silage runoff characterization
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DESCRIPTIONProceedings available at: http://www.extension.org/67602 Silage leachate is a high strength waste which contributes to surface and groundwater contamination of various pollutants from runoff, direct leaching through concrete storage structures, and infiltration of runoff. Feed storage is required for the majority of dairy operations in the country (which are expanding in size and fed storage requirements) leading to widespread potential contamination. Limited data on silage leachate quality and treatment has made management and regulation based solely on observation. This project investigated three bunker silage storage sites to assess the water quality characteristics of silage leachate and runoff from various feed sources and surrounding environmental factors. Surface samples were collected from feed storage structures and analyzed for numerous water quality parameters. Using collected hydrologic data, contaminant loading was analyzed for various storm events and assessed for first flush effects and potential to impact handling and treatment designs. Determination of first flush provides essential data for separation of waste streams (high and low strength) to ease management in terms of operation and cost, reduce loading to treatment systems, and reducing the overall environmental impact.
- 1. Silage Runoff CharacteristicsMichael HollyUniversity of Wisconsin - Madison Dr. Rebecca Larson, AdvisorApril 3rd, 2013
2. Introduction Silage Fermented forage used as animal feed Corn and alfalfa are commonly used forage for dairyoperations Silage Leachate Liquid by-product from ensiling forage High nutrient concentration Silage Runoff Flow of surface excess water over an area containingsilage 3. Introduction Silage Runoff Characteristics Nutrient concentrations within silage runoff are variable Dependent on the following factors Event size Seasonality Bunker condition Silage quantity First-flush Analyzed in studies of urban runoff 80% of the total pollutant mass is transported within the first30% of the total volume (Bertrand-Krajewski el al.,1998) 4. Introduction Impacts Surfacewater Phosphorus and nitrogen loading of watersheds Oxygen depletion Eutrophication and fish kills Low pH erodes structures and harms vegetation Groundwater Conversion of organic nitrogen to nitrates Metal leaching Contamination of aquifers 5. Introduction Benefits of SilagewatershedsRunoffCharacterization Knowledge ofrelationship of loadingthroughout an event Reduction of utilizedmanure storage andhauling Improved treatment ofsilage runoff Standards forprotection of 6. Introduction Characteristic Raw Silage Residential LeachateWastewaterpH3.5-5.5 6-9P (mg/L) 300-600 5-20Organic N (mg/L)800-3,7005-40 NH3 (mg/L)350-70010-50 BOD5 (mg/L)12,000-90,000 100-400Table 1 Typical Silage Leachate and Residential Wastewater Characteristics (McDonald et. al.,1991 and Burks, et al., 1994) 7. Introduction Horizontal Bunkers Common type of silagestorage for large dairies Filled immediately afterharvest Forage is compacted andsealed High potential for silagerunoff 8. Methods Three Sites Sampled in WI over Spring, Summerand Fall Arlington Agricultural Research Station (AARS) US Dairy Forage Research Center (DFRC) Private Producer ISCO Automated Samplers Used for Sampling 2 Samples per bottle, 14 bottles total Flow activated samples Samples refrigerated within sampler Analysis Completed at UW-Madison Alkalinity, NH3, BOD5, COD, NO2, NO2 + NO3, SRP, pH,total P and total solids 9. Methods - AARS 530 head dairy 1.3 acre concretesilage bunker 0.3 acres pad 1 acre bunker Separate surfaceand subsurfacecollection system Surface samplescollected 10. Methods - AARS 11. Methods - DFRC 350 Head Dairy 0.6 acre asphaltbunker 0.2 acresbunker pad 0.4 acresbunker No subsurfacecollection Surfacesamplescollected foranalysis 12. Methods DFRC 13. Methods - Private Producer 3,500 head dairy 1.7 acre bunker 0.5 acres bunker pad 1.2 acres bunker Surface andsubsurface wererouted to the sameculvert Surface andsubsurface wassampled 14. Methods Data Analysis Average Storm NutrientConcentrations (mg/L) Normalized CumulativePollution Load Curves Dimensionless plot of thedistribution of pollutantload with volume(Tabei et. al., 2004) 15. AARS Storm Characteristics MaxAverage Max AverageDuration, intensity, Intensity, Flow,Flow,No. DateDepth, in hin/h in/h cfscfs 111/2/2011 0.98 14.30.360.0698 0.6390.0462*11/5/2011 1.524.20.720.0190n/an/a 34/26/2012 0.52 86.50.040.0056 0.8570.085 45/30/2012 0.19 7.3 0.120.0267 0.6990.236 57/18/2012 1.717.70.360.0972 