Chapter 5Disposal

The main disposal methods for municipal solid waste (MSW) is open dumping andsanitary landfill. Uncontrolled dump sites are smoky with a lot of leachate gen-eration with severe environmental pollution. On open dumping grounds generatefoul odors and habitat for vectors and rodents. The disposal need not have to occurwithin the same country. For example, some materials from waste in Bahrain areexported after being compressed to a scale below their actual size.

Since the landfill is restricted by European Commission and its member countries,waste derived fuel from MSW is strategic component of integrated waste manage-ment policy. In Denmark and the Netherlands, land filling of MSW is already inplace. However, some bulky waste is land filled in Denmark and the Netherlands.Separated combustible waste cannot be land filled in Sweden since 2002 and the landfilling in France is limited to an ultimate waste since 2002 (EC 2003).

5.1 Landfill

Historically countries disposed waste on land and covering it up. In many casesuncontrolled burning of waste would precede or follow dumping activity. Landfillsare the final depository of a waste after all other waste management options havebeen carried out. Landfills can be categorized according to open dumps, controlleddumps or sanitary landfills (or secured landfill or engineered landfill). Figure 5.1shows a typical schematic diagram of landfill.

An engineered landfill or sanitary landfill facility is an integrated waste man-agement disposal system. Disposal in an engineered waste landfill facility is thefinal stage in the waste management process, providing long-term confinement ofwaste materials. An appropriate treatment may be needed to process the waste forfinal disposal. Some of the processing may include minimizing or eliminatinghazardous properties, stabilizing the waste, and/or reducing its volume. Engineered

R. Chandrappa and D. B. Das, Solid Waste Management,Environmental Science and Engineering, DOI: 10.1007/978-3-642-28681-0_5, Springer-Verlag Berlin Heidelberg 2012

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bioreactor landfills are designed to minimize the infiltration of rainwater and/orsnowmelt into the solid waste. Over the past decade or so, several field scale pilotstudies have been conducted to develop and improve landfill techniques anddesigns.

Sanitary landfill facilities are generally located in areas where the potential fordegradation of the quality of air, land, and water is minimal. Similarly, a sanitarylandfill should be located away from an airport to avoid air accidents betweenbirds and aeroplanes. The location should preferably be outside 100-year floodplain and should not be located in the close proximity of wild life sanctuaries,monuments and other important places which is ecologically important. Locationof sanitary land fill should also consider seismic sensitivity of the area to avoidenvironmental damage during earthquake. Table 5.1 shows important factors to beconsidered while evaluating a landfill site.

In comparisons to other possibilities, landfill should be the last option to managewaste. For example, Denmark which generates about 13 million tons of waste peryear has banned land filling waste suitable for incineration (DEPA 1999).

Landfill is the physical facility specifically designed, constructed and operatedfor the disposal of waste. Even after well-planned waste reduction, recycling andtransformation programs, the residual waste from such operations still ends up on alandfill.

Landfills can also be classified into general or hazardous waste disposal sitebased on the waste disposed.

A typical landfill will undergo the following activities during its life time: (1)planning, (2) site selection, (3) site preparation, (4) landfill bed construction, (5)leachate and gas collection system incorporation, (6) land filling, (7) monitoring,(8) closure of landfill, and (9) post closure monitoring.

This section discusses the general landfill objectives and practices. The specialprecautions and practices followed in hazardous waste land fill are discussed indetail in Chap. 7.

The typical landfill process during operation involves: (1) waste dumping at theworking face, (2) waste spreading, shredding and compaction, and (3) wastecovering (Fig. 5.2).

The land fill method can be broadly classified into trench method, area methodand depression method as explained in the subsequent paragraphs.

Excavated Cell/Trench Method: This method is ideally suited in areas wherethere is an adequate depth of cover material and water table is not near the surface.In this method, solid wastes are placed in cells/trenches excavated in the soil(Fig. 5.2). The soil excavated in the site is used for daily/final cover. The cells/trenches are lined with lining system to restrict the movement of landfill gases andleachate. The cells are provided with side slopes of 2:13:1 and vary from 50 to300 m in length, 13 m in depth, and 515 m in width.

Area Method: This method is used where the terrain is not suitable for theexcavation of cells or trenches. Liner system as provided to manage leachate andcover material must be hauled from other places.

118 5 Disposal

Storm water drain

Final Cover

Leachate Collection Sump

Working Face

Storm water drain

Fig. 5.1 A typical schematic diagram of landfill

Table 5.1 Important factors to be considered while evaluating a landfill site

Sl. No. Factor Remark

1. Access to land Existing road/railway/water way should be considered2. Climate Rainfall, temperature, humidity, wind speed, snow fall etc., need

to be considered3. Disaster history of

the locationEarth quake, cyclone, draught, flood, tsunami, hurricane,

terrorism, war, sabotage, industrial accidents etc. shall beevaluated

4. Extent of landavailable

Should be capable of accepting waste to an extent so that aninvestment is feasible

5. Final use of land Long term use of land needs to be evaluated6. Geology and

hydrogeologyGroundwater quality and quantity as well as permeability of the

geological strata need to be studied7. Haul distance Distance from source/transfer station decides to economy of

operation especially when a site receives waste from morethan one source

8. Local and nationallegislation

Regulatory issues decide the ultimate location

9. Local environment The local environment with respect to biota, monuments,religious setting, physico-chemical environment like noise, airquality, water quality, land use pattern shall be considered

10. Public acceptability Local public shall accept the idea and project for success of theproject

11. Soil sharacteristics Soil characteristics and availability of cover material need to beevaluated

12. Surface waterhydrology

Drainage pattern, distance from major water bodies, water shedboundaries shall be considered

13. Topography Contours and slope need to be studied

5.1 Landfill 119

Canyon/Depression Method: In this method compact solid waste is placed incanyon/depression. Usually, filling begins at the head end of the canyon andconcludes at the mouth, in order to prevent the gathering of water behind thelandfill. In this method sites are filled in multiple lifts.

Landfill Airspace which is the permitted height, length and breadth the landfillmay finally occupy. Landfill airspace determines the lifespan of a site. Efficientoperations will increase the use of the space. Once airspace is completely utilizedthe site is closed and capped with a layer of impermeable clay and layer of top soil.Grass and other suitable vegetation types are planted on landfill site to stabilize thesoil and improve the appearance. Environmental monitoring is carried out for aperiod of up to 30 years after the closure of the site. Table 5.2 shows examples oflandfill sealants. Table 5.3 shows factors to be considered landfill design. Table 5.4shows factors to be considered during construction and operation. Table 5.5 showsfactors to be considered during post closure.

5.1.1 Processes Within a Landfill

Organic matter in MSW composes of mainly of proteins, lipids, carbohydrates, andlignins which are easily degradable. Other organic matter like lignin and celluloseare recalcitrant. Some of the biodegradable portions are readily biodegradable andothers are moderately biodegradable fraction. The landfill ecosystem is diverse and

Leachate collection pipe Impermeable linerWaste

Cap

Daily CoverFig. 5.2 Typical trenchmethod of landfill setup

120 5 Disposal

hence promotes stability, however, it is influenced by environmental conditionslike temperature, pH, moisture content, etc.

Stabilization of MSW in landfill happens in five phases (Willium and Aarne2002). Such phases may not happen at all in landfill meant exclusively for C&Dhazardous waste. The five phases occurring in MSW landfill sites are:

(1) Initial Adjustment Phase: In this phase microbes acclimatize to the landfillcondition.

