An apparatus for detecting oil and other lighter-than-water contaminants in an effluent stream in a sewage system. The apparatus includes a disposable detector which floats in the effluent stream and detects oil and other contaminants having a specific gravity lighter than the water by absorbing the...http://www.google.com/patents/US4919892?utm_source=gb-gplus-sharePatent US4919892 - Apparatus for detecting oil and other lighter-than-water contaminants in an effluent stream
