Federation Farm manager Gary Coulton has started using biosolids, or ‘sludge’, from the Narrabri sewerage treatment plant as fertiliser.
The farm has successfully provided an outlet for treated Narrabri effluent water generated by the town for the past 14 years, but it was also initially developed to allow for the disposal of sludge, which is a by-product of the sewerage treatment process.
The farm now has a two-pronged environmental benefit for the community, removing the need to release effluent into the Namoi River, but also ensuring sewerage sludge is put to good use.
Extensive testing was completed to ensure the waste could be safely used on the farm, and it’s taken 20 years to accumulate enough sludge to fertilise approximately 40 hectares, or two crop fields.
Farm Manager Gary Coulton spread 525 tonnes of biosolid material on one 18 hectare field planted with cotton and is excited to find out whether it increases yields or soil health.
“We want to improve the country and get organic matter back into the soil, and the biosolids contain high levels of organic nitrogen and phosphorus so it’s the nutrients and improvements in the soil’s organic matter that we’re looking for,” he said.
“A new researcher at the cotton research centre is overseeing the trial so he will be able to define the benefits.
“Even if there is no definite advantage we still have a way to use the biosolids otherwise it would have to be accumulated somewhere else and the best place to use those materials is to spread them out thinly in the environment where they’re over time consumed by the soil.”
Mr Coulton only has about 500 tonnes of sludge left to use as fertiliser, but if the trial is successful he plans to outsource material from other shires.
“It may be worthwhile bringing some in from other treatment plants, but the cost of freight becomes the important issue, it might cost you $100 per hectare to get it here, but you might only get a financial benefit of $50 or $60 dollars through improved yields,” he explained.
Federation Farm continues to pay huge dividends for the local community, 14 years after the Narrabri Shire Council initially attracted funding from the Federal Government to buy and develop a sewerage effluent re-use farm.
The dropping of treated effluent water back into river systems is the most common disposal method but the Environmental Protection Authority provides incentive schemes for councils to keep effluent water out of the river systems.
The farm is jointly owned by council and the Narrabri Community Education Trust, which includes Narrabri High, Narrabri West Public, Narrabri Public and St Xaviers Schools.
Council and the Trust employ farm manager, Gary Coulton, and then share the profits generated by crop production on the farm.
Approximately $500,000 has been shared between the four Narrabri schools since 2000.
Mr Coulton said the farm has disproved early concerns it wouldn’t be financially independent.
“It was always unknown how successful the farm would be in the medium term,” he said.
“We’ve had our ups and downs, there are times when we have had disappointing farming results, which results in a tough year or two financially, but we’re still here, operating successfully after 14 years so that in itself shows it’s successful.
“We have no debt, we haven’t had to borrow money, we do benefit from council being benevolent towards the farm, and we still have some sponsorship contributions, but most importantly the farm is operating successfully at what it does which is basically growing cotton, wheat and chickpeas.
“We’re able to sustain our own production even with the ups and downs you get in farming, and still pay council their share and make that distribution back to the schools, so it’s really considered to be a win win.”
“After all expenses are met, and council’s share is paid annually, the profits are then distributed back to the four schools in Narrabri, based on student numbers, so the farm is run on a not for profit basis.”
He said soil on the farm hadn’t been affected by the use of up to 1200 megalitres of effluent water each year on irrigation crops.
“In the effluent water we probably get a third of our nitrogen requirements, and also phosphorus,” he said.
“Effluent water is high in salt but testing has shown no net increase in soil salinity levels.”
The farm is made up of six irrigation fields and 70 hectares of dryland. This year 52 hectares of cotton has been planted, down slightly on a 60 hectare cotton crop last year, but Gary says Federation Farm is less effected by drought than other farms.
“Our main source of water is effluent, that supply of water is pretty reliable every year, we don’t have bore licences or river licences,” he said.
The farm also has an extensive tree planting program around the perimeter, with some areas of revegetation now reaching maturity.