A system to reduce dairy shed water consumption by 75 per cent, use worms to break down effluent solids and vegetables to treat the liquid was on display at Fieldays.

Coll Bell of Simple Water Solutions, based at Matakana in Northland, is the inventor of Clean Cow which he says is an efficient, natural effluent disposal system for dairy cows.

Coll Bell of Simple Water Solutions with a tomato grown hydroponically as part of the Clean Cow dairy effluent treatment system.

Using tunnel houses to grow plants hydroponically can also provide year-round food.

“We’ve had good success with a range of plants including rhubarb which my grandkids call ‘poobarb’ because of how it’s grown.”

The system is the latest in a series of innovations from Coll, who also came up with the “Short Drop” worm composting toilet system, which is ideal for remote areas or water shortage situations as this does not require flushing.

The company also produces the Solid Waste Digester, a verma-composting bin built from roto-mould plastic. All the solids from the toilet and kitchen sink are trapped on a bark filter where the worms turn it to compost.

There is no smell and the liquid is drained into a series of plant filters for treatment.

The Clean Cow natural effluent disposal system includes a solid waste digester and hydroponic tunnel houses.