Gippsland - How Now Gippy Cow
January 2011 Edition
Dairy upgrade, an opportunity to recycle water
Brenda and Alex Spencer are mid-way through a dairy upgrade at the 200-cow farm they are leasing from Alex’s parents Russell and Joan Spencer at Leongatha North.
Alex explained: “We are halfway through extending the cow yard and plan to also relocate the laneways to improve cow flow and comfort. As part of this plan we also hope to recycle effluent for yard washing.”
So far Alex and Brenda have installed hydrants in the cow yard, which Alex hopes will reduce the amount of time it takes for yard washing.
“We are spending 30 minutes a day cleaning the yard, so these hydrants will free up a bit more time” he said.
The hydrant washers will be using effluent from the effluent system to wash the yard. This will save 5000 litres of fresh water being used per day. That’s 1.8 megalitres, or 1,800,000 litres over a year. The water saved will help to reduce the dependence on the spring-fed dam that supplies the farm. The water in the dairy is licensed through Southern Rural Water with a dam registration licence.
The property is set up to capture as much rainfall from shed roofs as possible. The dairy shed has well-maintained guttering on all roof areas that flow into a plastic water tank. This water is then used to clean the plant and for vat washing. The dairy shed roof, which has an area of approximately 490 m², can capture 443,156 litres per year (based on an annual rainfall of 952mm and assuming that 95 per cent of the rainfall enters the tank). Some of this water might overflow once the tank is full.
Using rainwater for plant and vat washing has many benefits because it is typically better quality than river water or bore water. River water used in the dairy might require filtration to remove sediments that can build up in the hot water service. River water can also contain organic matter that can bind up chemicals and detergents too.
Bore water might be high in mineral salts such as iron oxide and might be hard, preventing detergents from working efficiently. Consequently, higher concentrations of detergent or specially formulated detergents might be needed. Poor-quality bore water can also corrode metalwork in the dairy. Bore water quality should be regularly monitored and tested.
The plate cooler in the Spencers' dairy shed recycles rainwater. The water comes from a well, through the cooler and back into the well. Plate-coolers are often the biggest user of water in the dairy. When considering water use efficiency on-farm, it’s important to consider where the plate-cooler water goes. If plate-cooler water leaves the shed to a storage tank, check to see that the tank doesn’t overflow when the plate-cooler is running for longer periods of time. If it is overflowing, there is a potential opportunity to capture this water.
The hot water rinse from the plant wash is recycled and used for the following milking’s first flush. This saves approximately 300 litres per day, or 109,500 litres per year.
In order to recycle effluent effectively, Alex and Brenda are planning to upgrade the effluent system. This will involve cleaning out and enlarging the existing single pond, and might include some form of solids removal such as a trafficable solids trap.
Brenda and Alex also plan to plant more trees on the farm to create shade for their cows. This can have the added benefit of reducing the stock drinking water consumption. A lactating dairy cow can drink as much as 200 litres per day in the peak of summer. The volume of water stock drinks will depend upon many factors including condition of the animal, diet, level of activity, quality of the water and environmental conditions such as humidity and temperature.
With rainfall at average levels for the first time in many years, now is the perfect time to be considering the reliability of supply of your farm water system. For assistance with farm water planning or further information contact Benita Kelsall from the Department of Primary Industries, Ellinbank on (03) 56242218.
Information is also available on the DPI website at www.dpi.vic.gov.au by searching under ‘farm water solutions.’
More water saving tips can also be obtained from Dairy Australia by going to www.dairyaustralia.com.au selecting ‘Farm’ and then ‘Saving Water in Dairies’.