The following chemicals can be disposed of in the sanitary sewers (drains) as long as the treatment does not precede disposal. Treatment is defined as using a material to neutralize hazardous waste. Examples include neutralizing an acid solution just so that it can be disposed of in the sewer system, or running copious amounts water in the drain to bring concentrations of hazardous waste to acceptable levels for sewer disposal. Also, a log must record the date, quantity and chemicals being disposed. This log should be retained with other hazardous waste information. The pH must be above 3 and below 9. Treatment to bring the pH of a RCRA Regulated Chemical within this range is not allowed.
The disposable chemicals include:
- Inorganic acids and bases that have pH 5–9 (provided that no other regulated chemical is present);
- Aqueous buffer solutions lacking any other regulated materials and biohazards (e.g. common salt solutions and cell culture media). Contact EHS with the formulation. EHS will issue written email permission to dispose of this particular waste stream in the sanitary sewer.
- Solutions containing less than 24% of ethanol, propanol or isopropanol. This does not apply to any solution containing acetonitrile or any other organic solvent, which must be disposed of as hazardous waste. A disposal log must be kept. Dilution to bring the alcohol concentration below 24% for disposal purposes is not allowed.
- Other chemicals may be disposed of in the sanitary sewer only with written email permission from EHS.