In my county we're required to have a septic system in order to have composting toilets. Before proceeding, please understand that I am only catering to this expensive formality and safeguard. I fully intend to safely and properly composthumanure and have already been separating urine to mix with wood ash and comfrey for brief aging into a balanced* fertilizer.
I've been digging and probing holes for weeks to figure out how the soil will work and where to site a septic field. This 50" probe was what the company lent me to do the legwork.
The lasting concern on my rolling-hill property is a perched water table. 6 months out of the year, the groundwater rises or runoff settles to a certain point, 24-38" below the surface, and abides there, preventing aerobic activity in combination with clay-rich soils. This can be seen in the soil profile of a 5' deep hole: a grey layer indicates an anoxic environment, whereas reddish brown means that even if the soil is soaked, it still breathes enough for aerobic bacteria and thus permits root movement. This aeration is necessary for a functioning gravity septic. One can barely work a pocketknife into a soil profile at 36" deep because of "mottling" where clay increasingly composes deeper soil layers. What's above that restrictive layer is good soil, especially because conifers that would acidify it were removed decades ago.
I was told to look for deeper soils wherever huckleberry grew, because its roots are deep enough that to remove it, the soils would have to be scraped/eroded almost down to hardpan. The septic site I found, possibly a gravity but no worse than a shallow pressure septic, was an expanse rich in huckleberry, but also sword/deer ferns.
The hummocked areas, where the soil was mounded around an apparent path, were said to be the wakes of skid trails, where logs were hurled out of the forest to landings. This eroded or scraped away the soil along those paths.
The topsoil is limited at my site, and of course I've found great info on permies about how to build that soil. I'm not sure how concerned I should be about that; we are aiming to rehabilitate abused land, after all. I only aim that my rehab should benefit a place I'll get to enjoy before my dotage.
I'm planning to mulch the 20 year regrowth of alder there for soil building and mushroom beds. It's a useful tree but prone to widowmakering (dead tops falling off) and falling uprooted when it gets too big in shallower soils. I'll leave some to fix nitrogen but thinning them will provide N-rich organic matter for my imported trees, which seems like a good idea.
As ever, any thoughts or reflections are welcome. Thanks!
Well, at least you are not in Pacific county, Washington-the home of the dumbest building codes in the state. A high percentage of the minions in Washington state are failed civil engineers who are thoroughly convinced that water runs up hill naturally. I bet they will hit you with installing a "mound" system before long and ignore completely the fact that you are seeking a composting setup-which they already have sidestepped. I wish you luck but the toads up in that part of the country are abysmally stupid and seem to think that Jerry Brown is the answer to any problem that they can't understand. Most counties on the western slope of Washington state have simply adopted one version or another of California building codes. So much for intelligent thought. To require a septic system for a composting toilet is one of the most outrageously stupid responses I have ever heard of. Welcome to King county.
Buy the turds a cup of Starbucks and maybe they will jitter away down the road and leave you alone... Good luck.
Rehabilitation of abused land generally means soil building.
Septic systems are usually "perked" with the hole method. In Arkansas, we deal with bed rock a lot since it isn't far down.
What might work for you would be to dig deep trenches for the field lines and fill the bottom half with coarse rock then finer rock then sand.
The field line will need a "sock" most likely then you fill around that and above it with more sand finished off with soil.
On Buzzard's Roost we have a septic system that was done this way, it works very well and doesn't leach pathogens into the soil.
Be sure to add bacteria to your system on a regular basis and make sure the soil above those lines are fungi rich so you don't have to worry about pathogens the way a "standard" system would allow.
Thanks Redhawk. Incidentally, I did perc the holes, then was told WA state doesn't honor that technique anymore :/. I'm not as worried about the septic. I'm getting a 2nd opinion after having first consulted the county's priciest installer. The larger worry is the topsoil on the property overall: the limited topsoil, the perched water table for 6 mos out of the year, the heavy clay inclusions past a certain point. I know it's not insurmountable but I hope to be able to do what is needed by the land and me, within my budget.
Quite coincidentally, I saw this article today. It quotes Savory, Yeomans and others from that vintage, and says that one can build more than an inch of soil per year by implementing effective protocols as outlined by Yeomans, Savory et al.
It was tweeted by Eric Holthaus, a journalist of some note, and led to some recent debate on Twitter. I can see being worried that Eric Holthaus is being an apologist for the industries and social forces that have been denuding our topsoil for millennia. But the article he links discusses what I hear in permaculture, and it will be a primary concern of mine on this new piece of land.
So is this what happens when permaculture theory about soil building goes mainstream?
And. more prosaically, Redhawk, what bacteria do you add to your septic? Sourced from where?
hua Freddy, The bacteria I use come from two sources the first being a commercial product called RIDEX then I also extract bacteria from some compost and add that to the system around 10 days after the RIDEX treatment, which I use bi-monthly.
Yes, the simple act of growing plants will improve soil, if you regularly grow, cut and let rot in place you will speed up the natural process of soil improvement.
Anne, I plan to hire a contractor. But if the ultimate design is simple enough, I'd rent an excavator and dig it, sure! (Hoping I'd finish in time to do some of my own extra work with the excavator.)
And yes, the placement is key to where the house will be built. But since I don't know what I'm building, where to place it is hard to say. I'd like to be 1/3 of the way down the hill, not at its top, but the least slope and most compaction for foundation purposes is on the plateau. So for septic purposes I'm supposing the residence will be somewhere near there.
Thanks Redhawk, I've heard of RIDEX before, maybe here, but I'll look up how to extract bacteria from compost. I hope to be as precise in my methodology as possible: having inherited my father's microscope, I plan to use it for spore prints, compost sampling, and safe humanure production. All this might be naive but I've yet to learn that! If it turns out feasible for an ordinarily smart person, that would be a great book with color prints: MICROSCOPY FOR THE HOMESTEAD.
1. Place the compost in the compost bag (0.5 to 1 pound per 5 gallons of water) (Make at least one slide and check for bacteria with your microscope, if needed use graham stain to see the bacteria)
2. Briskly massage the bag for 30 seconds to a minute
3. Check the tea to make sure it has the organisms needed. (make a few slides for your microscope)
4. If not enough organisms, then extract another 0.5 to 1 pound, repeat if necessary until organisms reach minimum or desired levels.
6. If the compost you are using has good sets of organisms in it, perform the procedure above.
7. But if you do not know if your compost is good or not, then add foods (humic acid or fish hydrolysate, or steel ground oats, or bran or.....whatever fungal food desired) to the compost 3 to 7 days before extracting (good air flow around the compost, don't let it get stinky).
That is the method I use.
Oh btw, I'm not working on one of those books, Elaine is working on one with some of her students I believe.
The book I use is my microbiology text book, "Advanced Microbiology"