(2) Transition Phase: In this phase transformation from aerobic to anaerobicenvironment occurs.

(3) Acid Formation Phase: The continuous hydrolysis of solid waste, followedby the microbial action on biodegradable organic fraction results in the gen-eration of intermediate volatile organic acids.

(4) Fermentation Phase: During this phase, intermediate acids are converted intomethane, carbon dioxide, hydrogen sulfides and ammonia, by microbialaction.

(5) Maturation Phase: During this phase nutrients become scare and the bio-logical activity shifts to dormancy resultin in drop in gas production and andleachate strength will be at lower concentrations. Slow decomposition ofresistant organic matter may continue resulting in humic-like substances.

5.1.2 Controlling Leachate and Gas

Wastes in land fill generate leachate which is defined as the water that has per-colated through the wastes which is a source of soil and groundwater pollution andgas produced by the fermentation of organic matter. Precipitation is the majorreason for generation of leachate. The soluble and suspended components from thebiodegrading waste will combine with percolating water in landfill site throughseries of complicated physical and chemical reactions. Other contributors toleachate creation are groundwater inflow, surface water runoff and biologicaldegradation (Reinhart and Townsend 1998).

The quantity of leachates depends on: (1) rainwater percolation through wastes,(2) biochemical processes in wastes cells, (3) inherent water content of the wastes,and (4) the degree of compaction of the waste. The leachate production is usuallygreater when the waste is less compacted as compaction reduces the filtration rate(Lema et al. 1988). Composition of leachates from landfill varies with the age ofthe landfill (Silva et al. 2004). As landfill age increases, concentration of organicsin the leachate decreases whereas the concentration of ammonia nitrogen increases(Kulikowska and Klimiuk 2008; Cheung et al. 1997). Recirculation of leachatemay result in high concentrations of ammonia but lower concentrations ofdegradable carbon compounds (Cheung et al. 1997).

Leachate disposal into the sewer system has advantage of easy maintenance andlow operating costs (Ahn et al. 2002). Recycling leachate back into landfill is oneof the least expensive options for treating leachate (Lema et al. 1988). Lagooning

5.1 Landfill 121

may not be a acceptable treatment option for leachate (Zaloum and Abbott 1997).Activated sludge processes found to be not adequate for treating landfill leachatetreatment in recent decades (Lin et al. 2000). Flotation has been used for manyyears to decrease colloids, macromolecules, ions, microorganisms and fibres(Zouboulis et al. 2003).

Coagulation-flocculation can be utilised in treating stabilized leachates from oldlandfill sites (Silva et al. 2004). Chemical precipitation can be used as leachate pre-treatment to eliminate high strength of ammonium nitrogen (Abdulhussain et al.2009). Chemical oxidation is necessary for the treating of wastewater with solublenon-biodegradable organic/toxic substance (Marco et al. 1997). Ammonium strip-ping is widely used for the removal of ammonia nitrogen from landfill leachate(Abdulhussain et al. 2009). Electrodialysis, microfiltration, nanofiltration, ultrafil-tration and reverse osmosis are used if high quality treated effluents are required.

Single-Liner SystemsSingle liners (Fig. 5.3) contain clay liner, geosynthetic clay liner or geomem-

brane. Single liners are used in landfills designed for construction and demolition ofdebris.

Composite-Liner SystemsA composite liner (Fig. 5.4) comprises of geomembrane and clay liner. Com-

posite-liner systems are more efficient at limiting leachate migration. Compositeliners are used mostly in MSW landfills.

Double-Liner SystemsDouble-liner systems (Fig. 5.5) are used widely in hazardous waste landfills. A

double liner contains either two composite liners or two single liners or

Waste

Soil Layer

Protective Layer

Waste

Recompacted Clay

Protective Layer

Sand / Gravel

Sand / GravelGeomembrane

Fig. 5.3 Examples of singleliner system

122 5 Disposal

combination of a single and a composite liner. The upper liner functions to collectthe leachate whereas the lower liner backup to the primary liner and used for leakdetection.

Leachate Collection SystemsAll liner systems are integrated with leachate collection system. Leachate

collection system is composed of gravel and sand or a geonet (plastic net-likedrainage blanket) along with a sequence of leachate collection conduits to drainthe leachate to holding tanks for treatment (Fig. 5.6).

Waste

GeotextileSand / GravelGeomembraneRecompacted Clay

Waste

Sand / Gravel

Recompacted Clay

Geotextile

Geomembrane

Protective Layer

Protective Layer

Geonet

Fig. 5.4 Examples ofcomposite liner systems

Waste

Sand / Gravel

Recompacted Clay

Protective Layer

Sand / GravelRecompacted Clay

Protective Layer

GeomembraneRecompacted Clay

Geotextile

Geomembrane

Sand / GravelGeosynthetic Clay Liner

Geomembrane

Waste

Sand / Gravel

Fig. 5.5 Examples of doubleliner system

5.1 Landfill 123

The upper drainage layer of double-liner systems acts as a leachate collectionsystem and the lower drainage layer is used for the leak detection. The leachate inthe lower drainage alerts landfill management to take necessary corrective action.

Components of the liner system are provided with protective layer composed ofsoil, sand, and gravel or a layer of soft solid waste such as paper, shredded tires,organic refuse, and rubber.

Liner ComponentsClay: Clay liners are laid to avoid groundwater contamination. A simple liner

will comprise of 30 cm1 m thick compacted clay layer. The effectiveness of clayliners is affected by fractures stimulated by freezethaw cycles, presence of somechemicals and drying out.

Geomembranes: Geomembranes or flexible membrane liners (FML) are con-structed from a variety of plastic materials which include polyvinyl chloride (PVC)as well as high-density polyethylene (HDPE). Figure 5.2 shows geomembranelayed before placing waste in landfill and Fig. 5.7 shows geomembrane placed onlandfilled waste prior to closure and Fig. 5.8 shows position of geomembrane inlandfill cap.

Geotextiles: Geotextiles (Fig. 5.9) allow the movement of water and trapparticles to reduce blockage in the leachate collection system. They are used toavoid the movement of minute waste and soil particles into the leachate collectionsystem and to protect geomembranes from punctures.

Geosynthetic Clay Liner (GCL): These liners comprises of a clay layer of 46 mm between the layers of a geotextile.

Geonet: A geonet is net-like drainage blanket of plastic used in landfill liners inplace of gravel or sand for the leachate collection layer. Geonets are more vul-nerable to clogging by minute particles.

Storage of solid waste in landfills contributes to the greenhouse gas (GHG) dueto degradation of organic component of waste. Total European emissions are about2 % of the total GHG of 5,000 Million ton per year (EEA 2009). Areal emission

Fig. 5.6 Leachate treatmentfacility

124 5 Disposal

Fig. 5.7 Geomembraneplaced on landfill prior toclosure

Waste

Gas Venting

Clay

Sand / Gravel

Cover soil

Top SoilGrass

Geomembrane

Geotextile

Fig. 5.8 Example ofdifferent layers in landfill cap

Fig. 5.9 Geotextile in Landfill area

5.1 Landfill 125

rate of gaseous pollutants from landfills is difficult to control and meteorologicalfactors some time lead to enhancement of lateral migration of Land Fill Gas (LFG)that cause gas explosion accident (Mohammed et al. 2009) Tables 5.2, 5.3, 5.4and 5.5.

