silage runoff characterization

Silage Runoff Characteristics

Michael HollyUniversity of Wisconsin - Madison

Dr. Rebecca Larson, AdvisorApril 3rd, 2013

Introduction Silage

Fermented forage used as animal feed Corn and alfalfa are commonly used forage for

dairy operations Silage Leachate

Liquid by-product from ensiling forage High nutrient concentration

Silage Runoff Flow of surface excess water over an area

containing silage

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

first 30% of the total volume (Bertrand-Krajewski el al.,1998)

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

Introduction Benefits of Silage

Runoff Characterization Knowledge of

relationship of loading throughout an event Reduction of

utilized manure storage and hauling

Improved treatment of silage runoff

Standards for

protection of watersheds

Introduction

Characteristic Raw Silage

Leachate

Residential

Wastewater

pH 3.5-5.5 6-9

P (mg/L) 300-600 5-20

Organic N (mg/L) 800-3,700 5-40

NH3 (mg/L) 350-700 10-50

BOD5 (mg/L) 12,000-90,000 100-400

Table 1 Typical Silage Leachate and Residential Wastewater Characteristics (McDonald et. al., 1991 and Burks, et al., 1994)

Introduction Horizontal Bunkers

Common type of silage storage for large dairies

Filled immediately after harvest

Forage is compacted and sealed

High potential for silage runoff

Methods Three Sites Sampled in WI over Spring, Summer

and 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

Methods - AARS 530 head dairy 1.3 acre concrete

silage bunker 0.3 acres pad 1 acre bunker

Separate surface and subsurface collection system

Surface samples collected

Methods - AARS

Methods - DFRC 350 Head

Dairy 0.6 acre

asphalt bunker 0.2 acres

bunker pad 0.4 acres

bunker No subsurface

collection Surface

samples collected for analysis

Methods – DFRC

Methods - Private Producer 3,500 head dairy 1.7 acre bunker

0.5 acres bunker pad

1.2 acres bunker Surface and

subsurface were routed to the same culvert

Surface and subsurface was sampled

Methods – Data Analysis Average Storm

Nutrient Concentrations (mg/L)

Normalized Cumulative Pollution Load Curves

Dimensionless plot of the distribution of

pollutant load with volume

(Tabei et. al., 2004)

AARS – Storm Characteristics

No. Date Depth, inDuration,

h

Max intensity,

in/h

AverageIntensity,

in/h

MaxFlow,

cfs

AverageFlow,

cfs

1 11/2/2011 0.98 14.3 0.36 0.0698 0.639 0.046

2* 11/5/2011 1.5 24.2 0.72 0.0190 n/a n/a

3 4/26/2012 0.52 86.5 0.04 0.0056 0.857 0.085

4 5/30/2012 0.19 7.3 0.12 0.0267 0.699 0.236

5 7/18/2012 1.7 17.7 0.36 0.0972 2.544 0.253

6* 7/24/2012 0.64 7.7 0.92 0.0821 n/a n/a

7* 7/24/2012 0.56 46.9 1.16 0.0119 n/a n/a

8 8/2/2012 0.05 47.6 0.04 0.0010 1.818 0.016

9 8/7/2012 0.18 103.7 0.04 0.0001 3.774 0.230

Table 2 AARS Storm Characteristics

Results - AARS

Figure 1 Normalized Nutrients vs. Normalized Flow for AARS Grouped by Season

0.98’

0.52’

0.05’

1.7’

Results - AARS Maximum average storm nutrient concentrations

for NH3, BOD5 and TP took place during early spring

Minimum concentrations for COD and TP occurred in the summer

Storms three, five and eight illustrated an increase in concentrations with flow and a moderate delayed storm curve

