Your Photo seems to inciate that the water fall from the constructed wetland to the pond.
The waterfall is not part of the pond/wetland system. It is part of a secondary system which is primarily aesthetic (a lower pond, not shown, and flowing stream fed by recirc pump in pond), but which can also be used as a secondary redundant system if the first one fails.
Is the water being pumped back from the pond to the wet land.
Yes. But, as noted above, not with the waterfall visible in the picture. A small fractional hp submersible pump in the pond recirculates water from the pond to one end of the root-zone filter.
What are the dimensions of the wetland.
The pond is about 5' diameter. The 'wetland' (more properly, a subsurface flow root-zone filter?) is a lined trench about 16" wide by 12" deep around 1/2 (or a bit more, say closer to 2/3?) the circumference of the pond, filled with pea gravel. The plants include pickerel weed, umbrella palm, dwarf papyrus, duckweed and some grasses. Fish in the pond are my water quality monitors (canaries in the mine).
As the water fall down throught the garden soil how many layers of of soil/ sand/ gravel does it fall through.
Two. The "indoor leachfield" is 12' wide by 30' long with a sloping bottom varying between 4' and 8' depth. It is filled with sand and gravel (pit run) to about 18" from the surface, which is covered with geofabric, and topped with soil. Water from the pond overflows to perforated drain pipe laid in the soil layer.
What are the detentions times of each of your treatment units?
OK. Thinking out loud here.... Average daily flow is < 50 gpd. But it can be as high as 100+ (if, say, run a load of wash, plus dishwasher plus 2 showers, etc.).
The primary treatment unit (current design, anyway) consists of three 55 gal drums, so let's say it holds about 150 gallons. (HRT: avg: 3d, peak flow: 1d)
The pond is about 5' diameter by avg 24' deep, so that's about 40 cu ft, or ~ 300 gallons. Volume of the root-zone is about 5' x 3.416 / 2 x 1 x 1.5 = 12.8 cu ft. Assuming, say, 20% voids in the gravel, lets say it holds about 2.5 x 7.48 ~ 20 gallons (HRT: avg ~6d, peak flow: 3d -- for entire pond/root-zone system)
Volume of the 'leach-field' is 12' x 30' x 6' x ~.1 (a wild guess as to void space?) x 7.48 gal/cu ft ~ 1,600 gallons. (hrt not valid concept for this system, as there is some channelization. Next time, I would replace the pit run gravel with better graded sand, or make other design changes)
Volume of storage cistern is about 5,000 gallons, though depending on rainfall, time of year and usage patterns it is often less than full.
Have you had any sample analyzed for.
Yes. It has consistently tested bacteria-free. In the 20 years we have lived here, the system has evolved. At first we didn't drink the water, using the recycled water for everything but (including washing dishes and brushing teeth, but not actually consuming). Then, as we gained experience and confidence in it, we installed a RO unit at one kitchen sink just for potable water. Then after a few years of that we replaced the RO with a capillary membrane filter (0.35 micron absolute) -- which offers distinct advantages.
Does your 5000 gallon sictern remain aerobic??
I assume so, though I've not checked DO levels. But I bubble air in it continuously. Again, as an ongoing experiment, I have also bubbled ozone through it, though not currently doing so.
My inital test bed for an eclogical engineered water recycle system will be an 18'ft saliboat. My water consumption will be 5 gal/day. I'll shower with a misting system to acheive such a small water useage.
Whoa. Very interesting, but way different from my system, and I'm not sure how well my system parameters would scale. Are you familiar with NASA's CELSS? Probably way more high-tech and complex than what you are after, but maybe some good ideas that could be borrowed.
My first thought would be to enlarge the scope of your question from "How can I convert sewage to drinking water?" to include other things like reducing BOD at the source. If you can avoid putting your shit, piss and food scraps in it in the first place, it becomes a lot easier to treat back to drinking water quality.