Table 5.2 Examples of landfill sealants

Sl.No.

Sealant Example Remarks

1. Compacted soil Silt, black cotton soil,sand

Should contain cohesive property

2. Compacted clay Bentonite, Kaolinites Layer must be continuous and should notbe allowed to crack

3. Inorganic chemicals Sodium silicate,pyrophospate

Use must be decided based on availabilityand local soil characteristics

4. Synthetic chemicals Polymers May be considered after pilot studies5. Synthetic membranes/

GeotextilePolyvinyl chloride,

polyetheleneProperties of material and available skills

within operating staff need to beconsidered

6. Asphalt Layer must be continuous and should notbe allowed to crack

7. Others Concrete, tiles May be considered suitable after pilotstudies

Table 5.3 Factors to be considered in landfill design

Factors Remarks

Access Road, rail and other transport modeCell construction and Cover material Cover material available onsite and off siteDrainage Existing and required drainageEmergency Preparedness Plan (EPP) and

Disaster Management Plan (DMP)Comprehensive EPP and DMP should prepared

Environment Management Plan (EMP) Extensive EMP should be preparedEquipment requirement Need to be assessedExtent of land area To be arrived considering on at least 10 years of

operationLand filling method To be evolved depending on local environmental

settingLitter/rodent control Litter/rodent control plan should be finalisedOnsite storage and pretreatment May be required in case hazardous and special

wasteProject specific consideration Need to considered considering local requirement

like loss of livelihood, market for salvagedmaterial

Regulatory issues Need to be considered extensivelyReception, weighing, security, Unloading

and vehicle washingetc.

Provision shall be made for reception,weighing and security

Spread and compaction Need to be considered type of waste and covermaterial

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The decomposition of biodegradable waste happens in five stages. In the firststage, aerobic bacteria produce CO2, water and heat. CO2 may be released as a gasor absorbed by water to form carbonic acid contributing acidity to leachate. Insecond stage proteins, carbohydrates and lipids hydrolyzed by facultative bacteriato sugars. Sugars are further decomposed to CO2, hydrogen, ammonia and organicacids. In third stage organic acids will be converted into acetic acid (CH3COOH),H2, CO2, H2S. In the fourth stage methanogenic microorganisms degrade theorganic acids to CH4, CO2, CH4 and H2O. In the final stage, CH4 generated will beconverted to CO2 and H2O. H2S gas may also formed in final stage if contains highconcentration of sulphates.

LFG generation is influenced by several factors: (1) the gas migration prop-erties through the waste layers and top layer of the landfill, (2) gas collectionefficiency, (3) CH4 oxidation activity, (4) pH, (5) composition of waste, (6)temperature, (7) water content, (8) shredding, (9) compaction, (10) leachaterecirculation, (11) meteorological condition (Mohammed et al. 2009; Cernuschi

Table 5.4 Factors to be considered during construction and operation of landfill

Factors Remarks

Communication Shall have comprehensive communication arrangementDays and hours of operation Should consider non-operating period due to

holidays/calamities/climatic reasonEmployee facility Shall have proper rest house and bath roomEnvironment monitoring and

surveillanceShall have comprehensive environment monitoring and

surveillance arrangementEquipment maintenance/repair Shall have equipment maintenance schedule and

arrangements for minor repairsOperational records Operational records shall include quantity of waste

received and disposed, vehicles records etc.,required by statute and operation

Project specific activity Tree sapling plantation, awareness, corporate socialresponsibility shall be considered

Regulatory issues Shall take measures to fulfil all statutory requirementSafety and security issues Shall take measures to fulfil adequate safety and security

requirementSalvage Need to be done or avoided depending on local condition.

Table 5.5 Factors to be considered during post closure of landfill

Factors Remarks

Environmental monitoring Shall be done up to twenty years and beyond basedon project and local regulation

Landfill gas ventilation/leachate treatment Shall be done to avoid environmental degradationPost closure maintenance Arrangement shall be made for lawn/drainage/

lighting etc.Safety and security Need to be done to safe guard people and animals

5.1 Landfill 127

and Giugliano 1996; Christensen et al. 1996; Gurijala et al. 1997; Naranjo et al.2004; Sormunen et al. 2008; Tecle et al. 2008; Williams 2005; Zhang et al. 2008).

90 % of LFG contains methane and carbon dioxide. Although most of themethane escapes into the atmosphere, they can also move laterally. If the LFG isnot vented out properly it will accumulate below buildings or other spaces as itsspecific gravity is less than air.

Carbon dioxide is about 1.5 times denser than air and 2.8 times denser thanmethane. Hence it will move towards the bottom of landfill and lowers the pH ifenters groundwater thereby increasing hardness and mineral contents of the water.Therefore it is essential that movement of LFG be controlled by constructingvents, barriers and recovery. Gases generated from a landfill are either vented(Fig. 5.10) to the atmosphere or collected for power generation (Fig. 5.11).

Methane (CH4) gas is important GHG as its global warming potential is morethan carbon dioxide (CO2) (Ishigaki et al. 2005). Concentration of atmosphericmethane has more than doubled over the past 150 years (Stern et al. 2007). LFG isknown to be generated both in managed landfill and open dump sites becauseof un-aerobic decomposition of organic matter in waste. It consists of 5060 %

(a)

(b)

(c)

Gravel Packed Vent

Gas Movement

Gas MovementFinal Cover

Packed gravel trench

Packed gravel gas well

Fig. 5.10 Usual methods of venting landfill gases: (a) cell, (b) barrier, (c) well

128 5 Disposal

methane and 3040 % of carbon dioxide and other gases in trace amount (Wang-Yao et al. 2006). Landfills are the main source of methane emissions in US andemitted nearly 37 % of total US carbon emissions in 1997 (EPA 1999).

As the production of methane will begin immediately after waste, bio-tarpcan be used as a means to mitigate methane from open landfill cells. These bio-tarps also serve as a substitute to daily cover during landfill operation. Multilay-ered bio-tarp comprising of alternative layers of two geotextiles is capable ofremoving 16 % of the methane passing through the bio-tarp and addition of landfillcover soil/compost/shale amendments to the bio-tarp would increase the methaneremoval up to 32 % (Bryn et al. 2011).

Traditional cover material reduces the storage capacity. As per the studiesconducted by Zezhi et al. (2011) intermediate covering system using high-densitypolyethylene (HDPE) geomembrane increases gas flow by 25 %. However, settingup of a high permeability layer near surface of landfill improves LFG collectionefficiencies. The permeable layer would lessen the influence of cracks in thecovering material on O2 intrusion and CH4 emissions promoting uniform andgreater CH4 oxidation in the cover layer.

Solid waste in landfills

Different layers of waste cap

Fig. 5.11 Gas collection system in landfill

5.1 Landfill 129

Combustion is the common technique for controlling as well as treating LFG.The most common combustion technologies are flares, boilers, gas turbines,incinerators as well as internal combustion engines. Combustion will typicallyensure more than 98 % destruction of organic compounds. During combustionmethane is converted to carbon dioxide there by reducing impact due to release ofGHG. At methane concentration of more than 20 % by volume, the LFG will forma combustible mixture with air in atmosphere and only an ignition source isrequired for operation. If the methane in LFG is less than 20 % methane byvolume, additional fuel like natural gas will be required to operate flares. Flarescan be open flame flares or enclosed flame flares. Open flame flares comprises of apipe through which the LFG is pumped, a source of spark, and a mechanism toregulate the gas flow. The main disadvantages of open flame flares include inef-ficient combustion, poor aesthetics and monitoring difficulties. In enclosed flameflares gas and air entering is controlled, making combustion more efficient andreliable.

