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Hazardous Waste Management Hierarchy

Hazardous Waste Management Hierarchy. SECURED LANDFILL . A controlled site for disposal of wastes on land , run in accordance with safety and environmental requirements laid down by a regulatory authority. A FACILITY WHERE . WASTES ARE PLACED PERMANENTLY IN SECURED MANNER

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Hazardous Waste Management Hierarchy

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  1. Hazardous Waste Management Hierarchy

  2. SECURED LANDFILL • A controlled site for disposal of wastes on land, run in accordance with safety and environmental requirements laid down by a regulatory authority

  3. A FACILITY WHERE • WASTES ARE PLACED PERMANENTLY IN SECURED MANNER • WASTE IS ENCAPSULATED FROM THE ENVIRONMENT BY IMPERMEABLE BARRIERS/ LINERS • LEACHATE IS COLLECTED, REMOVED & TREATED THROUGHOUT ITS LIFE.

  4. WHY LANDFILL ? • All hazardous waste treatment options result in residues and One of the safer methods for disposal of them • Best techno-economic option for some wastes.

  5. SECURED LANDFILL FACILITY • Last Option • Primarily Containment of contaminants

  6. TYPES OF LANDFILL • ATTENUATE & DISPERSE: • Sites where leachate and waste is allowed to escape into the environment at a controlled rate. Pollution is reduced by degradation and attenuation within the landfills and by dilution of the leachate in the aquifer

  7. Containment : Sites are aimed at isolating wastes and leachate from the surrounding environment for a considerable time. • Archival : Sites are specifically engineered to contain wastes indefinitely, but also to permit later identification and retrieval.

  8. METHODS OF LANDFILL Co-disposal : Disposal with M.S.W or similar wastes to take advantage of attenuation processes occuring in such wastes; Critical assessment for compatibility Mono-disposal: Disposal of wastes having same general physical and chemical form Multi-disposal: Disposal of chemically different wastes in the same site

  9. MULTI-BARRIER SYSTEM FOR SLF DESIGN • Barrier No: 1 • Degradation or fixation of pollutants in the waste prior to disposal • Barrier No: 2 • Suited location of the landfill site with regard to the geological/ hydro-geological situation of the area • Barrier No: 3 • Leachate collection and treatment system

  10. Barrier No: 4 : Bottom Liner System • Interface between waste body & subsoil hinders leachate percolation. • Barrier No: 5 Cover Liner System • Avoids penetration of surface and rain water into waste body avoiding formation of leachate • Barrier No: 6 Proper operation and maintenance of SLF • Barrier No: 7 Post Closure measures & Repairability of barriers

  11. BASIC COMPONENTS OF LANDFILL • Impermeable Liner System on the base and side • Top cover • Leachate collection, removal and treatment scheme • Surface Water Control Systems • Other site infrastructure

  12. Landfill

  13. Why the Liner is required ? • Isolate the waste body from the environment • Contain the toxic leachate within landfill • Prevent contamination of Land and Groundwater • Avoid remediation in future

  14. Which liner systems are available? • Mineralic • Geo-membrane • Composite (Mineralic + Geo-membrane) • Geo-synthetic Clay/ Bentonite Mats • Bituminous Membrane • Asphalt Concrete Liner

  15. BOTTOM LINER • Prevent migration of wastes or ‘by-products’ out of the landfill into subsoil, ground or surface water • Should have chemical properties, sufficient strength and thickness to prevent failure due to : • - Pressure gradients • Physical contact with the waste or leachate • Climatic conditions • Stress of installation and • Stress of daily operation

  16. TYPICAL BOTTOM LINER COMBINATIONS • CLAY LINER ONLY • ASPHALTIC CONCRETE LINER • COMPOSITE LINERS • ONE CLAY LINER & ONE FLEXIBLE MEMBRANE LINER • ONE CLAY LINER & TWO FLEXIBLE MEMBRANE LINERS

  17. Total Thickness # 45 - 60 cm

  18. DOUBLE COMPOSITE LINER (AS PER CPCB GUIDELINE)

  19. ASPHALTIC CONCRETE LINER WASTE BODY 3 SEAL LAYERS 2 BASE LAYERS FOUNDATION LAYER

  20. USEPA SPECIFICATION FOR BOTTOM LINERS • Three type of liners are specified by USEPA • Flexible Membrane Liners (FMLs) • Compacted Clay Liners • Composite Clay Liners (FML + Compacted Low permeability soil liners)

