food waste: down the drain, or out with the trash?

Years ago a roommate suggested that rather than shoving food scraps into the garbage grinder, I should scoop them into the trash. His reasoning was that although they will take up space in the landfill, putting them into the sanitary sewer system will increase the energy and chemical-use requirement at the water treatment plant.

It made sense to me then, although I still don’t have any proof either way. Given that I’m not composting, which is more “environmentally friendly,” and which costs less money?

A)put food scraps down the drain of my kitchen sink, where they go to the water treatment plant and get addressed with flocculent, chlorine, agitation, and so on.

B)put food scraps in my trash, where they end up in a landfill, taking up space and slowly releasing methane for a few years.


I’m an engineer at a sewer/water utility.

If the wastewater treatment plant has the available treatment capacity, there is no real problem with putting food waste down the drain.

The problem is that many treatment plants are already at their treatment capacity, especially with the increasingly stricter discharge limits. In that case, the utility may discourage or even prohibit the use of food disposer units until they can increase treatment capacity. Note that this is always a major project and typically costs in the tens of millions of dollars.

Note that the disposal of food waste is a separate issue from the disposal of trash. Trash (including razor blades, condoms, dental floss, paper towels, etc.) should never be disposed of down the drain.

Finally, note that it is almost always a bad idea to use a food disposer unit it you have a septic system. Septic systems are almost never properly sized to handle a food disposer unit, and even if they are properly sized, the tank needs to be pumped at a much greater frequency–which people rarely do. If the tank fills up and the solids make it into the leach field, it can cause premature failure of the whole system, which can cost tens of thousands of dollars to replace.

–robby, P.E.

Aren’t they going to decompose into much the same substances no matter where they are sent?

Most landfills have no oxygen available for decomposition – the stuff just sits there.

Might be time to take another look at your rejected third option, composting.

on this aside

that is good advice, the bacteria that do human waste aren’t the ones that do the food waste. it just adds to the solids.

3 years is a good length of time to inspect if pumping is needed.

archeologists have drilled landfills and brought up still recognizable food (hot dogs and corn were some as i recall) from maybe 50 years ago, they dated it by printed paper that came up at the same time. landfills are covered rapidly and so there is not decomposition by anaerobic bacteria. anaerobic bacteria in the mix of a landfill work very slowly.

composting can be done stink free and rodent free (don’t add meats, fats, eggs). you can do it in a small plastic garbage can. people do it with worm assist indoors so that method is rapid and stink free.

By definition, oxygen is not required for anaerobic decomposition, which results in the production of methane. Most solid waste landfills tap this gas to prevent its buildup in the landfill. The gas is either flared off or used for energy.

While the process is relatively slow, a large landfill will produce large amounts of methane from decomposing organics, including food waste.

This brings up a question I’ve had for a while but never got around to asking anyone.

Say you’re a city dweller with no desire for houseplants and no yard for gardening.

What do you do with compost once you’ve created it? Don’t you then have the the same dilemma regarding your compost that you had about the original un-composted waste - into the trash stream vs down the drain?

I often just throw old banana peels and old fruit out into the bushes. My thought is that it just decomposes on its own and enriches the soil and bug life a little bit. Is that a good alternative?

put it anywhere there is dirt underneath you. if you only had lawn then just fling it around, it will work its way down on its own or you could rake it in.

aged compost makes good potting soil, so you could give to anyone with houseplants or garden, they would appreciate it.

Fats down the sink/disposal are the problem. ** You don’t want to put fat/grease into the water treatment system**. It causes much grief…

Cite from water treatment folks:

T*he results of a grease-blocked sewer pipe can be:

* Sewage overflows in your home or your neighbor's home
* Expensive and unpleasant cleanup that often must be paid for by the property owner. The average cleanup cost is about $3,000 which does not include replacing carpets and repairing walls.
* Possible contact with disease-causing organisms
* An increase in operation and maintenance costs by the local sewer district and King County's regional treatment system, which causes higher sewer bills for customers. *

Right. We call this the FOG (fats, oils, & grease) problem.

Also, a nitpick…you mean wastewater treatment plants.

Water treatment plants produce potable water. Wastewater treatment plants treat sewage to make the effluent safe to discharge into the environment.

The garbage grinder only makes sense to me when I’ve got something that will smell very quickly, like a pear core. And even then if I have something on the top of the trash to put it into, like a bread bag, I’ll use that. I’ve wasted too much time with clogged drains to give them a lot of chances to stop flowing.

Goes to my dog [meat stuff and bacon grease/drippings not made into gravy] and chickens [veggie peelings, leftover veggies]

Ack! Did not realize this was GQ. Deleted MPSIMS-style reply.