Experimental considerations on monitoring ORP, pH, conductivity and dissolved oxygen in nitrogen and phosphorus biological removal processes

An experimental study on monitoring Oxidation Reduction Potential (ORP), pH , Conductivity and Dissolved Oxygen (DO) in an Enhanced Biological Nutrient Removal process has been carried out. In the anaerobic phase, while ORP an d conductivity were not reliable in monitoring simultaneously denitrificati on and P-release, pH showed the best performances. A significant relationsh ip between P-released and pH variation was found. During the aerobic phase both ORP and pH were able to monitor successfully the nitrification, even though pH was much more reliable. pH can be also us ed for monitoring and control enhanced P-uptake. It has been concluded that , for a reliable and effective control of biological N and P removal proces ses a more sophisticated control system seems to be necessary.