Re-Use Detergent Wash - Case Study

CIP Recycling Saves Water

Peter and Wilma Mackay of Poowong East in south Gippsland are saving 800 litres a day and minimising chemical costs by using a cleaning in place (CIP) system to clean their milking plant.  They simply flick a switch after each milking and the fully automated system cleans the milking plant, and stores the cleaning solutions at the correct temperature ready for the next milking.

Each milking they save about 200 litres of caustic solution and a similar amount of acid sanitiser, which is recycled over a six-week period.  The whole system is calibrated twice a week to ensure the correct detergent strength is maintained.

The old solutions are then emptied into the manure pit where they are neutralised and then spread onto pastures later.  Peter got the idea when he visited another Victorian dairy where they used old milk vats for storage.

“I thought it was a really great idea,” he said.  Facing an upgrade of their plant in 1992, the Mackays decided to make the change.

It meant a complete changeover of plant costing about $3000.  “The most expensive part was the stainless steel hot water service,” Wilma said.

Several years later they spent more money automating the recycling system to save 20 minutes of supervision at the end of the milking.

“At first the automated system was a challenge but the CIP system is working well,” said Peter.

“We just flick the switch to ‘wash’ and walk away. It gives you time to do other tasks after milking,” Wilma said.  “The only thing we have to do is keep an eye on the valves actuated by the programmable logic controller that controls the system.  But there is a battery back-up in the event of a power failure and manual override switches if needed.”

The Mackays do not farm in a rain-strapped region.  They average 1200mm of rain per year.  “Stored rainwater is precious,” said Peter.

Our system is environmentally friendly because we are minimizing the amount of chemicals dumped and saving chemical costs at the same time,” said Wilma.

They milk about 220 cows twice daily and are constantly in the premium band. 

Want more information?

Contact CowTime Project Manager
Department of Primary Industries, Victoria
Phone (03) 5624 2221 or e-mail

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