Question:
I am designing a septage holding system for temporary accommodation during the Olympics. The building is a modular unit placed on a paved parking lot. It will be in use for three months. My plan is to plunk down a big plastic holding tank and install a pump vault under the home.
My problem is: What about freezing? I am considering wrapping the unit with 2-inch blueboard. Do you see any flaws in my plan? I know it will be ugly, and so does the customer, but they declined to go with my more appealing but more expensive options. For the record, we usually get a few weeks of around zero degrees every winter. How about a heat lamp? Agitator?
Answers:
- Where are you located and what is the usual frost line? Not what regulators say it is but the actual at low temperatures. Depending on use, it shouldn’t freeze if it’s underground, because the ground stays at 48 degrees F most of the year within 1.5 feet from the surface.
- What about putting an insulated skirting around the modular unit. If that is too expensive for them, what about a brine solution in the tank? Electric blanket set up on an inline thermostat covered with a canvas tarp?
- The blueboard sounds good, but I would also put some kind of heater in the tank, like a cattle stock tank heater. If you don’t need it to heat all the time, you could put it on an inexpensive timer.
- You could run a circulation pump that keeps it stirred up. Make sure the splash can’t hit the sides, or you will have an ice dam forming on the side. Just a mixing pump that takes from the bottom and pumps to the top to keep it stirred up. A little ice on the outside is fine, just so it doesn’t freeze solid.
- How about putting septic heaters on the tanks? Construction companies use them for their aboveground holding tanks on their portable office buildings.
- I think a stock tank heater with a thermostat would be the least costly to operate.
- You may want to check with your state regulatory agency. A local pumper ran afoul of the Illinois EPA when he tried to establish a holding facility just to keep from land applying when the ground is frozen. Illinois public health regulations prohibit land application on frozen ground.
The U.S. EPA decided that what he wanted to do was defined as a “regional pollution control facility” which entails studies and a $100,000 deposit. The agency made that determination because the material is “liquid,” even though EPA regulations exempt septage from jurisdiction. The pumper wanted to erect a slurry structure, which EPA promotes for livestock manure management. However, when it comes to septage, that apparently wasn’t good enough.
