.1 m), is used rota~ed by a kelly bar, driving the core barrel through a top cross braclng. The core barrel has a bottom ring of downward and slightly outwardly inclined cutting teeth. There is a helical retaining ring interior of the barrel, which retains the internal core oP cut rock.
Large diameter core barrels are commercially available Por rock drilling, but are often custom made.

Another problem is excessive water, for example from a perched water table, which can collapse ~he already drilled hole. This is typlcally the case when the soil is water bearing sllt, sand or gravel. In this case the hole is drillQd to the depth where problems are noted. Then a casing Oe ~2 to 3~4 inch (12 to 20 mm) steel, coupled like drill stem coupling, iP required by threadin~ and rubber gasketr is utilized. The outer casing diameter i5 slightly smaller than the drilled hole, and has a length to complete the planned hole, from the surPace, optionally the casing has bottom teeth. The casing is then slid down until it contacts the bottom oP the pre~ent hole, and a ~tandard model vibrohammer is used to vibrate th~ casing down through the ~oil to the desired depth. The soil wlthin the casing is then removed by a heavy duty double Plight double cuttlng edge auger, oP external diameter sli~htly less than the internal casing diameter. The casing is then retrieved using a vibrohammer. Again this clearly indicates that Hignite teachings using conventional equipment cannot extend his excavatlons below the water table or in soil conditions that develop sloughing such as is generally encountered .

It is an object of the invention to provide a sanitary .

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landfill system for municipal 501id waste including vertical cells for waste storage and treatment. Other ob~ects ~will he apparent to those skilled in the art from the following specification, appended claims and accompanying drawings.

DESCRIPTION OF TME IN~ENTION

In one aspect of the invention it is directed to a vertical landflll cell comprising a vertical excavation of 2 to 50 ~eet (0.6 to 15 m) across, and depth 8 to 195 feet (2.4 to 60 ~). Conveniently the exca~ration is a vertical cylinder 2 to 30 feet (0.6 to 9 m) in diameter. More usually such cells are up to 110 feet ~33 m) deep, sometimes 130 feet (40 m) deep, and 8 to 30 feet (2.4 to 9 m) across.
Preferably the cell is lined wlth impervious liner means.
Waste is stored in the completed cell, which may be toxic waste, or compacted waste, which may be organic. The waste i~ preferably enclo~ed within the impervious liner means.
The cell is typlcally sealed at the upper end by compacted 8011 means. The cell ls more preferably lined to reduce or ellminate percolation of it~ contents into the ground water.
The ground water tabl~ in much of North America lies up to 80 ~eet (2~ m) below ground level, generally 8 to 12 ~eet l2.~ to 3.6 m), more so nearly any vertical land~ill cell will penetrate into the water table. When the waste is toxic the liner should preferably also be chemically inert.

The excavated hole which is preferably lined with an impervious liner of concrete, steel, plastic derivative, or ceramic material, as wowld be known-to those skilled in the art, is then ~illed with selected wa~te materials. Waste materials are increasingly being sorted ~or recycling. Most preferably they can also be ~orted for disposal. All 80rts o~ figures for waste are quoted, but they vary widely it is fairly certain cellulosics, including newsprint and related paper products (telephone directories, cardboard, paper wrapp.ings, etc.) ~orm a large part of the volume of municipal solid waste . Steps are increasingly being taken , ~ :

2~3~7 ~;
to recycle these celluloslcs. It is proposed to separate solid organlc waste other than these from the residue of metals, wood, glass, plastic, construction and demolition, ceramic and miscellaneous waste~, which will also be sorted.
Preferably each different type of waste will ~e either recycled directly or stored separately in vertical cells.

The cell as required by local conclitions may receive bottom lift of compacted 50il 1 to 3 feet (0.3 to 0.9 m) deep. Waste i5 then deposited, preferably in 30 to 60 feet ~9 to 18 m) li~ts in the cell which ar~ then compacted to reduce volume. Again as requlred by local conditions a sandwich li~t of compacted ~oil 1 to 3 Peet (0.3 to ~.9 m) deep ~ay be depo~ited within the shaft to produce 1 cell of the unit. The process is repeated until the compacted waste fllls the cell to within 4 to 6 feet (1.2 to 1.8 m) of the surface. To complete the cell a lift of ~oil ls compacted within the top o~ the cell, until orlglnal ~rade level i~
reached. Slmilar cells may be constructed followlng a grid system, which ~or instance may place cells at the centre and corners o~ an arra~ of squares of side two cell diame-ters.

