Recycling Shower Experiment #1: 4 Gallons of Gray Water, 1/26/09

I started the experiment by collecting 4 gallons of dirty shower water from the interceptor tank in the garage (In the garage, I cut the 4” drain pipe, and ran it into a 35 gallon tank to collect shower water for experimentation). The water was from a shower taken by me on 9/30/08. Therefore, the water had been setting in the tank for almost four months. The water was quite ripe, and had a significant odor of rotten eggs as I transferred it via a hose attached to a boiler valve in the bottom of the interceptor tank into a five gallon bucket. It also foamed quite a bit. I carried the bucket into the workshop/laboratory and let it sit for 15 minutes. It had the typical gray cloudiness of gray water, and most of the foam had dissipated within 10 minutes. It still smelled, but only if you put your nose very close to the top of the bucket. I took a sample of the dirty water, and then poured the four gallons into the holding tank for the recycling shower. When I poured the dirty gray water into the shower holding tank, the odor was again very noticeable. The previous week, I used approximately 15 gallons of water to test the plumbing concept; so, that water was still in the system. With the additional 4 gallons of dirty water, I estimated the total volume in the system to be approximately 20 gallons at a starting temperature of around 50 degrees.

 

I began the recycling experiment at 3:06PM. I opened all the shut-offs, plugged-in the pump and UV light, attached a 2” PVC pipe to the shower faucet to prevent splashing and placed a thermometer under the end of the 2” PVC pipe to monitor temperature. I then turned-on the shower and let the system run. I let the system run at a flow rate of approximately ¾ gallon per minute (the flow rate varies as the pressure tank cycles from 50lbs to 30lbs, and back again about every minute and 45 seconds) for an hour and ten minutes (until 4:16), observing and taking readings periodically.

 

I took a reading of the temperature about two minutes into the experiment, and observed the temperature to be around 65 degrees. The tankless heater did not provide the instantaneous hot water as I thought it would; but I have made no adjustments to it. I will read more on its instructions, and work on calibrating it in future experiments (a table of temperatures thru the experiment is presented below).   As the shower began to take-up the dirty water, the odor of rotten eggs intensified.   The odor became quite intense as the water heated-up (after about 15 minutes the temperature was in the mid-90’s; but then, the odor disappeared after about 20 minutes). My assumption was that the filters had begun to do their job. Even when the water temperature exceeded 120 degrees and was steaming, I could note no odor when I put my nose close to the steam.

 

I took three water samples. The first sample was of the raw gray water that I got from the interceptor tank. The second was of the recycled water from the shower faucet after 20 minutes of operation. The third was of the recycled water from the shower faucet after 1 hour of operation. I plan to take these three samples, along with the baseline water sample from the previous plumbing proof-of-concept test, to IUP for thorough analysis.

 

Overall, I think the experiment went very well. The crude plumbing system worked smoothly and efficiently; it purred like a kitten. The filters and UV seemed to eliminate all odors, and the end water seems perfectly clear (after 1 hour of operation). The tankless heater didn’t work as expected, but I haven’t calibrated it at all; and it did eventually heat the water to over 120 degrees. The results of the water analysis will help determine the next round of experimentation.

 

 

 

3:06        50 degrees

3:08        65 degrees

3:20         80 degrees

3:26         92 degrees

3:42       112 degrees

3:49      120 degrees

Thereafter, 120+ degrees (too hot to touch)

Note: the thermometer only went to 120 degrees