This document discusses leachate management and treatment. It begins with an introduction to leachate, how it is produced, and its characteristics over time. The key methods of leachate collection, treatment options like biological and physical/chemical treatment, and factors affecting leachate quality and generation are covered. Models for predicting leachate production are also mentioned. The focus is on explaining leachate from landfills and the various strategies for managing and treating it.

1. Prof. M.R.Ezhilkumar
Assistant Professor
Department of Civil Engineering
Sri Krishna College of Engineering and Technology
Coimbatore
ezhilkumar@skcet.ac.in
I only feel angry when I see waste.
When I see people throwing away
things we could use. – Mother
Teresa
1
17CE413
SOLID AND HAZARDOUS
WASTE MANAGEMENT
3.5 – Leachate Management

2. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 2
Learning Outcomes
☼ Leachate production
☼ Leachate Collection
☼ Leachate Treatment
☼ Leachate Management
3.5 – Leachate Management

3. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 3
Video Session

4. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 4
Leachate
 Infiltrative water percolates through waste materials, results in the leaching of
organic and inorganic compounds (McBean et al. 1995).
 A complex organic waste that changes with time
 Problematic components
– Degradable & nondegradable organics
– Hazardous organics and inorganics
– Ammonia, nitrate, and nitrite
– Suspended solids
– Color and odor
– Pathogens

5. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 5
Leachate
 Leachate is the liquid (or wastewater) that forms when water (rainfall,
groundwater) travels through solid waste
 Leachate can migrate into underlying groundwater, resulting in contamination
 Leachate can contain many different chemicals, depending on what is in the
solid waste

6. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 6
Leachate

7. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 7
Leachate
How is Leachate Produced?
 Waste Decomposition
• Phase I
– Aerobic
• Phase II
– Anaerobic
– Facultative
• Phase III
– Methanogenic

8. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 8
Leachate
Leaching Mechanisms
 Leaching of inherently soluble materials
 Leaching of soluble biodegradation products
 Leaching of soluble products of chemical reactions
 Washout of fines and colloids
 Leachate generation continues for typically 30-40 years following site closure

9. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 9
Leachate
Importance of Leachate Quality and Quantity Determination
 Design leachate collection systems
 Design leachate treatment facilities
 Determine acceptability of offsite treatment
 Estimate offsite migration potential

10. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 10
Leachate
Leachate Management Principles
 Chemical composition of leachate varies considerably depending on:-
– Waste composition – Site characteristics
– Climatic conditions – Age of landfill
 Leachate management strategies must be:-
– Practical – Cost effective
– Flexible – Developed for long term environmental
management

11. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 11
Leachate
Leachate Management Technologies
 There is a wide range of leachate management technologies adopted by
Landfill Managers. Technology selection often depends on a number of critical
factors including:
– Composition of leachate
– Type of collection method
– Volume of leachate generated
– Available space on site
– Access to sewer
– Availability of technologies

12. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 12
Leachate
Planning Treatment and Disposal
 Estimate leachate flow, Q
– WBM/HELP
– Variations with site age
 Estimate leachate contaminant conc., C
– Type
– Variations with age
 Identify treatment and disposal options with discharge standards and cost
 Select treatment and disposal system
– Introduce uncertainty
– Maintain flexibility

13. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 13
Leachate
Leachate Production Characteristics

14. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 14
Leachate
What Characterizes Leachate?
 Phase I
– Brief
– CO2
– H2
 Phase II
– Years
– High BOD
• >10,000mg/L
– High BOD:COD
• >0.7
– Low pH
• 5-6
 Phase II
– Smells
– High Ammonia
• 500-1000 mg/L
– High Levels
• Fe, Mg, Zn, Ca, Mn
 Phase III
Decades (never)
High fatty acids
No O2
CH4
CO2
Stabilized
Low BOD
Low BOD:COD
 Phase III
High
Ammonia/Nitrogen
High Levels
Fe, Na, K, Cl2, SO4

15. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 15
Leachate
Factors Affecting Leachate Quality and Quantity
 Particle size
 Compaction
 Waste composition
 Site Hydrology
 Cover Design
 Conditions within Landfill
• Chemical & Biological Activities
• MC %, Temperature, pH, Degree of Stabilization
 Waste Age
 Landfill design/operation
 Sampling procedures
 Interaction of leachate with environment

16. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 16
Leachate
What are Trends in Leachate Contamination?

17. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 17
Leachate
Landfill Leachate

18. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 18
Leachate
pH
 Influence chemical and biological processes of precipitation, redox, sorption,
methanogenesis
 Controlled by volatile acids during acid phase
 After methanogenesis begins, controlled by carbonates and ammonia
 Major factor in controlling metal solubility

19. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 19
Leachate
Heavy Metals
 May act as inhibitors of biological stabilization process
 Water quality concerns
 No discernable chronological pattern
 Leachate concentration controlled by sulfide, carbonate, chloride, and
phosphate

20. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 20
Leachate
Nitrogen/Phosphorus
 Indication of nutrient availability
 Phosphorus may be limiting nutrient
 Ammonia important buffer
 Nitrogen present for long periods of time

21. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 21
Leachate
How do you Remove Leachate from the Landfill?
 Drain as much as you can by gravity (liner system and pipes)
 Pump from low points
– Penetration through the liner
– Pumps inside landfill

22. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 22
Leachate
Leachate Collection System
 If leachate flow is intercepted or impeded by a liner, then it should be removed
from the landfill by use of a leachate collection system.
 A leachate collection system is a high-permeability layer designed to transmit
leachate from the liner.

23. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 23
Leachate
Leachate Collection System with Graded Terraces

24. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 24
Leachate
How is Leachate Removed

25. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 25
Leachate
Leachate is then sent to Treatment and/or Storage Facility

26. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 26
Leachate
Leachate Storage
 Underground storage tanks
 Lagoons
 Above ground tanks
 Three day’s storage at peak annual flow

27. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 27
Leachate
How do you Predict Leachate Generation?
 You must estimate how much leachate is generated to design your landfill.
 HELP -- Hydrologic Evaluation of Landfill Performance
A Water Balance Model

28. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 28
Leachate
Notes about HELP Model
 Must assume an area and a depth (therefore not good for an open, operating
landfill)
 Many ways to manipulate
 Hydraulic conductivity of waste to high

29. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 29
Leachate
Porous cup suction Lysimeter for the collection of liquid samples
from the landfill

30. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 30
Leachate
Leachate Treatment Systems?
Options
 Full On-Site Treatment
 Partial On-Site Treatment
 Transport Off-Site
Considerations
o Recirculation
o Proximity of Sewer
o Haul Distance
o Pump System Costs
o WWTP Capacity
o Leachate Strength
Considerations
o Local Sewer Use
Laws
o Sewer Surcharges
o Surface Water
Discharge
Standards (On-Site)

31. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 31
Leachate
What are Common Leachate Treatment Types?
 Anaerobic or Aerobic Biological Treatment
 Physical & Chemical Treatment
 Leachate Recirculation & Land Application

32. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 32
Leachate
Anaerobic or Aerobic Biological Treatment
Biological Treatment
 Changes the form of Organic Constituents
 Removes BOD5, SS,NH3-N, Organic-N & Metals
 Generates large quantities of biomass (sludge)
Anaerobic Treatment
 Two-Stage Reactor
 Fixed Film Filters
Aerobic Treatment
 Lagoons
 Activated Sludge
 RBC’s
 Trickling Filters

33. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 33
Leachate
Anaerobic or Aerobic Biological Treatment
Biological Treatment
 Essential if BOD > 50 mg/L
 Expect
• BOD removal
• SS removal with sedimentation
• NH3-N and Org-N removal by biouptake and nitrification
• Metal removal by biosorption and precipitation at oxides and carbonates
• Priority organics removal

34. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 34
Leachate
Leachate Management Technologies

35. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 35
Leachate
Physical & Chemical Treatment
 More appropriate treatment as a landfill stabilizes
 Polishes biologically treated leachate
 Types of Treatment
Granular Filtration Carbon Adsorption
Chemical Precipitation Ultrafiltration
Reverse Osmosis Breakpoint Chlorination
Air Stripping Ion Exchange

36. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 36
Leachate
Reed Bed
 Removal of heavy metals, BOD, TSS, Nitrogen, & Phosphorus

37. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 37
Leachate
Constructed Wetland
Uses
 Polishing treatment
 Complete treatment
Advantages
 Relatively inexpensive to build/operate
 Associated with ‘green’ technologies
 Wetlands credits
Disadvantages
 Large land requirement
 Cold weather
 Mediocre results especially for
complete treatment systems

38. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 38
Leachate
Proposed Leachate Treatment

39. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 39
Leachate
Suitability Of Evaporation
Cost Of Operation
 Extremely Cost Effective
 Relatively High Initial Capital Costs
 Minimal Operating Costs
Effect Of Evaporation
 Leachate Volume Reduction
 Extremely Concentrated Solution
 Minimal Contamination Level Reduction
Risks
 Pond Overflow
 Leaks - Monitoring Bores
 Drowning - Perimeter Fencing

40. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 40
Leachate
Suitability Of Evaporation
Local Weather Conditions
 Evaporation Substantially Higher Than Precipitation
 Local Weather Data
 Theoretical Evaporation Greater Than Actual Evaporation
Leachate Composition
 Leachate Composition Affects Evaporation Rate
 Salinity and Concentration Reduce Evaporation Rate
 Dark Colour Increases Evaporation Rate

41. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 41
Leachate
Suitability Of Evaporation
Site Constraints
 Large Surface Area Required
 Possible Odour Issues Hence Buffer Zones Required
 Wind Direction And Intensity
Regulatory Approval
 Possible Regulatory Approval Required
 Location and Design Constraints
 Operational and Management Constraints

42. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 42
Leachate
Leachate treatment-issues
 High strength and magnitude of pollution potential
 Variation from landfill to landfill
 Seasonal and temporal variations in quantity and quality
 Processes designed to treat the leachates from an young landfill should be modified in the
future to treat old leachate/ to achieve changes in effluent standards

43. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 43
Leachate
Leachate Recirculation & Land Application
 Leachate is collected & returned to the top of landfill
 Accelerates the stabilization of organic materials present in the MSW
 Spray Irrigation or Well Injection
 Evapotranspiration

44. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 44
Leachate
Landfill as a Bioreactor Measure of Success
 Faster landfill stabilization
 Increased air space
 Reduced leachate management costs
 Reduced gases and odors
 Reduced long-term care costs
 Possibly, mining to regenerate cover material - a perpetual landfill?

45. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 45
Leachate
Leachate Recirculation
Demerits:-
 Ponding/localized accumulation of leachate
 Severe localized subsidence/side slope stability problems
 Other management requirement due to excess leachate production
 Selective attenuation of contaminants recirculation, thus further treatment required
 Mass/fluid transfer limitation

46. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 46
Leachate
Leachate Recirculation
Methods of Recirculation
 Spray irrigation
 Working face application
 Gravity well/trench
 Injection well/trench
 Infiltration ponds

47. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 47
Leachate
It is important to consider
 Leachate characteristics
 Its hazardous nature
 Discharge alternatives
 Regulatory limits
 Operational needs
 Costs
 Conduct of treatability studies

48. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 48
Assessment Time
Review
Question Recommend a suitable landfill method for Coimbatore region
based on the composition of waste generated in the city.

49. SHWM – Module 3 – SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT  Mr.M.R.Ezhilkumar 49