‘Current NZ Dairy Effluent Management’ Theresa Wilson Development Team Leader Sustainability 22 nd April 2015
• ~270 staff • Levy organisation and vote by farmers every 5 years (May 2014 was voting!) • Receives 3.6 c per kg milk solids from farmers (~$60M) • 100% farmer focused
Sustainable Dairying: Water Accord • All dairy companies and DairyNZ • Has broad industry support • Applies to all farmers • Pan-industry commitments • National standards for our industry • Time and support for meeting commitments
Effluent Resources
Effluent Technical Notes
New Zealand Dairy Industry
Sheep and cattle numbers Cattle & Sheep Numbers 1990-91 to 2012-13 75,000 6,000 65,000 Dairy +82% 5,000 Sheep (000) Cattle (000) 55,000 4,000 Beef -14% 45,000 3,000 Sheep -44% 35,000 25,000 2,000 1990-91 1992-93 1994-95 1996-97 1998-99 2000-01 2002-03 2004-05 2006-07 2008-09 2010-11 2012-13f Source: Beef + Lamb New Zealand Economic Service Statistics New Zealand
Regional Milk Production, % of total + 32 % 2003-04 2012-13 1.25 m tons milk solids 1.66 m tons milk solids 5 7 North Island North Island 71% 58 % 33 27 8 7 13 10 10 9 South Island South Island 29% 42 % 4 4 12 20 13 18 Source: DairyNZ Economics Group, Dairy Statistics
System Changes System 1 All grass self contained, all stock on the dairy platform System 3 Feed imported to extend lactation (typically autumn feed) and for dry cows System 5 Imported feed used all year round, throughout lactation and for dry cows Source: DairyNZ Economics Group
Stand-off pads Covered housing Free stall barns Slatted floor
Environmental Footprint
Sustainable Milk Plan • Good practice plan / continual improvement • Sets out the farmer’s own time bound action plan to improve performance • Tailored to individual farms • Avoids duplication & adds value to other activities • 5 target areas: Nutrients Effluent Waterways Land Water use
Where are the hot spots and risks?
Improved Dairy Farm Effluent Systems in New Zealand
Dairy Industry Aims • Keep all untreated effluent out of surface and groundwater. • Keep land applied effluent nutrients in the root zone to capture the nutrient and economic value. • Ensure all systems are compliant 365 days
Key Aspects of Land Application Systems • Require capital investment in variety of infrastructure • Requires farm labour to move/maintain irrigation system • Skilled design needed for cost effective solution • Environmental risk if not managed well Advice based on science knowledge and research trials • Land application systems can be designed for all dairy regions (with an agreed system variation for very high rainfall areas eg West Coast) • Return on investment in fertiliser savings ~ 5-12 years • Pity to waste nutrients which grow great grass
Land Application Systems- Travelling Irrigator
Land Application Systems- Low rate
Land Application Systems- Pivot (direct or underslung)
Land Application Systems- Slurry Tanker
Pond Treatment Systems • Still prevalent in Taranaki,1,700 farms with ~1,000 direct discharge however changes coming • Northland with ~300 farms direct discharge and another ~600 with consent to discharge • Phasing out in Waikato (only being granted 2 year consents)
How much are we actually dealing with? Table 3 . Total methane emissions from dung in the field over measurement periods of c. 10 days Methane emitted (mg CH 4 m- 2 ) Animal Type Diet Dairy cow Grass-clover (grazed) 1702 Silage and concentrate (housed) 716 Dairy cow Dairy cow Fertiliser grass and concentrate 2040 Table 9. Characteristics of fresh dairy-farm effluent Quantity cow -1 day -1 “Effluent from the dairy shed is Annually cow -1 Characteristic Typical Range highly variable in nature, being a Total volume produced (litres) 50 30-70 13,500 combination of manure and urine, Total solids (kg DM) 0.55 0.3-0.6 148.5 spilled milk, soil and feed residues, detergents and other chemicals and BODs (kg) 0.12 0.04-0.13 32.4 wash down water, varying form day 8.5 8.0-8.5 - pH to day and within individual farming practice” Total N (g) 22 7-30 5940 Total P (g) 2.5 0.5 to 0.45 675 From Saggar et al NZ J Agri Res 2004 Vol 47, 513-544 “A review of emissions of methane, ammonia and nitrous oxide from animal excreta deposition and farm effluent application in grazed pastures”
‘Effluent Balance’ 330 cow herd and wash down effluent (270 days) = Assume roof 6,888 m 3 per year At 5 l/sec or 18 m 3 per hour diverted but no need to be pumping 512 storm water. hours per year All concrete catchment area (600 m 2 ), with 1,100 mm rainfall = 660 m 3 of liquid Feedpad (1155 m 2 , 3.5 m 2 /cow), volume produced= Total volume into pond = 1,591 m 3 10,239 m 3 per year Evaporation at average of 2.8 m 3 /day = 1,022 m 3 per Pond is 25 m by 40 m and year 3 m deep so 3,000 m 3 , with 1,100 mm rainfall receives So 9,217 m 3 to be 1,100m 3 pumped
NZ Dairy Effluent Trends • Stand-off, feedpads, housing on the increase • Increasing moving to single storage ponds (although barn systems often need separate effluent storage/management) • More pond stirrers being used; helps reduce odour & sludge buildup, more consistent effluent applied on land • More solids separation (weeping walls, screw press, slope screens etc) which useful for large herds and high risk soils for ease of irrigation of liquids • Solids usually managed by application to cropping paddocks but can be sprayed thinly to pasture
DairyNZ Storage Recommendations • Dairy effluent irrigated fresh is best • Use storage pond/tank when soil conditions are unsuitable for irrigation • Storage volumes differs widely due to: • Regional variation eg 12-15 days in Canterbury to up to 100 days in Northland • Within region by soil risk profile • Within region by irrigation method • Biggest source of non- compliance is ‘ponding’ due to poor irrigation decisions, often because insufficient storage and forced to irrigate • This time of the year all farms should be going into winter with empty storage ponds!!
Energy Capture Role in NZ • DairyNZ trying to understand value proposition for energy capture • Many excellent reports from US, UK, Australia that outline the risks • One such report from Australia has a self-assessment and scoring system that is of value • To be built other than project being a neat idea? • Point person/organisation in charge? • Is there long term storage available? • Is there acreage to receive effluent nutrients? • Will the industry be alive in 10 years? • Food waste proximity to the site? • Is the biogas usable • Etc From “Assessment of methane capture and use from the intensive livestock industry”, a report by GHD Ltd for Australian Government (June 2008)
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