Using this ~ystem properly calculatlon has shown, will enable storage on a 5quare site o~ 1 acre (0.~ ha~, o~ some 130,000 cubic meters op compacted waste. A conventional landfill 136 feet (41 m) thick, 60 feet (18 m) below grade and 76 feet (23 m) above grade, wlll store less material ~ome 100,000 cubic meters. This does not include sorting or recyclin~ the wast~. Additional advanta~es are all storage i9 below orl0inal grade level, avoidiny the mountain of rotting waste. Soil and air pollution are eliminated, when an impervious liner ls utilized. ~itter, birds and rodents are eliminated. The site can be planned to accommodate the ongoing volume of waste products ln the locality. Each cell is confined to a llmited area, allows safe construction practices to be esta~lished and enforced. The variation in vertical cell size, allows considerable variation in cell capacity to allow for dif~erent waste volume nee~s. Cells : . , .

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can be utili7ed for temporary storage of hazardous, toxic or corrosive, industrial wastes. The cell system can be constructed under all weather conditions.

As an alternative (or ln addltion to) providin~ an impervious lining to the cells linin~ the cells) as may be required by specific condltions or regulations, a slurry wall can be constructed around the lans~fill perimeter. The slurry wall is con~tructed by excavating a trench from 0.5 to 4 feet (0.15 to 1.2 m) wide is excavated to below maximum depth of the landfill slte, pre~erably footed in solid rock and filled with bentonite or other material that prevents migration of leachates, etc.,- into the surroundlng area.
This is pa~ticularly effective in preventing the miqration of hazardous chemicals such a~ PCBs.

The waste is preferably sorted and stored according to type. Organic solid waste, preferably not including wood and other cellulosic~, is preferably deposited sepaxately in designated cell~. These include a cylindrical excavation of d.~ameter about 6 to 30 feet (1.8 to 9 m)~ and depth ~ to 195 feet ~2.4 to 60 m). A central hole is cored, after compaction of the waste to form a central core hole preferably of 16 to 30 inch (0.~ to 0.9 m) diameter. When completed an enclosed central perforated sleeve means preferably of diameter about 1~ to 30 inch (0.4 to 0.9 m) extends from top to bottom of the cell, filling the core hole. The sleeve means extends from top to bottom o~ the cell. The sleeve means is connected to a conventional gas collection ~ystem by first tube means. The ~leeve means ls ~illed by porous materlal, typically pea gravel, gravel, sand etc. A second tube means, may extend from top to bottom of the cell. This second tube means is perforated, and connects to the first tube means. The slee~e means outside the second tu~e means is filled by porous material.
A third tube means may extend from top to bottom of thecell.
Thls third tube means connects to a conventional liquid distribution ~ys-tem. Preferably impervious liner means r~ r~ ~i enclose compacted solid organic wa~te surrounding the sleeve means. The third tube means may be within the sleeve means, outside the second tube means, or outside the ~leeve mean~.
The third tube means may be perforated. When per~orated it can be used to introduce anaerobic microbial cultures and liquid into the cell. When not perforated it can be used to remove liquids from the cell.

In another broad aspect the invention is directed to a process of fermentatlon of solid organic waste comprising (a) allowing compacted solîd or~anic waste to ferment anaerobically within vertical landfill cell means havin~
impervious liner means to produce ~aseous products includin~
methane, and (b) withdrawing the gaseous products from the cell means. Preferably the additional step is taken (c) of introducing an aqueous anaerobic microbial culture into the compacted solid organic waste. Such cul~ures are well known see for example Ghosh, USP 4,323,36~ and references therein.
Eventually the steps of (d) allowiny the ~ermentation to termlnate and ~e) removing ~ermented solid organic wa~te ~rom the cell mean~ are taken. The ~ermented or~anic waste is now compost, and may be sold as ~uch. The solid organic waste first ferments aerobically consuming oxygen within the sealed liner, as in existing landfill~. When the oxygen i8 consumed, anaerobic fermentatlon begins.

The use of fermentation cells effectively harnesses methane production, and el:l~inates it as a pollutant. It further reduces the amount of waste to be stored. It is belleved that about halP of residential waste by weight is such ~ermentable organic waste. This gives an estimate of methane generated per capita in North Amerlca o~ 6500 cubic feet, and compost generated per capita of about 1000 lbs.

In a further broad aspect the invention is directed to a method of vertical landfill cell preparation comprising (a) excavating vertical shaft means, (b) lining the shaft with impervious liner means. When the shaft strikes a water :
' ;) 7 r table, or noncohesive soil, as will often be the case, the method ls adaptecl to (c) drlving cylindrical ~teel casing means into the ground by vibrohammer means, (d) removing soil withln the ca~ing means by to ~orm sha~t means co~erminous with the ca~ing mean , and (b) lining the shaft ~eans with i~pervious liner means. Then the step o~ ( e~
removing the casing means f rom the shaft means by vibrohammer means ls taken. This may be done before or after insertion of the liner means. The casing is left in place if the liner cannot be inserted in its absence. The casing may be left in place duriny filling and compacting waste inside the cell, and removed by vibroh~mmer means later.