A mild first flush occurred in the fall

DFRC – Storm Characteristics

No. Date Depth, inDuration,

h

Max intesity,

in/h

AverageIntensity,

in/h

MaxFlow,

cfs

AverageFlow,

cfs1 10/23/2011 0.19 7.283333 0.32 0.02375 0.628 0.0488182 11/2/2011 1.04 12.63333 0.48 0.152461 0.766 0.1918013 11/8/2011 1.14 17.33333 0.52 0.12 0.79 0.1467874 4/29/2012 0.76 12.25 0.4 0.057281 1.141 0.1674885 5/30/2012 0.28 6.983333 0.16 0.036894 0.348 0.0592836 7/18/2012 1.26 3.45 3.68 0.33767 0.684 0.1279777 7/24/2012 0.56 41.18333 0.84 0.013363 2.663 0.1943898 8/26/2012 0.38 21.78333 0.08 0.014462 1.536 0.0517889 9/6/2012 0.03 77.91667 0.04 0.00036 0.923 0.019656

10 10/9/2012 0.19 6.466667 0.08 0.026525 0.036 0.00928511 10/13/2012 0.33 12.8 0.08 0.026946 0.171 0.01905412 10/14/2012 0.28 20.21667 0.04 0.0126 0.45 0.03485213 10/25/2012 0.28 9.266667 NA NA 0.13 0.011481

Table 3 DFRC Storm Characteristics

Results - DFRC

Figure 4 Normalized Nutrients vs. Normalized Flow for DFRC for Select Storms

0.56’

1.26’

1.14’

0.52’

0.76’

0.19’

Results - DFRC

Figure 2 BOD5 and COD (mg/L) vs. Cumulative Flow for DFRC Storms One, Three and Ten

DFRC Sample Bottles October Event

Figure 3 Samples Bottles for DFRC Storm Number One

Results - DFRC Maximum average storm concentrations for NH3, BOD5,

COD, SRP, TKN, TP, and TS took place immediately after filling the bunker (large amount of feed on pad)

Minimum average storm concentrations for BOD5, COD, and SRP occurred during the summer with a large storm (high dilution effect)

In the fall runoff indicated strong decay of nutrient concentrations with accumulated flow

In the spring weak first flush

In summer with large storm events with high peak flows resulted in a more delayed nutrient loading

Private Producer – Storm Characteristics

No. Date Depth, inDuration,

h

Max intesity,

in/h

AverageIntensity,

in/h

MaxFlow,

cfs

AverageFlow,

cfs

1 4/29/2012 0.71 10.9 0.36 0.0639 15.412 1.378684

2 5/30/2012 0.53 38.81667 0.36 0.013731 8.433 0.706653

3 7/18/2012 0.82 11.91667 0.92 0.063687 32.945 3.081982

4 7/24/2012 0.75 8.116667 0.92 0.093755 7.472 0.726338

5 7/25/2012 0.49 6.766667 0.72 0.073995 4.864 0.943187

6 8/9/2012 0.44 6.9 0.68 0.065835 9.67 1.459689

7 8/16/2012 0.51 6.616667 0.64 0.079687 7.821 1.513229

8 8/25/2012 0.52 34.7 0.28 0.01508 7.821 0.665683

9 10/13/2012 1.74* 31.21667 NA NA 3.071 0.296152

10 10/17/2012 0.67* 14.95 NA NA 1.681 0.173354

11 10/18/2012 0.78* 145.4333 NA NA 0.894 0.014115

Table 4 Private Producer Storm Characteristics

Results – Private Producer

Figure 5. Normalized Nutrients vs. Normalized Flow for Select Private Producer Storms

0.51’

0.52’

0.53’

0.49’

Results – Private Producer Lag time in sample collection may have missed peak

concentrations

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 and all corn silage had been used)

Some summer runoff events displayed a moderate delayed storm curve

Following filling in the fall, data demonstrated a moderate first flush

Conclusions Strongest first flush evidence took place in the fall

while strongest delayed storm curves were documented in the summer

Highest average storm nutrient concentrations were in the fall following filling and sometimes in the spring

Lowest average storm nutrient concentrations were in the summer

Highest concentrations among all sites was for DFRC’s initial samples in the fall (due to collection methods)

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

References Burks, B.D. and M.M. Minnis (1994).  "Onsite

Wastewater Treatment Systems. " Madison, WI: Hogarth House, Ltd.

McDonald, P., et al. (1991). The Biochemistry of Silage, Scholium International: 340.

Taebi, A. and R. Droste (2004). "First flush pollution load of urban stormwater runoff." Journal of Environmental Engineering and Science 3(4): 301-309.

Questions?