SOLID WASTE SOLID WASTE MANAGEMENTMANAGEMENT

CE 102CE 102

DEFINITIONDEFINITION

•Solid wastes comprise all the wastes arising from human and animal activities that are normally solidand that are discarded as useless or unwanted. •Solid waste management may be defined as thediscipline associated with the control of generation, storage, collection ,transfer and transport ,processing, and disposal of wastes in amanner that is in accord with the best principles of public health, economics, engineering,conservations.

Functional elements of solid waste Functional elements of solid waste Management systemManagement system

Waste generation

Waste handling,separationStorage and processing at the source

Collection

Disposal

Transfer and transportSegregation & Processing &

Transformation of solidwaste

Small townsSmall towns 100g/p/day100g/p/day Medium townsMedium towns 300-400g/p/day300-400g/p/day Large townsLarge towns 500g/p/day500g/p/day

In general varies between 0.3-0.6 kg/p/dayIn general varies between 0.3-0.6 kg/p/day

Characteristics of Municipal Solid Waste Characteristics of Municipal Solid Waste Generated by Metro CitiesGenerated by Metro Cities

Sl. No.

Metro city Paper Textile Leather Plastic Metal Glass Ash, Fine

earth & others

Compostable matter

1 Mumbai 10.0 3.6 0.2 2.0 - 0.2 44.0 40.0

2 Delhi 6.6 4.0 0.6 1.5 2.5 1.2 51.5 31.78

3 Hyderabad 7.0 1.7 - 1.3 - - 50.0 40.0

4 Jaipur 6.0 2.0 - 1.0 - 2.0 47.0 42.0

5 Kanpur 5.0 1.0 5.0 1.5 - - 52.5 40.0

6 Chennai 10.0 5.0 5.0 3.0 - - 33.0 44.0

7 Visakhapatnam

3.0 2.0 - 5.0 - 5.0 50.0 35.0

Characteristics ( Percent by wt. )

Characteristics of the wasteCharacteristics of the waste

PhysicalPhysical

CompositionComposition

DensityDensity

Moisture contentMoisture content

Composition of WasteComposition of Waste

Chemical

CarbonVOCAsh contentNitrogenPhosphate

•Calorific value

TYPES OF SOLID WASTESTYPES OF SOLID WASTES

Based on the source of generationBased on the source of generation Residential wastesResidential wastes

• Commercial wastesCommercial wastes• Institutional wastesInstitutional wastes• Construction and demolition wastesConstruction and demolition wastes• Municipal services Municipal services • Treatment plant wastesTreatment plant wastes• Industrial wastesIndustrial wastes• Agricultural wastesAgricultural wastes

Based on decomposabilityBased on decomposability

• Non-decomposible Non-decomposible • Decomposible wasteDecomposible waste

Based on combustibilityBased on combustibility

• Combustible wasteCombustible waste• Non-combustible wasteNon-combustible waste

Based on the contents of the wasteBased on the contents of the waste RubbishRubbish Food wasteFood waste AshesAshes Dead animalsDead animals Treatment plant wasteTreatment plant waste Industrial wasteIndustrial waste Mining wasteMining waste

Collection systemCollection system Low rise buildingsLow rise buildings

CurbCurb AlleyAlley Setout-setbackSetout-setback SetoutSetout Backyard carryBackyard carry

High rise buildings—High rise buildings— Crew can collect wasteCrew can collect waste Waste taken to service area by tenantsWaste taken to service area by tenants Tenants putting the waste in chuteTenants putting the waste in chute

Types of Collection systemTypes of Collection system

Haul container system (HCS)Haul container system (HCS) Stationary container system (SCS)Stationary container system (SCS)

Transportation systemTransportation system

Motor vehicleMotor vehicle RailwaysRailways HydraulicHydraulic PneumaticPneumatic Compressed air/vacuumCompressed air/vacuum

Need of TSNeed of TS

Illegal dumpsIllegal dumpsdisposal site too fardisposal site too farSmall capacity collection truckSmall capacity collection truckLow density areaLow density areaMore waste to large distanceMore waste to large distance

