More and more around the world, you are hearing of various wastewater reuse schemes. It’s happening more often than you think in more ways than you’d imagine. Admittedly I am not a wastewater reuse expert, but what follows is a quick summary and specific brewery technologies and applications.
Effluent from any sort of wastewater treatment system is a form of wastewater reuse. A septic system discharges in to the groundwater. Most wastewater treatment plants discharge treated effluent in to a river or other receiving body of water. In both cases, there is probably a town downstream that is using that water as drinking water. Wastewater doesn’t disappear, it is reused for eons. So before you say ‘Yuck!’ about wastewater reuse, think about the water cycle we all learned in primary school.
If you don’t have eons to wait, and you have a brewery in a water restricted area, you can throw technology at the problem. Eons can be shortened to hours- but with that of course comes a cost. And it probably makes more sense to put some of that money towards efficiency first. Are you being as efficient as possible with the equipment you already own? Is upgrading to more efficient equipment a better use of your money compared to wastewater reuse?
In order to consider wastewater reuse, you first have to install wastewater treatment. Duh right? In most cases this doesn’t make financial sense. Of course every situation is unique, so let’s say you’ve done the math and installation and operation of treatment is cost effective for you. Great. Next you would be looking at reuse equipment. We’re talking about ultrafiltration and reverse osmosis, plus a disinfection step. Expensive to buy, expensive to operate, and the output is water- which is usually pretty cheap. If you are in an area with very high wastewater rates and very tight restrictions, and you are limited on your incoming water supply due to drought or capacity, wastewater reuse starts looking good. But that’s a pretty limited number of brewers.
Then what would you do with the water? Irrigation works, but it’s seasonal and you didn’t install all of that expensive equipment just for irrigation did you? You can certainly use it for boiler feed water and cooling tower make-up water. Both of these pieces of equipment are sensitive to water quality, but you can add some chemistry to get it to work well. Next you would be looking at CIP water, floor wash down water, external bottle rinse and conveyor lube. Next comes product, and I don’t think too many breweries would want to tackle that potential PR nightmare.
Don’t get me wrong, water reuse and efficiency are awesome things. But we are running a business, and paying close attention to all of the costs associated with reuse rarely pencils out.