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

2. Sludge Disposal Sludge treatment and disposal may account for up to 80% of the total wastewater treatment cost. Options:  Land disposal – cheapest  Landfill  Beneficial use (fertilizer, brick component, etc.)  Incineration – most expensive 2

3. Sludge Generation, Treatment, and Disposal (1) 3 Sludge Treatment ? Large catalog of available technology Sludge Disposal Land application Landfill Incineration Processed sludge Raw sludge Influent Effluent Wastewater Treatment

4. 4 Sludge Disposal Land application Landfill Incineration Influent (Septage?) Effluent Raw sludge, grit, screenings Sludge Treatment What goes here depends on the method of final disposal. Solids concentration Pathogen reduction Wastewater Treatment Sludge Generation, Treatment, and Disposal (2)

5. 5 Sludge Disposal Land application Landfill Incineration Raw sludge, grit, screenings Sludge Treatment Gravity thickening Gravity belt filter Vacuum filter Filter press Anaerobic digestion Aerobic digestion Heat treatment Alkaline stabilization Composting Irradiation Influent (Septage?) Effluent Wastewater Treatment Sludge Generation, Treatment, and Disposal (3)

6. Thermal Treatment 6

7. Land Application of Sludge 40 CFR Part 503 Regulations  Domestic biosolids and septage  Rules incorporated into NPDES permits  Quality requirements for bulk or bagged biosolids applied to land for beneficial use  Apply at agronomic rates to agricultural land, pasture, forest, parks, golf courses, mine spoils 1, etc. 1 Intermixed unconsolidated rock, rock fragments and soil that result from a surface mining operation 7

8. Background – 503 Rule As Required by the Clean Water Act  EPA developed the 40 CFR Part 503 Rule to protect public health and the environment from any reasonably anticipated adverse effects of certain pollutants that might be present in sewage sludge/biosolids.  Biosolids are a primarily organic solid product produced by wastewater treatment processes that can be beneficially recycled (or disposed of).  Sewage Sludge vs. Biosolids (untreated vs. treated)  Part 503 establishes requirements for the final use and disposal of sewage sludge/biosolids when: Biosolids are applied to the land for beneficial use (soil conditioner/fertilizer) Placed on a surface disposal site for final disposal Fired in an incinerator 8

9. Risk Assessment  Many of the requirements of the 503 Rule are based on the results of an extensive multimedia risk assessment: 25 pollutants were addressed 14 exposure pathways  Concurrently, EPA developed a new methodology that provided for the protection of the environment and public health.  This methodology was reviewed and approved by EPA’s Science Advisory Board.  Most recently, it was concluded that more research is needed. However, there is no evidence that we have failed to protect the public health and environment.  From these observations, one might conclude that biosolids may be safely recycled when treated and used as prescribed in the 503 Rule. 9

10. 40 CFR Part 503 Overview  5 Subparts to Part 503 (parts is parts) Subpart A – general provisions, applicability, purpose, etc. Subpart B – requirements for land application (beneficial use) Subpart C – requirements for surface disposal Subpart D – requirements for Pathogen and Vector Attraction Reduction (treatment) Subpart E – incineration requirements  Applicability Any person who: Land applies - biosolids Land disposes - biosolids/sewage sludge Incinerates - biosolids/sewage sludge  Part 503 is Self-Implementing Persons are required to follow the rule even if they have not been issued a permit for such activities…EPA can take enforcement actions against persons who violate the Part 503 requirements (permitted or not) 10

11. Land Disposal of Sludge Two quality levels with respect to: 1.Heavy metals Ceiling concentration (4,300 mg/kg for Cu) Pollutant concentration (1,500 mg/kg for Cu) 2.Pathogens Class A Fecal coliform < 1000 MPN/g TS Salmonella sp. < 3 MPN/g TS Enteric virus < 1 plaque forming unit (PFU)/4 g TS Helminth ova < 1 #/4 g TS Class B Fecal coliform & Salmonella sp. < 2 million MPN/g TS 3.Vector attraction reduction (insects, rodents, birds) Processing Barrier 11 * Most probable number

