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Jae K. (Jim) Park Dept. of Civil and Environmental Engineering University of Wisconsin-Madison 1.

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Presentation on theme: "Jae K. (Jim) Park Dept. of Civil and Environmental Engineering University of Wisconsin-Madison 1."— Presentation transcript:

1 Jae K. (Jim) Park Dept. of Civil and Environmental Engineering University of Wisconsin-Madison 1

2  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  Treatment experience  Lab & pilot scale: good treatment, large data base  Field scale: limited data base 2

3  Leachate disposal can be costly.  Development of the disposal process should take into account several areas  Regulatory requirements  Nature of leachate  Operational considerations  Available disposal options  Failure to solve a problem with all constraints can lead to  High capital and operating costs  Difficulty in operation  Compliance related problems 3

4 Off-site facility On-site facility Complete Partial Disposal Effluents Sludges etc. 4

5 10 0 Flow m 3 /ha∙day Time, months Options  Overdesign and treat peak flow  Equalize flow in landfill (recycle) or storage tanks 5

6  Some peak quickly and decline: e.g., BOD  Some persist for long periods: e.g., NH 3 -N  Daily and seasonal variations occur Options  Same as for flow  Modify treatment system 6

7  Young Leachate - Biological Treatment  BOD in 10,000’s  Mostly VFA  Older Leachate - Carbon Adsorption  BODs in 100’s; COD in 1,000’s  Humic and fulvic acids  Priority organics 7

8  Nitrogen  Ammonia (NH 3 -N) - Air Stripping  Organic (Org-N) - Chlorination  Combined - 100’s mg/L - Biouptake, Biological Nitrification/Denitrification  Heavy Metals - Chemical Precipitation Iron (Fe) mainly; Zn, Pb, Cu 8

9  Conservative Ions - Reverse Osmosis  High TDS  Chloride  Sulfate  Sodium  Acidic pH - Neutralization 9

10  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 Q t C t 10

11 COD pH NH 3 Landfill age Concentration Phase 1 Adjustment Phase 5 Maturation Phase 4 Methanogentic Phase 2 Transition Phase 3 Acetogenic 11

12 12 POTW Disposal (39.9%) Sewer discharge (14.3%) Private/industrial treatment(13.5%) Not collected (9.0%) On-site treatment (7.5%) On-site treatment/ sewer or POTW (3.8%) Evaporation (2.3%) Other (9.7%) POTW: Publicly Owned Treatment Work

13 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 13

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19 19 Leachate ParameterCell 1Cell 2Effluent pH Alkalinity (mg/L as CaCO 3 )5,1505, COD10,60010, BOD4,1004,2003 TOC3,0702,98080 Fatty acids (as C)1,7021,946ND Acetic576344ND Propionic 4701,290ND iso-Butyric 12844ND n-Butytic 18034ND iso-Valeric ND n-Valeric ND Ammonia (mg-N/L) Nitrate (mg-N/L)< Nitrite (mg-N/L)0.30.3< 0.1 Sulfate (mg/L) Phosphate (mg/L)1.83.3< 0.1

20 20 Leachate ParameterCell 1Cell 2Effluent Chloride (mg/L) 4,6702,1803,870 Sodium (mg/L)1,3601,2101,070 Magnesium (mg/L) Potassium (mg/L) Calcium (mg/L)1,0401,03025 Chromium (mg/L) < 0.04 Manganese (mg/L)2.74.0< 0.1 Iron (mg/L) Nickel (mg/L) Copper (mg/L) Zinc (mg/L) Cadmium (mg/L) < 0.01 Lead (mg/L) < 0.04 Arsenic (mg/L)

21  Off-Site  Removal by road tanker to sewage works  Removal via pipeline or sewer to POTWs  Most common  On-Site  Biological  Physical/Chemical  Mixed 21

22  Secondary Treatment  Excellent Removal BOD, SS, coliforms  Some removal Metals (Fe, Zn), organics, NH 3 -N  Little Removal Metals (Ni, Al), solvents, Cl -, Na + 22

23  Wisconsin (1986), 6 cities Flow ($/1000 gal)BOD ($/lb) Average Range0.11~ ~0.25 Example: 50 acre site with 12” precipitation/yr, BOD - 10,000 mg/L, and average $ above; then ~ $150,000/yr 23

24  Little data available  Lab co-treatment studies with sewage  2% by volume is OK  But organic load is much higher (> 50%)  Expect  Increased oxygen and P required  Sludge production: biomass, metal precipitates  Foaming, Odors  Effluent: TDS, NH 3 -N, resistant organic  No adverse impact - Metro Toronto (1985) 24

