The research, funded by the Avon Catchment Council and undertaken by the Department of Water, has focused on six different small-scale pilot trials in drains and has shown composted organic mixes of straw and sheep manure could hold the key.

Each year, millions of litres of saline acidic water flow through a network of drains in the West Australian Wheatbelt, as farmers try to reclaim land damaged by shallow saline groundwater.

The acidic saline water can pose a threat to aquatic life in naturally occurring lakes and waterways.

The department’s Dr Brad Degens has spent the past two years trying to find practical and readily available materials as treatment solutions for acidic waters.

“From these trials we found there are a number of ways in which acidity in these drainage waters can be treated, but which one you would use depends on your circumstances,” he said.

“The treatment options trialled used a range of materials such as an organic mix of straw and sheep manure, as well as industrial hydrated lime and lime sand, which have neutralizing qualities.”

Dr Degens said the most practical treatment option was the use of composted straw and sheep manure in a waterlogged pit, which grew micro organisms that helped lower acidity.

“At a trial of a composting pit at Beacon, the acidic saline water percolated through the compost and was then returned back into an evaporation basin,” he said.

“Prior to treatment, the water was similar to weak vinegar and twice as salty as the sea, with a pH of between 3 and 3.5.

“After treatment the pH of the water increased to between 5 and 6 which is a drop in acidity. This compares with rainwater pH being about 6.”

Three hundred square metres of the organic mix was treated with about 750 kilolitres of acidic water in the first 12 months.

Research indicated there was a drop in the effectiveness of the composting treatment after about six months - highlighting that more work is needed to find a mixture that will continue to work well in the long term.