12. Class A Biosolids  Fecal < 1000 MPN/g or Salmonella sp. < 3 MPN/4 g (based on seven individual samples per event) AND Use one of 5 approved methods to Further Reduce Pathogens:  Time/temp depending on solids content  pH/time then dry to at least 50% solids  Testing for enteric viruses/viable helminth ova  Testing for reduction of these analytes  PFRP: composting, heat drying, heat treatment, thermophilic aerobic digestion (TAD), beta ray irradiation, gamma ray irradiation, pasteurization, other methods as approved by the permitting authority PFRP: Process to Further Reduce Pathogens 12

13. Class B Biosolids  7 samples - Geometric Mean < 2,000,000 MPN/g or CFU (based on seven samples per event) OR Use 1 of 5 Approved PSRP methods:  Aerobic Digestion: 40 days at 20°C no less than 60 days at 15°C  Air Drying: 3 months with two months above 0°C  Anaerobic Digestion: 15 days at 35-55°C no less than 60 days at 20°C  Composting: Minimum 40°C for 5 days with min 4 hours at 55°C  Lime Stabilization: Add lime to raise pH to 12 after two hours of contact  Other as approved by the permitting authority PSRP: Process to Significantly Reduce Pathogens 13

14. Distribution & Marketing Class A Unrestricted Use (lawn & garden)  Table III Metals  Exceptional Quality (EQ) Class A Restricted Use (containerized or bulk)  Table I Metals - Pollutant Concentration  Subject to APLR – Annual Pollutant Loading Rate Class B Restricted Use – (agricultural)  Table III Metals – Pollutant Concentration (PC)  Table I Metals Subject to CPLR – Cumulative Pollutant Loading Rate 14

15. Vector Attraction Reduction (VAR) 1.38% volatile solids reduction (VSR) 2.Anaerobic: bench scale test (40 days) 3.Aerobic: bench scale test (30 days) 4.Aerobic: SOUR ≤ 1.5mg O 2 /hr at 20°C 5.Aerobic: 14+ days at > 40°C (avg. > 45°C) 6.pH: 12+ for 2 hrs then 11.5+ for 22 hrs 7.Dry to 75% when stabilized solids used (digested) 8.Dry to 90% when unstabilized solids used (undigested) 9.Subsurface injection (no significant after 1 hr) 10.Surface application w/ incorporation (within 6 hrs) 15

16. Land Disposal of Sludge  Bulk biosolids applied to lawns and home gardens must be Class A and meet pollutant concentration limits and vector reduction restrictions.  Class B biosolids can be applied to farms, forests, etc. 16

17. Disposal Methods - Class A Pathogen Reduction 1. Composting In-vessel or static aerated pile ≥ 55°C for 3 days Windrow ≥ 55°C for 15 days (min 5 turns) 2. Heat Drying ≥ 50°C for 30 minutes Dryness ≥ 75% total solids No unstabilized biosolids 3. Alkaline Stabilization pH > 12 for 72 hours and temp > 50°C for 12 hr Dryness > 50% total solids 17

18. 4. Surface Disposal Monofill Dedicated surface application site  Piles or mounds on POTW site  Impoundments or lagoons 5. Incineration Emission limits: Total hydrocarbon < 100 ppm (monthly average, corrected to 0% H 2 O and 7% O 2 ) NESHAPs ( National Emission Standards for Hazardous Air Pollutants ) for Be and Hg; limits on Pb, As, Cd, Cr, and Ni 18 Disposal Methods - Class A Non-beneficial Use

19. Septage  Septage can be applied to farmland at a rate of 19

20. Class B Crop Class B Crop Harvesting Restrictions  Food crops with harvested parts that touch biosolids or grow above surface – 14 months  Food crops with harvested parts below surface and biosolids remain on surface for 4 months prior to incorporation – 20 months  Food crops with harvested parts below surface and biosolids remain on surface for less than 4 months prior to incorporation – 38 months  Food, feed and non-food crops – 30 days 20

