Where does (sh)it go?



Well, this is crappy…

Just saw a large box of baby wipes get delivered to an office. They were Kirkland brand, but that doesn’t really matter. In a larger font than the actual product name was the text “FLUSHABLE” written on almost every side of the box. On top of the fact that baby wipes, hand wipes, wet towelettes, etc. are single-use items, which zero wasters passionately try to avoid, these items should not be flushed down the toilet. Ever.

Just because something can be flushed down the toilet, technically making it flushable, does not mean it should be flushed down the toilet.  I could explain the breakdown, but why not see it for yourself in this clip from Adam Conover:


But, this isn’t just about baby wipes, or Q-tips, or the things we flush that we’re not really supposed to. This is about EVERYTHING we put down the drain that doesn’t come from… us.

This includes the food you put down the garbage disposal, too. In-sink garbage disposals are probably one of the worst municipal ideas ever designed. They are a massive contributor to landfill and water pollution.

Let me explain why.

After you flush, wash your hands, your dishes, all that water goes to the same place in the Bay Area of San Francisco. If you’re not from here, your city probably has a very similar design. This waste gets collected, treated, and is separated by solids and liquids. The solids go to landfill, the liquids eventually go back to the ocean.

Here’s where the, “There is no away” quote really comes into play. People often toss Q-tips, baby wipes, and cotton balls into the toilet. That adds up. They peel vegetables and use the garbage disposal, or pour bacon fat down the sink drain. In many situations, people flush old medicine down the toilet. Some medical facilities are instructed to toss dyes down the drain. People flush their illegal drugs down the drain. Less than moralistic companies dump toxins down the drain. Untrained hospital staff dump chemicals down the drain. In fact, wastewater coming from hospitals is some of the most biohazardous water in the world. The list goes on, but you can really use your imagination when you consider how much just gets flushed and forgotten about.

But again, there is no away.

All that solid matter collects, the chemicals, the medications and toxins; it all accumulates. As shown in the Adam Conover clip, the mass of congealed waste solids get stuck in our sewage systems, and cost the tax payers millions annually to clear. They’re called fatbergs, because they look like giant icebergs of lard.

66 foot long fatberg blocking the sewer systems in London


What is the most common item found in the fatbergs clogging the San Francisco sewer systems?


Baby wipes.


When the sludge finally makes it to the wastewater treatment facilities, it starts the process in a fairly easy to understand method: they filter the gunk through large metal screen. This is called Preliminary Treatment.

In the next step, the Primary Treatment or Sedimentation Phase, water is simply allowed to settle. The fats and oils eventually float to the top and the remaining solids sink to the bottom, leaving the cleanest water in the middle. Then the solids are raked from the bottom, the oils are skimmed from the top.



Treatment Graphic alone
Source: http://www.svcw.org/



The Secondary Treatment phase is the arguably most important step in the wastewater treatment process. The wastewater is poured onto screens covered in microorganisms like bacteria, protozoa, and fungi, that digest the waste in the water, cleaning it. The wastewater is then oxygenated again in a process called Aeration – where air is blasted up from the bottom of the tanks, exciting the microorganisms into feeding.

In many cities, this is where the waste water treatment ends. It either goes straight to the ocean or is flooded over wetlands or marshes for further filtration. Still, leading to the ocean eventually.

But in the Bay Area, our wastewater treatment facilities take it a step further with Tertiary Treatment, which passes the treated wastewater (called effluent) through a fine screen called a dual media filter as it first passes through sand, then through Anthrocite coal.  The water then is disinfected in a contact tank with added chlorine, then gets dechlorinated with Sodium Bilsulfite, (Exhausting, huh?) Finally, the effluent is exposed UV light, killing the DNA of any remaining microorganisms. Destroying pretty much anything left alive.

Still not considered safe to drink, the effluent is pumped over designated wet lands, acting as a natural filtration source before entering the Pacific Ocean.

So, if you were worried that your tap water was recycled toilet water, you can rest at ease. It’s not. Actually, San Francisco has some of the cleanest, purest tap water in the world. Our water comes from Sierra Nevada snow melt. Why buy plastic water from a swamp in Florida when you can get pure mountain water from your faucet in the kitchen?

And one more really important thing….

All those solids that were collected in the Preliminary and Primary Treatment phase? They’re processed with anaerobic bacteria (bacteria that doesn’t need air to survive) and turn that nasty sludge into a compost-like substance called BioSolids. Biosolids usually end up in landfills, but if they’re considered safe enough, they can be used as compost for crops. That’s why it’s so important not to flush medication down the toilet.

So, if you thought your cucumber peelings would eventually make it out to sea, I’ve got some bad news for you. Save the solids for the compost bin. Don’t use the disposal in your kitchen sink as a composter!!!!! 

Side note: Did you know the anaerobic bacteria I mentioned above are called methanogens? When you cover something in landfill, you take away the oxygen. Most bacteria need air to digest matter, and release C02 as a byproduct. When you take away the oxygen, only the methanogens can survive. And they release methane, which is 72% more toxic to our atmosphere than carbon dioxide.

Luckily, the bay area of San Francisco developed technology to capture to methane and use it to power their facilities. Genius!


How does your city treat its wastewater? Laws can be very lax in some states. Is your city a pollution contributor? 









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