  21. MATERIALS FOR FMLs • Chlorosulfonated Polyethylene • Linear LDPE / Very LDPE • Polypropylene • Ethylene Inter polymer alloy • Neoprene • Poly Vinyl Chloride • Thermoplastic elastomers • HDPE

  22. Key factors considered for • selection of FML • Chemical compatability with waste leachate • Ageing and durability • Stress and strain characteristics • Ease of installation • Water permeation

  23. CLAY LINER –USEPA SPECIFICATION • Thickness of compacted clay bottom liner = 3 feet • Permeability of soil liners < 1 x 10-7 cm/sec • To achieve this, following characteristics of soil should be met. • Soil should have at-least 20% fines i.e. fine silt and clay sized particles • Plasticity Index (PI) > 1% (soils with PI higher than 30 to 40% are sticky and difficult to work within the field) • Coarse fragments should be screened to no more than about 10% gravel size particle. • No soil particles or chunks of rock larger than 1 – 2 inches in diameter.

  24. BLENDED SOILS –USEPA SPECIFICATION • On-site soils can be blended with imported clay minerals. • (e.g on-site sandy soils + imported sodium bentonite) • Calcium bentonite, lime, cement, clay soil from nearby or other areas ,etc are also used. • Clay soil is likely to form chunks and difficult and hence easier to blend on-site sandy soils with dry bentonite powder.

  25. COVER LINER (AS PERCPCB GUIDELINE)

  26. Slope 3% Cover Liner 2 m Soil Bund 2 m 2:1 A A 0.5m 375 m 0.7 m Storm Water Drain Channel Section HDPE Liner Gravels

  27. USEPA GUIDELINES FOR TOP LINER VEGETATIVE COVER – MIN. 60 CM THK (UPPER SLOPE : 2 TO 5 % SOIL DRAINAGE LAYER – MIN. 30 CM THK FLEXIBLE MEMBRANE LINER (MIN. 20 MILS ) COMPACTED SOIL – MIN. 60 CM THK WASTE BODY

  28. TOP LINER – NPC DESIGN VEGETATION 2 X 25 CM THK MODERATELY COMPACTED SOIL 2 X 25 CM THK WELL COMPACTED SOIL 3 MM THK POLYESTER BASED MODIFIED BITUMINOUS FELT 25 CM THK COMPACTED SOIL WASTE BODY

  29. SIDE LINER – NPC DESIGN WASTE BODY MASTIC ASPHALT LAYER 2CM THK 3 MM THK POLYESTER BASED MODIFIED BITUMINOUS FELT 75 MM THK P.C.C 1:3:6 COMPACTED SUBBASE

  30. LEACHATE COLLECTION & REMOVAL • Drainage Layer • Granular (Sand or gravel, no fine, 2-5 cm dia particle, min.30 cm thk, min K=1 cm/s) • Synthetic (nets, mats, geo-textiles) • Pipes and Appurtenances • Cushions LEACHATE STORAGE & TRANSFER Epoxy coated RCC Sump with level control submersible pump LEACHATE TREATMENT

  31. SURFACE WATER CONTROL SYSTEMS • RUN-OFF • Collect and control run-off from active and inactive portions of the landfill from 24 hour – 25 year storm • Collect and contain leachate contaminated storm water that accumulates in active fill area • Protect integrity and effectiveness of landfill cover system • RUN-ON • Intercept and divert run-on away from active and closed land fill cells from peak discharge of 25 year storm • Minimise site erosion

  32. GROUND WATER MONITORING • Designed to detect contaminant leakage shortly after its occurrence and before significant contamination of ground water • Hydraulically up-gradient and down-gradient wells • Placed around perimeter of fill area within several hundred feet of SLF • No. of wells- Site specific, depends on Size of SLF, Hydro-geology • Minimum Requirements • 1 well in up-gradient (Background) • 3 wells in down-gradient

  33. IDENTIFICATION OF WASTES THAT CAN BE LANDFILLED 1.Wastes that will definitely need to be landfilled as no other options are practicable e.g. Asbestos 2. Wastes that could be safely landfilled without prior treatment e.g. Bio-degradable wastes – technically possible; Better options often exist.

