Wednesday, September 21, 2011

Septic System Installation Underway!

WAHOO! HOORAY! Dirt is finally getting moved on the property. After a minor heart attack when the health department said they didn't have my well test results, all has been rectified and the septic system installation is now in progress.

This is an overview of the working area. The tank lids and inlet cleanout are visible in the foreground. The backhoe in the background is on the near edge of the field of Glendon Biofilter

I'm not overly thrilled with how close the tank and inlet is to the surface, but that is apparently a health department requirement due to the perceived high groundwater table. It is workable. The required fall is only 1/4in per ft so I've got room to make the fall and still come out underground from the home pad. I may change the elevation control through so it can come out a bit higher. I will have to recheck some levels on the pad site.

This is one of the four Biofilter pods. You can just see the second one to the far right in the picture. The basins for the other two pods haven't been placed yet.

Overall, I'm impressed with the amount of work they got done in a single day. I think they are planning to finish up on Friday. That will make me very happy. I'll be even happier if I get my official water test form back from the health department with the magical and mystical approval stamp.

Sunday, September 18, 2011

Even Slow Progress is Progress

This whole process has been "discovery learning." It seems that at each phase, I find some new requirement or hoop that I have to jump through. It has taken waaaaay too long to get to this point. I've decided that the garage will have to wait until next year's building season. Not happy about it, but it makes the most logical sense.

Good news - the well water analysis results finally came back. When the bacteria sample has to be tested the same day it is taken, why does it take almost 3 weeks to get the full results back? Maybe the inorganics tests take longer to do. The water is hard which I expected. Any hardness over 120 is considered hard water. At 123, I'm just above the line between "moderately hard" and "hard". Not a big deal. A water softener in the pump house will handle that. I was told to expect high iron and manganese levels by a couple different people. At 2.2mg/L for iron and .10mg/L for manganese I'm see what they're talking about. Both of them can be removed by a water softener, but will very quickly clog the softener. I've found a couple different filtering solutions. Iron rapidly precipitates if the water is oxidized. It can then be filtered with dedicated filters. As an oxidizer, I've chosen chlorine injection. That has added benefit of dealing well with iron bacteria. I don't appear to have a problem with iron bacteria now, but folks say it is only a matter of time.

In general, water will flow from the DC well pump to the pump house. It will first get filtered for large sediment particles (30micron and 15micron) and then the chlorine will be injected on the way to the storage tanks. The retention time in the storage tanks will be more than adequate by a couple orders or magnitude. Water from the tanks will be pressurized by the demand pump and pressure tank. It will then pass through finer sediment filters, the iron filter (pyrolox or similar), a carbon filter (taste and odor - removes the last of the chlorine as well), and finally to the water softener. Next year, as part of the garage build, I will install a set of outdoor spigots. Those spigots will tee off the main pressure line prior to the water softener. Softened water is generally not good for irrigation due to the higher sodium levels.

Opinions vary on whether drinking softened water is safe over the long-term. I'm taking a conservative view. I will put a reverse osmosis package under the sink which will feed the refrigerator water/icemaker and a faucet next to the main sink faucet. This setup is relatively common and easily done.

Better News! I just got done talking to my dirt guy that will be doing the foundations for the home and pump house. He said my drawings cover all the bases and he'll be getting with his concrete guy and turning a bid around to me quickly. I'm not bothering to bid this one out to multiple vendors. Dan has done work for me before that was priced reasonably and done well.

While you can put a manufactured home on compacted soil, I don't like the idea. While it is cheaper and faster in the short term, you buy yourself a long term and recurring requirement to relevel the home every couple of years. Given the amount of rain we get here, it may be more often than that. I'm going with a full concrete slab and reinforced concrete perimeter wall. It makes the installation what is generally referred to as a "pit set." Instead of the home sitting up 3-4 feet off the ground, it is set over a pit. It looks much more like a site-built home this way. I'm using this method to help handle the slope of my site.

I took the general code requirements and used them as a minimum. I went for a reinforced wall design typically used for basements rather than the thinner and less reinforced wall typically used for pony walls or pit sets. The difference is the thickness (8in vs 6in) and the size/spacing of the vertical rebar (#5 @ 16in OC vs. #4 @ 48in OC). I also added a foundation drain at the footing which is shown for the lighter wall types, but not the reinforced wall. Seemed like a good idea. I don't think an inspector is going to ding me for having a stronger wall with better drainage. Much the same thing was done for the main slab. The code designs only show the #5 bar reinforcing. I added 5x5 mesh. Mesh is relatively cheap and it adds overall reinforcement between the bar grid ties.

The same concepts apply to the pump house foundation. I added mesh and made the footing deeper to ensure it is raised above the gravel pad where the tanks sit. In the event a tank ruptures or leaks, I want some good clearance for all that water to drain without flooding the pump house. The water and drain lines all come up through the foundation and will be buried at least 2 feet deep. Freeze protection will be provided by a product a found which places the heated wire inside the pipe rather than on the outside.

The septic install company I've chosen was out week before last. I got their bid and sent them the downpayment check. Now I'm just waiting for word that they've gotten the install permit from the county and a date for them to start work. WAHOO! We're getting to the point where all the various groups start moving dirt. I would have rather been at this point in late July, but it is what it is.

Whew! Long enough update? As soon as permits start coming in, I'll update more with pictures of the actual build process.