I've been exploring the idea of a system to allow re-use (drinking) of RV greywater, or at least the freedom to dump in storm drains (I think the requirements are looser about this, but it still has to be somewhat purified)

Greywater is wastewater that does not contain feces. The primary contaminants would be food waste, various soaps (probably only biodegradable or non-antibacterial), and used shower water. I would also probably add urine, after sterilization to remove pathogens.

I was thinking of pre-filtration to remove larger fragments and detritus. Probably with the highest grade of this

-Processing rate would have to be 10 liters per day absolute minimum. 2x to 3x that would be best.

-Weight and volume are both at premium

  • $\begingroup$ How are you testing the purity or cleanliness of your filtrate (the water thats been filtered)? $\endgroup$
    – CKM
    May 12 '17 at 16:22
  • $\begingroup$ why portable considering shower? any aquarium filter generates a heap of bacteria that process all useable impurities in the water to grow a mat. the bigger aquarium filter the better. it's ultra simple question to me having worked with many dank water ecologies and aquaria. it's only a function of bacterial medium substrate (sponges) temps and wather throughput in a given surface are of sponge. aquarium filters are designed fo rthat, soaps are mostly phosphate. $\endgroup$ May 12 '17 at 20:10

Any kind of sponge and pump filters will breed nitro bacteria to remove organic content. Added to a drip filter made from pure mineral sands and clays, you'd have a bacterial sponge and plant aquarium plus a sand filter.

You can make you own activated carbon too.

Urine requires at heavy plant growth to purify. You already have a tank, volume not given so I'll say it's 125 L. Here's a two stage bio filter: one with an incoming and circular bacterial filter to filter incoming water in graded sponges up to about .05 - 1 mm finest incoming particles for foods and stuff. Use 2 divisions in the tank, one of 100 L, one of 25 L that you can prepare 10 L from every day.

Use 2 fish filters AC of 7 - 20 watts (?) or 12 V (DC) pumps similar to fish ones. Use 500 ml - 1L volume of filter sponges with fast access so you can squeeze out the bacterisl mats periodically because they will fill with nitrogen and phosphate and oxygen based pond organisms.

If you can fill the 100 liter tank with algea, it's ideal.

Put a valve to keep 2nd 25 L tank separate. Filter final 10 L drawn daily through mountain mineral sand from places with great spring water, i.e. dolomites / chalky to add trace elements. It's recommended you use sunlight and lots of plants in the first tank.


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