What does a brewery wastewater system typically look like? For starters your brewery wastewater system should be separate from your sanitary (toilets, sinks) and kitchen wastewater.
At a bare minimum, you start with floor drains that lead to drain pipes under your slab.
Stainless steel floor drains are the very best. I know you don’t want to hear that, too expensive I know. But I consider floor drains a permanent part of your infrastructure. Cast iron drains do work, but only for about 10 years; they slowly corrode away in to nothing. Replacing them requires a new drain, concrete work, and a new floor coating. And of course labor to install. Now you can see why $700 on a stainless drain compared to $300 for cast iron is a much better deal. To save money you might consider having stainless drains made by a local welding shop. Top-of-the-line stainless steel floor drains are available off the shelf from Kagetec.
A great idea mentioned to me is you could have a local sheet metal fabricator make trench drains from stainless sheet on his brake; weld caps on the end and give it an outlet pipe, then drop the whole thing in place in one piece. Google ‘trench drain grates’ for a wide variety of options for covers. Make sure the outlet pipe is sized to slip inside your drain pipe. How cool is that!
You can also form a large drain in concrete. Have a fairly steep slope leading to a small stainless drain, or direct to the pipe.
One drain I really do not is prefab trench drains. These are very common in breweries, and the look great when they’re new. However these types of drains have a history of breaking, especially in traffic areas, but also due to corrosion. You can read more on drains on this blog post.
After the drains, the water heads to pipes under the slab. Stainless steel is always best for wastewater piping under your slab, again, it’ll be there forever. However no one wants to pay for stainless in an application they’ll never see. I have had good results with ABS in gravity situations. 4″ minimum diameter. Sometimes you’re lucky and just head straight to sewer from your drains. If you need to pretreat you will need a wastewater tank. Since the drains flow by gravity, your first tank will be underground. This can be a small lift station, or a whole automated pH adjustment system can be in that tank. As your brewery grows you can add above ground tanks. I have done this many times for many breweries, contact me for more information.
Very important: Sanitary wastewater (toilets, sinks) should flow directly to the sewer, your kitchen (if applicable) will probably need a grease trap and then straight to sewer. The brewery system might also flow directly to the sewer, but make sure it’s in a separate pipe as it leaves your brewery. Once outside the building the sanitary and process pipes can combine before they reach the sewer, or they can enter the sewer at separate outfalls. The reason for this is if you wind up having to do some sort of pretreatment before sending the brewery wastewater to the sewer, even years down the road, you will be very happy to have separate pipes so you don’t have to pretreat turd water; or dig up your slab to separate the pipes.
Most often pH will be the city’s primary concern. This is a corrosion concern as mentioned in the Intro. The city is also required by law to regulate pH sources in their waste stream. So you will probably have to adjust the pH of your wastewater before discharge and have proof that you have done so. pH adjustment is a permit compliance issue, there is usually no financial payback by doing this.
Load is usually the city’s second main concern. Load is a combination of quantity and concentration. Quantity is usually measured in gallons. Concentration is usually expressed as mg/L of BOD or COD. Load is usually expressed as pounds of BOD per day (or COD, or TSS). I like to describe load this way: Imagine you have a keg of beer and dump it down the drain. Now imagine you have a keg of beer and add it to 1000 gals of water, then dump all of that down the drain. The quantities are very different but the load is the same. Frequently I have seen very small municipalities express limits only with respect to concentration (mg/L). This should raise red flags, load is what they really are concerned about.
Temperature may also be a concern of your City, especially if the treatment plant is really small and the brewery is close by. The most cost effective method to lower the temperature of your wastewater is by storing the water until it cools. Cold water could be added, but that is counter productive.
Solids is usually the last concern. As described in the Intro, the best way to address solids is to not put them in the drain in the first place.
With any tank, especially wastewater tanks, confined space entry is something to be aware of, read about that here. Brewery employees have died due to confined spaces.
The next few sections describe pH, load, and solids control strategies.