Manufacturing: recycling and treating wastewater
To improve the quality of our treated wastewater streams, Fonterra invests in research and capital to ensure that treatment technology is best practice, meets regulatory requirements and minimises any environmental impact from our wastewater discharge.
Many of Fonterra’s manufacturing sites throughout New Zealand irrigate treated wastewater onto surrounding land. This recycled wastewater contains nutrients at levels useful to promote pasture growth.
At several sites we have developed wastewater treatment processes which have cut the nitrate levels of treated wastewater when it is discharged to a waterway, also saving on energy use.
Our Te Awamutu site has achieved a nine per cent reduction in its water use compared to the previous season, through installing a more efficient drier and a hot water recirculation system, reusing evaporator condensate streams, centralising the milk treatment process and replacing wet vacuum pumps with dry ones.
We have installed a new wastewater treatment facility at our Stirling site to improve the quality of New Zealand’s largest river, the nearby Clutha River. This NZ$12 million membrane biological reactor plant is the first of its kind for the New Zealand dairy industry and lifts the site’s wastewater treatment process to the highest of international standards.
Firstly a Dissolved Air Floatation (DAF) unit removes solids, fat and protein from the waste. Then bacteria digest organic components in the wastewater. Finally, water is passed through an ultra-filtration system that removes any remaining solid material and bacteria in the wastewater.
Similar DAF plants have recently been installed at our New Zealand sites of Longburn and Morrinsville, and also in Wagga Wagga in New South Wales, Australia.
Water conservation initiatives at the New Plymouth coolstore site have resulted in a first for Fonterra in New Zealand – a site which does not need water from an external source to operate. Water is used as a cooling medium to keep the coolstore’s refrigeration system operating effectively. In the past, the site drew water out of the nearby Mangaotuku Stream, used it for cooling the condensers then shifted the water to a pond on-site before final discharge.
The coolstore now meets all its cooling needs without taking stream water. It manages this by cycling water through a holding pond (which receives stormwater and groundwater seepage) and passing this through the cooling tower then back to the pond. The stormwater and seepage exceed the evaporated volume – leaving the site self-sufficient in its water use.
The Te Rapa manufacturing site has cut its production losses into the wastewater plant from milk processing by 45 per cent over two seasons. New technology, monitoring, data analysis and a permanent loss reduction technician and higher staff awareness have all contributed to this impressive reduction.
Our Edendale site has reaped significant rewards from our emphasis on integrating environmental matters and areas of potential improvement into the site’s business plan. Edendale has managed a 20 per cent cut in water consumption to milk ratio this season and has also reduced the number of product losses.
Optimising the site’s wastewater irrigation system has reduced groundwater nitrate levels by more than six per cent over the past 12 months. Further improvements are being worked on.
Fonterra is close to concluding a major study of sustainable options for the treatment and disposal of high strength waste generated by our manufacturing sites in the Waikato. These waste streams are currently spread onto land or used as stock food. Fonterra is in final stages of investigating the anaerobic digestion of this waste which, if adopted, will be a major change from current practice.
Our DairiConcepts joint venture in the United States managed to save approximately 200,000 litres of water a day through replacing a water-cooled air compressor at its El Dorado Springs site in Missouri.
Case study – Squeezing every last drop at Darnum
The Darnum milk processing facility in Victoria, Australia is an excellent example of how Fonterra integrates environmental factors into its decision-making processes. From the design and development of the plant, the underlying philosophy of Fonterra’s operations at the site is that good environmental performance makes good business sense.
The facility can process over three million litres of milk per day, around 87 per cent of which is water. During the milk evaporation process, a large percentage of this water is captured as condensate. Through a reverse osmosis water filtration process, we purify this condensate water, which is used to wash the production plant. This process reduces our reliance on town water procured through Gippsland Water.
Once the water has been used to clean the plant, it is pumped into one of two 100-megalitre treatment lagoons, where the water is treated to improve its quality. It is then used to irrigate approximately 100 hectares of farmland and 20 hectares of local blue gum plantation.
