California: Get Ready To Drink Toilet To Tap Water

It’s not exactly something to celebrate. But, yes, soon California’s largest cities will be taking residential sewage and converting it into “fresh” drinking water. Your renewable toilet water, of course, will cost more. The processing is expensive, and there must be oversight to ensure the systems don’t fail. But all that aside, there will be more water to sell during droughts.

How will all of this work? There are six “purification” steps between flush and faucet:

1. Preliminary Treatment: All the random debris in sewage is filtered out, typically using bars and grates. Essentially the treatment process starts by removing the largest objects and moving on to the smallest. You never know what goes into one’s toilet beyond human waste, but used tampons or condoms, perhaps?

2. Primary Treatment: The waste is then sent to settling tanks where heavy solids, such as fecal matter, sinks to the bottom and forms a sludge. Meanwhile, oils and soapy chemicals float to the top and form scum.

3. Secondary Treatment: The next step is to remove organic matter and other biological contaminants from this “clarified” water. In aeration tanks, oxygen bubbles into the water, allowing microorganisms to gradually digest contaminants. After gorging, these microorganisms clump together and settle to the bottom of the tank.

4. Tertiary Treatment: Wastewater that will be used for non-potable purposes, such as irrigating crops (lettuce?) or golf courses, must then be disinfected. Typically, chlorine is used to kill bacteria, making the water safe for many purposes, but not drinking.

5. Advanced Purification: Additional steps are taken to purify the water enough to consume. It is disinfected with ozone, digested by microbes and filtered through activated carbon. Reverse osmosis clears away chemicals and salt, and finally advanced oxidation with UV light cleanses remaining contaminants.

6. Almost There: Then, finally the wastewater will be subjected to the regular treatment that all drinking water currently undergoes.

There’s a positive spin for this new source of drinking water, and a timeline for when it will begin flowing from California’s residential taps. Are there potentials risks? Yes, you can read all about it here in the Long Beach Post.