Presentation on theme: "Environmental Issues of LANDFILLS"— Presentation transcript:
1 Environmental Issues of LANDFILLS Philosophy: To contain the waste in a environmentally sound mannerLandfill method of Solid Waste DisposalLandfill Siting considerationsLiner Systems for landfillsLeachate Collection & Removal SystemFinal Cover SystemLeachate & Landfill Gas ManagementEnvironmental MonitoringLandfill Closure
3 Landfills ComponentsA liner system at the base and sides of the landfillA leachate collection arrangementA cover system at the topA gas collection systemA surface water drainage systemAn environmental monitoring systemA post-closure plan for maintenance and utilization of the landfill after its closure
5 Life Cycle of a Landfill Landfill PreparationGW monitoring facilities installed first of allLiner & leachate collection pipes laid on bottomWaste placed on the landfillGas collection pipes laid on the wasteFinal cover placed on the top of the landfill for landfill closureStarting of environmental monitoring & Post-closure careSite ready for alternative use
6 Reactions Occurring in a Landfill Biological, physical/chemical reactions occurring in the landfillPhysical Reactions:Gases diffusion, leachate movement & landfill settlementChemical ReactionsDissolution, suspension, evaporation, sorption, de-halogenation and decomposition of chemicalsBiological ReactionsAerobic & anaerobic, affecting the quality & quantity of leachate & LFG
7 Concerns with Landfills Landfill Gas (LFG)causing odour & other potentially dangerous substancesImpact of LFG on greenhouse effect in atmosphereImpact of leachate to the GWSlope Stability for waste and other components of the landfillSurface water contaminationLocal air contamination due to fugitive dust and bad odour,Other problems such asincrease in rodents and pests;risk of fire;bird menace; andblockage of surface water drainage paths
12 Leachate Movement Source Receptors Vadose zone Pathway Aquifer zone LandfillLinerVadose zoneGround- water wellPathwayDirection of GW flowAquifer zoneGroundwaterRock stratum
13 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.Post-active periodActive lifeTimeConsideredExpectedLeachate strength
20 LFG Management Active & Passive Control Control of VOCs emission Vacuum is induced (Active)Pressure built-up in the landfill is used (Passive)Control of VOCs emissionPassive control e.g. Pressure Relief ventActive Control e.g. Perimeter gas extraction & odour control Wells
21 LFG Management Flaring of landfill gas LFG energy recovery system Thermal Destruction in presence of oxygenLFG energy recovery systemTo produce electricityUsing combustion engine or gas turbinesMoisture & H2S needs to be removedGas purification & recoveryCO2 may be separated using physical adsorption, chemical adsorption or by membrane seperation.
22 Environmental Monitoring Vadose zone monitoring for gases & liquidsGroundwater monitoringAir Quality MonitoringVadose Zone monitoringLiquid monitoring to detect any leakage of leachate from landfill bottomGas monitoring to detect movement of LFG in lateral directionGroundwater MonitoringTo detect changes in water quality due to escape of gases & leachateAir Quality monitoringMonitoring of ambient air qualityMonitoring of LFG extracted from the landfillMonitoring of gases from gas processing facility
23 Landfill Closure & Post-closure Care To define what is to happen to the landfill in the future and estimating the funds requiredLong-term closure planDesign of landfill cover & landscaping of completed siteControl of run-off, erosion control, gas & leachate collection & treatment and environmental monitoringPost-closure careRoutine inspection of completed landfill siteMaintenance of infrastructureEnvironmental monitoringDecision on whether to continue/NOT
24 LANDFILL OPERATIONA 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 phaseFINAL COVER LAYER is applied to entire landfill surface of phase after all land-filling operations are completed.
25 ENVIRONMENTAL ISSUESWASTE 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.
26 ENVIRONMENTAL ISSUESNOISE- 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 waste with water.
27 ENVIRONMENTAL ISSUES… 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.
28 ENVIRONMENTAL ISSUES… 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.
29 ENVIRONMENTAL ISSUES… 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.
30 ENVIRONMENTAL ISSUES… LITTER– Windblown litter may be due to poor compaction 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.
31 ENVIRONMENTAL ISSUES… 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.
32 ENVIRONMENTAL ISSUES… 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.
33 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.
34 Landfill componentsExternal 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
35 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); andmachinery 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.
36 More detailsThe 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
37 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.
38 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.
39 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.
40 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.
41 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.
42 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.
43 Identify key environmental issues associated with the proposed landfill project?