Landfill in most of developing countries is not properly constructed and heaped inopen dumps leading to generation of methane gas. Most of developing countriesreceive good precipitation which makes decomposition slow leading to anaerobiccondition. Hence in modified landfill method termed as Fukuvoka method leachate iscollected through perforated surrounded in graded boulders pipe thereby introducingan aerobic condition. As leachate is removed earliest possible time the internal wastelayer will have lower moisture contents leading to early stabilization of waste.

5.1.2.1 Monitoring of Landfills

Landfill monitoring is carried out for: (1) leachate quantity and quality, (2) leakagethrough liner, (3) groundwater quality, (3) ambient air quality, (4) gas in the sur-rounding soil, (5) landfill-gas quality and quantity, and (6) stability of the final cover.

Leakage through liner is usually detected using a lysimeter. Groundwatermonitoring is accomplished through drilling monitoring wells around land fill. Gasextraction wells are be placed to collect any landfill gas.

5.1.2.2 Closure of Landfills

The land filled waste is covered with daily covers to form cells. But in practice itmay not happen in many places. The waste heap is covered with liners to protectwaste from rain (Fig. 5.12). Once the land fill size attains limit of capping thewaste is covered with layers of geomeberane, clay, gravel, geotextile and top soil(Figs. 5.13 and 5.14).

Landfill closure and postclosure care are necessary for 3050 years after cap-ping to ensure safety and avoid damage to environment. A closure plan shouldinclude land scaping, runoff control, gas and leachate collection and treatment,erosion control, and environmental monitoring.

130 5 Disposal

Fig. 5.12 Protection ofsolids filled in landfill fromrain prior to capping

Fig. 5.13 Layering of coversoil on landfill

Fig. 5.14 Covering claywith topsoil in landfill cap

5.1 Landfill 131

Postclosure care shall include routine inspection and plan for remedial ifunacceptable levels of emissions and leachtes are observed during monitoring.

A final cover system shall be placed after completing of land fill to: (1) min-imize infiltration of rainwater, (2) avoid fugitive emission, (3) to separate wastefrom environment, (4) minimize soil erosion, (5) minimize frost, (6) resist bur-rowing animals, (7) resist penetration of roots.

The permeability of the final cover shall be less than the underlying liner in orderto prevent the bathtub effect wherein water infiltrate through the cover system andare contained by liner system increasing the hydraulic head on the liner system.

The final cover system consists of an infiltration layer of about 50 cm inches ofearthen material covered by 15 cm soil capable of supporting native plant growth.An alternative cover design can be used if the cover guarantees protection againstinfiltration and erosion.

Even though not an economical option, welded HDPE geomembrane of at least2.5 mm thick in intimate contact with a mineral layer is the generally desirable insealers for landfill capping (August 1992; August and Tatzky-Gerth 1991; Augustand Tatzky-Gerth 1992; August et al. 1992; Mller and Lders 1995; Meggyes andMcDonald 1995; Meggyes et al. 1998; Mller 1993; Mller 1995; Mller et al. 1995).

Post-closure care activities involve maintaining the integrity and effectivenessof final cover system, groundwater monitoring system, LFG gas monitoring sys-tem, and leachate collection system.

Landfill capping shall have following components:Surface vegetation: Vegetation helps in erosion of capping material. It will

pose danger if there is penetration of deep roots into landfill.Reclamation layer: This layer supports vegetation as well as protects the lower

layers. Its thickness is determined by the depth of frost and root penetration(Rettenberger 1988; Jessberger H 1990).

Drainage layer: This layer has to divert the water penetrating through thereclamation layer. Hence it should have sufficient permeability for the purpose.Gravel, sand, glass ash, and incineration slag. Water collection is achieved usingHDPE/PVC pipes.

Protective layer: Mineral layers or geotextiles are used to protect the geo-membranes (Mller and Mller 1993).

Sealing layer: The sealing layer is provided to prevent rain-water percolationinto the landfill and escape of landfill gas into the atmosphere. This layer is madeup of polymer sheeting (known as geomembranes) or clayey materials or asphalticliners or bentonite mats.

Regulating layer: This layer is used to separate the capping from the waste andprovide a base for the compaction of the sealing layer.

Gas drainage layer: The gas drainage layer shall collect LFG generated fromlandfill and is made up of material stones or gravel.

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5.1.3 Operation of Landfills

Operating precautions include control of the size cells, placement of interim cover,and use of proper storm water drainage controls. The movement, positioning, andcompaction of solid waste and cover in landfill need a variety of big machines liketractors, loaders, compactors, motor graders, hydraulic excavators, fire extin-guishing vehicles, water trucks, and service vehicles. Specially built landfillcompactors are now used in most of the landfills in developed countries. Dailycover is excavated and placed using pans or scrapers. At an active landfill, solidwaste wastes are placed in layers on the liner and leachate-collection system.Precaution should be taken not to place any compatible material adjacent to eachother in hazardous landfill sites.

Waste in the lowermost layers shall be free from sharp objects to avoidpuncturing of liners. The waste must be placed in such a way that equipments donot damage the leachate-collection system. Filling shall begin in a corner andmove outward. The filling sequence shall be established at the design stage. Wasteshall be covered at the end of every working day with soil or alternative dailycover (like textiles, geomembrane, or other proprietary materials) to control vec-tors and rodents; to reduce odor, litter, and air pollution; to reduce the risk of fire;and to reduce leachate production.

Run-on in landfill area can be prevented by deviating storm water from activelandfill areas. The landfill sides should be sloped to achieve slope stability. Facilitymust be capable of handling maximum storm water generated in single day in past25-years. Typical measures to manage run-off include contouring the land adjacentthe landfill cell and constructing ditches, dike/culverts to divert flow.

5.1.4 Use of Old Landfill Sites

Closed landfill sites can be used for other purpose like golf courses, recreationparks, ski slopes and parking lots.

The closed landfill site is subjected to differential settlement, LFG generation,leachate generation. Settlement occurs rapidly in the first 112 months. Thisperiod of primary settlement is followed by secondary settlement which occurs1520 years after primary settlement. The rate and extent of settlement depends onland filled waste.

5.1.5 Landfill Mining

Digging up old landfills to separate the non-biodegradable material is calledlandfill mining. The non-biodegradable fraction can be reused and finer fraction

5.1 Landfill 133

can be used as cover material for landfills. Opening the cap of landfill may result inthe escape of landfill gas to the atmosphere and produce contaminated runoffduring rains.

5.1.6 Land Filling Hazardous Waste

The land filling hazardous waste is different from the MSW as the hazardous wastewill have no compatible material which may result in heat, explosion and otherundesirable reaction if not properly pre-treated and stabilised. Unlike the MSW,the hazardous waste needs tracking and recording which extend to locations withinthe disposal site. Records shall include source of waste and characteristics of wasteso that remedial action could be taken place some day in future when undesirableevents occur resulting in ground/surface water contamination. The tracking ofwaste also helps in ensuring waste compatibility.

