Environmental issues of landfills
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Environmental Issues of LANDFILLS. Philosophy: To contain the waste in a environmentally sound manner Landfill method of Solid Waste Disposal Landfill Siting considerations Liner Systems for landfills Leachate Collection & Removal System Final Cover System

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Environmental Issues of LANDFILLS

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Environmental issues of landfills

Environmental Issues of LANDFILLS

Philosophy: To contain the waste in a environmentally sound manner

  • Landfill method of Solid Waste Disposal

  • Landfill Siting considerations

  • Liner Systems for landfills

  • Leachate Collection & Removal System

  • Final Cover System

  • Leachate & Landfill Gas Management

  • Environmental Monitoring

  • Landfill Closure



  • Landfill Types

    • Inert Waste Landfills

    • Non-hazardous waste or MSW Landfills

    • Hazardous Waste

Landfills components

Landfills Components

  • A liner system at the base and sides of the landfill

  • A leachate collection arrangement

  • A cover system at the top

  • A gas collection system

  • A surface water drainage system

  • An environmental monitoring system

  • A post-closure plan for maintenance and utilization of the landfill after its closure

A typical landfill

A Typical Landfill

Life cycle of a landfill

Life Cycle of a Landfill

  • Landfill Preparation

    • GW monitoring facilities installed first of all

    • Liner & leachate collection pipes laid on bottom

  • Waste placed on the landfill

  • Gas collection pipes laid on the waste

  • Final cover placed on the top of the landfill for landfill closure

  • Starting of environmental monitoring & Post-closure care

  • Site ready for alternative use

Reactions occurring in a landfill

Reactions Occurring in a Landfill

Biological, physical/chemical reactions occurring in the landfill

  • Physical Reactions:

    • Gases diffusion, leachate movement & landfill settlement

  • Chemical Reactions

    • Dissolution, suspension, evaporation, sorption, de-halogenation and decomposition of chemicals

  • Biological Reactions

    • Aerobic & anaerobic, affecting the quality & quantity of leachate & LFG

Concerns with landfills

Concerns with Landfills

  • Landfill Gas (LFG)

    • causing odour & other potentially dangerous substances

    • Impact of LFG on greenhouse effect in atmosphere

  • Impact of leachate to the GW

  • Slope Stability for waste and other components of the landfill

  • Surface water contamination

  • Local air contamination due to fugitive dust and bad odour,

  • Other problems such as

    • increase in rodents and pests;

    • risk of fire;

    • bird menace; and

    • blockage of surface water drainage paths

Environmental issues of landfills

GW contamination hazard rating

GW contamination hazard rating

Landfill contamination

Source hazard

Source hazard rating


Pathway hazard rating

Receptor hazard rating


Sub-soil / groundwater

Groundwater users

Waste quantity

Waste composition

Infiltrating precipitation



Aquifer zone

Waste quantity

HW fraction


C&DW fraction

HW fraction


C&DW fraction


Cover system

Vadose zone parameters

Landfill cover parameters

Aquifer zone parameters

Landfill siting criteria

Landfill Siting Criteria

  • Haul Distance

  • Location Restrictions

  • Available Land Area

  • Site Access

  • Soil Conditions & Topography

  • Climatological Conditions

  • Surface Water Hydrology

  • Geologic & Hydro-geologic Conditions

  • Local Environmental Conditions

  • Potential Ultimate Uses for the Completed Site

Leachate management

Leachate Management

  • Leachate Recycling

  • Leachate Evaporation

  • Leachate treatment

  • Discharge to a wastewater treatment plant

Leachate movement

Leachate Movement





Vadose zone

Ground- water well


Direction of GW flow

Aquifer zone


Rock stratum

Determination of leachate strength indicator



Active life

Post-active period


Determination of leachate strength indicator

  • Leachate strength indicator of wastefill varies with waste composition and wastefill depth / height.

  • It varies with time is considered to be maximum at the time waste placement.

Leachate strength

Environmental issues of landfills


Environmental issues of landfills


Landfill gas

Landfill Gas

  • Generated as a product of waste biodegradation

    • Aerobic Biodegradation

      CaHbOcNd +(4a + b − 2c + 3d)/4 O2 → aCO2

      + (b − 3d)/2 H2O + dNH3.

    • Anaerobic Biodegradation

      CaHbOcNd + (4a-b-2-3d)/4 H2O → ( 4a-b+2c+3d)/8 CO2

      + (4a+b-2c-3d)/8 CH4 + dNH3

Landfill gas composition

Landfill gas composition

CH4 is considered as a relatively important gas as compared to the

other constituents

Environmental issues of landfills

  • Landfill methane generation at its peak shortly after initial waste

  • placement.

Lfg management

LFG Management

  • Active & Passive Control

    • Vacuum is induced (Active)

    • Pressure built-up in the landfill is used (Passive)

  • Control of VOCs emission

  • Passive control e.g. Pressure Relief vent

  • Active Control e.g. Perimeter gas extraction & odour control Wells

Lfg management1

LFG Management

  • Flaring of landfill gas

    • Thermal Destruction in presence of oxygen

  • LFG energy recovery system

    • To produce electricity

    • Using combustion engine or gas turbines

    • Moisture & H2S needs to be removed

  • Gas purification & recovery

    • CO2 may be separated using physical adsorption, chemical adsorption or by membrane seperation.

