1. LEACHATE MANAGEMENT AND TREATMENT
Ahmed A.M. Abu Foul
Environmental Department
Islamic University of Gaza

2. Overview Leachate characteristics Impacts due to leachate
Leachate sources
Leachate collection
Leachate treatment

3. Leachate Properties
Leachate is liquid that percolates through the layers of the landfill and transports organic and inorganic compounds.

4. Typical Leachate BOD = 10,000 mg/l COD = 18,000 mg/l pH = 6
Total hardness = 3,500 mg/l
Chloride (Cl) = 500+ mg/l
Sulphate (SO4) = 300 mg/l
Iron (Fe) = 60 mg/l

5. Factors Affecting Leachate Quality and Quantity
Particle size
Compaction
Waste composition
Site Hydrology
Cover Design
Waste age
Landfill design/operation
Sampling procedures
Interaction of leachate with environment

6. Leachate Impacts Groundwater contamination Surface water pollution
Odours
Unsightliness

7. Leachate Generation
Precipitation
Surface water
Run-on
Water balance

8. Control of Liquids Run-off and run-on Precipitation Evapotration
Water balance
Water in waste

9. Water Balance

10. Monitoring and Mitigation
Monitoring wells
Collection and treatment
Visual inspections
Remediation

11. Leachate To Groundwater
Most serious problem
Expensive to correct
Movement varies/hard to predict
Depends on geology and soils

12. Groundwater and Leachate Migration

13. Leachate Collection System

14. Slotted Collection Pipes

15. Collection Pipe Above Liner

16. Leachate Management - Storage

17. Typical Collect and Treat

18. Leachate Treatment

19. Leachate Treatment Systems
Recirculation
Evaporation
Biological treatment
Natural Systems (Land application, Lagoons and wetlands)
Conventional Systems (Activated Sludge, Sequencing Batch Reactor(SBR)
Chemical treatments (Precipitation, Coagulation and Flocculation, oxidation)
Physical treatments (Air Stripping, Filtration, Adsorption)
Combination of Physical-chemical and biological treatments

20. Determine best alternative for treatment
Designed on-site treatment system using current leachate data.
Determined cost of treatment options.
Compared on-site and off-site treatment.

21. FACTORS AFFECTING ON LEACHATE TREATMENT A- BOD/COD Ratio
Relative biodegradability of leachate
Present for as long as 100 years
Tends to decline following onset of methane formation

22. Relative Biodegradability of Leachate
BOD/COD
COD/TOC
Low
< 0.5
< 2
Medium
0.5 – 0.75
2 – 3
High
> 0.75
> 3

23. B- 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

24. C- Effluent Limitations & Permitting Process
Case-by-case basis based on:
Type of receiving water body
Aquatic life present in receiving water body
Concentration of toxic chemicals based on pH, hardness, temperature, etc.
Parameter
Units
Average Standard
BOD5
mg/L 30
Total Suspended Solids
NH3\N (May-October) 3
NH3\N (November-April) 6
Dissolved Oxygen
4 (minimum) PH
S.U.

25. Example for Leachate Treatment
Equalization Tanks
Remove heavy metals and solids (optional)
Remove biodegradable organics, ammonia, nitrite/nitrate, some heavy metals, and toxic compounds
Air diffuser
UV disinfection to remove pathogens
Sludge wasting
Lined reed bed for polishing treatment
Discharge to local sewer system
2 SBRs with 24 hr cycle; gal. capacity
NaOH to increase pH
H3PO4 to bring pH down and add phosphate
Air stripping tower to remove ammonia (optional)
Na3PO4 to add phosphorous without changing pH

26. Sequencing Batch Reactor(SBR)
A variation of the activated sludge process which incorporates equalization, aeration, and clarification.

27. Reed Bed
Removal of heavy metals, BOD, TSS, Nitrogen, & Phosphorus

28. Heavy Metals Removal

29. Ultraviolet radiation (UV) Disinfection
Removes pathogens
Contact time only 5 seconds
No disinfection by-products
O&M Costs Low
Simple Operation

30. Optional Components Chemical Addition Processes Phosphorus Addition
Achieve optimum BOD:N:P ratio of 100:5:1
pH Adjustment
Control pH levels to optimize performance
Processes
Metals Precipitation
When metals concentration gets too high to meet effluent standards
Ammonia Stripping
When concentration of Ammonia is over 1000 mg/L