The detailed discussion of land filling hazardous waste is done in Chap. 7.

5.2 Co-Processing of Solid Wastes

Co-processing is the use of waste in industrial processes. Generally 3040 % ofthe production cost (excluding capital cost) in an industry is spent on energy usage.Use of waste is becoming more popular to fulfil energy requirement and cutproduction cost. Figure 5.15 shows waste stored in a cement manufacturing facilityfor co-processing.

Co-processing waste has the following advantages in cement industry:

The alkaline conditions favour the absorption of volatile matter from the gasphase.

The reactions of clinker at 1,450 C allow chemical binding of ashes to theclinker.

Co-processing will have the following problems associated with it

Concentration of hazardous substances should be done above 1450 C and atresidence time of over two seconds to avoid formation of dioxins and furans,and

Melted plastic can hamper or block the substance flow from the pre heater to thecement kiln in case high plastic materials are present in the feed.

134 5 Disposal

5.3 Incineration and Waste to Energy

Incineration is one of the most widely used methods used to dispose all com-bustible waste. Combustion process results in air pollutants and needs to becontrolled. Incineration is less practised in the developing countries due to highcapital/operating costs. As per (Psomopoulos et al. 2009), the USA has over 1,500incinerators out of which 87 are Waste to Energy (WTE) plants and operatingthese WTE by burning nearly 26.3 million tons of MSW serve a population of30 million.

Incineration is a waste treatment/disposal wherein waste is burnt in specializedengineered set up. Incineration is also called thermal treatment as it involvesheat to obtain a desired result. Combustion converts the waste into ash, flue gas,and heat. The flue gases must be fitted with air pollution control equipment toavoid impact of air pollution on environment.

Energy from an incinerator can be recovered for industrial purpose. Incineratorsreduce the combustible material by 8085 % of the initial mass. In order to avoidair pollution due to possible emission of intermediate combustion products likedioxins and furans the air from solid combustion chamber is made to enter asecondary chamber wherein the gas is subject to high temperature. The temper-ature of the primary chamber shall be maintained at 800 50C from where thegases enter the secondary chamber maintained at 1,050 50C where gas resi-dence time shall be at least 1 (one) sec with minimum 3 % (w/w) oxygen in thestack gas.

Waste-to-energy combustion has recently slowed due to issues like flow con-trol, impact on recycling, cost effectiveness, as well as to political acceptability.

The term Refuse Derived Fuel (RDF) is usually used for the segregated fractionof MSW with high calorific value. Other terms used for MSW derived fuels areRecovered Fuel (REF), Paper and Plastic Fraction (PPF) Packaging Derived Fuels(PDF), and Process Engineered Fuel (PEF). Terms Substitute Fuel Secondary

Fig. 5.15 Waste stored in acement manufacturingfacility for co-processing

5.3 Incineration and Waste to Energy 135

Fuel and Substitute Liquid Fuel (SLF) are used for processed waste from indus-tries. The total RDF from processed MSW used for energy installations, powerplants, district heating plants and industries is more than 2 million tpa in EuropeanUnion.

RDF is incinerated as well as co-incinerated in Scandinavian countries in dis-trict heating plants. MSW is used as RDF in cement kilns after sorting and ballingin Austria, Belgium, Denmark, Italy and Netherlands.

5.3.1 Heat Value of Refuse

The heat values of waste are necessary for making decisions about disposaloptions. The heat values of waste can be measured with a calorimeter. In theabsence of calorimeter the calorific value can be estimated in accordance with theexample in Box 5.1.

The success of a waste incineration project depends on accurate data about thefuture waste quantities and characteristics. The lower calorific value (LCV) shouldbe above a minimum level. The specific composition of waste is also important.Combination of tyres and C&D waste is not suitable even if the average LCV isrelatively high. In order to operate incinerator continuously, waste availabilitymust be stable through the year. Hence, the seasonal variations of characteristicsand LCV must be established before launching the project. Waste compositiondepends on cultural differences, socio-economic conditions and climate. Hence,the data of one place cannot be used at another place. The effect of recycling andrag picking which change the composition of MSW must be considered prior tofinalization of waste conversion to energy. In many countries the moisture or ashcontent (or both) in the waste will be high. Waste from commercial (withexception like fish/meat/vegetable/fruit market) and industrial activities have amuch higher LCV than domestic waste. Waste from demolition and constructionactivities which contain hazardous or explosive material are not suitable forincineration.

The waste composition will also change in time due to additional recycling oreconomic growth. Such changes can alter the quantity of waste and LCV. Theaverage LCV of the waste should be at least 6 MJ/kg during all seasons and theannual average LCV should not be less than 7 MJ/kg (World Bank 1999).

As per the actual operating data collected in the US on the average, incinerationof one metric tonne of MSW in a modern Waste to Energy power plant produces anet of 600 kWh of electricity thereby avoiding importing one barrel of oil ormining a quarter tonne of high quality US coal (Psomopoulos et al. 2009). But stillnew WTE facilities were established in the USA between 1996 and 2007 due toenvironmental and political pressures. The main environmental concern in thisregard was the perceived release of toxic substances into the environment.

136 5 Disposal

Box 5.1 Combustion chemistry of wasteAs discussed earlier carbon, hydrogen and sulphur are major elements ofmost of the waste components in municipal solid waste. Even in case ofhazardous waste or biomedical waste combustibility of the matter dependson availability of carbon, sulphur and hydrogen. In the absence of thismaterial in appreciable quantity combustion would not take place and needto be disposed in different method other than incineration. Combustion is theprocess of generation of energy during following major reactions.

CO2 ! CO212 32 44

2H2 O2 ! 2H2O4 32 36

S O2 ! SO232 32 64

The numbers in parenthesis are molecular weights.Considering oxygen content of air to be 23.15 % by mass,Amount of air required for total oxidation of 1 kg of carbon is

32=12 1=0:2315 11:52kgAmount of air required for total oxidation of 1 kg of hydrogen is

32=4 1=0:2315 34:56kgAmount of air required for total oxidation of 1 kg of sulphur is

32=32 1=0:2315 4:32kgIt is assumed that oxygen in waste will be combined with hydrogen in thewaste to from water.Example of air requirementFor example after performing proximate analysis of waste if the chemicalformula of waste is C40 H100 O40 SThe molecular mass = (40 x 12) ? (100 x 1) ? (40 x 16) ? (1 x 32) = 1252Percentage distribution of basic elements

Element Calculation of percent by mass Percent by mass

Carbon (40 x 12/1252)100 38.34Hydrogen (100 x 1/1252)100 7.99Oxygen (40 x 16/1252)100 51.12Sulphur (1 x 32/1252)100 2.56

5.3 Incineration and Waste to Energy 137

Net available hydrogen = (7.99-51.12/8) % = 1.6Air requirement

5.3.2 Combustion and Energy Recovery

Use of waste for energy is as old as invention of fire itself. All over the world thewaste material with sufficient calorific value is used as fuel either for cooking orheating. In many countries cow dung is used as fuel after it is dried in the form ofbriquettes (Fig. 5.16). The waste from wood processing like wood chips and sawdust was also used as fuel. With the civilization leading to more and moreurbanization, there was priority shift in the communities. Instead of living in singlehouses people chose to live in multistoried building wherein burning waste or solidfuel is limited due to safety reason, there by generating huge quantity of wastefrom highly populated cities.