BRIEF DES R PTION_OF_H DR WINGS

Pre~erred embodiments are indicated in the drawings whers:
Fig. 1 shows a slde sectional view oP a prePerred embodiment of the invention;
Fly, 2 shows a plan view o~ the embodiment o~ Fig. 1;
Figs. 3 to 6 ~hows part slde ~ectional view~ oP other prePerred embodiments o~ the invention;
Fig. ~ shows a side sectional view o~ another preferred embodiment of the invention;
Fig. 8 shows a side sectional view of a ~urther preferred embodiment of the invention;
Fig. 9 shows a top plan view of a portion of a landfill according to the invention.
DES~RIPTION OF _ E REFERRED EMBO~_MENTS

The general description of the invention i9 now expanded by reference to the drawings, which illustrate prePerred embodiments of the invention.

Numeral 10 generally indicates a vertical cylindrical hole ~orming a cell excavated from original grade level 8 in 1~

2 ~ a ~ ~ ~ 7 30il 9, by known developed methods. The~e cell~ can be typically 2 to 30 feet (0.6 to 9.1 m~ cliameter and 6.5 to 195 feet (2 to 60 m) deep. Impervlous liner or geomembrane 11 lines hole 10, ~ormed from suitable materlals concrete, ~teel, plastlc derivative, or oeramic material, as would be known to those sXilled in the art. Cell 10 can then filled by an initial layer or lift 14 of compalcted soll some 1 to 3 ~eet (0.3 to 0.9 m) thick, which i8 then covered with a compacted layer or lift 16 of organic solid waste ~ to 30 10 feet (2.4 to 9.1 m) thlck (Figs. 1 and 2). In turn this is covered with li~t 18 of compacted 50il, which in turn is covered with another lift 16 of compacted solid wa~te. When the cell ~ull a c~ntral hole 20 is bored some 16 to 30 inch (40 to 90 cm) diameter. Into this is inserted 16 to 30 inch (40 to 90 cm) per~orated sleeve 22, of pvc or similar material, as known -to those skilled in the art, which forms a central hollow core, within whlch is centrally placed 6 inch (15 cm) perPorated take o~ or extraction pipe 24, also o~ pvc plastic or sim.llar ma~erlal, optionally 2 lnch (5 cm) per~orated in~ection plpe 26 of pvc plast:lc or sim:Llar material is with:in sleeve 22 outsic1e pipe 24. Extraction pipe 24 is connected via coupling pipe 28 to 8 inch (20 cm~
lead of~ pipe 30, which connects to a conventional ~as collection system. When present in~ection pipe 26 i~
connected via coupling pipe 32 to lead off or lead in pipe 34, which may be connected to a conventional liquid distribution sy~tem. Sleeve '~2 is filled with porous material 35, for lnstance pea gravel. The top portion of hole 10 is Eilled by compacted soil plug 3~ to or.iginal grade level 8, (om.itted ln Flg. 2).

In Figs. 3 to 6 are shown alternative a:rrangements of the embodiment o~ Fig. 1. In Fig. 3 sleeve 22 has no interior tubes and is connected directly to take of~ pipe~
In Fiy. 4, pipe 27 is not perforated within sleeve 22. In Flg. 4, pipe 26 is perforated within sleeve 22. In Fig 5., pipe 27 is per~orated outside sleeve 22. In Fig 5., pipe 2 is not perforated outside sleeve 22.

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In use the injection pipe 26 is used to inject an anaerobic microbial culture, numerous such conventional cultures are known, into compacted solid organic waste 16, which begins to 510wly ferment produciny methane and ~ome other products. These percolate into casing 22 and are led off through pipes 24 and 30. Pipe 27 can be used either to introcluce or remove llquid from cell 1(). Organic solid waste ferments to compost, and when methane production ceases lt can be e~cavated and sold as a commercial product, Methane production is conservatively loosely estimated at 6.5 cubic feet~pound ~0.4 cubic meters/Kg) of solid organic waste. Empty cell 10 then can be relined if required, and reused.