25 ParametersControl % Leachate (V/V%) 0.2%1%10%25%50% 25 Operating conditions Aeration time (hrs) Solids retention time (days) Mixed liquor temp. (°C) pH DO (mg/L) MLSS (mg/L) MLVSS/MLSS ratio F/M ratio (kg BOD/kg TS/day) Respiration rate (mg O 2 /mg VS/hr) Sludge volume index (mL/g)                               6 Removal efficiencies BOD removal (%) COD removal (%) SS removal (%) TKN removal (%) Ammonia removal (%) Color (Influent/Effluent) Dominant wave length (nm) Hue Luminance (%) Purity (%) 500~505 Green 84/84 3/3 500~505 Green 76/77 3/3 500~505 Green 79/79 3/3 575~580 Yellow 82/82 20/20 575~580 Yellow 76/77 30/30 575~580 Yellow 47/51 40/40 MLSS: mixed liquor suspended solids; MLVSS: ML volatile SS; F/M: food/microorganisms

26  Physical/Chemical Processes  Coagulation/flocculation/settlement  pH control and aeration/air stripping  Activated carbon adsorption  Reverse osmosis  Oxidation with hydrogen peroxide  Oxidation with hypochlorite  Degassing  Evaporation  Biological ( )  Aerobic: trickling filter, activated sludge, aerated lagoon, rotating biological contactor, sequencing batch reactor (SBR)  Anaerobic: submerged filter, upflow anaerobic sludge blanket (UASB)  Anoxic: denitrification  Mixed  Land treatment  Vegetated ditch/root zone treatment 26

27 Trickling Filter Plastic cross-flow packing Plastic random packing 27

28  Suspended growth system  Completely mixed mode; batch mode with discontinuous flow  Typical F/M = 0.05~0.1 (comparable to an extended aeration type process) Influent 23 1 Fill React Settle Effluent 4 DrawIdle 5 28 Mixing

29 29 Surface aerator Raw wastewater Effluent  Suspended growth system  Comletely mixed mode  Contact time limited to hydraulic retention time due to no recycle of sludge  Limited effluent quality

30 30  Attached growth system  Plug flow mode  Design based on specific surface area  Aeration provided by rotating disks  Better performance than other fixed- film systems due to lower organic loading per mass of biomass, longer detention time, and little short-circuiting

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32 32  Effluent recycle (sufficient alkalinity) to raise pH to 7  Possible buildup of nonbiodegradable solids in reactor  Loading rate: 0.42~3.4 kg COD/m 3 ·day at 25°C; 60~80% COD removal; e.g. Landfill leachate: pH 5.4, COD 54,000 mg/L, 45% fatty acids, loading 7.9 kg COD/m 3 ·day  89% removal  Sludge age: > 100 days VSS: > 20,000 mg/L  Increased efficiency and rapid elution of toxic sludge  Not good for wastes containing a large portion of particulates and/or carbohydrates due to clogging  Possible to treat low strength waste at nominal temperatures economically

33 33  Difficult to maintain low effluent SS levels and occasional unexplained biomass washout  High sludge age at high loadings with separation of gas from the sludge solids  VSS: 20,000 ~ 150,000 mg/L  Sugar-beet waste: reactor size 800 m 3, loading 10 kg COD/m 3 ·day, and HRT 4 hrs  treatment efficiency 80%

34 Technology Achievable eff. conc. (mg/L) Metal Sulfide precipitation/filtration Carbon adsorption Ferric hydroxide co-precipitation Arsenic Sulfate precipitation0.5Barium Hydroxide precipitation at pH ZincHydroxide precipitation at pH Co-precipitation with ferric hydroxide Sulfide precipitation Cadmium Hydroxide precipitation at pH NickelSulfide precipitation Alum co-precipitation Ferric hydroxide co-precipitation Ion exchange 0.01~0.02Mercury Hydroxide precipitation Sulfide precipitation 0.02~ ~0.02 Copper Sulfide precipitation 0.05Selenium 34

35  Essential if BOD > 50 mg/L  Expect  BOD removal  SS removal with sedimentation  NH 3 -N and Org-N removal by biouptake and nitrification  Metal removal by biosorption and precipitation at oxides and carbonates  Priority organics removal 35

36  Biomass in Suspension  No Biomass Recycle Facultative pond, aerated lagoon  Biomass Recycle Activated sludge  Biomass Attached RBC, packed bed filter, trickling filter 36

