Manure to compost – fast

23 March 2001

Manure to compost – fast

Need a composting machine

to produce higher value

manure and waste for use on

organic farms? Andy Moore

reports on the Austrian-built

Morawetz machine

WITH its ability to convert farm manure into a richer and more fertile material, the Morawetz TS IV has proved to be an indispensable machine at Sheepdrove Farm in Berks.

The organic livestock/arable unit at Lambourne invested in the machine last summer after its waste spreading workload rose from 9000t to 14,500t a year.

"We bought the Morawetz to replace a three-year-old American machine which used to take twice as long to aerate compost windrows," says Charles Maclean who manages the 895ha (2210 acre) farm. "The old machine burnt fuel like it was going out of fashion and was mechanically unreliable."

Mr Maclean has been using the Morawetz to compost green waste produced by local supermarkets as part of a trial scheme set to continue until June.

In addition to green waste, the farm also composts manure produced from its beef, sheep, pig and poultry units together with waste from a local racing stable and coffee factory.

Waste is formed into 2m wide windrows created by two 12t ECE rear discharge spreaders and left for a week to biodegrade before being aerated with the Morawetz.

Operated in an offset position, the Morawetz TS IV is mounted on a 140hp Case MX135 tractor. Power is supplied from the pto which is transmitted through a 90í reduction box to drive the machines 4m wide Optimix mixing rotor. This is housed inside a hood with rear deflectors to form the windrow.

In operation, the Morawetz travels over the 2.20m high windrows, with the Optimix rotor turning at 350rpm to create a mixing, churning action.

"The rotor has hardened tines arranged in spiral formation which effectively shred and mix material," says Mr Maclean. "There are more tines fitted in the centre of the rotor, allowing waste to be moved thoroughly from the inside to outside of the windrow."

Complete mixing and aeration of windrows is ensured by operating the Morawetz at a snails pace.

Speeds of 50m to 500m/hour are achieved by the machine having its own self-drive system rather than being towed by the tractor.

The Morawetz is driven by a dual and single wheel powered by hydraulic motors which are supplied with oil flow from the tractor.

Propelling the 4.5t machine through a windrow requires a hydraulic flow of 50-80 litres/min at 180bar pressure, says its manufacturer.

In sticky conditions, Mr Maclean uses his tractors creep gears to provide extra traction and the required slow forward speeds.

Running at 1600rpm, he says his tractor has no thirst for fuel – the only cost being the tines which are replaced every 100-350 hours, depending on material type.

"After a single pass, the tined rotor does a good job at aerating and mixing the windrow, causing it to almost double in height," he says. "This helps to keep the windrow temperature at 55-70C so that aerobic bacterial activity can be maintained. Subsequent passes are then carried out every 10-14 days."

During the first pass, the rotor can be lowered hydraulically to just a few inches above the ground to disturb underlying material and the raised to 30cm (1ft) for the second pass.

High value compost, says Mr Maclean, is produced typically over 12 weeks and average value compost produced within six weeks.

"Leaving the windrow for longer periods allows organic matter to fully degrade, producing higher value compost. "Aerobic activity also reduces the volume of the waste by 50%, while killing off pathogens and weed seeds."

The Morawetz TS IV is distributed by Richard Newton, based at Barnsley, South Yorks, and priced from £40,000. &#42

The Morawetz compost turner at work on Sheepdrove Farm.

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