PROCESSING OF WASTESPROCESSING OF WASTES

SegregationSegregation

CompactionCompaction

ShreddingShredding

To reduce the volume and quantity

Bioconversion

BiomethanationBiomethanation

CompostingComposting

ConventionalConventional vermicompostingvermicomposting

CompostingComposting

Biological transformation of the waste.Biological transformation of the waste. Transformation of biodegradable waste into Transformation of biodegradable waste into

biologically stable matter using micro organisms.biologically stable matter using micro organisms. Reduces the volume of waste.Reduces the volume of waste. Destroy pathogens/insects.Destroy pathogens/insects. End product is a humus like material called compost End product is a humus like material called compost

that is rich in nutrients.that is rich in nutrients. Compost can be used to support plant growth and as a Compost can be used to support plant growth and as a

soil amendmentsoil amendment..

In the Principle of Microbial Infallibility, it is assumed that all organic materials can be biodegraded, given proper biological, chemical and physical conditions. The provision of these conditions requires that bio-systems be engineered to create an environment conducive to a substrate's biological utilization.

1. Oxygen and Aeration2. Organisms3. C:N Ratio4. Moisture5. Particle Size6. Temperature7. Time

Factors Affecting the Composting Process

Worms

Eudrilus eugineae

Eisena foetida

Vermicomposting

• Combustion processCombustion process

Thermal processing of solid waste by chemical oxidation Thermal processing of solid waste by chemical oxidation with stoichiometric or excess amounts of air.with stoichiometric or excess amounts of air.

End products-hot gases, water vapour (flue gas), and non-End products-hot gases, water vapour (flue gas), and non-combustible residue (ash).combustible residue (ash).

Energy can be recovered by heat exchange from the hot Energy can be recovered by heat exchange from the hot combustion gases. combustion gases.

Incineration

PyrolysisPyrolysis

Thermal processing of waste in the complete absence Thermal processing of waste in the complete absence of air.of air.

End products-solids (char), liquids (tar/oil) and gases End products-solids (char), liquids (tar/oil) and gases (hydrogen. methane, carbon monoxide, carbon (hydrogen. methane, carbon monoxide, carbon dioxide etc.)dioxide etc.)

Endothermic process, external source of heat is Endothermic process, external source of heat is required.required.

GasificationGasification

Process of partial combustion of solid waste in which Process of partial combustion of solid waste in which air is supplied less than stoichiometric air.air is supplied less than stoichiometric air.

End products-Flue gases( carbon monoxide, End products-Flue gases( carbon monoxide, hydrogen, carbon dioxide, hydrocarbons (methane)), hydrogen, carbon dioxide, hydrocarbons (methane)), condensible liquids, solid residue (char).condensible liquids, solid residue (char).

Energy efficient technique for reducing the volume of Energy efficient technique for reducing the volume of solid waste and the recovery of energy.solid waste and the recovery of energy.

The gas generated can be used to generate electricity The gas generated can be used to generate electricity using gas turbines or can be used in boilers as fuel.using gas turbines or can be used in boilers as fuel.

DISPOSALDISPOSAL Open dumpingOpen dumping

Land fillingLand filling

Disposal of residual solid wastes in the surface soils Disposal of residual solid wastes in the surface soils of the earth.of the earth.

Barging in to seaBarging in to sea

Feeding to hogsFeeding to hogs

LANDFILLLANDFILL

Primary means of MSW disposalPrimary means of MSW disposal

Disposal of residual solid wastes in the surface Disposal of residual solid wastes in the surface soils of the earth.soils of the earth.

CLASSIFICATIONCLASSIFICATION

1.1. Secure landfills /Class 1 landfillsSecure landfills /Class 1 landfills Designed to handle hazardous wastesDesigned to handle hazardous wastes ..

2.2. Monofills /Class 2 landfillsMonofills /Class 2 landfills Designed to handle particular types of wastes Designed to handle particular types of wastes

such as incinerator ash or sewage sludge that such as incinerator ash or sewage sludge that are relatively uniform in characteristics and are relatively uniform in characteristics and require special handling.require special handling.

