Milking Center Wastewater: Planning, Design, Construction, Documentation Peter Wright PE Agricultural Engineer PRO-DAIRY LCBP, NEIWPCC, and EPA are funding partners 1
Vermont RAP Section 6. Required Agricultural Practices; Conditions, Restrictions, and Operating Standards 6.01 Discharges a) Farms shall not create any discharge of agricultural wastes to surface waters of the State through a discrete conveyance such as, but not limited to, a pipe, ditch, or conduit without a permit from the Secretary of ANR. b) Production areas, barnyards, animal holding or feedlot areas, manure storage areas, and feed storage areas shall utilize runoff and leachate collection systems, diversion, or other management strategies in order to prevent the discharge of agricultural wastes to surface water or groundwater.
NRCS Standards efotg http://efotg.nrcs.usda.gov/ Standards Statements of Work Guidelines Specifications O&M
NRCS Standards Filter Strip Standard (VT 393) Heavy Use Area Protection Standard (VT 561) Roofs and Covers (NAT 367) Roof Runoff Structure (VT 558) Waste Treatment (VT 629) Ag Waste Management Supplement Milking Wastewater Infiltration System https://www.nrcs.usda.gov/internet/fse_documents/nrcs142p2_010237.pdf
NRCS O&M OPERATION AND MAINTENANCE PLAN FOR WASTE TREATMENT - MILKHOUSE WASTEWATER INFILTRATION AREA OPERATION AND MAINTENANCE PLAN FOR HEAVY USE AREA PROTECTION
Vermont Farm*A*Syst Worksheet #10 Assessing the Risk of Groundwater Contamination from Milkhouse Wastewater Treatment Worksheet #8 Assessing the Risk of Groundwater Contamination from Barn Yard Management
Concentrated Sources Waste Wash water Barnyard runoff Silage Leachate
Estimated BOD LB/yr 50000 45000 40000 35000 30000 25000 20000 15000 10000 5000 0 Milking Center Waste Silage Leachate Barnyard Runoff Domestic Waste
Estimated N LB/yr 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Milking Center Waste Sila ge Leachate Barnyard Runoff Domestic Waste
Estimated P LB/yr 500 450 400 350 300 250 200 150 100 50 0 Milking Center Waste Silage Leachate Barnyard Runoff Domestic Waste
Concentrated Sources Amounts and concentrations vary daily seasonally from farm to farm They can be Managed When Rain Driven the impact is less diluted not observed
Concentrations N P Milking Center 400 ppm 60 ppm Silage Leachate 4,400 500 Barnyard 1,000 200 Manure 5,600 900 Domestic Waste 30 7
Annual Load from Concentrated Sources N P Milking Center 3,000 lb 30 lb Silage Leachate 3,900 440 Barnyard 700 150 Manure 31,600 5,000 Domestic Waste 70 22
Concentrated Sources Pollution is Perception Total load from manure spreading But: Concentrated sources = point sources Concentrated Sources will be closely examined
Resource concern? Volume Concentration Distance Flow path Destination
Conclusions Concentrated sources need to be controlled Prevention is key Look for low cost alternatives to treatment
Prevention Eliminate Reduce Reuse
Wash Water Reduction Eliminate Leaks and Spills Manually rinse or scrape first Reuse gray water Design system for easy cleaning
Quantities Range 1-40 gal/cow/day Typical 2-5 gal/cow/day
Reduce at the Source Feed Milk First flush Colostrum, treated milk Scrape Manure Parlor and holding area floors Correct Soap Amounts No Precooler Water
Phosphorus Reduction
Reuse Wash parlor and holding area floors Water savings Wash cycle water recycled Water savings Soap savings Heat savings
Treatment Aerobic with oxygen Low odors Fast rate By products - Carbon dioxide and water
Treatment Anaerobic without oxygen Odors produced Slow rate By products - plug soil pores
Liquid Manure System Advantages Easy Low pollution potential Helps manure flow Disadvantages More to haul Larger storage needed
