Emergency disposal of milk
Over time there are likely to be occasions when milk will have to be discarded due to a number of situations, such as:
- refrigeration failure
- problem with milk collection from the factory
- contamination of the milk making it unsuitable for processing.
There are options for the disposal of milk on the farm without causing pollution, smell or damage to pasture.
While the principles that need to be observed are common to all farms, each farm will have different constraints and opportunities that will influence the final decision as to the best option.
Factors to be considered
The following factors need to be considered when deciding what the best option will be at the time:
- the equipment available on the farm for applying the milk to pastures or available for digging trenches
- proximity of neighbouring houses and the farm house to the disposal site
- topography of the farm
- weather conditions at the time
- volume of milk involved
- possibility of selling the milk to neighbours with stock that could use the milk
- likely number of days milk will have to be disposed.
Milk disposal methods
Feeding to livestock
Whole milk may be fed to animals where there are suitable storage facilities.
Discharging into effluent ponds
This is not a recommended option.
Effluent ponds that accept milk will produce odour and a reduction in treatment efficiency. Ponds that have had large amounts of milk added will take many months to recover and severe odour problems will occur for many months to follow.
If using spray irrigation:
- tractor mounted sprayers, or dairy effluent irrigation systems can be used to spray milk onto pasture
- milk should be diluted to a ratio of 1 part milk to 10 parts water
- if sufficient water is not available, then the milk should be sprayed onto the pasture, followed by whatever water is available or shed washings, to rinse milk residues off the leaves
- sprinklers should be kept well clear of watercourses and should be moved after each irrigation.
Dedicated pond or trench
A trench or pond, capable of holding 2 days milk, can be constructed using a front-end loader then:
- siting of these ponds should be well away from any houses and the farm dairy as odour may occur
- the pond should be backfilled immediately after the last discharge to reduce odour.
- subsequent ponds or trenches should be dug if more than 2 days milk is to be disposed
- trenches should only be used in areas where suitable soils exist — otherwise the trench may allow the waste milk to leach into the groundwater or a stream system.
Milk can be dumped onto a piece of non-productive land clear of watercourses, houses and the farm dairy.
Pasture damage and odour can be expected and to minimise this — each dumping should be carried out on a different site — followed by flushing with water to wash the milk off the leaves.
The application of the milk to an area that is to be cultivated will be advantageous.
Milk is approximately a 100 times more powerful a pollutant than dairy-shed effluent.
Discharging milk into watercourses has 2 major effects:
- all aquatic life is killed
- agricultural and domestic users downstream cannot use the water due to contamination by the milk and by the dead fish and vegetation.
The damage to streams is long term and therefore under no circumstances should watercourses be subjected to discharges of milk.
Under the Environment Protection Act 1970, milk must not be discharged into watercourses. Offenders may be prosecuted.