21. Class B Class B Site Restrictions  No domestic livestock grazing for 30 days after application  Turf may not be harvested for 1 yr  High public exposure sites - limit access for 1 yr  Low public exposure sites – limit access for 30 days 21

22. Wisconsin NR 204 Domestic Sewage Sludge Management  Discharge standards, monitoring and record keeping and reporting requirements for the use and disposal of sewage sludge and screenings  Permit required to discharge any pollutant into “waters of the state ”. “Waters of the state” is defined to include groundwater.  “beneficial use is encouraged…” 22

23. NR 204 Applies to: 1.Use and disposal of sludge, grit and screenings generated by any domestic wastewater treatment plant. 2.Quantity and quality of sludge that is applied to land or landfilled, including sludge that is combined with any other material (septage, manure, composting material). 3.Land on which sludge is applied and any landfill which receives sludge 23

24. NR 204 not Apply to 1.Use or disposal of sludge that is defined as hazardous waste by NR 600. 2.Septage (NR 113), except when combined with sewage sludge 3.Sludge that is incinerated 4.Bulk or bagged material that is derived from exceptional quality sludge. 5.Industrial sludge 6.Sludge with PCB conc. > 50 mg/kg 7.Incinerator ash 8.Sludge generated through treatment of drinking water 24

25. NR 204.07 - Land Application of Sludge (1) Approved Sites - each site must be inspected and approved. Site CriteriaSurfaceIncorporationInjection Depth to bedrock 3 ft 3 ft 3 ft Depth to high GW 3 ft 3 ft 3 ft Allowable slopes 0-6% 0-12% 0-12% Distance to wells Community 1000 ft 1000 ft 1000 ft Private 250 ft 250 ft 250 ft Min. distance to residence 500 ft 100 ft 100 ft 25

26. Site CriteriaSurfaceIncorporationInjection Min distance to streams, lakes, ponds, or wetlands Slope 0% to < 6%200 ft150 ft100 ft Slope 6% to 12%not allowed200 ft150 ft Min distance to grass waterways, or dry run with 50 ft grass strip Slope 0% to < 6%10 ft50 ft25 ft Slope 6% to 12%not allowed100 ft50 ft Soil permeability0.2 - 6.00 - 6.00 - 6.0 range (inch/hr) 26 NR 204.07 - Land Application of Sludge (2)

27. Minimum Duration between Application and Harvest/Brazing/Access for Class B Sludge Applied to Land CriteriaSurfaceIncorp.Injection Food crops whose harvested parts may 14 mos.14 mos.14 mos. touch sludge/soil Food crops whose harvested parts grow20/38 mos.20/38 mos.38 mos. in the soil Feed or other food crops (Corn, hay, etc.)30 days30 days30 days Grazing of animals30 days30 days30 days Public access restriction (30 days or 1 yr, depending on exposure) 27

28. Heavy Metals - Ceiling Concentrations Sludge may not be applied to land if the conc. of pollutants in the sludge exceeds the ceiling conc. Limits in Table 1 of NR 204.07 PollutantCeiling conc. (mg/kg = ppm dry wt) Arsenic75 Cadmium85 Copper4,300 Lead840 Mercury57 Molybdenum75 Nickel420 Selenium100 Zinc7,500 28

29. Heavy Metals - Pollutant Concentrations Sludge that meets the pollutant concentration limits can be bulk applied to land, subject to cumulative loading limits PollutantMonthly Average conc. (mg/kg dry wt) Arsenic41 Cadmium39 Copper1500 Lead300 Mercury17 Molybdenumdeleted until EPA revises Nickel420 Selenium100 Zinc2,800 29

30. Heavy Metals Cumulative & Annual Loading Rates Lifetime cumulative Annual pollutant Pollutant metal loadings loading rate kg/halb/acre Arsenic41362.01.78 Cadmium39341.91.69 Copper150013397566.9 Lead3002681513.4 Mercury17150.850.76 Nickel4203752118.7 Selenium1008954.4 Zinc------140125 30

