im in the process of building a small brewery, part of the regulations include a bathroom (flush toilet needed). no sewer onsite, the plant needs to be on septic.
the brewing (or cleaning) process uses some pretty harsh chemicals (and low concnetration). we generate 50 liters of 2 ppm caustic soda, 50 liters of 2 ppm nitric acid, and 50 liters of a iodine based sanitizer~3 days/week. by design, it kills microorganism, which will mean keeping a healthy septic system going difficult.
my current working plan is this. basically having two systems, one for the toilet, the second for the sinks/area drains of teh brewery. The two stsyems would have a shared leach field/reed bed (more on this below). i would like to design the primary box for teh chemical system to have a candy cane outlet. letting a good amount of water (100-200 liters) be stored, and when it reaches the fill point, the entire box will be syphoned out and discharge to the leech field. allowing to two cleaning chemicals to be mixed and to cool down. the toilet would have a sediment trap at the road (for cleanout of solids) and discharge to the same leach field.
leach field; we have about 30-50 cm of top soil and the sub soil is heavy clay (and sesonally high water table). if this was going to be permitted in the US, it would never pass the perc test. That is why i am thinking about a wetland/reed bed tretament, and over flow discharge. i think the reedbed would be 1 m wide x 1 m deep x 2-3 m long, filled with gravel. i would want to install a few baffles to slow down flow and limit short circuiting. overflow would go to a existing drainage ditch which connects to a abandoned oxbow meander.
Location: Central Texas zone 8a, 800 chill hours 28 blessed inches of rain
posted 3 years ago
Help an old man out, it has been many decades since Chemistry 101. Have you run tests on small amounts of the caustic soda and nitric acids to see what they yield? Caustic=basic (high ph) and Acid=acidic (low ph). I am wondering how much they will neutralize one another and what will remain as the product of the reaction. Also may want to test those to together to see if it is a exothermic reaction that may need some additional precautions.
Overall, I think it is a good plan to separate the two waste streams, until biology has done its thing to the human waste. I am just not so sure how bad the other will be to a leach field at all. The idea of overflow into a stream ruffles my delicate sensibilities; but don't know your laws and regulations. Do you have any waste heat from the brewing process to evaporate some of the aqueous solution? Better to handle a chemical in a solid state than liquid. Cheaper and easier to contain.
posted 3 years ago
Yes, when the two chemical solutions are the mixed, you basically get water.
The overflow will be into a ditch (grasslined), that connects (~400 meters) to an oxbow lake. which is basically isolated from the river. In extreme events, it will overflow into the river.
A dilute acid mixed with a base will give a salty water result. Exactly what kind of salt and how concentrated depends on the source chemicals, but it will not be plain water. You might find that some salt-tolerant grasses or other plants work best at filtering the outflow.