How to Evaluate and Manage Non-Biosolids
Residuals
Greg EvanyloCrop & Soil Environmental Sciences
Virginia Tech; [email protected]
Management Strategy Benefit Scale
Source reduction and water conservation
10 – Maximum benefit to processor and environment
Recovery for human uses 7
Recovery for animal uses 4
Recovery for soil conditioners and fertilizers
2
Disposal in landfill, and impoundment or incineration
0 – No benefit ↓ increasing cost
Disposal in hazardous waste management facility
Residuals Utilization and Disposal Hierarchy
Property Use
Solids Determine wet application method and rate
TKN, NH4-N, Org N Calculate plant available N (PAN)
Volatile solids, OM Determine carbon content, value as soil amendment
FOG, BOD, COD Determine potential odor, O2 depletion, soil quality effects, direct plant effects
C:N Estimate N mineralization for PAN
P, K, S, Ca, Mg, micros Calculate nutrient supply, potential antagonistic effects (e.g. Ca:Mg-induced grass tetany)
By-product Properties Necessary to Evaluate Land Application Benefits and Drawbacks
Property Use
Heavy metals, B, Mo, Na, Cl, Al, Fe
Prevent toxicity to plants and animals, food chain concerns, and soil quality loss; P-binding
Synthetic organic compounds
Prevent toxicity to plants and animals, food chain concerns, and water quality impairment
Electrical conductivity (EC), soluble salts, Na absorption ratio (SAR)
Prevent phytotoxicity and soil structure destruction
pH, CaCO3 equivalency (CCE)
Determine liming potential, micronutrient availability
Microbial density Estimate pathogen risk
By-product Properties Necessary to Evaluate Land Application Benefits and Drawbacks
Water treatment residuals (WTR) Food processing residuals (FPR)
◦ Plant –based◦ Animal-based
Incinerator ash
Residual By-products to be Evaluated
Flocculated suspended sediment and organic matter from water treatment facilities
Generated with additions of Al2(SO4)3 (alum), Al polymer, FeCl3 and/or lime
Consists largely of soil mineral, amorphous Al and Fe oxides, and organic matter
Low nutrient value and high P-binding medium
Value as a pathogen-free, low heavy metal-containing topsoil substitute and environmental P sorbent
Water Treatment Residuals
Hagerstown WTRVariable Conc (%) Lbs per dry ton
Total AvailableSolids 26.1
TKN 0.45 9.0 ≤2
NH4-N 0.01 0.2 0.2
Org-N 0.44 8.8 1-2
P 0.12 2.4 ? (P2O5)
K 0.19 3.8 4.6 (K2O)
Al 7.47 149
Fe 2.91 58
Sorption comparisons◦100-600 mg P/kg soil◦ 15,000-30,000 mg P/kg WTR
Higher P binding by fresh (amorphous) than aged (crystalline) WTR
Phosphorus saturation index (PSI = [Pox]/[Alox + Feox]) can be used to calculate WTR application rates for reducing P in drainage from low P-sorbing soils.
Limitations◦ High EC (15-30 dS/m) in Fe-rich WTR◦ Highly soluble C can reduce WTR P binding
Use of WTR to bind P
Incidental organic by-product generated by processing agricultural commodities◦Feed and spent brewery grain◦Fruit and vegetable◦Meat and milk
Key compositional factors◦N and P◦Dissolved and suspended solids◦Fats, oils and grease (FOG)◦Low pollutant concentrations
Food Processing Residuals (FPR)
Pickling Liquid Effluent (Vlasic)Property Conc Lbs/10,000 gals (0.37 acre-
in)Total Available
Solids (%)
1.55 1294
TKN (%) 2.58 33.4 28 (est)
NH4-N (%)
2.00 25.9 25.9
Org-N (%)
0.58 7.5 2.3 (@30% min)
P (%) 1.29 16.7 38 (P2O5)
K (%) 0.96 12.4 15 (K2O)
VS=50%, C=29%, C:N=11.3
Pickling Liquid Effluent (Vlasic)
Property
Concentration
Total lbs/10,000 gals
pH 7.50
S (%) 1.61 21
Ca (%) 1.88 24
Mg (%) 0.25 3
Na (%) 8.63 112
SAR = Na/[(Ca + Mg)/2]0.5 = 19.4
Sea Watch Liquid
Property Conc Lbs per dry tonTotal Available
Solids 25.1TKN (%) 8.68 173.6 93 (est)NH4-N(%) 0.58 11.6 11.6
Org N (%) 8.10 162 81 (@50% min)
P (%) 1.32 26.4 60 (P2O5)
K (%) 1.35 27.0 37 (K2O)
VS=71%, C=41%, C:N=4.7
Sea Watch LiquidProperty Concentration
100% 50% (diluted w/ water)
pH 5.38 5.00Ca (%) 0.44 0.49Mg (%) 0.28 0.27Cl (%) 10.7Na (%) 7.78 6.79SAR 1.92 ?