Small Holding Tank Figure 5 page 21 DPC 15 / NRAES 115
Liquid Manure System 1,000 gal. of milkhouse wastes may contain: 1.67 lbs. Nitrogen 0.83 lbs. Phosphorus 2.50 lbs. Potassium 5.00 lbs. of nutrients @ $0.25/lb. = $1.25 Spreading costs: 1,000 gallons @ $0.005 per gal. = $5.00
Grass Filter Advantages Lower cost Efficient treatment Small space Disadvantages Needs O&M Extreme cold weather problems
Milking Center Waste Estimated Nitrogen Fate Immobilized Soil OM Denitrified Crop Uptake Leaching Total 68 Lbs. 98 Lbs. 104 Lbs. 55 Lbs. 325 Lbs.N/Acre 1.3 Lbs N/cow /year 250 Cows
Milking Center Waste Estimated Nitrogen Fate Immobilized Soil OM 21% Denitrified 30% Crop Uptake 32% Leaching 17% Total 100%
Milk House Waste Discharges P Concentration from Pipe Avg. - 17 mg/l, Range from 2 to 43 mg/l
Overall average and range of dissolved P from discharge pipe 40 Dissolved phosphorus, mg/l 35 30 25 20 15 10 5 Modeling the results y = 32.107e -0.0182x R 2 = 0.7907 y = -0.2471x + 29.101 R 2 = 0.6798 Avg Min Max Stan Dev Linear (Avg) Expon. (Avg) Linear (Max) Expon. (Max) y = 6.3885e -0.0187x R 2 = 0.7566 y = -0.067x + 6.765 R 2 = 0.6288 0 0 20 40 60 80 100 120 Distance from loading source, feet
Settling Tank and Pump
Dosing siphon
Aerobic Lagoon Advantages Storage included Disadvantages Site limitations size, soils Initial cost high Effluent needs further treatment
ORGANIC FILTER BED Advantages Low odors Works in cold weather Disadvantages Potential high cost Potential ground water concerns
Constructed Wetland Advantages Politically correct Disadvantages High cost Effluent needs further treatment Hard to establish
Stone Filled Trench Advantages Works until cold weather Underground Disadvantages High cost Milk must be removed Potential for ground water pollution
Lime Flocculated Treatment Advantages Potential low cost Low pollution potential Disadvantages Milk must be removed Process in inside New
Wash Water Treatment Plan ahead for expansion Maintenance is important
Milking Wastewater Infiltration System (Chapter 10 Vermont Supplement Part 651.1004(k) Agricultural Waste Management Field Handbook) Components <350 gallons /day Air Trap Air Vent Pipe Settling Tank 6X daily flow Grease Trap Effluent Filter Pump Distribution Box Disposal Field
Disposal field Design Location Soils investigation Design Class Hydraulic Loading Soil Modification Actual Flow Flow Multiplier Bed Area
Disposal Field Depth to Bedrock Depth to Hydraulic Restriction Design Class Hydraulic Loading
Design Class 1 System is allowed 4 System not allowed 15 to Bedrock 7 to water table or restriction Poor soils
Design Class 2 Modify Soil Separation distance 24 to Bedrock 12 to water table or restriction And/or Curtain Drain 12 to water table
Design Class 3 Modify Soil Separation distance 24 to Bedrock, water table or restriction And at least 6 of proper fill over sands and gravels
Proper Fill Coarse sand to gravelly course sand 15 30 % gravel 4 8 % fines < 2% clay
Actual flow Water meter for two weeks Calculate Range 2.4 8 gallons/day/lactating cow
Flow Multiplier = [ (total suspended solids mg/l + BOD5 mg/l) / 240 ] 1/3 Milkhouse and Parlor (>350 gallons/day) Typical TSS = 6000 mg/l Typical BOD 5 = 1000 mg/l Typical Flow Multiplier = 3.0 Conservative flow Multiplier = 3.0
Milking Wastewater Infiltration System O&M Minimize manure, milk and grit Pump out tanks Clean Effluent Filter Inspect for build up at least 2X/Year Safety: Confined Space Grates and guards
Conclusions: Concentrated Sources Need to be Controlled Prevention is Key Look for Low Cost Alternatives to Treatment