2.5440.2536*7/24/2012 0.64 7.7 0.920.0821n/an/a7*7/24/2012 0.56 46.91.160.0119n/an/a 88/2/20120.05 47.60.040.0010 1.8180.016 98/7/20120.18103.70.040.0001 3.7740.230 Table 2 AARS Storm Characteristics 16. Results - AARS 0.980.52 0.051.7Figure 1 Normalized Nutrients vs. Normalized Flow for AARS Grouped by Season 17. Results - AARS Maximum average storm nutrient concentrations forNH3, BOD5 and TP took place during early spring Minimum concentrations for COD and TP occurred inthe summer Storms three, five and eight illustrated an increase inconcentrations with flow and a moderate delayedstorm curve A mild first flush occurred in the fall 18. DFRC Storm Characteristics MaxAverageMax Average Duration, intesity, Intensity, Flow, Flow,No. Date Depth, inhin/h in/hcfscfs 110/23/2011 0.197.2833330.32 0.02375 0.628 0.048818 2 11/2/2011 1.0412.633330.480.152461 0.766 0.191801 3 11/8/2011 1.1417.333330.52 0.12 0.79 0.146787 4 4/29/2012 0.7612.250.40.057281 1.141 0.167488 5 5/30/2012 0.286.9833330.160.036894 0.348 0.059283 6 7/18/2012 1.26 3.45 3.68 0.33767 0.684 0.127977 7 7/24/2012 0.5641.183330.840.013363 2.663 0.194389 8 8/26/2012 0.3821.783330.080.014462 1.536 0.051788 99/6/2012 0.0377.916670.04 0.00036 0.923 0.01965610 10/9/2012 0.196.4666670.080.026525 0.036 0.0092851110/13/2012 0.33 12.8 0.080.026946 0.171 0.0190541210/14/2012 0.2820.216670.040.01260.45 0.0348521310/25/2012 0.289.266667 NA NA0.13 0.011481 Table 3 DFRC Storm Characteristics 19. Results - DFRC0.56 1.261.14 0.520.76 0.19 Figure 4 Normalized Nutrients vs. Normalized Flow for DFRC for Select Storms 20. Results - DFRCFigure 2 BOD5 and COD (mg/L) vs. Cumulative Flow for DFRC Storms One, Three and Ten 21. DFRC Sample Bottles October Event Figure 3 Samples Bottles for DFRC Storm Number One 22. Results - DFRC Maximum average storm concentrations forNH3, BOD5, COD, SRP, TKN, TP, and TS took placeimmediately after filling the bunker (large amount of feedon pad) Minimum average storm concentrations forBOD5, COD, and SRP occurred during the summer witha large storm (high dilution effect) In the fall runoff indicated strong decay of nutrientconcentrations with accumulated flow In the spring weak first flush In summer with large storm events with high peak flowsresulted in a more delayed nutrient loading 23. Private Producer Storm CharacteristicsMaxAverage MaxAverageDuration, intesity, Intensity, Flow, Flow,No. DateDepth, in h in/h in/h cfs cfs 1 4/29/20120.7110.90.36 0.063915.412 1.378684 2 5/30/20120.5338.816670.360.013731 8.4330.706653 3 7/18/20120.8211.916670.920.063687 32.945 3.081982 4 7/24/20120.758.1166670.920.093755 7.4720.726338 5 7/25/20120.496.7666670.720.073995 4.8640.943187 68/9/20120.44 6.90.680.0658359.671.459689 7 8/16/20120.516.6166670.640.079687 7.8211.513229 8 8/25/20120.5234.70.280.015087.8210.665683 9 10/13/20121.74*31.21667NA NA3.0710.29615210 10/17/20120.67*14.95 NA NA1.6810.17335411 10/18/20120.78*145.4333NA NA0.8940.014115 Table 4 Private Producer Storm Characteristics 24. Results Private Producer 0.510.53 0.52 0.49 Figure 5. Normalized Nutrients vs. Normalized Flow for Select Private Producer Storms 25. Results Private Producer Lag time in sample collection may have missed peakconcentrations Max flow weighted nutrient concentrations for NH3, COD, TKN,TP, and TS took place during filling Minimum flow weighted concentrations for NH3, BOD5, SRP,TP and TS were in the spring (a large portion of the feed andall corn silage had been used) Some summer runoff events displayed a moderate delayedstorm curve Following filling in the fall, data demonstrated a moderate firstflush 26. Conclusions Strongest first flush evidence took place in the fallwhile strongest delayed storm curves weredocumented in the summer Highest average storm nutrient concentrations werein the fall following filling and sometimes in thespring Lowest average storm nutrient concentrations werein the summer Highest concentrations among all sites was forDFRCs initial samples in the fall (due to collectionmethods) 27. Acknowledgements Wisconsin Groundwater Coordinating Council Funding Dr. Rebecca Larson Advisor Zach Zopp Lab and Field Tech Shayne Havlovitz Undergraduate Research Assistant Dr. John Panuska Committee Member Dr. KG Karthikeyan Committee Member 28. References Burks, B.D. and M.M. Minnis (1994). "OnsiteWastewater Treatment Systems. " Madison, WI:Hogarth House, Ltd. McDonald, P., et al. (1991). The Biochemistry ofSilage, Scholium International: 340. Taebi, A. and R. Droste (2004). "First flush pollutionload of urban stormwater runoff." Journal ofEnvironmental Engineering and Science 3(4): 301-309. 29. Questions?