Proper Drain Disposal Guidance
What May Be Disposed?
Generally, materials suitable for sewer disposal in limited quantities must meet the following physical and chemical criteria:
- They are liquids and readily water soluble (at least 3% soluble)
- Easily biodegradable or amenable to treatment by the waste water treatment process
- Are simple salt solutions of low toxicity inorganic substances
- Are dilute organic substances of low aquatic toxicity and low concentration
- Have a pH between 3.0 and 10.0
When discharging waste to the sanitary sewer, you must:
- Always discharge to a drain that leads to the sanitary sewer.
- Use a sink that does not have a history of clogging or overflowing.
- Use a sink in your laboratory.
- Flush with at least 10-20 fold excess of water after drain disposal to thoroughly rinse out the sink and sink trap, and to fully neutralize or inactivate the waste for discharge.
- Limit the quantities being discharged to 100 grams of solute per laboratory per day.
- Wear gloves, eye protection and a laboratory coat.
- Inactivate biological materials (e.g., autoclave or bleach-treat) before releasing to sewer.
What May NOT Be Disposed?
- Ashes, cinders, sand, mud, straw, shavings, metal, glass, rags, feathers, tar, plastics, wood, manure, hair and fleshings, entrails, paint residues, solid or viscous substances capable of causing obstruction to the flow of sewers.
- Oil, grease, petroleum, or other water insoluble chemicals
- Materials that are not biodegradable or would pass through the sewage treatment plant into the river and be toxic to aquatic organisms or accumulate in sediments.
- Materials that could interfere with the biological processes of sewage treatment or would contaminate the sludge-making disposal
- All compounds that could result in the presence of toxic gases or
- Infectious substances
- Hazardous Wastes – either listed or characteristic hazardous wastes, for example:
- Halogenated hydrocarbons;
- Nitro compounds (organic compounds that contain one or more nitro functional groups (-NO2) and are often explosive);
- Mercaptans (thiols);
- Flammables (immiscible in water) or at concentrations of concern;
- Explosives such as azides and peroxides;
- Water soluble polymers that could form gels in the sewer system;
- Water reactive materials;
- Malodorous chemicals;
- Toxic chemicals such as carcinogens, mutagens, teratogens;
- Nanomaterials
- Substances that boil below 50 °C (122 oF) ;
- Solid or viscous substances in amount s that will cause obstruction of the flow in the sewerage system;
- Flammable and combustible solvents (flashpoints less than 140oF)
- Discharges with a pH below 3.0 or higher than 10.0;
- Wastes that could impart color that cannot be removed by treatment process (dye wastes, stains);
- Metallic ions and salts
