Modelling real-time control of WWTP influent flow under data scarcity

Abstract

In order to comply with effluent standards, wastewater operators need to avoid hydraulic overloading of the wastewater treatment plant (WWTP), as this can result in the washout of activated sludge from secondary settling tanks. Hydraulic overloading can occur in a systematic way, for instance when sewer network connections are extended without increasing the WWTP's capacity accordingly. This study demonstrates the use of rule-based real-time control (RTC) to reduce the load to the WWTP while restricting the overall overflow volume of the sewer system to a minimum. Further, it shows the added value of RTC despite the limited availability of monitoring data and information on the catchment through a parsimonious simulation approach, using relocation of spatial system boundaries and creating required input data through reverse modelling. Focus was hereby on the accurate modelling of pump hydraulics and control. Finally, two different methods of global sensitivity analysis were employed to verify the influence of parameters of both the model and the implemented control algorithm. Both methods show the importance of good knowledge of the system properties, but that monitoring errors play a minor role.

Weather radar rainfall data in urban hydrology

“…Other real-time control applications have been used to estimate the loads on waste water treatment plants in order to reduce spills of untreated waste and stormwater and to optimize treatment processes during rain (Quirmbach and Schultz, 1999;Fuchs and Beeneken, 2005;Vezzaro and Grum, 2014;Kroll et al, 2016). With large linked hydrological systems, centralization of treatment plants in urban areas, advances in model predictions and data, there seems to be a large potential for global predictive control of hydrological systems in cities, which is not yet fully exploited.…”

“…According to the rational method (Kuichling, 1889), increasing concentration times will lead to greater critical rainfall aggregation levels (in this case coarser temporal resolution). Due to the dependence between temporal and spatial resolutions described above, increasing concentration times will reduce the demands for high spatial resolution.…”

Modeling, Instrumentation, Automation, and Optimization of Water Resource Recovery Facilities

“…in rainy, winter, spring and summer seasons in the raw, treated wastewater and activated sludge in an activated sludge process (ASP) based sewage treatment plant (STP) located in Haridwar, India. Results of this study also demonstrated that removal efficiency, assessed in terms of physicochemical and microbiological parameters, was maximum in summer and reached minimum in rainy season Kroll et al (2016). demonstrated the use of rulebased real-time control (RTC) to reduce the load to the WWTP while restricting the overall overflow volume of the sewer system to a minimum.…”

Reply to review by Remko Uijlenhoet

“…The concentration time of the urban catchment or to a point of interest in the system are of importance and affected by many factors. According to the rational method (Kuichling, 1889), increasing concentration times will lead to greater critical rainfall aggregation levels (in this case coarser temporal resolution). Due to the dependence between temporal and spatial resolutions described above, increasing concentration times will reduce the demands for high spatial resolution.…”

“…Other real-time control applications have been used to estimate the loads on waste water treatment plants in order to reduce spills of untreated waste and stormwater and to optimize treatment processes during rain (Quirmbach and Schultz, 1999;Fuchs and Beeneken, 2005;Vezzaro and Grum, 2014;Kroll et al, 2016). With large linked hydrological systems, centralization of treatment plants in urban areas, advances in model predictions and data, there seems to be a large potential for global predictive control of hydrological systems in cities, which is not yet fully exploited.…”