The Proteus is a sensing platform for real-time, reagent less monitoring of dissolved or total organic carbon concentration. It is ideally suited to on-line monitoring of DOC/TOC at all stages of the drinking water treatment process. In particular, the sensor can be used to continuously monitor DOC levels and alert when specific thresholds are exceeded that may interfere with the disinfection process or lead to the formation of harmful by-products. Efficiency of specific stages in the treatment process can be monitored to ensure assets are performing within tolerances and refinements made in near-real time. In addition, the Proteus can be used to monitor potable water supplies for the presence of bacteria (Coliforms). When used on-line at the treated end of a plant bacteria the Proteus that can act as a vital safe guard for drink water supplies.