A new approach to designing dairy shed effluent storage and management systems firstly addresses the question of how the effluent is to be spread.

Rural Solutions SA Waste Management Systems Consultant Michael O’Keefe says once the spreading method has been decided the effluent can be treated and managed to best suit the spreading method and optimise the nutrient utilisation.

Mr O’Keefe recently presented a paper titled ‘Resource – Not Waste” at an Australian Water Association seminar in Sydney attended by wastewater engineers, food processors, plant managers and water technologists.

The new dairy shed effluent paradigm is funded by the National Landcare Program that aims to provide practical assistance to dairy farmers, enabling them to implement best management practice for dairy shed effluent.

Dairy shed effluent guidelines for the South East, Mt Lofty Ranges, Murray Darling Basin and the Northern and Yorke regions of SA were updated and released to farmers between 2005 and 2007.

Rural Solutions SA has been involved in the design of dairy shed effluent management systems for dairies ranging between 200 and 2,000 cows.

Mr O’Keefe said the key elements are effective separation of the solid and liquid components of effluent, reducing freshwater consumption for dairy yard washing, recycling effluent and utilising effluent to replace synthetic fertilisers.

“The program aims to improve effluent management by dairy farmers through highlighting examples from demonstration farms, as well as disseminating up-to-date effluent management technology via on-farm technical assistance,” he said.

There are several other benefits that farms can achieve with their dairy shed effluent management system. 

Larger dairies are adopting more advanced effluent treatment systems, with many installing mechanical separators and multi-stage gravity settling ponds to separate the solid and liquid components.  This process generates two valuable, and re-usable products. 

The separated liquid effluent can be recycled for yard washing and/or used as fertigation when pumped through centre pivot and traveling irrigators.  The separated solids can be used as a soil ameliorant, composting feedstock or dried and re-used as a bedding source in free stall barns.” 

Historically the design of dairy shed effluent systems has been about how effluent can be captured and stored. Frequently designs have resulted in the need to spread stored effluent during the winter, when plant uptake is poor or when soils are waterlogged.  Applying effluent at this time of the year greatly increases the risk of contaminated run-off being generated.

Dairy shed effluent contains valuable nutrients, but if spread on paddocks at the wrong time of year these nutrients can enter water resources and become potent pollutants.

Issued by: Terry Price, Media & Communications Consultant, Rural Solutions SA, Telephone 08 8226 2833, Mobile 0434 367 029

Media Contact: Michael O'Keefe, Waste Management Systems Consultant, Rural Solutions SA, Telephone 08 8842 6272, Mobile 0408 284 475

Pictured: Michael O'Keefe

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