Effluent breakthrough cuts water use

A breakthrough in effluent technology that allows dairy farmers to treat dairy shed ‘‘green water’’ so it can be confidently reused as yard wash, could lift the dairy sector’s effluent and water efficiency.

The emerging technology, known as Cleartech, was developed in a joint project between fertiliser co-operative Ravensdown and Lincoln University and looks to cut freshwater use, help existing effluent storage go further, and reduce the environmental and safety risk linked with farm dairy effluent.

The pilot project, which is installed at the Lincoln University Demonstration Farm, represents a $1.5 million investment so far by Ravensdown.

Cleartech will be available commercially later this year, once testing is complete, in a managed rollout.

Ravensdown effluent technology manager Jamie Thompson said about a quarter of a dairy shed’s fresh water use is used during yard washing, so the potential benefits were enormous of safely reusing treated water. ‘‘Cleartech will look to save 42 billion litres of freshwater a year – the equivalent of 17,000 Olympic-sized swimming pools through the reuse of safer water for dairy yard washing.’’

The technology, which binds effluent particles together in order to settle them out from the water, is installed between the dairy shed and the effluent pond. Effluent circulating in the system is automatically monitored and treated. The separation process kills up to 99 per cent of microorganisms such as E. coli and reduces smell.

Farm dairy effluent is typically 99 per cent water and one per cent effluent particles.

Cleartech links to computer processors, controllers, tanks, pumps and pipes and can be retrofitted.