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Ahmed A.M. Abu Foul Environmental Department Islamic University of Gaza.

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Presentation on theme: "Ahmed A.M. Abu Foul Environmental Department Islamic University of Gaza."— Presentation transcript:

1 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 (SO 4 ) = 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 Bio- degradability BOD/CODCOD/TOC Low < 0.5< 2 Medium0.5 – – 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. ParameterUnitsAverage Standard BOD 5 mg/L30 Total Suspended Solidsmg/L30 NH 3 \N (May-October)mg/L3 NH 3 \N (November-April)mg/L6 Dissolved Oxygenmg/L4 (minimum) PHS.U

25 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 H 3 PO 4 to bring pH down and add phosphate Air stripping tower to remove ammonia (optional) Na 3 PO 4 to add phosphorous without changing pH Example for Leachate Treatment

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 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


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