Hi KarenRei, welcome to the site.

Just a few observations about the methods you cited:

1. Quicklime - I like the idea of using a flocculant, but keep in mind it only works on suspended solids, unless it generates a chemical reaction to precipate something in solution, which there is a possibility of, but not comprehensively. Flocculants will clear turbid water, and may capture some biologics, but I would not rely on it to disinfect the water.

2. pH adjustment - Because many of the organisms that cause problems have a level of protection against most common pH levels, you really have to swing it hard to start disinfecting. It can be done, but the subsequent solution is a hazard just to handle, and will have to be neutralized in order to be consumed, which can also create other problems. Water passed through wood ash extracts Lye, which is what changes the pH and is pretty hard on the digestive system. You would want to neutralize the solution, which again introduces chemicals into the water that may not be consumable. Think of it like shocking pool water, you wouldn't want to consume it, much less bath in it. You know, it does bring to mind the idea that carrying a couple pool test strips in my PSK might be of some benefit.

3. Infiltation methods depend on a sterile environment. You might have to go pretty deep to get passed contaminated soil far enough for the straining effect to be reliable. A lot of wells get contaminated from local sewage for being too shallow and/or downstream of the underground effluent gradient. I would still recommend boiling or other approved form of dinsinfection as a minimum.

I encourage you to continue your contemplations. Primitive systems were simple, but not always effective. Look at modern technology, understand what it is you need to accomplish, and see if there's a way to apply more mundane methods to meet the same standards or water quality. MacGyverisms are sometimes more field expedient. There is a certain amount of science behind safe drinking water that goes a bit beyond common sense, so a little more research may be of benefit.

Hope to see many more posts from you. New ideas stimulate thought.

Cheers