Tuesday, October 26, 2010

Oct. 2010: Septic system, part 1

The time was nigh for a long put off project. I had been trying to wrap my mind around this certain necessity since before I began building the house sculpture. During this October visit, three years into the project, I, with the help of my parents (yet to arrive) would build a code septic system. I had plans drawn up, but the building process was still foggy in my mind. As usual it was my intention to learn as I went along, one step at a time. I knew I would need a lot of gravel and sand so I called a local contractor, Steve Roche. He had brought me fill for my driveway the previous year and the locals spoke highly of him. Steve also turned out to be helpful whenever I had questions regarding the construction of the system as he had built a few of this type himself. This sort of design is called an enviroseptic system because of the special pipe used in the drainage field. Each length is 10 ft. long and 12 inches in diameter. Each piece is ribbed, perforated plastic wrapped in a filter cloth.
I also knew I would need a site leveler to know at what depth in the soil to place each row of the enviroseptic drainage pipe. Ted Pellerin, who had designed my system, offered to let me borrow one of his. It was an old fashioned sort, just fine for what I was up to.
With the leveling device I could determine how much from grade level to take off of the drainage field. I first made some 8ft. stakes to mark the four corners of the field. They needed to be tall in order to pass level of the fixed point at which the system would be built: a nail in a small fir tree nearby. Ted had picked this point and sited everything against it. By lining up the leveler with the nail, and aligning it to my stakes I could calculate how deep I needed to dig for the pipes to sit in their proper places: seems I still needed to take away another foot of dirt. More tractor time!
With the tractor's backhoe I lowered the grade level by about a foot. By that time Steve had delivered two loads of fill, one gravel and one sand. I used this material to build a berm on the lowest side of the drainage field. The lowest side would need to be built up more than the other three; about 30" from grade level. At this point I turned my attention to the location of the future septic tank. I needed to dig a large pit located between the house and the drainage field. The tank would need to sit at a depth relative to the waste pipe coming from the house. Set at a slight angle of 1/4" per foot, the pipe could enter the inlet flange at 54.5" from the bottom of the tank. The depth would change in accord with it's distance from the house. The plans called for a standard 1000 gallon tank which measures about 6ft. X 8ft. side to side and about 6ft. tall, (54.5" to the bottom of the inlet).
I had already measured and positioned the 4" waste pipe's angle starting where the main interior drain would be located under the house to where it would exit the side of the house. Knowing that height I was able to extrapolate the depth of the tank. I wanted to put the tank as far from the house as possible because it must by code be located at least 10ft. from any structure. My future plans for the house involve an addition to this side of the existing house. The location of the tank would therefore dictate how wide my addition could be. I thus began digging next to the drainage field. A big concern when digging in Maine is stone ledge. It's everywhere and makes digging to any great depth very difficult. In my case I needed to have a pit that was about 5ft. deep. With an excavator that isn't too difficult to achieve but with my little backhoe it's a little trickier. I had to dig around a bit and displace a lot of dirt and large stone before finding the spot where a level 6'X8' bed could be made.
It was at this point on a Thursday afternoon that some very welcome guests arrived. It was my parents all the way from Roseburg, OR to help with the completion of this mighty project.

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