Good Management Practices for Effluent and Wastewater

How you can do this:

Farm Dairy Effluent (FDE) design

• Ensure effluent is collected and contained from all sources: farm dairy, yards, barns, feed and stand-off pads, underpasses, and feed storage areas.
• For new systems: use an Accredited Effluent Designer. Choosing an accredited provider gives you confidence that their work will meet good practice expectations.
• All new effluent systems should be designed to Farm Dairy Effluent (FDE) Design Standards and Code of Practice. 
• Ensure the storage facility meets the requirements of the Building Act.
• Make sure the system design is appropriate for the soil type, topography, and climate.
• Ensure storage facilities are sealed - see  DairyNZ - Effluent Pond Seepage Testing Code of Practice, which replaces Section 8.6 of the IPENZ Practice Note 21.

System Assessment  

• Conduct effluent system checks at least annually, including testing for application depth and rate.
• Perform Pond Seepage Assessments (for guidance, see:   effluent-pond-seepage-testing-code-of-practice.pdf).
  • Visual Inspections - pond wall/pipework integrity, wet/bogy areas around the pond, evidence of over-topping. 
  • Pond Level Monitoring - observation of changes in Pond surface levels. 
  • Leak Detection Testing - observation for a leak detection system installed under the pond liner.  
  • Pond Drop Test - performed by specialist PDT test suppliers. 
• Perform maintenance as needed to ensure there is no decline in system performance. 

You can show that you meet this GMP with:

• Effluent system design plans.
• Effluent bladder or tank/pond liners: specifications and warranties.
• Confirmation that the designer is certified and/or the effluent design company is accredited.
• Engineer’s Final Completion Certificate:

• Regular Effluent WOF assessment reports and actioning any fixes that are then captured by time-stamped photographs. You can learn more about  WoF  assessments  here

How you can do this:

New Systems or Significant Modifications:

• All new effluent systems should be designed to FDE Design Standards and Code of Practice using an accredited effluent designer.
• If you’re building a new effluent pond or making big changes to an existing one, ensure it is consistent with IPENZ Practice Note 21 "Farm dairy effluent ponds".                                  ➡️ NOTE: This is a Leading Practice for DairyNZ

All Systems:

• The volume of the FDE storage system is appropriately sized and meets the 90th percentile as calculated by the Dairy Effluent Storage Calculator (DESC).
• The storage facility meets the requirements of the Building Act.
• Actively manage storage to ensure capacity is available when required.
• Routinely remove effluent solids that accumulate to maintain storage capacity.
• Have safety barriers, equipment, and signage.
   

You can show you meet this GMP with:

• Dairy Effluent Storage Calculator report.
• As-built storage design plans.
• Effluent bladder or tank/pond liners: specifications and warranties.
• Geomembrane, clay, or concrete-lined ponds:  Dairy NZ - Effluent Pond Seepage testing - Code of Practice (drop-test)  
• A signed Final Completion Certificate from a qualified engineer confirming the pond matches design plans, is fully functional, and meets all the above criteria (See GMP 16).
• A cleaning/maintenance plan with servicing records and invoices.

How you can do this:

• Calibrate spreading equipment according to its design specifications specific to the product (liquids or solids) being spread.
• Routinely inspect and maintain effluent and pumping equipment.
• Evaluate your effluent system annually to demonstrate optimal performance, e.g. through an application efficiency test (i.e., the 'Bucket Test').

You can show you meet this GMP with:

• Maintenance schedules and records.
• Servicing invoices.
• Effluent calibration results – the Bucket Test.

How you can do this:

Have an effluent management plan that includes: 

• Identifying risk areas for effluent application and show these on your farm map along with any waterways, buffer and exclusion zones, high and low-risk soils, and system layout (hydrants and run-lines).
• System operating procedures and maintenance checks.
• Emergency procedures and contacts.
• Application log – recording all applications including effluent form liquids and solids date, location, soil conditions, weather, application amount, depth and rate. 
• Staff training register -  system operation and maintenance. 

System Operation:   

• Store effluent and defer irrigation until application matches plant uptake to mitigate potential loss of nutrients.
• Adjust effluent application timing and rates based on soil moisture levels. Do not apply effluent when soils are at or above field capacity or when rainfall that would saturate the soil is forecast.
• Spread the nutrient load evenly across the largest practical area.
• Ensure the average application rate does not exceed soil infiltration rates (i.e. avoid ponding on the soil surface). 
• When calculating fertiliser requirements for the effluent disposal area, consider nutrients supplied by effluent or manure.
  • Test effluent to understand nutrient concentrations and loading when applying to land 
  • Soil test your effluent paddocks biennially and adjust fertiliser applications accordingly.  
  • Download this handy tool:  DairyNZ's Farm Dairy Effluent (FDE) Spreading Calculator to take the guesswork out of determining your effluent nutrient loadings.

• Consider odour impact during application.
• Implement failsafe mechanisms, including:
  • Low-pressure pump cut-of,
  • Irrigator movement pump cut-off, and
  • Pond level sensor.
     

You can show you meet this GMP with:

• Soil test results.
• Lab reports of effluent test (N,P,K,S)
• Results from  DairyNZ's Farm Dairy Effluent (FDE) Spreading Calculator based on your effluent lab test results (N, P, K, S). 
• Nutrient budget ( OverseerFM® – effluent report), ensuring the effluent block is modelled as its own unique management block.
• Effluent application area risk map.
• Rainfall/soil moisture records for effluent application decision-making.
• An effluent log/record  DairyNZ's  Effluent Irrigator Run Sheet is a useful template you could use. 
• Staff training records.
• Operations Manual.
• Council compliance records.