Challenges and Innovations in Dairy Factory Wastewater Treatment

Annual Conference

In recent years, Fonterra has expanded a number of their dairy manufacturing sites to increase the overall milk processing capacity of its New Zealand operations. A new dryer was installed at Fonterra’s Pahiatua site in 2015 and a new milk powder dryer is being built at the Co-operative’s Lichfield site. In order to accommodate the increased wastewater flows from the sites, new wastewater treatment plants (WWTPs) were required as part of the overall expansions.

Dairy factory wastewater has a number of characteristics that require careful management, including influent pH swings of 2-13, high fat loads and variable incoming organic and nutrient loads. Variations occur both on a seasonal and daily basis.

A number of innovations and features were incorporated into the Pahiatua and Lichfield treatment plant designs to overcome these challenges including:

  • Use of a mixed liquor recycle to buffer pH swings
  • Use of mechanical surface aerators with floating acoustic covers
  • In-pond anoxic cycling to promote denitrification
  • Use of dynamic process modelling to assess the sensitivity of the design to peak loads and aid in the development of risk management strategies
  • Beneficial irrigation of waste activated sludge on to surrounding farms

Elements of this approach to wastewater treatment in the dairy industry could be adopted in a wider setting. For example in municipal plants treating an industrial wastewater component or municipal oxidation ponds that require upgrading to meet more stringent consent conditions.

Conference Papers Resource - Conference Papers Rural Systems Wastewater Treatment

13.30 - Jess Daly Bram Beuger - Challenges And Innovations In Dairy Factory Wastewater Treatment .pdf

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22 Nov 2016