Effluent is a slurry of water, manure, urine, milk and other waste collected in the wash down liquid. It is a particularly strong form of organic waste that is characterised by its high oxygen demand, high volatile solid content and high phosphorus, nitrogen and potassium levels.
Managing effluent is a major concern on many New Zealand dairy farms due to increased herd size, intensification and environmental scrutiny and regulation.
Dairy farmers do have an obligation to contain, manage and dispose of livestock effluent within their property’s boundaries in a manner that prevents pollution of surface and ground water.
On many New Zealand dairy farms, a single pond is used to capture wash down liquid. Following “settling out” over several weeks or months, liquid effluent is then discharged into a area or into an irrigation pond and spread over pastures as part of their usual effluent disposal program. Although the volume and composition of effluent produced varies greatly according to the individual property and season, many single-pond systems are now incapable of handling the increased volumes of effluent generated.
A correctly functioning effluent pond should contain high levels of oxygen and therefore aerobic bacteria that digest organic material:
Reducing organic matter and nutrient levels
Removing suspended solids and salts
Creating an acceptable ph
This process is assisted via a complex interaction of sedimentation, precipitation and mineralisation.
What are the signs of a non-functioning effluent pond?
Non-performing effluent systems are instantly recognised by the presence of surface crusting and their unpleasant odour. A common symptom is the formation of a crust, whereby undigested solids form a crust up to 50 cm thick on the surface of the pond. Besides harbouring vermin, insect pests and weeds, this crust creates an anaerobic environment underneath. The depletion of oxygen in the water, combined with lack of sunlight, reduces microbial digestion. Nutrients may remain at toxic levels or settle within the sludge, where they become “locked up” in forms that are unavailable to plants. The proliferation of anaerobic bacteria can lead to an increase in hydrogen sulphide (i.e. rotten egg gas) and increased pH (i.e. alkalinity). High temperatures can also stimulate anaerobic bacteria at the bottom of the pond.
Biobugs is a fermented microbial culture that helps to create and maintain a balanced microbial environment in effluent ponds, thereby stimulating microbial digestion of organic matter. Following an initial application to the pond, it is added in small amounts to the wash down solution each day.
Stimulates aerobic microbial activity in effluent ponds
Digests suspended solids into plant-available liquid nutrients
Reduces turbidity and increases the liquids to solids ratio
Reduces surface crusting, solid waste and the need for desludging
Reduces unpleasant odours
Biobugs is good for all types of effluent management systems, particularly:
Non-functioning effluent ponds
Older systems that have become overloaded by increased herd size
Large herds or those with high effluent loads
Or where effluent ponds are close to dwellings, neighbours or towns.
Can be used in direct application and multi-pond systems.
Depending on the thickness of the surface crust, a number of physical and chemical changes can be observed in ponds within four to six weeks of treatment with Biobugs. These effects to depend on the individual characteristics of the pond, but include:
Increased aerobic microbial activity
Dissolving of the surface crust
Increased liquids-to-solids ratio in pond due to digestion of dissolved and suspended solids
Bubbling due to increased microbial activity
Clumps of solids released from the pond bottom
A pleasant environment for workers, family and neighbours
Biobugs helps to convert solids into “biologically-active” liquid nutrients that can be beneficial for plants and soil microbes. Farmers can strategically utilise treated effluent as part of their pasture plan to optimise plant growth, animal health and herd performance.
The cost of a year-round or seasonal program using Biobugs depends upon the herd size. However, as a guide, the cost of a program typically ranges from approximately 2.5 cents up to 4 cents per head per day.
BioBugs New Zealand
26 Gordon Terrace