37  Phase 1: Removal of high M.W. humic carbohydrate-like organics - adsorption to microorganisms  Phase 2: Removal of free volatile fatty acids - decrease in ORP, conductivity, and DO  Phase 3: Formation of intermediates - excretion of high M.W. humic carbohydrate-like organics  Phase 4: Removal of high M.W. humic carbohydrate-like organics 37

38 Schmitzer and Kahn (1972)  Polymerized waste product  Inert material from lyzed cells  20~50% of effluent COD (M.W.: 500~30,000)  Reduced removal of heavy metals due to chelation  Reduced removal of pathogens  Source of color 38

39 Painter et al. (1961); Bunch et al. (1961)  Humic material: 65~75%  High molecular weight: 21~49% Rebhun and Manka (1971)  Humic substances: 39~45% Hurst and Burges (1967)  Refractory organics: humic acid (M.W ~100,000); fulvic acid (2,000~10,000) 39

40 Barker and Somers (1970); Finch et al. (1972)  Certain high M.W. carbohydrates alone or in combination with humic material are resistant to microbial attack, which were isolated from exocellular polysaccharides.  High M.W. carbohydrates were excreted at the end of the logarithmic growth phase and appeared to help forming flocs by bridging of bacterial cells. 40

41 Biological treatment  No COD decrease after 184 hrs of aeration (COD/TOC=2.1; BOD/COD=0.03) Activated carbon  59~94% COD removal - impractical  Good for old stabilized leachate treatment Ozonation  22% COD removal after four hour test  Not promising because of strong resistance of fatty acids, especially acetic acids, to ozone 41

42 BOD (COD), mg/LRetention Source InOutTime, day Boyle & Ham2, Uloth & Mavinc ¶ 36, Chian & DeWalle(35,200)(1,030)7 Spencer & Farqunar(15,200)(260)10 pH Fe, mg/L % removal Zn, mg/L % removal Cd, mg/L % removal Pb, mg/L % removal Ni, mg/L % removal Moderate inhibition in a few cases, 20~24°C, lime & PO 4 added 42

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44 Bryn Posteg Landfill Site, Wales 44

45  Posteg Landfill, Wales, UK Aerated pond Lined HDPE V = 1,000 m 3 HRT = 10 days F/M  0.25 Temp. = 4  C Facultative pond Settling: SVI = 40 PO 4 (nutrient) 0~150 m 3 /d Sewer Sludge to landfill 45

46  Posteg Landfill, Wales, UK Contaminant InfluentEffluent PeakAve. BOD 5, mg/L> 10,0003,70024 NH 3 -N, mg/L>1, Fe, mg/L> pH Cost Capital - $120,000 (1985) O&M - $1/1000 gal Sewer surcharge without treatment - $9/1000 gal Savings - $68,000/yr 46

47  Grows Landfill, Tullytown, PA EPA supported demonstration project Data source: Steiner & Fungaroli (1979) Conditions:  Landfill - 50 acre, 800 ton/day, 85% MSW  Treatment to meet sewer standards  Flow: variable, ave. 10~15 gal/min  Operating problems: NH 3 -N toxicity PO 4 -P deficiency Winter: reactor temp. 35°F 47

48  Grows Landfill, Tullytown, PA Chemical Treatment Mixed reactor Sedimentation Ammonia Stripping Aerated pond Activated Sludge Biomass recycle Chlorination CaO Metallic sludge NH 3 -N Biosludge HRT = 1 day pH  10.5 HRT = 1.8 day pH = 7.5 F/M = 0.3 N2N2 Sewer 48 H 3 PO 4 Cl 2

49  Grows Landfill, Tullytown, PA Efficiency (average) Parameter Concentration, mg/L% removal StandardInfluentEffluent BOD , NH 4 -N SS Fe Cl - -3,1722,

50  Loading:F/M < 0.3 kg BOD/kg VSS/day SRT > 10 days (20°C); 20 days (10°C)  Sludge production: 1 kg TSS/kg BOD removed  O 2 supply: high for young leachates  PO 4 -P supplement: usually required  NH 3 -N conversion: biomass uptake at BOD:N:P = 100:5:1; nitrification may dictate design for old leachate, may be inhibitory at high conc.  Recycle of biomass: not required for high strength leachate  Precipitate formation: CaCO 3 & Fe 2 O 3 can coat pump impellers and aeration components  Sequencing batch reactor (SBR): < 100 m 3 /day 50 SRT: Solids retention time

51  Comparison of Anaerobic vs. Aerobic If BOD 5 > 1,000 mg/L, then Anaerobic No O 2 required Lower biomass produced CH 4 is useable Remove NH 3 -N Increase BOD & SS removal 51 Aerobic