Environmental monitoring

Environmental Monitoring

  • Monitoring

    • Vadose zone monitoring for gases & liquids

    • Groundwater monitoring

    • Air Quality Monitoring

  • Vadose Zone monitoring

    • Liquid monitoring to detect any leakage of leachate from landfill bottom

    • Gas monitoring to detect movement of LFG in lateral direction

  • Groundwater Monitoring

    • To detect changes in water quality due to escape of gases & leachate

  • Air Quality monitoring

    • Monitoring of ambient air quality

    • Monitoring of LFG extracted from the landfill

    • Monitoring of gases from gas processing facility

Landfill closure post closure care

Landfill Closure & Post-closure Care

  • To define what is to happen to the landfill in the future and estimating the funds required

  • Long-term closure plan

    • Design of landfill cover & landscaping of completed site

    • Control of run-off, erosion control, gas & leachate collection & treatment and environmental monitoring

  • Post-closure care

    • Routine inspection of completed landfill site

    • Maintenance of infrastructure

    • Environmental monitoring

    • Decision on whether to continue/NOT

Landfill operation


  • A phase consists of cells, intermediate cover, liner and leachate collection facility, gas control facility and final cover over sub area.

  • CELL- Volume of material placed in a landfill during one operation period, usually one day.

  • LIFT- Complete layer of cells over active area of the landfill.

  • DAILY COVER (15 to 30cm) of soil is applied to working faces of landfill at end of each operating period.

  • INTERMEDIATE COVERS are placed at end of each phase

  • FINAL COVER LAYER is applied to entire landfill surface of phase after all land-filling operations are completed.

Environmental issues


  • WASTE CHARACTERISTICS: Waste from all sources tested for composition, physical, chemical, biological, thermal, toxic and geotechnical properties.

  • TRAFFIC: Heavy lorry traffic give rise to nuisance, damage to road surface, verges and routing problems. To avoid traffic congestion, routing to residential areas be avoided, one-way traffic in narrow roads, upgradation of road, limiting vehicle movements number and restriction of traffic movement hours are essential.

Environmental issues1


  • NOISE- Movement of heavy vehicles, fixed and mobile plants. May have adverse impact on local community. Peak noise analysis at site and nearby inhabited zone on monthly basis to be done. Peripheral noise abatement measures may be adopted.

  • DUST - Site preparation and restoration, disposal of fine particles and traffic. Ambient air quality monitoring particularly PM10 on a monthly basis specifically at noon during hot, dry and windy days is essential to protect vegetation planted on rehabilitated landfill surface and to meet specified standards. Dust suppression can be effected by limiting vehicle speed, spraying roads and fine particle wastewith water.

Environmental issues2


  • FIRES– Problems of health, air quality and social acceptance with surrounding community. Can cause serious damage to infrastructure of landfill and can be a major hazard for site staffs. All fires on-site should be treated as potential emergency and dealt with accordingly. All sites should have tipping area set aside from the immediate working area for deposition of waste materials known to be or suspected on fire.

  • BIRD MENACE– Attracted by food waste. They are seen as noisy and messy, and carriers of pathogens or cause of local nuisance through fouling of roofs and roof-water supplies. Measures to mitigate bird nuisance are good landfill practice, small active working areas, and progressive prompt covering of waste.

Environmental issues3


  • MUD- Common causes of public complaint. Can result in accidents. Providing wheel cleaning facilities may prevent mud carry off site by vehicles.

  • GROUND WATER MONITORING- Minimum of three samples from each aquifer analyzed on monthly basis for drinking water quality parameters.

Environmental issues4


  • CONTROL OF SURFACE WATER– Minimum of 3 samples from storm water drain to be analyzed for parameters relevant to wastewater drains on monthly basis to quantify extent of run off contamination from completed cell by waste materials.

  • CONTROL OF LEACHATE- It has potential to contaminate groundwater. Leachate quality has to be assessed at both laboratory and field for leachate treatment strategy. Effective operational practices and engineering controls at landfill facility is a must.

Environmental issues5


  • LITTER– Windblown litter may be due to poorcompaction or un-covered waste.Offensive to neighbours. It results in water pollution and nuisance to surrounding property. Good operational practice in terms of waste discharge, placement, compaction and covering minimize wind blown litter.

  • LANDFILL GAS MONITORING- LFG is a hazard at landfill sites due to its explosive and asphyxiation risk. LFG consists of methane, CO2, H2S and other gases. Monitoring of LFG is essential to minimize odour generation, to prevent off-site migration of gases and gas recovery.

  • SAFETY ASPECT- Includes site safety, first aid and handling of waste materials. Emergency safety plans should be laid down at landfill sites.

Environmental issues6


  • PEST AND RODENTS- Threat to public health. Rats and flies are main vectors which require control. Vectors can be controlled on the landfill by not providing sources of food and water or shelter. This can be achieved by applying daily cover or by spraying insecticides on exposed faces and flanks of the tipping area.

