19Leachate Treatment Systems RecirculationEvaporationBiological treatmentNatural 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
20Determine 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.
21FACTORS AFFECTING ON LEACHATE TREATMENT A- BOD/COD Ratio Relative biodegradability of leachatePresent for as long as 100 yearsTends to decline following onset of methane formation
23B- PHInfluence chemical and biological processes of precipitation, redox, sorption, methanogenesisControlled by volatile acids during acid phaseAfter methanogenesis begins, controlled by carbonates and ammoniaMajor factor in controlling metal solubility
24C- Effluent Limitations & Permitting Process Case-by-case basis based on:Type of receiving water bodyAquatic life present in receiving water bodyConcentration of toxic chemicals based on pH, hardness, temperature, etc.ParameterUnitsAverage StandardBOD5mg/L30Total Suspended SolidsNH3\N (May-October)3NH3\N (November-April)6Dissolved Oxygen4 (minimum)PHS.U.
25Example for Leachate Treatment Equalization TanksRemove heavy metals and solids (optional)Remove biodegradable organics, ammonia, nitrite/nitrate, some heavy metals, and toxic compoundsAir diffuserUV disinfection to remove pathogensSludge wastingLined reed bed for polishing treatmentDischarge to local sewer system2 SBRs with 24 hr cycle; gal. capacityNaOH to increase pHH3PO4 to bring pH down and add phosphateAir stripping tower to remove ammonia (optional)Na3PO4 to add phosphorous without changing pH
26Sequencing Batch Reactor(SBR) A variation of the activated sludge process which incorporates equalization, aeration, and clarification.
27Reed BedRemoval of heavy metals, BOD, TSS, Nitrogen, & Phosphorus
29Ultraviolet radiation (UV) Disinfection Removes pathogensContact time only 5 secondsNo disinfection by-productsO&M Costs LowSimple Operation
30Optional Components Chemical Addition Processes Phosphorus Addition Achieve optimum BOD:N:P ratio of 100:5:1pH AdjustmentControl pH levels to optimize performanceProcessesMetals PrecipitationWhen metals concentration gets too high to meet effluent standardsAmmonia StrippingWhen concentration of Ammonia is over 1000 mg/L