Waste Water Treatment with Floating Wetlands

Work has begun on our new brewery and we’re installing a new innovative water treatment approach, using floating wetlands, to help recycle as much as possible.

Australia is the driest continent on Earth. Water is a scarce resource and its availability is becoming less certain and more unpredictable with accelerating global heating. We in Australia take clean, potable water for granted, but many millions of people around the world aren’t so lucky. There’s an obvious moral imperative to use this precious resource as efficiently as we can.

Water is also the achilles heel of the brewing industry: it comprises about 95% of beer and so is completely irreplaceable, but it takes many litres of water to produce one litre of beer. Exactly how much varies depending on what is counted, because the vast majority of water used to make beer (>90%) actually occurs on the farm where the grain is grown. On-farm water use is very hard for a small brewery to influence (large breweries often have their own farms!), so we are focussing our efforts to influence what we can: water use in the brewery. 

We’ve learned a lot about ways to use water more efficiently in the two years we’ve been running our existing brewery, and as we build our new brewery we’ll be implementing actions to reduce the amount of water we pull from the Shoalhaven’s dams. A key first step is measuring what comes in, so we’ll be installing a flowmeter which will give us precise data on mains water use. This will allow us to easily calculate how much water we’re using per litre of beer produced.

Of course measuring is great, but we want to actively reduce the amount of water we’re using. So we’re building in two key steps. The first is simple, well-known and widespread: rainwater. We’ll install a rainwater tank, pipe it into the brewery and use the water for cleaning (and maybe we’ll even make the odd brew with Jervis Bay rain…) The second step is experimental. We’re building two big ponds that will each hold 12,000L of water and support floating wetland vegetation. These ponds will receive the waste water produced by the brewery, known as liquid trade waste. All water that enters the brewery drains has to be treated before being discharged to the sewer – we’re not allowed to just put it down the drain. This treatment will happen in a series of tanks that will remove sediment, aerate the water and balance the pH to neutral. After water leaves the tanks, it’ll enter the ponds. We’re hoping that the ponds will further treat the water by removing nutrients (the wetland plants will turn nitrogen and phosphorous into leaves and roots) and oxygenating the water by exposing it to the air. Assuming that the system works, we’ll pump the now-pretty-good water from the ponds into a holding tank, and from there back into the brewery where we can use it for washing floors, the outsides of tanks etc. Of course, as we do this, the water will go back into the drains and through the trade waste system again, meaning that the same water can be used multiple times.

This is pretty novel stuff, so we’ll have to do plenty of testing to make sure the water that’s coming out of the ponds is of a decent quality. Shoalhaven Water has helpfully agreed to work with us to do this, because the results will be interesting for any industry or business that produces waste water as a part of their processes. Who knows, perhaps in a few years onsite water treatment and recycling will be the norm, not the exception!

Check out this video of our brewer Oisin explaining the work being done to prepare the site for this innovative project.

*Note: The feature image used is an example of how the ponds could look. Ours will be a different shape, but contain similar wetland plants.