Cell 10 may also be used for general wa~te stora~e (Fig. ~). In -this example cell 10 has been drilled below the water table into noncoheslve ~oil 38, cylindrical steel casing 40 ~orms the bottom portion of cell 10. Cement plug ~2 seals the bottom of the ca~:Lng preventlng water flow.
Liner 12 ~its within casing 40. Cell 10 when complet~
contain~ waste 44, and ls sealed with compactecl ~o~l plu~
36. Alternatively Fig. 7 may be regarded as showing a cell full of solid organic waste before coring to insert gas collection apparatus. Cell 10 may also be excavated partly into impervious rock (Fig. 8), liner 12 in this case ex-tend~
into rock 46, ~ut need not extend to the cell bottom to form a water tight seal. When the waste 44 does not fe~ment the cell may be sealed off.

The landfill (Fig. 9) i8 contemplated a~ lnclucling an array of cells 10, spaced in alternating rows 4~ and 50, each alternate row separated from the next but ane by a cell diameter. Optionally a slurry wall 51 surrounds the landfill, formed by trench 52 and slurry 54.

The system envisages separation of solid organic waste from all other solid waste, for example metal, wood, plastic, newsprlnt, construction and/or demolition rubble, 2 ~ 7 r~ 7 atc. These other solid wastes can be recycled or stored permanently or temporarily in vertical cells 10. Similarly toxic wastes can be stored in vertical cells of th.is system.

~ 8 those skilled in the art would realize these preferred illustrated dimensions, details and components can be subjected to substantial variation, modi~ication, change, alteration, and substitution without a~ecting or modifyin~
the function o~ the illustrated embodinnents.
This invention is not limited to the embodiments described above, and it will be apparent to persons .skilled in the art that numerous modi~ications and varlations ~orm part o~ the present invention insofar as they do not depart from the spirit, nature and scope of the claimed and described invention.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A vertical landfill cell comprising a vertical excavation 2 to 50 feet (0.6 to 15 m) across, and depth 8 to 195 feet (2.4 to 60 m).

2. A vertical landfill cell of claim 1, wherein said excavation is cylindrical of diameter 2 to 30 feet (0.6 to 9 m).

3. A cell of claim 1, further comprising impervious liner means and waste.

4. A cell of claim 3 further comprising compacted solid waste enclosed within said impervious liner means.

5. A cell of claim 3 wherein said waste is toxic waste enclosed within said impervious liner means, and said impervious liner means is chemically inert.

6. A cell of claim 1 comprising a cylindrical excavation of diameter about 6 to 30 feet (1.8 to 9 m), and depth 8 to 195 feet (2.4 to 60 m), having an enclosed central perforated sleeve means extending from top to bottom of said cell, said sleeve means connecting to a conventional gas collection system by first tube means, said sleeve means being filled by porous material.

7. A cell of claim 6 comprising second tube means, extending from top to bottom of said cell, said second tube means being perforated, and connecting to said first tube means, said sleeve means outside said second tube means being filled by porous material.

8. A cell of claim 6, additionally comprising third tube means extending from top to bottom of said cell, said third tube means connecting to a conventional liquid distribution system.

9. A cell of claim 6, having impervious liner means enclosing compacted solid organic waste surrounding said sleeve means.

10. A cell of claim 7, having impervious liner means enclosing compacted solid organic waste surrounding said sleeve means.

11. A cell of claim 8, having impervious liner means enclosing compacted solid organic waste surrounding said sleeve means.

12. A cell of claim 9, wherein said third tube means is within said sleeve means, outside said second tube means.

13. A cell of claim 12, wherein said third tube means is perforated.

14. A cell of claim 9, wherein said third tube means is outside said sleeve means.

15. A cell of claim 14, wherein said third tube means is perforated.

16. A process of fermentation of solid organic waste comprising (a) allowing compacted solid organic waste to ferment anaerobically within vertical landfill cell means having impervious liner means to produce gaseous products including methane, (b) withdrawing said gaseous products from said cell means.

17. A process of claim 16, additionally comprising (c) introducing an aqueous anaerobic microbial culture into said compacted solid organic waste.

18. A process of claim 16, additionally comprising (d) allowing said fermentation to terminate and (e) removing fermented solid organic waste from said cell means.

19. A process of claim 17, additionally comprising (d) allowing said fermentation to terminate and (e) removing fermented solid organic waste from said cell means.

20. A method of vertical landfill cell preparation comprising (a) excavating vertical shaft means (b) lining said shaft means with impervious liner means.

21. A method of claim 20 comprising (c) driving cylindrical steel casing means into the ground by vibrohammer means, (d) removing soil within said casing means to form shaft means coterminous with said casing means, (b) lining said shaft means with impervious liner means.

22. A method of claim 21, additionally comprising (e) removing said casing means from said shaft means by vibrohammer means.