52  Anaerobic Fixed Film Reactors (AFFR) Films better than digesters  Biomass washout reduced  Higher loading possible  Kinetically better  Experience  Field - limited, WMI, Milwaukee  Laboratory: support medium - granular carbon, plastic film, sand, plastic rings; COD removals - 90~97% 52

53  SW: 700 ton/day; Leachate: 80 m 3 /day Chemical Precipitation Anaerobic Fixed Film Reactor Aerated Lagoon Facultative Pond CaO Sludge Neutralize pH Precipitate metals BOD removal, 32°C Plastic rings 4 kg COD/m 3 /day BOD removal 70 day HRT, 20°C Nitrification CH 4 Effluent Raw Leachate SS removal 70 day HRT, 20°C Denitrification A B C D 53 PO 4 -P

54  Treatment Efficiency - Pilot Scale TypeABCD COD22, BOD 5 16, TOC8, Humic Acid NH 3 -N Fe Zn Ca1,7402, Cl - 1,110-1,0151,080 SO Alkalinity3,8504,2002,5631,800 TDS15,30019,2004,2204,215 pH

55  Omega Hills Landfill, Milwaukee, WMI (1987) Designed for discharge into a POTW Holding Tank Media Heat Exchanger (Landfill/Filter Gas) Filter Solids Contact Clarifier V = 200,000 gal HRT = 2 days Mixer V = 56,500 ft 3 ; HRT = 7.4 day; Loading = 442 lb/day/1000 ft 3 ; Media depth = 20 ft; T = 95°F; Dia. = 20 ft; Q r /Q = 10/1 Dia. = 30 ft POTW 55 Dia. = 30 ft

56 Omega Hills Landfill Leachate Treatment Facility 56

57 Design Conditions Field Conditions 100,000 gal/day (Flow) 20,000~30,000 gal/day 38,000 mg/L (BOD) 7,000 mg/L (ave.) 900 lb/day/1000 ft 3 (Loading) 67 lb/day/1000 ft 3  Excellent Treatment ContaminantInfluentEffluent BOD3,700~24,000350~700 TSS 2,500~15,000100~500 Cd Cu Pb Ni Zn  Seeded with manure  Underloaded - needs other high strength organic wastes 57

58  Used with bioprocesses except for old leachate (BOD 5 < 50 mg/L) and contaminated groundwater ProcessesFor Removal of Carbon AdsorptionNonbiodegradable organics: solvents, pesticides, humic acids, etc. Chemical PrecipitationHeavy metals: Fe, Zn, etc. Suspended solids Air StrippingNH 3 -N Volatile solvents Granular FiltrationSuspended solids Membranes -Conservative: organics, irons: Cl reverse osmosis Na +, etc. 58

59  Addition of simple chemicals followed by a sequence of mixing, coagulation/flocculation, and settlement  Chemicals tested:  Hydrated lime  Quick lime  Sodium hydroxide  Magnesium hydroxide  Alum  Ferric chloride  Ferric sulfate  Polymeric coagulant aids 59

60 Influent Lime Sludge Backwash Effluent Carbon Adsorption Granular Filtration Sedimentation Chemical Precipitation Precipitate metals Settle precipitates Clarify influent to carbon adsorption Carbon regeneration plus afterburner at 1200°C Adsorb TOC and solvents Destroy TOC and solvents 60

61 Leachate Tubular, cellulose- acetate Spiral wound, composite Permeate StreamLandfill Concentrate Ultrasil ® - cleansing Oxonia ® - disinfection STORK-Wafilin,VAM, Wijster, NL 1,000,000 tons (1986) Waste disposal: mainly composting Costs Capital: $2.5  10 6 (US, 1988) Operating: 1.4¢/gal (US, 1989) > 80% Liquid < 20% 98% 61

62 ParameterLeachatePermeateConcentrate (estimated) Flow, gpm154119(35) COD, mg/L2,8603(15,000) BOD, mg/L2172(1,100) TKN, mg/L9555 * (4,700) Cl, mg/L3,1607(15,500) Zn, mg/L (3.0) Cu, mg/L (0.7) Ni, mg/L (3.5) AOX **, mg/L * Does not meet discharge standard ** Adsorbable Organic Halides Potential Concentrate Treatment Evaporation (30% solids) + heat drying (96% solids) 62

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64 64 ItemValue Flow (gpd)25,000 Reactor volume (gallons)224,100 Hydraulic residence time (days)2.48 Sludge age (days)25 MLVSS (mg/L)4,000 Loading (F/M) (g COD/g VSS/day)0.2 Nutrients (COD:N:P)100:2:0.38 Sludge yield (g VSS/g COD)0.3 Aeration typeFine bubble

