Environmental Health and Safety

Effective Date: 11/03/00

Policy Statement 13: Disposal of Wastes to Water


This policy concerns the disposal of the described wastes, generally hazardous in nature, into the sanitary sewer by release through sinks, drains, etc. Any discharge of hazardous materials to the sanitary sewer require prior approval from the Hazardous Waste Manager.

No Release

Heavy Metals - Cadmium (Cd) and Mercury (Hg) are not to be released to the sanitary sewer. Based on an effluent of four million gallons/day, eight grams would result in average concentration in excess of 0.5 micrograms/liter, the discharge limit for these metals.

Traces Only

Oils - Only trace quantities of oils associated with cleaning and washing operations should be released to the sanitary sewer. Oil wastes from vacuum pumps, transformers, motors, etc., should be accumulated for pick-up and disposal by the current contractor for this service. Oils containing PCBs must be identified as such.

Water and Lead or Copper-Free Pipes

Sodium Azide - Solutions containing sodium azide, commonly used as a preservative in many in vitro diagnostic products and with automatic blood cell counters, can be discharged to the sanitary sewer, if done so with generous amounts of water and where drain lines are lead and copper-free. The accumulation of lead and/or copper azide in the drain pipes can become potentially explosive.


Other Toxic, Poisonous, and Noxious Agents - Consideration must be given to the effect of possible interaction with acids and bases in the sewerage system which may result in formation of toxic gas or highly volatile substances which may escape through vents and untrapped drains, and the effect on maintenance personnel who must repair sewer lines and enter manholes.

Waste Pick-up

Hazardous Waste - Hazardous chemical waste will be picked up by the Environmental Health and Safety Office upon receiving a call, giving the department, location, name(s) of the chemical and amount. No material will be picked up unless it is properly contained and labeled with the above information, in addition to the percentages of each chemical in waste mixtures. DO NOT COMBINE CHEMICAL WASTES IF AT ALL POSSIBLE!