This is my #1 FAQ. There is obviously a lot of interest out there on this, and with the burgeoning farm brewery movement it’s getting even bigger. But, there is no great solution…
To be clear, I am not a septic system designer. But seriously, I get this question all of the time. A brewery on septic isn’t impossible, but it is high maintenance, expensive, problematic, and worse. Imagine a fermenting septic tank with foam trying to escape to give you an idea.
However this is somewhat a matter of scale and location. A small brewer with a 1/2 bbl kettle might be OK for awhile, but they usually want to discharge to their homes septic tank. A bigger brewer will usually have too much water for the system to deal with effectively.
Even if you get 100% removal of all BOD and TSS, you still have a lot of water to dispose of every day and not create a bog. The water reuse people would scream that we should reuse this, but uses of reclaimed water are limited. And water is cheap, equipment for reuse is expensive. Over time this will change, but we simply have to pay attention to economics.
Some of the issues of a brewery on septic are:
As mentioned, the septic tank will turn in a fermenter. It will fill with spent yeast, cause back pressure issues due to CO2 generation, and the environment of a fermenter will prevent the proper bacteria from populating the tank so there will very little actual treatment going on in that tank. The tank will have to pumped quite often to remove the spent yeast, and this gets expensive.
Suspended solids (yeast, grain, hops) and dissolved solids (sugar) will pass through the septic tank and will plug the drain field over time. The solution here is usually to dig up the drain field and start over, probably on a new patch of ground. It takes time for this to happen, probably years, but it has happened over and over again.
So what are some solutions? As usual, a lot of potential solutions are site specific. But the lowest techonology solutions are land application or hauling it all off site.
Land application for a tiny brewer this can be a simple lift station with a pump, hose, and sprinkler at the end. Some of these small brewers are generating 50 gallons of wastewater a day. For a larger brewer with higher volumes, land application may involve hauling the wastewater to a field. A few caveats to land application. You will probably need a permit for this. Land application is seasonal and weather dependant. You may not want to land apply on top of 3 ft of snow, and if it’s muddy you don’t want to be applying more water or driving on that land.
If you are land applying at any scale, it’s good to have a hauling back up plan. As mentioned, snow and mud can cause problems. Where else can the water go? Start by talking to the nearest wastewater treatment plant, they can probably accept it as septage receiving. Ask them what it would take for them to accept this water? For instance some may allow you to bring water to them in an IBC tote in the back of a pickup truck, or for your farmer to deliver it in their tank truck, others may require a licensed hauler.
You can also haul 100% of the brewery wastewater off site year round. Land application in the growing season, septage receiving in winter or mud season. Or septage receving year round?
Land application is low tech and inexpensive. Hauling gets expensive, but it’s low tech and easy. There are alternatives, such as on-site biological pretreatment, but as you’ll read later that gets expensive and complicated.
One general note regarding hauling is most haulers charge by the truck load, not by the gallon. So if a 3000 gal truck shows up and fills up with 500 gallons, it may cost you the full truckload price.