Development of a Sensor to Detect AFFF in Ship Bilge Water

摘要

The sensor system was developed primarily to detect the presence of aqueous film forming foam (AFFF) in bilge water off-loaded from a ship to a shore-side wastewater treatment plant. The foam sensor uses a combination of photo-optical and acoustic range measuring devices to determine the density and height of a column of foam produced by aeration of the wastewater sample. These data are used to estimate the concentration of AFFF in the wastewater sample. The sensor system can detect concentrations of AFFF as low as 10 ppm in approximately 45 seconds. Solutions containing higher concentrations of AFFF are detected in less time. When the concentration of AFFF exceeds a preset value, a switch within the sensor system is closed. This switch closure can be used to control functions such as operating a valve to divert the contaminated wastewater stream to a storage tank or a specialized treatment process, or to control other treatment plant processes.