31. Application Rates Amount of available nitrogen from sludge and other nitrogen sources shall not exceed the nitrogen requirement of the crop, as determined by University of Wisconsin-Extension Bulletin A-2100 (April 1991). Organic nitrogen available in first year of application = 25% (??) of total organic nitrogen in sludge Mineralization rates to calculate carryover of previous years’ application: 25% - 12% - 6% in years 1, 2 and 3 31

32. Storage Facilities Storage for 180 days 32

33. Guiding Principle Nitrogen requirement of crop satisfied by sludge nitrogen Nitrogen uptake by crop = nitrogen available from sludge 33

34. Corn Yield Potential of Soil CodeLevelQuantity 1Very high120-140 bu/acre 2High100-120 bu/acre 3Medium80-100 bu/acre 4Low60-80 bu/acre (Dane County is codes 1 to 3) 1 U.S. bushel = 8 corn/dry gallons = 2150.42 in 3 = 35.23907016688 liters 34

35. Nitrogen Requirements for Corn (lb N/acre) Code Organic Matter Content (ton/ac) 0-2021-3536-50≥50 1160140120100 214012010080 31201008060 4100806060 35

36. N, P, and K Uptake by Crops (P = 0.437 P 2 O 5, K = 0.83 K 2 O) CropYield Uptake (lb/acre) (bu/acre) NP 2 O 5 K 2 O Corn12015065170 14018580185 Soybeans5025750120 6033665145 Wheat6012550110 8018655160 Alfalfa8 tons45080480 36

37. Other Issues  Phosphorus in sludge may exceed that needed by the crop.  Presently no limit on phosphorus applied in sludge - this may change.  Potassium must be added as commercial fertilizer. 37

38. Nitrogen Available from Sludge f v = volatilization factor 1.0 for injected sludge 0.5 for surface application f n = mineralization factor (refers to availability of organic nitrogen applied in previous years) - NO as % 3 )NfNH + f2000(NO - N on4v3a  4 NH + as % 38

39. N Available from Mineralization of Organic N Applied in Previous Years Time afterMineralization applicationfactor 1 yearf n1 = 0.25 2 yearsf n2 = 0.12 3 yearsf n3 = 0.06 Wisconsin NR 204.07(8) 39

40. Allowable Annual Sludge Application Rate Land requirement 40

41. Example - Land Application (1) Sludge = 600 dry tons solids per year Crop = corn Surface application (f v = 0.5) 0% NO 3, 2% NH 4 +, 2% organic N Year 1 N a = 2000 [ 0 + 0.5(0.02)+0.40(0.02)] = 2000(0.018) = 36 lb N/ton dry solids 41

42. Crop uptake = 180 lb/acre-year Allowable annual sludge application rate = 180/36 = 5 ton/acre-year Land area required (year 1) = (600 tons/yr) /(5 ton/ac) = 120 acres 42 Example - Land Application (2)

43. Year 2 Fraction of organic N applied in year 1 that carries over in soil = 0.02 – 0.4(0.02) = 0.0012 Fraction of year 1 carryover becoming available = 0.25 Fraction organic N available from “new” sludge = 0.009 (same as year 1) Total available N = 2000[ 0 + 0.5(0.02)+ 0.4(0.02) + 0.25(0.0012) = 2000(0.0183) = 36.6 lb N/dry ton sludge solids 43 Example - Land Application (3)

44. Allowable sludge application rate = (180 lb N uptake/ac·yr)/(36.6 lb N/ton) = 4.9 ton/acre·yr Land area required = (600 ton/yr)/(4.9 ton/acre·yr) = 122.5 acres Because of carryover from years 1 and 2, the allowable sludge application rate will be lower in year 3 and the land requirement will increase. After 3 years the application rate does not change much. 44 Example - Land Application (4)