  34. 3.Wastes which could be landfilled after pre-treatment e.g., Liquid wastes; heavy metal salts.Pre-treatment options can include detoxification, precipitation, solidification as appropriate 4. Wastes that should not be landfilled e.g., Explosives, Compressed toxic gases, Liquid PCBs for technical reasons

  35. CRITERIA FOR DISPOSAL OF H.W IN SLF • To be dewatered up to the level of 60 – 70% solids • Following are not be allowed to dispose of directly in SLF if waste • Is a fluid, slurry or paste • Is delivered under pressure or under vacuum • Has an obnoxious odour • Reacts with moisture to generate high heat or gases • Is highly inflammable (flash point < 40oC) • Contains very strong oxidising agents • Contains volatile substances of significant toxicity

  36. CRITERIA FOR DISPOSAL OF H.W IN SLF • Contains > 10 mg/Kg Cyanide in the original sample • Contains > 10 mg/kg Chromate in the original sample • Contains > 0.5% (Wt.) Mercury • Falls below a pH value of 2, if eluated 1/10 • Contains > 10 mg/1 of water soluble Arsenic in a 1/10 eluate • Contains > 10 mg/1 of water soluble Mercury in a 1/10 eluate • Contains > 3% solvents free from Halogen • Contains more than 0.5% Halogenated solvents • Contains > 0.1% poly-halogenated substances of Significant toxicity (PCBs)

  37. Criteria for Hazardous Waste Landfilling in Germany due to “Technical Instructions for HWM” 1991

  38. ELUATE QUALITY

  39. ELUATE QUALITY

  40. CPCB CRITERIA FOR NON- ACCEPTANCE OF WASTE IN SLF • Bulk or non-containerized liquid hazardous waste • Slurry type hazardous waste containing free liquid or waste sludge • Incinerable / compostable waste or any other type of waste from which energy recovery is feasible • In-compatible wastes not to be placed in same landfills

  41. CPCB CRITERIA FOR NON-ACCEPTANCE OF WASTE IN SLF • Wastes in-compatible with liner material without containerisation • Extreme hazardous waste (e.g radioactive waste) • Non-hazardous waste (e.g MSW) not to deposited in HW Landfills

  42. LIST OF INCOMPATIBLE WASTES E ExPLOSIVE F FIRE GF FLAMMABLE GAS GT TOXIC GAS H HEAT GENERATION S SOLUBILISATION OF TOXINS

  43. CPCB SPECIFIED DESIGN REQUIREMENTS FOR LINERS • Stability at base of landfill (in soft soil) & in sides • Strength to withstand construction loads/ vehicle loads • Permeability and material properties as specified in guidelines • Compatibility with leachate & waste • Transition filters bt. Waste & leachate collection layer to prevent clogging of leachate collection layer

  44. CRITERIA FOR HAZ. WASTE LANDFILLS • CONSTRUCTION & OPERATION CRITERIA • INSPECTION, MONITORING & RECORD KEEPING CRITERIA • POST-CLOSURE CRITERIA • FINANCIAL ASSURANCE CRITERIA • CONTIGENCY PLAN FOR EMERGENCIES

  45. CRITERIA FOR HAZ. WASTE LANDFILLS • LOCATIONAL CRITERIA • SITE SELECTION • SITE INVESTIGATION CRITERIA • PLANNING & DESIGN CRITERIA • WASTE ACCEPTANCE CRITERIA • LANDFILL LINER CRITERIA & COVER CRITERIA

  46. CPCB SPECIFIED DESIGN REQUIREMENTS FOR LINERS • Protection layer / transition layer between each component of liner system may be provided • Between Leachate collection layer & HDPE • With Silt / local earth (15 cm thk) / Geo-textile • Adequate clay additive in amended soils

  47. ASPECTS CONSIDERED IN THE DESIGN OF SLF • Selection of appropriate liner system for SLF • Desired design period of the SLF in years • Type of landfill desired • Pit (cell wise development) / continuous • Depth of hard stratum from G.L. • Total lay out size & total area of the SLF

  48. Nearest G.W.T. reported in monsoon season • Depth of landfill below ground level • Height of stock pile above ground level • Inner side, bottom – longitudinal & transverse slopes • Provision and layout of roads, storm water drain, green belt, office, security, lab, weigh bridge, Vehicle washing area, leachate sumps, etc around the SLF

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