Some farmers in the central west of New South Wales have a surprising solution to help deal with what's been called the worst drought in living memory.

What are biosolids used for? Co-generation/power production/energy recovery

Co-generation/power production/energy recovery Land application in agriculture (vine, cereal, pasture, olive)

Land application in agriculture (vine, cereal, pasture, olive) Road base

Road base Land application in forestry operations

Land application in forestry operations Land rehabilitation (including landfill capping)

Land rehabilitation (including landfill capping) Landscaping and topsoil

Landscaping and topsoil Composting

Composting Oil from sludge (experimental) Source: biosolids.com.au

It is human sewage, treated and dewatered to produce biosolids, an organic fertiliser transforming about 30 farms in the region.

From more than 20 metropolitan treatment plants, Sydney Water is producing about 180,000 tonnes of biosolid fertiliser a year.

About 70 per cent goes directly to farms such as Ulabri, a 900 hectare grazing enterprise at Wattle Flats near Bathurst owned by Gordon and Linda Nash.

Like many properties on the edge of the Bathurst Rim, Ulabri has poor acidic soils high in aluminium and low in organic matter. It has also had successive years of drought with less than half its annual average rainfall recorded in the last 12 months.

Processes in a typical wastewater treatment plant which turns wastewater sludge to biosolids. ( Supplied: biosolids.com.au )

Mr Nash has been gradually improving his pastures for the past six years by incorporating biosolids into the soil and planting pasture species.

"I'm taking country that could run one sheep per acre up to three with introduced grass species and that, so it's definitely good value from my perspective," Mr Nash said.

He said his treated paddocks were more resilient in the drought and were keeping his 2,800 fine wool merino sheep in good condition.

"You might get a shower of rain and the paddocks we've had it applied to, they'll spark up straight away, whereas other paddocks are still like a desert," he said.

"My stock are doing so much better you know, wool cuts are up, you seem to be able to get a longer grazing period in your paddock because the plant species are just doing so much better."

At Caloola, south of Bathurst, Cliff Kelly and his sons Andrew and Stuart are hand feeding 90 per cent of their 10,000 sheep. Supplementary feed such as hay is in such high demand they've substituted the fodder crop with almond hulls from South Australia to boost the daily ration.

"It's the driest in my lifetime … so it's pretty good to have this sort of pasture coming along," Cliff Kelly (L) says. ( Landline )

Cliff Kelly, 69, said it was the worst drought he had experienced, with just 350mm of rain in the last 12 months.

"I've never seen it this bad, it's the driest in my lifetime, even worse than the drought in '78 to '83," he said.

The Kelly family has been improving its pastures with biosolids since 2013. So far they have treated 250 hectares of their 1600 hectare farm.

Agronomist Roger Crisp (L) and farmer Stuart Kelly (R) inspect soil. ( ABC News: Luke Wong )

Andrew Kelly said the treated paddocks were a Godsend for the family's 10,000 sheep. They save them for crucial periods such as when they wean new lambs from their mothers.

"This pasture here is just so responsive to even 10mm of rain, even 5mm of rain," he said.

"What it'll allow us to do is — ewes that have just lambed recently, we'll wean their lambs on this in four to six weeks," he said.

"What it means for them is they'll hit the ground running off their mothers and hopefully shouldn't even realise that it's a drought."

Five typical production systems for biosolids with possible alternative productions paths. ( Supplied: biosolids.com.au )

Not as good as rain — but it helps

Australian Native Landscapes is one of three companies being paid by Sydney Water to remove its biosolids, which would otherwise go to landfill.

The company provides transport and spreading of the rich organic material as well as advice from agronomists such as Roger Crisp.

Mr Crisp said biosolids could not drought proof a farm but they certainly made a difference.

Biosolids can help agricultural land thrive. ( Landline: Sean Murphy )

"The only thing that'll drought proof a property is water, adding water onto it," Mr Crisp said.

"Where biosolids have made a significant difference and a visible difference is it makes better use of the limited rainfall that you get.

"At the moment they're living hand to mouth on small falls of rain, 10 to 15mm of rain, and you'll notice in paddocks that have had biosolids applied to it, the grass responds a lot quicker to that small amount of rain, so they're getting a lot more feed off it and it'll last for longer because the root systems are longer and it'll penetrate down in the ground and it'll hang on for longer.

"It's not drought proofing but it's extending the window of grazing time that you can get which is so valuable in these really dry times."

Mr Crisp said it was not just grazing operations benefitting from biosolids, with some cropping and irrigation farms also on the program.

Agronomist Roger Crisp (L) and Josh Wright. ( Landline: Sean Murphy )

At Woodstock near Cowra, Josh Wright helps run a 3000 hectare family business growing wheat and canola crops as well as cross-breed sheep.

Biosolids are helping grow viable crops in the drought but the biggest benefit has been reduced reliance on chemical fertilisers such as urea and mono ammonium phosphate (MAP).

"We're five years into some of our program and our MAP is down to 20 kilograms from probably 80kg to the hectare," Mr Wright said.

"Our phosphorous levels are quite high so we're not putting on as much phosphorous even five years down the track.

"It [biosolids] is dear up front but you get that longevity of your fertiliser so you pick that up in the second and third year."

Mr Wright said he had no concerns about the safety of a product produced from sewage but sometimes wondered about its origins.

"It's quite funny, every now and then we'll have a tomato plant or something like that pop up and you often think of where it's come from," he said.

Strict guidelines in place

According to Sydney Water's biosolids program manager Graham Keating the Environmental Protection Authority has set strict guidelines for the production and use of biosolids.

"We test biosolids every day, for every 100 dry tonnes of biosolids we have one sample taken so it's a fairly robust system of regulation that we go through not only at the plant but also at the farm as well," Mr Keating said.

Graham Keating (R) says the biosolids testing system is "robust". ( Landline )

He said the waste material is baked for about 40 days to remove pathogens and heavy metals and the methane gas produced supplies 15 per cent of Sydney Water's energy needs.

All of the farms in the biosolids program had to undergo rigorous soil testing to identify any naturally occurring heavy metals, he said.

Once delivered the biosolids had to be secured in a location that could withstand a once-in-20-year rain event and had to be spread within 30 days. It then had to be incorporated into soil within 36 hours and could not be used on slopes or near occupied dwellings or water.

Mr Keating said livestock could not be run on treated paddocks for 30 days or 90 days for lactating mothers and certain vegetable crops were prohibited.

He said the restrictions were to protect the environment and manage public health perceptions.

"Twenty five years ago a lot of the sewerage went to the ocean to ocean outfalls. We've turned that around now and that's only in emergency situations that that would ever happen now," Mr Keating said.

"It's a great step forward for the environment as far as biosolids are concerned."

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