Handling Sand-laden Manure Wesley C. Wright, P.E. October 22, 2015
Free Stall Bedding Cows rest 10 or more hours per day Proper bedding should: Provide comfort Conform to cow s body Resist compaction and provide traction Maintain a low moisture content Inhibit bacterial growth
Bacteria in Bedding Inhibiting bacterial growth is crucial to cow cleanliness, udder health, and ultimately milk quality Major pathogens causing mastitis: Strep. Uberis Strep. Dysgalactiae Coag. Neg. Staphs. Coliforms Staph. aureus Strep. ag Mycoplasma Environmental Contagious
Bedding Bacteria Levels Minimal Risk Less than 300,000 cfu/g Moderate Risk 300,000 to 1,000,000 cfu/g High Risk Greater than 1,000,000 cfu/g
Organic Bedding Dried Manure solids Paper Straw Peanut Hulls Sawdust Shavings Crop Residue
Inorganic Bedding Gypsum Limestone Screenings Sand
Pros/Cons of Organic Bedding Pros: Readily available Low cost Absorbs moisture Cons: Supports growth of environmental mastitis pathogens Research has found <24 hours >1,000,000 cfu/g (high risk)
Pros/Cons of Inorganic Bedding Pros: Increases traction Inert Drains moisture Cons: Gypsum- could elevate H 2 S levels in manure slurry Limestone- prone to packing Sand- abrasive to equipment
Sand makes Good Bedding It s comfortable Provides excellent traction Limits bacterial growth Does not cause hock abrasions Can be recycled Easy to maintain in the Free Stall Barn
Free Stall Barn Flush System
Free Stall Barn Flush System Targets Flush Velocity - >5 feet/second Flush Depth - 3-4 inches Contact time - 10-12 seconds Controlled by Flush rate - gallons/minute Flush Time seconds Slope of alleys Length and width of the alleys
Alley Length (ft) Alley Slope %
Alley Length (ft) Alley Slope %
Alley Length (ft) Alley Slope %
Alley Length (ft) Alley Slope %
Alley Length (ft) Alley Slope %
Alley Length (ft) Alley Slope %
Why recycle sand from sand-laden manure?
Why recycle sand? Scenario 300 Cows / Free stalls 30 lbs./day sand per free stall 3,300,000 lbs./year sand 1650 tons 70 tandem truck loads $600 per load for certified mason s sand $42,000 per year Over 10 years $420,000 1 inch of sand over 7 acres Fill a >2,000,000 gallon lagoon
Recycling Sand Separation Lane
Sand Separation Lane Separation based on Density Water and manure - ~60 lbs. / cubic foot Sand - ~120 lbs. / cubic foot Dilution and Suspension High Velocity Flush Reduce the Velocity IF done correctly, sand settles and manure moves on in the flush.
Sand Separation Lane Recommended Targets: At least 150 feet in length Slope 0.20-0.25% Recommended Width 10-12 feet Flush velocity at the end of the lane 1-2 feet/second Uniform grade sand - ~0.5 mm
Case Study Little River Dairy
Problems Free Stall Barn flush not getting the alleys clean Deposition in the Gravity Trench causing overflow No separation in the Sand Lane
Solution Free Stall Barn Flush
Solution Gravity Trench
Solution Sand Separation Lane
Sand Separation Lane Target Slope 0.20-0.25%
Target Sand Separation Lane
Sand Separation Lane Target Recommended Width 10-12 feet
Target Sand Separation Lane
Sand Separation Lane Target Velocity at the end of the lane 1-2 feet/second
Target Sand Separation Lane
Sand Separation Lane Target Uniform grade of sand ~0.5 mm
Target Sand Separation Lane
Adjusting the Sand Lane Iteration 1 April 2014
Adjusting the Sand Lane Iteration 2 June 2014
Long sweep 90 ⁰ 30 inch wide Flare throat with 3 energy disrupter blocks
1.0 0.9 0.8 ASTM Range for Coarse Sand New Recycled Sand Old Sand New Sand 0.7 % Passing 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.01 0.1 1 10 Sand Grain Size (mm)
14 12 10 % Organic Matter 8 6 4 2 0 4/9/2014 4/11/2014 4/14/2014 4/16/2014 6/13/2014 6/23/2014 6/25/2014 7/2/2014 7/9/2014 7/16/2014 7/28/2014
Recycled Sand Quality October 7, 2015 Sample 0.51% organic matter Milk - Somatic Cell Counts Indicator of cows immune response to pathogenic bacteria Monthly average over the last year 133,000 Normal - 100,000 US limit - 750,000
Remember Free Stall Barn Flush Slope - 3% Velocity - >5 feet/second Depth - 3-4 inches Contact time - 10-12 seconds Sand Separation Lane Velocity at end of lane - 1-2 feet/second Uniform grade sand - ~0.5 mm (Certified Mason s Sand)
Questions?