Potential of turbidity monitoring for real time control of pollutant discharge in sewers during rainfall events

Abstract

Turbidity sensors can be used to continuously monitor the evolution of pollutant mass discharge. For two sites within the Paris combined sewer system, continuous turbidity, conductivity and flow data were recorded at one-minute time intervals over a one-year period. This paper is intended to highlight the variability in turbidity dynamics during wet weather. For each storm event, turbidity response aspects were analysed through different classifications. The correlation between classification and common parameters, such as the antecedent dry weather period, total event volume per impervious hectare and both the mean and maximum hydraulic flow for each event, was also studied. Moreover, the dynamics of flow and turbidity signals were compared at the event scale. No simple relation between turbidity responses, hydraulic flow dynamics and the chosen parameters was derived from this effort. Knowledge of turbidity dynamics could therefore potentially improve wet weather management, especially when using pollution-based real-time control (P-RTC) since turbidity contains information not included in hydraulic flow dynamics and not readily predictable from such dynamics.

Relationship between turbidity and total suspended solids concentration within a combined sewer system

“…Moreover, the wet weather samples at both the CB and SM sites showed turbidity values varying between 100 and 700 FAU, i.e. the most probable range of values in a combined sewer during wet weather (Lacour et al 2009b). As a result, we calculated the TSS concentration for turbidity values lying between 100 and 700 FAU.…”

Stormwater Pollutant Process Analysis with Long-Term Online Monitoring Data at Micro-Scale Sites

“…Aggregation of similar M (V)-curves is therefore required to extract relevant information. [16] for example, divide M (V)-curves in three different zones to classify similar events. Zone A contains curves with a dominant first-flush effect, while curves in Zone C tend to be more last-flush affected.…”

A real-time control strategy for separation of highly polluted storm water based on UV–Vis online measurements – from theory to operation

“…So far, the control system rule of "clean (storm water) runoff into the receiving water -polluted runoff into the treatment plant" has been thwarted, above all, by the rough operating conditions in the sewer and the mechanical requirements the latter impose on the measuring equipment. On the other hand, research projects (Lacour et al, 2009) show there is a great potential for pollution-based real-time control (P-RTC).…”

“…Matsché and Stumwoehrer, 1996;Geenens and Thoeye, 1998). In the sewage system, however, considerably more stringent requirements have to be met by measuring equipment and realtime data evaluation, especially if the results form the basis for a P-RTC system (Langeveld et al, 2005;Gruber et al, 2006, Joannis, et al 2008Lacour et al, 2009).…”

“…A parameter that is representative of the degree of storm water pollution is wastewater turbidity, which can be recorded exactly enough by photometric means and which, by means of calibration and correlation, enables the total suspended solids (TSS) to be determined (Hoppe et al, 2009;Lacour et al, 2009). As regards storm water pollution, heavy metals and petroleum hydrocarbons, a substantial portion of which are adsorbed onto solids, constitute a major problem.…”