I hesitate to even write this. A brewery on septic just is asking for trouble. However, it’s my #1 most frequently asked question, so here goes….
First of all, don’t do it! Don’t put brewery wastewater in to a septic tank unless it has been designed for it. Keep in mind what a septic tank is. It is a slow acting system working with anaerobic bacteria to digest nutrients before discharge to a drain field. No moving parts and it works, but it all happens very slow and most systems are designed for low flow rates. In general a brewery discharges far more water than a septic system can effectively treat. Of course, a septic system is just fine for your kitchen, restrooms, sinks, etc.
If you are a start-up brewery and you found a killer site at a screaming deal, go for it. Just realize that much of the cost savings of the site without sewer will eventually get eaten up by wastewater infrastructure.
Some of the problems you encounter with brewery wastewater in a septic system is yeast growth, both in the tank and in the drain field. Even if you side stream your spent yeast, some yeast will make it’s way down the drain and reproduce- then die, creating a thick sludge that builds up quick. Another problem is sugar in the drain field. This sugar can build up to a ‘caramel’ in the drain rock, eventually creating a virtually impenetrable layer that you will have to dig up and redo. Digging up the drain field annually could be budgeted as a cost of doing business, but it’s not the most environmentally responsible solution.
Grains and hops are another problem. Of course you will give most of this stuff to a farmer, but life happens. Stuck mash, a spill, valve left open, whatever. 1 mistake like this can fill your septic tank and your drain field. You’ll have to dig it up and start over, and of course this would be unplanned and might cause a brewery shut down for several days.
For at least the first year, I advocate hauling 100% of your brewery wastewater off site. That’s right, truck it off site. All of it. CIP water, spent yeast, floor cleaning water, waste beer, trub, everything. You can land apply this water as fertilizer, or you can truck it to a nearby wastewater plant, or a little of both. Some treatment plants are eager for this extra food source and will take it for free, others will want to charge you for it. Ask around.
What this does is eliminate the capital expense of an expensive treatment system from the construction phase of your brewery. This turns the hauling of your wastewater in to an operating expense. That’s a big difference and makes sense in a lot of ways. Also during this first year your production will be relatively low and this is a very feasible option.
Eventually hauling is going to become problematic. Maybe hauling is getting too expensive? The volume is getting too high? Winter is too much of a hassle. Maybe the State is telling you ‘No more!’. What then? This will be at least a year down the road, maybe longer. Your business will have cash flowing, you will have more experience as a brewer and owner, and you will hopefully be in a better place financially. Ahead of the drain field you can install an advanced aerated septic system, or a small aerobic treatment system. Figure $100,000 at least, even for a small brewery. You may get a quote for $50k, but when planning in support systems, insulation, a roof, and proper controls the cost escalates quickly. Plus at least a part time operator, repairs and maintenance, chemicals, electricity, depreciation, space, odor, weather, keeping up with variable production rates in the brewery. All of these things have a cost associated with them.
The next issue if you do install an onsite treatment system is getting rid of the water. Don’t even think about discharging to the creek in back. Too many regulations, and this would be the federal EPA you’d be dealing with. Options are a drain field, irrigation, and evaporation. Water reuse is also an option, that’s a topic for another day.
What are the requirements to discharge wastewater to a drain field? Start by asking the people at the county government. They will probably tell you something like 30/30 BOD and TSS. Maybe they’ll say 300/300? Either way it’s going to be expensive.
Irrigation is possible, talk to your local Dept of Agriculture about it. Plan to put it on non-human food crops such as pasture and hay fields.
If you do the drain field option, you will probably need several of them. Call them A, B, and C. Discharge to drain field A for a month, switch a valve and discharge to drain field B, and then go to C; then back to A. You might be able to get away with 1 drain field, but probably only if your site is very gravelly.
If you do install some sort of on site wastewater treatment, I would recommend not tying in your existing septic system for restrooms, etc. Keep them separate, forever. This makes dealing with the wastewater and maintenance much easier from a pathogenic prospective.
Anyway, please contact me if you have questions or need more information. I’ll do what I can, just be aware of what you’re getting yourself in to. There’s a lot to it.