Sciencemadness Discussion Board

Scrubber for waste

paulr1234 - 25-2-2012 at 23:54

I don't use a lot of very hazardous chemicals in my experiments, mainly just common salts such as copper sulfate, ammonium chloride and alike, solvents such as ethanol, methanol and dichloromethane, dilute mineral acids, ammonia, solutions of common bases such as sodium hydroxide etc.

I am thinking about buying a new home that will have a septic tank rather than a connection to the mains sewer. To be honest I've never been happy dumping experiment waste down the toilet, and was thinking about the merits of building some kid of chemical scrubber.

My initial idea was that I could build a large 'filter' perhaps from a large plastic trashcan filled with multiple layers of activated charcoal and other materials. My experimental waste would then be diluted with an excess of water and then passed through this, the effluent then collected and flushed.

The filter medium could periodically be recharged (soiled medium properly disposed of of course). I expect there could be multiple ways to test the effluent and gauge the status of the media.

Any thoughts on the merit of this idea and what to include in and how to structure the media. I thought alternate layers of activated charcoal, sand, calcium carbonate chips etc. might be a good starting point. perhaps the media could even be biologically 'populated' to aid the cleaning process (maybe something similar to the process of seeding bacteria in a new saltwater fish tank).

Cheers,

Paul.

Endimion17 - 26-2-2012 at 08:17

Unless your job is making chemicals in large quantities like a chemical plant (in that case more than a bucket is needed :D ), that's an incredibly wasteful endeavour and probably even environmentally unfriendly (because of the whole expense just to scrub small quantities of mild poisons.
Honestly, who cares about some copper in the drain? Judging by your description, that's the worst thing you'll dump.
Be reasonable. That would be expensive and useless.
Also, a septic tank is just delaying the problem. Those things eventually fill up, and the cleaning truck will have to collect the waste every now and then. They dump the stuff in another hole.

Magpie - 26-2-2012 at 08:36

I pretty much agree with Endimion. It sounds like your "scrubber" would create a big stinking mess. Plus, if you discharge acid into a can with carbonate it will pop the lid and be all over the place. :(

Not being on the city sewer/waste treatment plant system is going to be something you'll have to deal with, however. I would think that the discharge of heavy metal ions (of Cu, Cd, Sn, etc) could kill the bacteria in your septic tank thereby deactivating it.

I think that Honey Wagons that pump out septic tanks discharge their payload into the city sewer system - not a hole.

Neil - 26-2-2012 at 09:14

Treat each waste seperatly to remove what you can, oxidise things like chloro carbons and make insoluable any nasty metals.

Many metals can be cleanly cemented out with Al scrap in a bucket, for example Cu.

Your end waste can be safer then the cleaners you use on your sink.

Endimion17 - 26-2-2012 at 09:26

Quote:
Quote: Originally posted by Magpie  
I pretty much agree with Endimion. It sounds like your "scrubber" would create a big stinking mess. Plus, if you discharge acid into a can with carbonate it will pop the lid and be all over the place. :(


That would be hilarious. :D
Quote:
Not being on the city sewer/waste treatment plant system is going to be something you'll have to deal with, however. I would think that the discharge of heavy metal ions (of Cu, Cd, Sn, etc) could kill the bacteria in your septic tank thereby deactivating it.


Exactly. A deactivated septic tank is a dead tank that fills up quickly, and the heavy metals are there to stay.
Quote:
I think that Honey Wagons that pump out septic tanks discharge their payload into the city sewer system - not a hole.


Well, technically, the sewer system begins with a hole... :D

[Edited on 26-2-2012 by Endimion17]

entropy51 - 26-2-2012 at 10:45

I agree that you might want to neutralize your wastes individually.

There are several threads here on this topic that might be helpful.

There are a number of references for the procedures that you can use. A free book from the National Academy Press is Prudent Practices for Disposal of Chemicals from Laboratories. The link has been posted here, but Google should bring it right up.

The best reference is probably Hazardous Laboratory Chemical Disposal Guide by Magaret-Ann Amour.

Robert Thompson has some good suggestions for home chemists in his book Illustrated Guide to Home Chemistry Experiments.

You need not reinvent the wheel.