As mentioned earlier, solids in the wastewater can be an issue. Solids are fairly easy to address because they can be removed mechanically.
For the most part, solids in brewery wastewater are composed of small grain and hop particles, and yeast.
A good starting place is quality screens in the floor drains- with employees trained to dump the screenings in the trash (not down the drain, duh). Usually the screens that come with the drains (if any) are inadequate, you could have some custom stainless steel screen fabricated locally using perforated stainless steel sheet or screen. Screens that are easy to remove, easy to clean, and easy to reinstall are important; otherwise the screen will magically disappear. Good screens like this are most important in the brewhouse and packaging areas, between 1/8″ and 1/4″ perforations are good. Less important in the cellar and warehouse spaces. An even better idea is to not put the solids in the drain in the first place, side stream them.
If you have an underground tank, if you have room add a simple basket strainer under the outlet pipe in an underground tank to catch the big stuff, such as wrenches, gloves, TC fittings, pallet chunks, shrink wrap, etc. This can be as simple as a 5-gal bucket with many 1/2″ holes drilled in it.
Solids will actually grow in any brewery wastewater tank. Wild yeast and bacteria find a warm sugary wastewater tank an ideal place to grow. In time these critters will form a thick, stinky sludge at the bottom of your tank. For this reason it is important to drain or pump off the bottom of your tank. By draining/pumping off the bottom of your tank you get rid of these solids slowly so they aren’t able to form a thick sludge. This thick sludge can get to a toothpaste-like consistency. Not what you want; it stinks and it takes up space in your tank.
I’ve encountered several breweries who have a settling tank designed in to their wastewater system. I don’t like this idea, for the above reasons. Solids you put down the drain will settle, but then they’ll grow and in no time (~1 month) the settling tank is full and wastewater is skimming across the top and out the pipe.
It’s a good idea to have a septic pump truck come vacuum your tank at least once a year. They will remove all water and solids in your tank and give you an opportunity to inspect your tank and equipment and do any maintenance. Don’t use their hoses! Get your own, 2″ for light duty applications and 3″ for the big jobs. Make sure you have a cold water wash down hose available when sucking out the tank, use it to stir the tank and fluidize those solids.
Sometimes a municipality will apply temperature restrictions. As mentioned above, the most cost effective method to lower the temperature of your wastewater is by storing the water until it cools. An alternative it to add cold water, this works but it’s a waste of water and may even be prohibited. There is such a thing as a wastewater cooling tower, but this is a game you don’t want to play.