A dairy cow will dump up to 15 per cent of its daily manure output on the concrete yard of a dairy farm. It is then washed into effluent ponds. Managing this issue is important.
Biosolids - appropriately treated environmental sludge - and liquid effluent are potential resources that can be beneficially utilised in agriculture, helping to reduce emissions and fertiliser costs on farm.
According to Dairy Australia, 10-15pc of manure created by each cow on a daily basis is washed from dairy sheds into holding ponds, so reusing effluent can be a beneficial tool on farms.
Dispersing treated effluent across paddocks in instantly-usable liquid form or as a biosolid incorporated into the ground to act as a slow-release fertiliser helps save cuts costs of bought-in fertiliser.
The organic matter of effluent provides soil-conditioning properties and improves soil moisture and nutrient-holding capacity.
With a high nitrogen level, effluent provides productivity gains from pasture responses, which can result in increased production.
Effluent on EPA radar
Inappropriate storage of biosolids and effluent can have significant impacts on the surrounding environment and the dairy farmer's bottom line.
It is also on the radar of the Environment Protection Authority (EPA), because EPA officers respond to multiple pollution reports about dairy effluent every year.
These reports might be direct to EPA or through another authority.
In 2021, routine testing by South Gippsland Water staff identified the source of an effluent spill into the Powlett River, at Kongwak, that led to a dairy farmer being fined $1983.
The farmer had allowed dairy effluent from a milking yard running into a pond, which was overflowing across farm land and into a stormwater drain that fed into the Powlett River.
EPA officers also issued the dairy farmer with a minor works pollution abatement notice to undertake works to improve the effluent system; subsequent inspection showed the dairy farmer complied with the pollution abatement notice.
The EPA requires that farmers:
More recently, EPA officers successfully prosecuted some Gippsland dairy farmers for environmental breaches that included seepage and runoff from effluent ponds.
A spokesperson for the EPA said the prosecutions followed periods of snap inspections in the three major dairy regions of Victoria - south-west Victoria, northern Victoria and South and West Gippsland.
EPA south-west regional manager Carolyn Francis said the inspections were aimed at ensuring farmers understood their responsibility under the General Environmental Duties of the Environment Protection Act 2017.
Ms Francis said these responsibilities include ensuring there were procedures and assets in place on dairy farms that minimised the risk of activities creating harm to the environment.
Inspections in the Otway region followed concern about algal events that led to fish deaths in the Curdies River.
"Most farmers are doing the right thing and have good effluent management practices, and we were reassured by the high levels of compliance we saw," Ms Francis said.
Some dairy farmers received formal compliance advice and EPA officers are following up to ensure practice change has been implemented.
"Two of the 25 dairy farms weren't properly controlling their effluent and allowing it to discharge with a risk to harm waterways," Ms Francis said.
"We put more explicit requirements on these farms, using legally enforceable notices."
Ms Francis said farmers have a legal obligation to ensure effluent is well managed on site, and trained system designers can support them to achieve this goal.
Pollutants included nutrients, pesticides, fertilisers, milk from washdown and spillage, waste milk and contaminated soil moved by heavy rain.
The past couple of years of heavy rainfall and flooding have created challenges for managing effluent ponds, particularly when roads and laneways aren't accessible by truck.
EPA Gippsland regional manager, Jessica Bandiera saud inspections on dairy farms by EPA officers in South and West Gippsland earlier this year resulted in one official warning.
Ms Bandiera said officers spent time with farmers advising about how to improve their dairy effluent management system so they could comply with EPA requirements.
"Dairy farmers can prevent effluent ponds from overflowing by de-sludging, controlling weeds and irrigating the water component to pasture when weather conditions are appropriate," she said.
"Any rainy weather can send back up effluent pouring over the edge of the dam.
"Summer is the best time to clean out ponds ahead of winter wet weather.
"It's also a good time to ensure effluent irrigation equipment is in good condition and prepared to deal with any pipe or pump failures."
In follow-up inspections in spring this year, the effluent systems on 16 dairy farms in the district were found non-compliant.
Seven fines, totalling more than $20,000, were issued by EPA officers.
Nine formal notices required works to begin or be completed that ensured better management of effluent systems.
"EPA has consistently communicated with dairy farmers about the requirements regarding on farm management of dairy effluent," Ms Bandiera said.
"EPA won't hesitate to use our regulatory powers where dairy effluent is being mismanaged, or not managed at all, but we would much rather our inspections find everything is already in good shape.
"Dairy effluent can't be allowed to be discharged to waterways.
"It is high in substances that may be toxic and pose a risk to the environment and human health.
"The majority of non-compliance issues concerned dairy effluent ponds that were full or overflowing into paddocks and waterways; broken or ineffective equipment like pumps and irrigation systems; and not having an effluent management plan in place.
"Some farms even had pipes directly discharging into waterways."
Ms Bandiera said of the 19 farms visited in the Poowong North, Hallora, Nyora, Ripplebrook and Athlone areas, nearly half the inspected farms were expected to receive some kind of sanction.
She advised dairy farmers be proactive about improving their effluent systems, rather than wait for the EPA to wield its powers.
"It's the right thing for the environment, for your own farm, and for your neighbours downstream," Ms Bandiera said.
"There are assistance schemes, guidance and advice links available through EPA's website.
"This information can assist farmers so they can make the necessary improvements, retain valuable nutrients on their farms, and save them money while protecting the environment."
The EPA will continue to inspect dairy farms, including without notice, to ensure regulatory compliance.
"We'll continue with our inspection program and take strong regulatory action if we find non-compliance," Ms Bandiera said.
Hans van Wees, a sharefarmer at Tinamba in central Gippsland, Vic, utilises a purpose-redesigned 10-megalitre dam and irrigation system to manage effluent and utilise it for pasture growth.
Washdown water and effluent flow into a large solids trap at the side of the dairy. The trapped solids, when dry, are spread over nearby paddocks. The liquids are pumped into a dam, which is located about 300 metres from the dairy.
A stationary pump mixes the dam water to prevent slurrying.
When Mr van Wees wants to apply the effluent water to the paddocks, he opens a release valve into an irrigation channel connected to the dam.
The effluent water is then pumped into one or two other channels and diluted with irrigation water - at a rate of one part effluent to two parts irrigation water.
Mr van Wees can irrigate 120 hectares directly from this dam or shift the effluent to another dam further down the property and irrigate other paddocks from there.
The capacity of the effluent dam means there is no runoff or flow over into paddocks and consequently no effluent running off the farm in wet weather.
The backup dam further down the property provides double insurance.
Mr van Wees said the system returned fertiliser savings of 100kg/ha of single superphosphate over 120ha.}
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