View Full Version : BOD and Sewer discharge

03-09-2016, 09:05 PM
We have a 7bbl brewhouse, 30bbl CCTs and BBTs. We have been side streaming our yeast into 55 gallon drums and having them hauled off. Very little yeast enters the sewer system. Our TSS tested at 400 last month however our BOD was 12200. The day they tested we where brewing and not cleaning tanks therefore no yeast entered the sewer system. The only waste was excess wort from our mash. I assume due to how they test sample and analyze 5 days later there is a yeast culture growing out of control in their lab. I have no idea how that number could be this high if not the case. They have no suggestions for me either.

I'm trying to figure out how to get our BOD levels down as we are not streaming very much into the system and hauling off 99.9% of any BOD material.

What are other doing to keep this in control? Caustic additions to the trap or flow?

$1000 sewer bills are killing me.


03-10-2016, 04:20 AM
Your BOD issue has nothing to do with yeast it is the wort from you mash.
See definition

Also see this page for help. It is a great resource...


The solution is put less wort down the drain or none at all.

03-10-2016, 11:11 AM
Talk to your sewer dept., the flow/month you are creating is a drop in the bucket for their total usage. I usually try to work my brews around the testing schedule. We get a call a week before to schedule the sampling. Yeast down the drain would increase BOD and TSS potentially, wort is the more likely culprit, but say you put down 3000 gal/month, you maybe have 200 gallons of drainage from your kettle/mash tun in it. It ends up being a really small number, but most sewer departments just assume all 3000 gallons are that way. If they ask you to pay more capacity fees, point them to the Livermore Sewer Department, Steve Aguiar is the man in charge there, he is very practical about it and understands how breweries work. At a 7bbl brew length, there is no way that you are creating a problem for them, as you grow and the effluent volume increases, its a different story.