65 ConstituentInfluentEffluent(mg/L) COD BOD Ammonia Nitrogen Total nitrogenN/A100 TSSN/A30 Q = 6,500 m 3 /day 65 Korean Leachate Treatment Facilities

66 Chemical Sludge wasting Remove ammonia (optional) Remove organics, ammonia, nitrite/nitrate, and toxic compounds Polish the effluent Reed bed Discharge Leachate Equalization Tank Chemical Precipitation Chemical Equalize flow Remove heavy metals and solids (optional) Air Stripping SBR 66

67 No fertilizer Fertilizer No NH 3 stripping Design Services 1. Preliminary$165,000$165,000$165, Final$636,000$636,000$636,000 Construction 1. Mechanical $34,000,000$36,000,000$32,500, Wet lands$6,000,000$6,000,000$24,300,000 Start-up & Training$124,000$124,000$124,000 Total Cost$40,955,000$42,955,000$57,755,000 67

68  New/Young Landfill  Neutralization (NaOH, lime, pH = 7.5)  Biological Treatment  Anaerobic (UASB)  Aerobic (long SRT) o Activated Sludge o Sequencing Batch Reactor (SBR) o Nitrification/Denitrification  Disinfection  Membrane Process/Activated Carbon  Old Landfill: eliminate UASB Biological  Sludges & Concentrations: landfill, POTW POTW Land Large surface water Small surface water 68

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70  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? 70 Measure of Success

71  Can be used during the early stages when leachate production quantities are low.  Can be used in later stages to eliminate problems of off-site transport during peak production periods or during downtimes of the transport devices. Advantages  Attenuation of leachate strength/quantity  Increased rate of landfill stabilization  Enhanced gas production rates  Immobilization of metals from landfill material  Improved landfill settling rates  Increased compaction rates 71

72 Disadvantages  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 72

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74 Methods of Recirculation  Spray irrigation  Working face application  Gravity well/trench  Injection well/trench  Infiltration ponds 74

75 75 Pump Waste Soil cover Leachate collection system Clay/geomembrane liner system

76 Advantages  Good coverage  Moderate weather restrictions  Subject to evapotranspiration  Easily adjusted for settlement concerns Disadvantages  Subject to plugging  Sophisticated design and construction  Subject to freezing  Surface water contamination potential 76

77 Advantages  Portable  Good coverage  Moderate design, construction requirements  Moderate weather restrictions  Easily adjusted and maintained Disadvantages  Potential crushing of pipes  Subject to freezing  Surface water contamination potential (thru pipe leaks), limited use after capping 77

78 Advantages  Simple design  Most evaporation potential  Good coverage  Low capital investment  Least subject to plugging  Easily accessed for maintenance Disadvantages  Odor  Weather restrictions (wind, rain)  Health risk  Surface water contamination risk 78

79 Advantages  Minimal weather restrictions  No odor  Simple design  Easily combined with horizontal distribution lines Disadvantages  Poor coverage w/o horizontal distribution  Susceptible to differential settlement damage  Subject to plugging  Subject to short circulating of leachate  Difficult to maintain vertical levelness 79

80 Advantages  Fair to good coverage  Minimal weather restrictions Disadvantages  More sophisticated design and construction required  Susceptible to differential settlement damage  Virtually impossible repair or maintenance 80

81  Refuse K v < K h → Vertical injection wells better  Not good for well-compacted refuse with a substantial component of soils or waste of low K.  Clogging may occur when leachate is recirculated through horizontal pipes beneath the cap.  The leachate should be spread uniformly over the landfill surface through a network of piping.  Leachate spraying (similar to spray irrigation) has caused problems of odor and blowing of leachate.  Prewetting of refuse and surface ponding have been used with mixed success. 81

82 Source: Reinhart, D.R. and Carson, D. (1993). “Experiences with Full-Scale Application of Landfill Bioreactor Technology,” Solid Waste Association of North America, Preprint, SWANA, Silver Spring, MD. 82 Recirculation method Application rates Pre-wetting48 gal/ton or 1000 lb/yd 3 Vertical injection wellsa. 1 to 2.5 gpm/2.5-inch diameter well 1.7 to 4.1 gpd/ft 2 landfill area b. 20 to 200 gpm/4 ft diameter well 0.12 to 2.3 gpd/ft 2 landfill area Horizontal trenches 25~50 gpd/ft of trench length at 60 to 100 gpm Surface ponds0.13~0.19 gal/ft 2 /day Spray irrigation18 gpd/ft 2 of landfill area to gpd/ft 2 of landfill area


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