Silage Leachate: Waste Quality Assessment and Treatment

Background/Need
Silage storage is required for many livestock and poultry facilities to maintain their animals throughout the year. While feed storage is an asset which allows for year round animal production systems, they can pose negative environmental impacts due to silage leachate and runoff. Silage leachate and runoff have high levels of oxygen demand and nutrients (up to twice the strength of animal manure), as well as a low pH posing issues to surface waters when discharged. Although some research exists which shows the potency of silage leachate and runoff, little information is available to guide the design of collection, handling, and treatment facilities to minimize the impact to water quality. Detailed information to characterize the strength of the runoff through a storm is needed to develop collection systems which segregate runoff to the appropriate handling and treatment system based on the strength of the waste. In addition, more information is needed to assess filter strip performance where the waste is discharged for treatment to ensure there is no negative impact to surface and groundwater quality.
Objectives
This research aims to collect the necessary water quality data from silage storage runoff to make recommendations to reduce risk. Specific objectives include:

1. Assess the water quality from bunker silage storage systems
2. Determine the impact of system design and other management and environmental conditions on the runoff water quality (including seasonal variation)
3. Determine if first flush conditions exist for silage storage runoff (to potentially separate high and low strength waste for ease of management/treatment)
4. Make recommendations for silage storage collection systems to minimize volume collected and maximize pollutant load collection
5. Evaluate surface and subsurface water quality of a filter strip and modified filter strip which receives silage storage runoff