The first effort to dispose of solid waste with furnace is believed to have happenedin England in the 1870s (Waste Online 2011). The most common methods of MSWmanagement are biological treatment, land filling, composting, mechanical treat-ment, recycling, and waste-to-energy (WTE). The USA had 88 WTE plants that burnabout 26.3 million tonnes of MSW (Psomopoulos et al. 2009) in 2009. More than90 % of WTE facilities in Europe use mass burn incineration technology and thelargest WTE facility treats approximately 750,000 tpy (Thomos 2004). Use ofbiomass residues as fuel in ceramic furnaces was studied by (Jose Edmundo et al.2011) and observed economic feasibility. As per Simmons et al. (2006), about 7.7 %of the total MSW was processed for energy recovery.

5.3.3 Energy Production from Waste

With global sucrose production of approximately Mt 1,500 per annum bagasserepresents a prospective energy source of 3.8 x 109 Gigajoules (Stanmore 2011).

Element Calculation of air requirement Air requirement (kg/t)

Carbon (0.3834 x 1000)11.52 4416.77Hydrogen (0.0160 x 1000)34.56 552.96Sulphur (0. 0256 x 1000) 4.32 110.59Total 5080.32

Solid Waste Management: Principles and Practice

138 5 Disposal

5.3.4 Material and Thermal Balances

It is necessary to assess the heat material and thermal balance of the combustorprior the project. The material entering the system and coming out the system isshown in Fig. 5.17.

The materials entering or leaving the system can absorb or release heat and isschematically depicted in Fig. 5.17. Waste as well as subsidiary fuel materialreleases the heat whereas water and air entering the system will absorb the heat.Ultimately heat will be transferred to steam, ash and air coming in contact with hotsurface. Hence, the heat transferred to ash and air will not be economically useful

Fig. 5.16 Fuel briquettemade out of waste

Combustor

Ash

Stake gases

SteamWaste

Fig. 5.17 Material balancein waste incineration

5.3 Incineration and Waste to Energy 139

and considered as losses. Hence the heat loss in stack emission, ash has to beconsidered along with heat loss due to radiation Fig. 5.18

Heat released during combustion of solid wastes is partially stored in gases andash. The rest of the heat will be transferred by convection, conduction and radi-ation to the incinerator walls as well as the incoming waste. The unburnt carbonusually contains 48 % unburnt carbon. The heat loss through the reactor as wellas other appurtences to the surroundings will be around 0.0030.005 kJ/kg offurnace input (Howard et al. 1986). The latent heat of vaporization for water isabout 2420 kJ/kg. Apart from these there would be some heat lost with residue andstack gases. In order to ensure economics of the operation it is desirable that: (1)carbon, ash, moisture content in the waste be maintained properly and (2) tem-perature of exhaust gas in the stack be within predetermined temperature range.

5.3.4.1 Waste Heat Recovery

The furnaces walls of combustors are lined with tubes through which water iscirculated to recover heat. The steam generated in this process is used for drivingturbines or other industrial purpose. In the process hot air entering the chimneycarries heat which can be further recovered by passing the hot air through metalpipes carrying water. Waste heat recovered can be used for preheating the waterentering the furnace or for industrial purpose.

5.3.5 Other Technologies

A variety of thermal processes like incineration, melting, pyrolysis, or vitrificationhave been used for disposal of waste with an aim to reuse advantageously ordispose ultimately in an inert landfill (Colombo et al. 2003; Sabbas et al. 2003;Kuo et al. 2006).

Treatment of waste by thermal plasma technology is being practiced in someplaces as it does not emit much air pollution and will not generate much ash.Plasma is the fourth state of matter, comprising of electrons, ions and neutralparticles. Molecules will dissociate into the atoms at 2,000 C and will get ionisedat 3,000 C. Plasma technology involves the formation of a continuous electrical

Thermal valueof material

entering thesystem

Heat lossesHeat recovered

Fig. 5.18 Thermal balance in an incinerator

140 5 Disposal

arc by the passing electric current through a gas. The process of passing of electriccurrent through a gas is called electrical breakdown. Significant heat is generatedin the process which separates electrons from the gas molecules and formingionised gas stream, or plasma.

Thermal plasmas have many advantages including high intensity, high tem-perature, high energy density and non-ionising radiation. While burning fossil fuelcan achieve only 2,000o C, electrically generated thermal plasmas can attain atemperature of 20,000 oC or more and thermal gradients can be controlledautonomously of chemistry.

Thermal plasma reactors offer high throughput through compact reactor geometrybut has a disadvantage of use of electrical power as source of the energy. Thermalplasmas for waste treatment are generated by electrical currents up to 1 9 105, radiofrequency (RF) and microwave discharges and laser-induced plasmas.

Thermal plasma reactors have following advantages during destruction of haz-ardous wastes: (1) fast reaction times, (2) large throughput, (3) small reactor foot-print, (4) reduces formation of persistent organic pollutants (POPs), (5) can be usedfor a wide range of wastes, (6) rapid start-up and shutdown times, and (7) norequirement of oxidants Fig. 5.19.

Combustion

Gasification

Flue gas

Medium Heating Value gas

High Heating Value Gas

Boiler

Turbine

Synthesis

Engine

Boiler

Synthesis

Electricty

Steam

Methenol

Fuel Alcohol

Hydrogen

Electricity

Steam

Ammonia

Gas

ifica

tion

Inci

nera

tion

Fig. 5.19 Comparison of incineration and gasification with respect to flexibility

5.3 Incineration and Waste to Energy 141

Nanomaterials like cellulose, chitin and starch, often called whiskers, could beeasily extracted from waste. Nanobiocomposites have the potential to substitutecurrent petrochemical-based materials due to the high demand for green tech-nology and represent an element waste disposal strategies in the future. Wastefrom shellfish processing industry represent about 30-wt % in chitin. Worldwidenearly 105 t/year of chitin is manufactured from shrimp and crab waste materialfor industrial uses (Visakh and Sabu 2010). Chitin has found applications in manyareas other than food such as in biosensors (Krajewska 2004).

5.3.5.1 Gasification

Gasification is one of the emerging biological technologies. Gasification can beapplied to convert organic waste to low calorific gas. Gasification is usually fol-lowed by combustion of gasses generated in a furnace or internal combustionengines or gas turbines after cleaning of the product gas.

In the gasification process coarsely-shredded waste enters a gasifier wherein thecarbonaceous fraction of the waste reacts with a gasifying agent like oxygen,steam or carbon dioxide. Sometimes the gasifier is fed with paralyzed waste. Theprocess takes place at about 8001,100 C depending on the calorific value andchemical reactions. Fixed carbon is also gasified in the gasification process.

There are three types of gasification technologies namely fixed bed, fluidizedbed in addition to high temperature gasification. Among these methods, hightemperature method is used widely.

5.3.5.2 Plasma Technology

Plasma is a group of free-moving electrons and ions formed by applying a highvoltage across a gas at reduced or atmospheric pressure. Incinerators usually usecontrolled flame for combustion whereas plasma-arc technology uses an electriccurrent which passes through a gas (air) to create plasma.

When plasma gas passes on waste, it causes speedy breakdown of the waste intosyngas which is a gas mixture that contains varying quantity of carbon monoxideand hydrogen.