3.3. Sanitary landfills /Class 3 landfillsSanitary landfills /Class 3 landfills Engineered facilities designed to handle Engineered facilities designed to handle

MSWMSW..

TemporaryHolding area

Environmentalmonitoring facilities

Equipmentworkshop

Inspection/Screening facility

Weighingscale

Accessroad

Leachatetreatmentfacility

Gasflaringfacility

Surfacewatercollectionfacility

Typical Layout of a Landfill

Completed fill

Active filling area

Future fill area

Stock piled cover material

Office

Landfill Cell

Cell liner

Postclosure carePostclosure care Activities associated with the long-term monitoring Activities associated with the long-term monitoring

and maintenance of the landfill (typically 30-50 and maintenance of the landfill (typically 30-50 years).years).

Dump truck

Landfill operation

Facility on restored landfill

Example Estimating Landfill Example Estimating Landfill RequirementsRequirements

Estimate the landfill area needed to handle one year’s MSW for Estimate the landfill area needed to handle one year’s MSW for a town of 100,000 people. Assume national average discards, no a town of 100,000 people. Assume national average discards, no combustion, a landfill density of 600 kg/m³, and a single 3m lift. combustion, a landfill density of 600 kg/m³, and a single 3m lift. Assume that 20 percent of the cell volume is soil used for cover.Assume that 20 percent of the cell volume is soil used for cover.

Solution:Solution: United States discards 146.6 million tonnes of MSW per year. If United States discards 146.6 million tonnes of MSW per year. If

we assume a population of roughly 260 million, the landfill we assume a population of roughly 260 million, the landfill volume of refuse for 100,000 people would be volume of refuse for 100,000 people would be

Vmsw = (146.6×10^6 tonne ×10³ kg/tonne × Vmsw = (146.6×10^6 tonne ×10³ kg/tonne × 100000people)100000people)

260 × 10^6 people × 600 kg/m³

= 93,975 m³Since only 80 percent of a cell is landfill, the volume of cell needed is

Vcell = 93,975 m³ / 0.8 = 117,468 m³

The area of lift, at 3m cell depth isThe area of lift, at 3m cell depth is

A = 117,468/3 = 39,155 m²A = 117,468/3 = 39,155 m²

The actual sizing of a landfill would include a number The actual sizing of a landfill would include a number of additional factors, such as additional area of additional factors, such as additional area requirements for access roads and auxiliary facilities, requirements for access roads and auxiliary facilities, reduction in landfill volume as biological reduction in landfill volume as biological decomposition takes place and increases in decomposition takes place and increases in compaction as additional lifts are added.compaction as additional lifts are added.

Biological Reactions in LandfillsBiological Reactions in Landfills

Four stage processFour stage process

1.1. Aerobic PhaseAerobic Phase

2.2. Acid PhaseAcid Phase

3.3. Methanogenesis, unsteadyMethanogenesis, unsteady

4.4. Methanogenesis, steadyMethanogenesis, steady

Another way of studying the solid waste management is the 3R principle

INTEGRATED SOLID WASTE MANAGEMENTINTEGRATED SOLID WASTE MANAGEMENT

Selection and application of suitable techniques, Selection and application of suitable techniques, technologies and management programs to achieve technologies and management programs to achieve specific waste management objectives and goals.specific waste management objectives and goals.

3 R’s in waste management3 R’s in waste management ReduceReduce RecycleRecycle ReuseReuse

Why reduction and recycling?Why reduction and recycling?

To reduce the waste to burryTo reduce the waste to burry To reduce the pollution by reusing the resources.To reduce the pollution by reusing the resources. To reduce the rate of consumption of resourcesTo reduce the rate of consumption of resources

The waste has three valuesThe waste has three values

* The bulk value* The bulk value

*The food value or nutrition value*The food value or nutrition value

*The energy value*The energy value

RecycleRecycle

Biodegradable wasteBiodegradable waste Bio-methanationBio-methanation Composting Composting