Nothing hazardous down any sink.
Freshwater down sinks and seawater down seawater drains.
No agar, gelatin, etc down sinks, even when liquid.
Cross section of a compromised sinkdrain.
This can only happen when solvents are left in a sink overnight.
No solvents down the sink EVER!
Red line indicates shape of pipe before solvent was added.
This can only happen with a strong acid being left in the sink overnight. If it is less than pH 5.5 or greater than pH 10 then it MUST be collected as waste and NOT go down the sink!
DO use traps on vacuum lines so hazardous materials do not go down the drain with water aspirators or into the vacuum pump with oil and diaphram vacuum pumps.
Any biphasic material found in a sink trap is a violation. Solvents, oils and water do not mix.
UNDER THE SINK
DO NOT STORE HAZARDOUS MATERIALS UNDER SINK. Sooner or later the sink will leak. This could spread hazardous material throughout your lab. Always use secondary containment for cleaning supplies and make sure incompatible materials are in separate tubs. Example: Chlorox and ammonia when combined will form a lethal gas.
*SPECIAL NOTE ABOUT SEAWATER
Under normal conditions you would not put seawater down a sanitary sewer. This is because it can add too much salt for the bacteria to handle in the sewage treatment plant. However, there are two situations where you might need to put small amounts down a sink drain: 1) when using an non-native species (see also Tank Tags) NONE of the seawater used can go to the seawater drain and subsequently Monterey Bay. It must be either sterilized first in an approved manner or if a small amount, go down a sink drain. 2) some chemical has been added, typically Chlorox or an antibiotic. As with the non-native species, we can't have this ending up in the bay.
So, what is a small amount? This is not totally clear. Anything less than ten gallons per day can probably be tolerated.
ALSO: Be sure and flush the sink with lots of fresh water so the seawater does not corrode the pipes underneath.