5.3.5.3 Pyrolysis

Pyrolysis is thermal processing in total absence of oxygen. As landfill and inciner-ation become more expensive, emphasis is being given to new disposal options.Pyrolysis is a thermo-chemical decay of organic substance in the absence of oxygenat elevated temperatures. Pyrolysis is a method for the treatment in order to decreaseleaching and emissions to the environment (EEA 2002). Organic waste are thermallydegraded to produce useful liquid hydrocarbons, which can then added to fuel or

142 5 Disposal

solvent product, or returned a refinery where it is added to the feed stocks. Process canbe carried out in vacuum in which is referred as vacuum pyrolysis. In flash vacuumthermolysis, the residence time of the substrate at the working temperature isrestricted as much as possible, to minimize secondary reactions.

In this process waste shredded and fed into a reactor is operated in the absenceof oxygen under atmospheric pressure at 500700 C for 0.51 h. The process isreferred to as thermolysis if the temperature is 500 C or less.

References

Abbas AA, Jingsong G, Zhi Ping L, Ying Ya P, Al-Rekabi WS (2009) Review on landfillleachateleachate treatments. Am J Appl Sci 6(4):672684

Ahn WY, Kang MS, Yim SK, Choi KH (2002) Advanced landfilllandfill leachate treatment usingan integrated membrane process. Desalination 149:109114. doi:10.1016/S0011-9164(02)00740-3

August H (1992) Dicht auch ber Jahrhundertetechnische barri-eren fr deponien (Imperviousover centuriestechnical liners for landfills). Chem Ind 1:1718

August H, Tatzky-Gerth R (1992) Neue forschungsergebnisse aus langzeituntersuchungen anverbunddichtungen als technische barriere fr deponien und altlasten. (New research results oflong-term tests on composite liners as a technical barrier for landfills and contaminated land).In: Thom-Kozmiensky KJ (ed) Abdichtung von deponien und altlasten. FE-Verlag frEnergie und Umwelttechnik, Berlin, pp 273283

August H, Tatzky-Gerth R (1991) Neue forschungsergebnisse aus langzeituntersuchungen anverbunddichtungen als technische barriere fr deponien und altlasten (New research results oflong-term tests on composite liners as technical barrier for landfills and contaminated land).In: Kammer der Technik, Fachkongre Umwelt-technik (eds). Universitt Rostock,Tagungshand-buch 91:2224

August H, Tatzky-Gerth R, Preuschmann R, Jakob I (1992) Permeationsverhalten vonkombinationsdichtungen bei deponien und altlasten gegenber wassergefhrdenden stoffen(Permeation behaviour against water contaminants of composite liners for land-fills andcontaminated land). UFOPLAN des BMU. Forschungs-bericht (Research report) F ? E-Vorhaben. No 102 03 412 Durchgefhrt von der BAM im Auftrag des Umweltbundesamtes,Berlin, August 1992

Adams BL, Besnard F, Bogner J, Hilger H (2011) Bio-tarp alternative daily cover prototypes formethane oxidationoxidation atop open landfilllandfill cells. Waste Manag 31(5):10651073.doi:10.1016/j.wasman.2011.01.003 May 2011

Cernuschi S, Giugliano M (1996) Emission and dispersion modelling of landfilllandfill gas. In:Christensen TH, Cossu R, Stegmann R (eds) Landfilling of waste. Biogas E and FN Spon,London, pp 214233. ISBN 0 419 19400 2

Cheung KC, Chu LM, Wong MH (1997) Ammonia strippingstripping as a pretreatment forlandfilllandfill leachate. Water Air Soil Pollut 94:209221. doi:10.1007/BF02407103.-&gt

Christensen TH (1996) Gas-generating processes in landfills. In: Christensen TH, Cossu R,Stegmann R (eds) Landfilling of waste. Biogas E and FN Spon, London, pp 2550. ISBN 0419 19400 2

Colombo P, Brustain G, Bernardo E, Scarinci G (2003) Inertization and reuse of waste materialsby vitrification and fabrication of glass-based products. Curr Opin Solid State Mater Sci7(2003):225239

DEPA (Danish Environmental Protection Agency) (1999) Waste in Dekmark

5.3 Incineration and Waste to Energy 143

EC (Europian Commission) (2003) Refuse derived fuel. Current Pract Perspect (B4-3040/2000/306517/Mar/E3), European CommissionDirectorate General Environment, Final Report

EEA (2009) Annual European community greenhouse gas inventory 19902007 and inventoryreport 2009. European Environment Agency, Denmark

EPA (1999) Inventory of greenhouse gas emissions and sinks 19901997. Off Policy, Plan, andEval. U.S. Environmental Protection Agency, Washington, DC, EPA 236-R-99-003.(Available on the Internet at http://www.epa.gov/globalwarming/inventory/1999-inv.html.)

Kreith F (2002) Waste-to-energy compubston. In: Tchobanoglous G, Kreith F (eds). Introduction,Hand Book of Solid Waste Management

Jose Edmundo A, de Souza, Fabio de A, Filho P, Bertony P. C. da Silva, Nereu VN, Tenorio,Fabiana J. de Sousa, Rusiene M. de Almeida, Mario R. Meneghetti, Aline S. R. Barboza,Simoni M. P. Meneghetti, 2011: Biomass Residues as Fuel for the Ceramic Industry in theState of Alagoas: Brazil, Waste Biomass Valor, published on line 26 November 2011, DOI10.1007/s12649-011-9100-8

Gurijala KR, Sa P, Robinson JA (1997) Statistical modeling of methane production from landfillsamples. Appl Environ Microbiol 63:37973803

Peavy HS, Rowe DR, Tchobanoglous G (1986) Environmental engineering. McGrawhill bookCompany, New York

Ishigaki T, Yamada M, Nagamori M, Ono Y, Inoue Y (2005) Estimation of methane emissionfrom whole waste landfill site using correlation between flux and ground temperature. EnvironGeol 48:845853

Jessberger HL (1990) Bautechnische sanierung von altlasten. (Remediation techniques forcontaminated land). In: Arendt F, Hinsenveld M, van den Brink WJ (eds). Altlastensanierung90. Dritter Internationaler KfK/TNO Kongress ber Altlastensanierung, Karlsruhe. KluwerAcademic Publishers, Dordrechtpp, pp 12991306

Krajewska B (2004) Application of chitin- and chitosan-based materials for enzymeimmobilizations: a review. J Enzym Microbiol Technol 35:126139

Kulikowska D, Klimiuk E (2008) The effect of landfill age on municipal leachate composition.Bioresour Technol 99:59815985. doi:10.1016/j.biortech.2007.10.015

Kuo YM, Lin TC, Tsai PJ (2006) Immobilization and encapsulation during vitrification ofincineration ashes in a coke bed furnace. J Hazard Mater 133:7578

Lema JM, Mendez R, Blazquez R (1988) Characteristics of landfill leachates and alternatives fortheir treatment: a review. Water Air Soil Pollut 40:223250. doi:10.1007/BF00163730

Lin CY, Chang FY, Chang CH (2000) Codigestion of leachate with septage using a UASBreactor. Bioresour Technol 73:175178. doi:10.1016/S0960-8524(99)00166-2

Marco A, Esplugas S, Saum G (1997) How and why combine chemical and biological processesfor wastewater treatment. Water Sci Technol 35:321327. doi:10.1016/S0273-1223(97)00041-3

