posted 7 years ago
Hi Gary.
What's your soil like?
I would look at the spot you're considering for the line, and dig down to see if at any point you reach clay. Make sure you don't have your water transfer material sitting some feet below you, first off.
In some places, just trenching down to the clay layer and smoothing it into a trench shape, then backfilling it with large stones, either slowly decreasing the size of the covering stones, such that they eventually block soil from filling the voids, or covering the large stones with landscaping fabric, can do exactly what you need. If the trench at depth needs further sealing, bentonite clay can be used, as mentioned above.
As in all things permaculture, I would balance what is best with what is most accessible to you now. If the best solution is prohibitively expensive and incurs more carbon costs than, say, using construction materials off-cuts or PVC from the big box store, then it's likely not the best solution for you. Building a well-functioning greywater system that doesn't incur constant maintenance expense is more important, in my opinion, than designing a system that perfectly embodies the ethics.
Personally, I think ethics are the wrong focus here. No, I don't want to use piping made by bloodied children's hands somewhere in a developing country. I don't even want to financially support corporations and industries with which I disagree.
Ethical considerations are important, but only to a point, if your focus is to make the most use of resources passing through your hands (the use of greywater, in this case). I think that as long as the material used isn't directly counterproductive to your interests in its use (toxifying the greywater you seek to use to water your food, for instance), the larger issue of setting up a resilient and self-sustaining system might take precedence over the ethical sourcing of materials. I think toxicity is the more important issue.
I often see people frittering away their time debating the minutiae, worrying over every little detail, and not building up their systems as a result. Don't let the perfect be the enemy of the good.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein