These blog and Facebook posts are designed to keep the public, other researchers, our funder, and, most importantly, our partner communities informed about project progress, and to provide a two-way street of communication that supports the development of an optimally designed system. Last week we shared links to, and GIFs of, 360 views of the test cabin and treatment Conex — and here soon we will begin sharing some initial data from our tests — data on water quality, power requirements, and fixture flows, among other parameters of interest.
In the meantime, we’d like to take this opportunity to answer some questions that seem to crop up each time we have a visitor to the test site. The following questions pertain to household layout and uses. If you haven’t yet had a chance to check out our previous blog with video of the system, you might find it most useful to do that before reading these FAQs. [In later blogs, we’ll also touch on system design and operation, construction and maintenance, and details of the Water and Sewer Challenge (which is funding our work).]
Q1. Why are there so many wires, tubes and boxes?
We set up our test cabin so that visitors could easily see and understand where and how water is running through the system. In an actual home, many of the tubes and pipes would be grouped together and hidden in a duct or otherwise out of sight. Since we do not have people living in our cabin and using the shower, toilet, laundry and sinks, we have installed a lot of wires and control boxes to automate our system. This means that every fixture is automatically turned on/off and concentrated synthetic greywater, blackwater or urine is automatically dispensed into the sink each day to simulate a 4-person family living in the house. We also have Ethernet cables to log data onto a computer so that we can monitor the system and report on its operation. If this system were installed in a normal home, roughly half of the wires you see in our demonstration system would be needed, and most of the boxes, pipes and cords that are required could be installed out of sight. The multi-colored pipes and air vent would indeed be located in your home, running to and from every fixture. However, these could easily be grouped into a single duct and hidden, just like electricity and plumbing in city households. The small pumps and air compressor that deliver and remove water (which are the noisiest things in the test cabin) could easily be located in the treatment Conex to save space and reduce the noise of the system. It may also be possible to place the keg container (which collects solids from the toilet) in the treatment Conex.
Everything in the Conex is part of the treatment system and would remain out of sight within the shipping container, yet easy to access for maintenance. The treatment Conex would be located adjacent to the home.
The following pieces of our automated testing system would not be in a home:
- All automation control boxes (large gray plastic boxes)
- Power monitoring boxes (small gray boxes)
- Internet cables (blue and grey wires high on the wall)
- Valves and flow meters (connected to the pipes)
- Concentrate buckets and hoses at each fixture
- Black electrical cords that are running along the walls
Q2. Do I have to have color-coded tubes on my walls?
The tubes that take water to and from your fixtures are color-coded based on the type of water that they are carrying. Green tubes always carry clean wash water. Orange carries used greywater from the bathroom sink, laundry, and shower. Black carries reuseable greywater from the kitchen sink. Yellow carries urine from the separating toilet. White carries compressed air that pushes the sewer system. Blue carries treated drinking water. These colors aren’t required, but are highly recommended for a home system because they help easily identify the type of water you are working with when repairs are needed. For example, if you have to repair a leak or replace a part, you might want to know whether it is a water or airline so you can properly stop the system before you make the repair. However, we also recommend that the tubes be grouped together and put in a box out of view, both for aesthetics and safety.
Q3. What pieces are customizable for each household?
Every fixture in our home is made to operate independently of one another, which means that you can choose not to have any single fixture in your home. For example, if you do your laundry at the washeteria, you may choose not to have a washer/dryer fixture in your home. The locations of things like pumps and air compressors will also be individualized based on the preferences of the homeowner and the layout of the home.
Q4. How does the toilet work?
Our toilet in the test cabin has two unique features compared to toilets you commonly see in cities. First, it has a dual flush, which means you can press one flush button when you only need a little bit of water (like to rinse the bowl after urinating) and you can press a different button when you need a full flush (say, for after number two). This way your home doesn’t waste water with urine flushes, but you still have a normally functioning toilet.
Secondly, our toilet diverts urine to a separate tank than the one that collects solids. There is a separating wall in the toilet bowl that makes sure that urine goes into one hole in the front of the toilet and poop goes into a different hole in the back of the toilet. In this way, poop will be moved into a sealed container and urine is diverted by a small pump into the treatment system so it can be treated. The only difference in use is that everyone is encourage to sit down to urinate so that the liquid goes easily into the proper hole.
Otherwise, our toilet looks and feels like your average porcelain toilet with a seat, a lid, and a way to flush the waste away!
Q5. How does the washing machine work?
The washing machine in our demonstration cabin is a combination washer and dryer. Just like a normal washing machine, you put your clothes and laundry detergent in and select your cycles. You can choose to either have the washer go right into drying mode once the washing is done, or you can have it stop after the wash and you can reselect the dry cycle or choose to hang your clothes to dry. We chose this unit because it uses less water than a standard washing machine, and therefore reduces the costs of treating water for a single wash cycle.
The drying process works slightly differently than a normal dryer. There is no lint trap, so lint gets caught on a rubber piece near the door and is removed by the user when they desire. Clothes are primarily dried by really fast spinning and little heat, so they may be slightly damp when they are removed at the end of the dry cycle. If you remove the clothes and shake them out once, that usually takes care of much of the remaining moisture.
The final distinguishing feature of our laundry unit is the large white water tank behind the washing machine. This is a temporary holding tank that allows the washing machine to expel water faster than our valves can open and close to push the water into the Conex for treatment. This tank will partially fill up during normal washing machine operation, and then drain over the period of about an hour as the water is transferred by compressed air into the Conex. The homeowner shouldn’t have to do anything to this tank.
Q6. How long will the shower run?
Some early visitors have asked us “How long of a shower can I take?” after seeing that our shower drains into a 4-gallon temporary holding tank. So we timed it! Even though the temporary holding tank looks small, it will fill up and empty itself quickly enough that the shower will not overflow. Theoretically, you could take an endless shower, with the drain closing, emptying the temporary holding tank, then reopening every 3-5 minutes. The only limiting factor on your shower time would be how hot you want the water to be. We have a 4-gallon water heater attached to the shower, so if you shower for too long, it might get chilly.