Friday, Feb 14, 2014 at 00:51
The following
comes from here:
Error: Storage of
grey water
Storage rapidly turns
grey water into
blackwater (see photo, page 4). The word "storage" should immediately sound an alarm, as should anything that includes a tank bigger than 55 gallons (for residential systems). If you doubt this, just fill a bucket with
grey water and observe it as it progressively darkens and becomes more fetid. Bacteria multiply to
blackwater levels as
well, at least the indicator bacteria. In Mexico the trampa de grasa (grease trap) often included in
grey water systems is a very popular way to commit this mistake-omitting or bypassing the trampa de grasa would be much better.
Preferred practice
24 hours is generally considered the prudent maximum time for storage. Since this is not enough time to, for example, store
grey water from a time when irrigation is not needed to one in which it is, I find myself tuning designs to eliminate pooled
grey water anywhere it occurs; just send it all straight to the soil. The fewer little anaerobic corners and pockets the better. My latest designs drain COMPLETELY…all the collection plumbing, distribution plumbing, and surge tanks (if any) slope at least 2% across their bottom surfaces.
Manually distributed
grey water can be stored for the day to allow for manual distribution all in one session. Tanks for this purpose should be designed to drain COMPLETELY (not leave a bit of fetid
grey water at the bottom to inoculate the next batch) and NOT BE TOO BIG as this invites misuse in the form of letting the water sit too long.
FollowupID:
808609