Family flushed with biosolids success

Lauren CelenzaCountryman

Compost made from treated human waste is being used to grow crops in the Great Southern.

This seeding, Kojonup farmers Keith, Marlene and Brad Ashton have replaced synthetic fertiliser with by-products from the Water Corporation.

They initially thought the idea of using the biosolids was a bit on the nose, but the smell didn’t turn out to be as bad as initially feared.

So, after trialling it for the first time in 2009, the Ashtons used compost created from the treated human waste over their entire program last year and they are set to do the same this season.

The treated sewerage from the Albany Waste Water Treatment Plant is trucked to the family’s farm, where it is turned it into a spreadable fertiliser.

Last season, from 130mm of growing season rain, the family’s wheat yielded 2.3 tonnes per hectare.

While no test strips were done as a comparison, Keith was so impressed with the result that 1000ha destined for wheat and barley production will be covered with the compost this month ahead of seeding.

“We will apply the compost before seeding with a multi-spreader at a rate of 3t/ha,” he said.

Keith said his biosolids formula would suit any area and using biosolids had helped to retain water in drier years. “If you can get more humus (organic matter) into the soil, it will retain more moisture,” he said.

Keith had been paying about $600/t for superphosphate, and although not willing to detail the cost of making the compost, he said it was competitive at these prices.

However, the family’s main reason for ditching synthetic fertiliser was the benefit to the soil.

“We have been killing our soils for so long with synthetic fertilisers that the main reason I wanted to do this was to get natural microbes back into the soil,” he said.

The Ashtons had experimented with composts from chicken and pig manure in the past, but decided to give the biosolids a go when it became available.

Keith said despite the benefits, making the compost was not easy.

“It usually takes between eight and 10 weeks to complete the compost process,” he said.

The treated waste is mixed with straw and other manures. Minerals including dolomite, burnt lime and gypsum are added as required, after soil testing.

Each week Keith, who also runs a trucking business, makes the trip to Albany, carting back about 50t of biosolids.

Water Corporation environmental officer Sue Mills said she hoped others would consider being involved with the program.

She said the Ashtons were saving about 50t of sludge per week from going into landfill.

The WA Water Corporation produces about 85,000 wet tonnes of sludge per annum, which is distributed throughout the State for compost, forestry and agriculture.

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