  • ODOUR- Biodegradation of organic wastes, leachates and leachate treatment system, and landfill gas. Monthly analysis at site and at 200m intervals from landfill boundary to nearest inhabited zone to be done. Use of intermediate cover layers, gas extraction system, daily cover, adequate compaction and leachate management are effective odour control measure.

Environmental issues7


  • MAINTENANCE OF INFRASTRUCTURES- Routine maintenance such as white washing, daily cleaning and sweeping etc. should be carryied out at landfill site.

  • MANAGEMENT OF WORKING FACE– A working face is area where waste is deposited by trucks, leveled, compacted and where daily cover is applied. Poor working face management has potential to result in blowing litter and debris, greater potential for accident, inefficient use of air space, aesthetic problems, traffic movement problems and vector problems.

A proposed landfill project

A Proposed Landfill project

  • A site with a total area of 9.7 ha has been selected on territory belonging to the village.

  • The site, designed for the disposal of municipal waste, is situated about 8 Km southwest from the main town of the region.

  • It will serve three municipalities.

  • The landfill will comprise five separate cells, which shall be built simultaneously.

  • The project comprises a landfill and waste transfer station.

Landfill components

Landfill components

  • External communications and access roads, water supply, power supply, and drainage of leachate to the Wastewater Treatment Plant (WWTP);

  • Five cells, with a road and fence, controlled drainage, a bottom watertight seal and drainage system for leachate collection;

  • A front area including an office, traffic-control building, weigh bridge; garage with repair room and store, auto wash, an emergency generator plant, station for purification and burning of bio-gas and a WWTP

Landfill components1

Landfill components…

  • wells for monitoring and controlling ground waters (three outside the landfill and three around the station for the purification and burning of bio-gas); and

  • machinery and equipment, including a bulldozer (front-end loader) for spreading and flattening the loose wastes and for applying the daily soil cover; a compactor to carry out threefold compaction of waste; a dump-truck for transporting earth and other loose materials; and a central computer.

More details

More details

  • The construction of roads comprises development of an access road to the site, as well as a site network of service roads to allow dumping of wastes in the different sections on a daily basis.

  • Watertight sealing of the bottom of the cell shall include a clay screen, HDPE liner and sand. Drainage for leachate collection is placed above.

  • The main dike is envisaged to surround the cells with a road and fence. To form the five cells of the landfill, the construction of four partition dikes is planned. The dikes shall be made out of earth and will be faced with clay and an HDPE liner

Other landfill elements

Other Landfill Elements

  • Sealing: Sealing of the bottom of the landfill includes the following:

    • controlled drainage - the drainage system will be installed under the bottom liner after levelling the landfill;

    • leachate drainage - a system which shall be constructed in order to collect and drain away storm water from the body of the landfill storm that has infiltrated the waste. The leachate shall be pumped to the WWTP. After treatment, the water shall be discharged into the nearby drain, which meets the river subsequently.

Other elements

Other elements…

  • Gas abstraction system: For abstraction of the bio-gas from the landfill a gas extraction system shall be constructed. It will consist of:

    • three gas abstraction wells –which shall be constructed continuously and parallel with operation of the cells and the depositing of waste. In addition, there will be a surrounding gas pipeline for leading the gas away from gas wells to the gas-purification and burning station.

Other elements1

Other elements…

  • Fence: The fence will be constructed to prevent uncontrolled access of people and cattle. The fence, made of reinforced concrete, shall surround the site.

  • Daily operation: After completion of works, the operation of the landfill will start with the filling in of Cell 1. Dumped waste shall be spread and compacted in layers of 20 to 30 cm.

Other elements2

Other elements…

  • Deposition of waste shall be conducted daily in sections of 1.8 m in height. Sections shall be separated with soil and crushed construction waste. After reaching a thickness of 1.8 m, the waste layer shall be covered by a 0.2 m layer of soil.

  • Deposition will continue in this way until the crest of the surrounding and partition dikes is reached. Afterwards, the waste body will be shaped to form a slope with an inclination towards the dike’s crest. Operation of the other cells shall be similar.

Other elements3

Other elements…

  • Capping layer: After reaching the planned elevation of the waste body in each cell, the waste shall be covered with a capping layer. This shall include humus to allow grass to be planted.

  • Waste Transfer Station:Since two out of three municipalities that will be served by the landfill are located at a distance of 60 km from the landfill, a waste transfer station for these municipalities is envisaged. It shall be constructed on the territory of one of these municipalities, in the area of the existing waste depositing site.

Other elements4

Other elements…

  • The terrain selected for the waste transfer station has a total area of 0.7 ha.

  • The vehicles transporting municipal waste are brought up through a ramp in the transfer station.

  • They unload the solid municipal waste at a site located over the press.

  • The waste is dumped into the press funnel and is pressed directly into the containers.

  • Special vehicles transport the filled containers to the landfill for three municipalities. A weighbridge shall be installed next to the office of the transfer station.

Environmental issues of landfills

  • Identify key environmental issues associated with the proposed landfill project?

Thank you

Thank You!

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