EC (dS/m) 34.5Specific ion toxicity limits:Cl=0.01%, Na=0.007%
Sensient FlavorsProperty Conc Lbs per dt
Total AvailableSolids (%) 10.5TKN (%) 5.66 113.2 79 (est)NH4-N (%) 2.79 55.8 55.8
Org-N (%) 2.87 57.4 23.0 (@ 40% min)
P (%) 2.10 42.0 96 (P2O5)
K (%) 1.02 20.4 25 (K2O)VS=55%, C=32%, C:N=5.6
Sensient Flavors
Property
Concentration
Total lbs/10,000 gals
Density (lbs/gal)
8.76 87,600
Ca (%) 2.11 185
Mg (%) 0.30 26
Na (%) 7.70 675SAR = Na/[(Ca + Mg)/2]0.5 = 42
Interpretation of Soil EC ReadingsSaturated paste
2:1 water:soil
Rating Crops affected
-----mmhos/cm-----
<1.0 <0.40 Salinity effects negligible
Possibly beans
1.1-2.0 0.40-0.80 Very slightly saline
Clovers, carrots, bell pepper, lettuce
2.1-4.0 0.81-1.20 Moderately saline
Broccoli, potato
4.1-8.0 1.21-1.60 Saline Cotton, alfalfa, grains, bermudagrass
8.1-16 1.61-3.20 Strongly saline Only salt tolerant grasses, herbaceous plants, trees and certain shrubs will grow
>16 >3.20 Very strongly saline
Potential for Soil Permeability Limitations from Irrigation
SAR Use restriction for varying EC (mmhos/cm)
None Slight/moderate Severe
0-3 >0.7 0.7-0.2 <0.2
3-6 >1.2 1.2-0.3 <0.3
6-12 >1.9 1.9-0.5 <0.5
12-20 >2.9 2.9-1.3 <1.3
20-40 >5.0 5.0-2.9 <2.9
Poultry DAF Sludge (Allens Hurlock)
Property Conc Lbs per dry tonTotal Available (est)
Solids (%) 7.92TKN (%) 4.63 92.6 32NH4-N (%) 0.62 12.4 12
Org N (%) 4.01 80.2 20 (@25% min)
P (%) 0.56 11.2 26 (P2O5)
K (%) 0.03 0.6 1 (K2O)VS=96%, C=55%, C:N=12.0
Poultry Tank Cleanings (Allens Hurlock)
Property Conc Lbs per dry tonTotal Available (est)
Solids (%) 21.5TKN (%) 1.27 25.4 Net negative N
availability (immobilization)
NH4-N (%) 0.14 2.8
Org N (%) 1.13 22.6
P (%) 0.14 11.2 26 (P2O5)
VS=98%, C=57%, C:N=44.9
Poultry Processing Residuals (Perdue Pilkenrood)
Property Conc Lbs per dry tonTotal Available (est)
Solids (%) 4.38TKN (%) 2.97 59.4 15
NH4-N (%) 0.37 7.4 7.4
Org-N (%) 2.60 52.0 7.8 (@15% min)
P (%) 1.24 22.8 54 (P2O5)
K (%) 0.05 1.0 1 (K2O)
VS=90%, FOG=41%, C=52%, C:N=17.6
Particularly high in meat and poultry processing sludges
Can clog soil and leaf pores Surface application w/o incorporation can
result in odor problems Recommend limiting the FOG application
rate to 1.5% of soil weight (~30,000 lbs/acre) annually
Managing FOG
By-product BOD TSS FOG
----------------g/Mg----------------
Fruit 4.8-25 1- 6
Vegetables 1.7-70.9 3- 64
Grains for oil
Processing 9-1017 5- 116
Production 136-1607 68- 411
Poultry 705-1540 275- 2800 175-1735
Beef/pork 820-4900 520- 4500 140-5000
Fish & shellfish 500-3000 160-18000 115-1600
Wastewater Characteristics of FPRs
Sludge Incinerator Ash
Property Conc Property Conc
Solids (%) 44 pH 7.9SiO2 (%) 40.4 K2O (%) 1.88
Al2O3 (%) 17.3 As (ppm) <10.6
Fe2O3 (%) 10.4 MnO (ppm)
4900
P2O5 (%) 7.31 Cd (ppm) 47
CaO (%) 6.95 Cr (ppm) 455Soil Screening Levels (SSLs):As=0.4, Cd=78, Cr=235, Mn=3600
Brandt, R.C. and K.S. Martin. 1996. The food processing residual management manual. Natural Resource, Agriculture and Engineering Service (NRAES). Ithaca, NY. NRAES-92.
J.F. Power and W.A. Dick (Editors). 2000. Land application of agricultural, industrial, and municipal by-products. SSSA Book Series No. 6. Soil Science Society of America, Inc. Madison, WI.
References for Evaluating and Managing Non-biosolids Residuals