The paper presents a study correlating the profile of on-line monitoring parameters and off-line measurement of nutrient concentrations (NH4+-N, TN, NO3--N and TP) in a novel technology phased isolation tank step feed (PITSF) system, thereby utilizing the parameters as economical operational tool. A fixed-time control study showed that real control points (RCPs) on pH and oxidation-reduction potential (ORP) profiles accurately coincided with the major biological activities, whereas both DO and pH profiles are applied to control the end of nitrification and phosphate uptake process in aerobic phases, in particular, the “ammonia valley” on the pH profile for nitrification process. The analysis of the first aerobic tanks during the main phases showed that the RCP on DO profile can be used to distinguish the occurrence of simultaneous denitrification and nitrification (SND). Both the RCPs on the ORP profile and “nitrate apex” on the pH profile are applied to control the end of denitrification. The relationship between ORP and phosphorus release is linear and both (dORP/dt) and (dpH/dt) values are applied to control the end of anaerobic phosphorus release. Therefore, a new, reliable and effective real-time control strategy was developed using DO, pH and ORP as control parameters, to improve the performance of the PITSF process. As a final engineering observation, the proposed system is regarded as an effective process because the PITSF system can be operated safely under intercross real time control to treat low C/N domestic wastewater. The total nutrient removal efficiencies of COD, TN, NH4+-N, and TP with low C/N ratio and normal water temperature of (17-21) ℃ were 91.7, 83.2, 95.7 and 92.1%, respectively, which was approximately equal to the complete nitrification-denitrification with the addition of external carbon sources under low water temperature of (8-11) ℃.