How Fonterra treats water from factories


At Fonterra we care about the environment and the communities in which we operate. We’re always looking for ways to improve, and one area that’s always a focus for us is water.

As well as the good work farmers are putting in on-farm, we’re investing across our factories too.

This includes initiatives to reduce water use overall in our manufacturing facilities, as well as continuing to look at the most responsible ways to take care of any excess water from our manufacturing processes.

Each manufacturing site has different requirements in relation to water treatment and meeting its own regional limits and environmental standards.

When managed well, we can use the treated water from our factories to help grow grass and other crops such as hemp. We can then harvest these crops for worthwhile uses such as making animal feed. This provides us with a nice circular model for nutrient management.

This is the model we have in place in Hautapu where we’ve been operating a ‘cut and carry’ farm for a couple of years. You may have heard these referred to as ‘ghost farms’, as there aren’t any cows on them – but that’s not a real term. It’s actually that we’ve created an alternative use for this land, which enables us to grow crops, using water from our sites to provide the nutrients required for them to grow well.

Are you wondering if nitrates are safe for the environment and people?

The treatment processes we use are designed to ensure the impacts on the environment are acceptable and remain within the limits set by Regional Councils.

As the land-use around our factories has changed over time and is starting to become more residential, it’s important we change our approach to nitrogen management too.

We’re looking for ways to improve our operations to fit with the changing landscape. This is why we are wanting to invest over the next 5 to 10 years to upgrade our waste water treatment facilities at our Hautapu, Edgecumbe, Whareroa, Maungaturoto, Te Awamutu, Longburn, Reporoa, Kapuni and Clandeboye sites.

In the meantime, in Hautapu we’re constantly monitoring levels. When we do become aware of cases that come close to the limits, we help by offering to install filters on residents’ water supplies.

Safe drinking water is a serious issue and it’s important to understand the science on this topic. We work closely with the regulators and science providers to ensure our wastewater operations meet the needs of the environment and the community around them.


What causes water coming out of a manufacturing plant to contain nitrogen?

The main contributor is the cleaning process within our plants and sometimes a little milk.

How is Fonterra reducing nitrogen levels in water from manufacturing plants?

It starts with our operations where we make sure our cleaning processes are optimised, and milk residue is minimised. This limits the amount of nitrogen.

We also use various treatment processes to further reduce nitrogen. We do this through dissolved air filtration (DAF) plants, which clarifies wastewater by removing suspended oils or solids by dissolving air under pressure, and biological treatment plants, which use bacteria and other microorganisms to clean the water.

How is Fonterra reducing the risk of nitrates leaching into waterways when it applies wastewater to land?

Before we irrigate to land, there are several steps we take to reduce nitrogen leaching. These include assessing the type and structure of the soil (for example, if it’s a wet season we will reduce the amount we will irrigate), reducing stock and fencing off areas that are too wet to reduce pugging (where soil and mud are churned up and pushed back down by animals).

In addition, we plant a variety of different crops that help absorb the nitrogen. For example, we’ve recently been growing hemp on our farm near our Darfield site and on some of our other farms we’ve planted rye grasses. We monitor our operations regularly to let us know if we need to make any changes.

As councils let us know of upcoming changing environmental requirements, we have adapted our systems, proactively changing to meet increasing limits.

How many farms does Fonterra spread dairy factory wastewater on?

We have 29 Fonterra owned farms, which we have for the primary purpose of nutrient management.

What is the reason cows have been removed and the farms operate as ‘cut and carry’ farms?

The primary use of these farms is nutrient management. We continually assess the most efficient way to remove nutrients and the amount we spread on these farms. We look at factors such as climate, the soil type and structure to help determine the best use for the farm.

With freshwater reforms limiting farmers to 190kg of synthetic nitrogen per hectare per year, does Fonterra intend to reduce the amount of nitrogen loading from wastewater spread on properties to match this limit?

In all our operations we work within the guidelines set by the councils. When changes are made, we adapt our operations to fit. Our ‘cut and carry’ farms are a good example of this – it’s a model that allows us to operate within these limits.