Online Instrumentation to Protect Wastewater Facilities from Toxic Chemicals

Security concerns are driving current research to develop means of detecting toxic chemicals in wastewater influents as few online instruments are currently available for this purpose. Online respirometers such as the STIPTox are the obvious choice using existing, established technology. One of these units was recently used successfully in the WERF project 03-CTS-7S “Feasibility Testing of Support Systems to Prevent Upsets” to detect 5 out of 6 known toxins.In the same project a decision support system (DSS) was developed that used three simple sensors – pH, ORP and conductivity – to detect known toxins. The main difficulty in getting the DSS to work was in dealing with the noisy data caused by filter blockages and sensor fouling. With very good sensor maintenance the DSS based on simple sensors could work well, as proven by testing the DSS with “cleaned up” data which had much of the noise removed.Future advances in sensor technology will add more sensors to the suite that can be used in a DSS.