Mohammed F et al (2009) Review on landfill gas emission to the atmosphere. Eur J Sci Res30(3):427436

Mller W, Lders G (1995) Geomembranes. In: Holzlhner U, August H, Meggyes T, Brune MLandfill liner systems. A state of the art report. Anderson D, Meggyes T (eds), pp. E-1E-14.Solid and hazardous waste research unit of the university of newcastle upon tyne. PenshawPress, Sunderland. ISBN 0-9518806-3-2

Meggyes T, Simmons E, McDonald C (1998) Landfill capping: engineering and restorationpart2 engineering of landfill capping systems. Land Contam Reclam 6(1):1998

Meggyes T, McDonald C (1995) Landfill capping systems. In: Holzlhner U, August H, MeggyesT, Brune M. Landfill liner systems. A state of the art report. Anderson D, Meggyes T (eds)Solid and hazardous waste research unit of the university of newcastle upon tyne. PenshawPress, Sunderland. ISBN O-9518806-3-2. pp. O-1 - O-12

Mller W (1993) Stand der BAM-zulassungen fr kunststoffdichtungsbahnen in kombinationsd-ichtungen (State of the BAM certifications for geomembranes in composite liners. Mll undAbfall 4:282283

144 5 Disposal

Mller W (1995): Dichtigkeit und (Sealing efficacy and durability of materials for landfill liners).AbfallwirtschaftsJournal, 7 (1995), No. 12

Mller W, August H, Jakob I, Tatzky-Gerth R, Vater EJ (1995) Die wirkungsweise derkombinationsdichtungImmersionsversuche zur schadstoffmigration in deponieabdichtungs-systemen. (Operation of composite linersImmersion tests on contaminant migration inlandfill liner systems). In: Bartz WJ (ed). Asphaltdichtungen im deponiebau, einestandortbestimmung, Vol 488. Kontakt and Studium, Renningen-Malmsheim, Expert-Verlag,pp 2446. ISBN 3-8169-1296-6

Naranjo NM, Meima JA, Haarstrick A, Hempel DC (2004) Modelling and experimentalinvestigation of environmental influences on the acetate and methane formation in solidwaste. Waste Manage (Oxford) 24:763773

Psomopoulos CS, Bourka A, Themelis NJ (2009) Waste-to-energy: a review of the status andbenefits in USA. Waste Manage (Oxford) 29(2009):17181724

Reinhart DR, Townsend TG (1998) Landfill bioreactor design and operation, 1st edn. LewisPublishers, Boca Raton, p 189. ISBN 1-56670-259-3

Rettenberger G (1988) Oberflchenabdichtungen bei sonderabfalldeponien. (Landfill cappings forhazardous waste landfills). In: Thom-Kozmiensky KJ (ed) Deponie. ablagerung von abfllen,2nd edn. EF-Verlag fr Energie- und Umwelttechnik, Berlin, pp 440450

Sabbas T, Polettini A, Pomi R, Astrup T, Hjelmar O, Mostbauer P, Cappai G, Magel G, SalhoferS, Speiser C, Heuss-Assbichler S, Klein R, Lechner P (2003) Management of municipal solidwaste incineration residues. Waste Manage 23:6188

Simmons P, Goldstein N, Kaufman SM, Themelis NJ, Thompson J Jr (2006) The state of garbagein America. BioCycle 4(47):2643

Silva AC, Dezotti M, SantAnna GL Jr (2004) Treatment and detoxification of a sanitary landfillleachate. Chemosphere 55:207214. doi:10.1016/j.chemosphere.2003.10.013

Sormunen K, Ettala M, Rintala J (2008) Detailed internal characterization of two finnish landfillsby waste sampling. Waste Manage (Oxford) 28:151163

Stanmore BR (2011) Generation of energy from sugarcane bagasse by thermal treatment. WasteBiomass Valor (2010) 1:7789. doi:10.1007/s12649-009-9000-3

Stern JC, Chanton J, Abichou T, Powelson D, Yuan L, Escoriza S, Bogner J (2007) Use ofbiologically active cover to reduce landfill methane emissions and enhance methaneoxidation. Waste Manage (Oxford) 27:12481258

Tecle D, Lee J, Hasan S (2008) Quantitative analysis of physical and geotechnical factorsaffecting methane emission in municipal solid waste landfill. Environ Geol. doi:10.1007/s00254-008-1214-3

Visakh PM, Thomas Sabu (2010) Preparation of bionanomaterials and their polymer nanocom-posites from waste and biomass. Waste Biomass Valor 1:121134. doi:10.1007/s12649-010-9009-7

Wang-Yao K, Towprayoon S, Chiemchaisri C, Gheewala SH, Nopharatana A (2006) Seasonalvariation of landfill methane emission from seven solid waste disposal sites in centralThailand. The 2nd Joint International Conference on Sustainable Energy and Environment(SEE 2006), November 2006, Bangkok, Thailand, pp 2123 http://www.jgsee.kmutt.ac.th/see1/cd/file/D-026.pdf

Malkow Thomas (2004) Novel and innovative pyrolysis and gasification technologies for energyefficient and environmentally sound MSW disposal. In Waste Manag 24(2004):5379

Waste Online NA(2011) History of waste and reycling. http://www.wasteonline.org.uk/resources/InformationSheets/HistoryofWaste.htm. Accessed November 22

Worrell WA, Aarne Vesilind P (2002) Solid waste engineeringWilliams PT (2005) Waste treatment and disposal, 2nd edn. Wiley, England. ISBN 0-470-84912-

6, pp. 171-244World Bank (1999) Municipal solid waste incineration, technical guidance report, the world bank

Washington, D.C

References 145

Zaloum R, Abbott M (1997) Anaerobic pretreatment improves single sequencing batch reactortreatment of landfill leachates. Water Sci Technol 35:207214 10.1016/S0273-1223(96)00898-0

Che Zezhi, Gong Huijuan, Zhang Mengqun et al (2011) Impact of using high-densitypolyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.Waste Management 31(5):10591064. doi:10.1016/j.wasman.2010.12.012 May 2011

Zhang H, He P, Shao L (2008) Methane emissions from MSW landfill with sandy soil coversunder leachate recirculation and subsurface irrigation. Atmos Environ, in press. doi: 10.1016/j.atmosenv.2008.03.010

Zouboulis A, Jun W, Katsoyiannis A (2003) Removal of humic acids by flotation. Colloids Surf.A: Physicochem. Eng. Aspect 231:181193. doi:10.1016/j.colsurfa.2003.09.004

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5 Disposal5.1Landfill5.1.1 Processes Within a LandfillLandfill5.1.2 Controlling Leachate and Gas5.1.2.1 Monitoring of Landfills5.1.2.2 Closure of Landfills

5.1.3 Operation of Landfills5.1.4 Use of Old LandfillLandfill Sites5.1.5 Landfill Mining5.1.6 Land Filling Hazardous WasteHazardous Waste

5.2Co-Processing of Solid Wastes5.3IncinerationIncineration and Waste to Energy5.3.1 Heat Value of Refuse5.3.2 Combustion and Energy Recovery5.3.3 Energy Production from Waste5.3.4 Material and Thermal Balances5.3.4.1 Waste Heat Recovery

5.3.5 Other Technologies5.3.5.1 GasificationGasification5.3.5.2 PlasmaPlasma Technology5.3.5.3 PyrolysisPyrolysis

References