Occurrence of Micropollutants in Wastewater and Evaluation of Their Removal Efficiency in Treatment Trains: The Influence of the Adopted Sampling Mode

Abstract

The monitoring of micropollutants in water compartments, in particular pharmaceuticals and personal care products, has become an issue of increasing concern over the last decade. Their occurrence in surface and groundwater, raw wastewater and treated effluents, along with the removal efficiency achieved by different technologies, have been the subjects of many studies published recently. The concentrations of these contaminants may vary widely over a given time period (day, week, month, or year). In this context, this paper investigates the average concentration and removal efficiency obtained by adopting four different sampling modes: grab sampling, 24-h time proportional, flow proportional and volume proportional composite sampling. This analysis is carried out by considering three ideal micropollutants presenting different concentration curves versus time (day). It compares the percentage deviations between the ideal concentration (and removal efficiencies) and the differently measured concentrations (removal efficiencies) and provides hints as to the best sampling mode to adopt when planning a monitoring campaign depending on the substances under study. It concludes that the flow proportional composite sampling mode is, in general, the approach which leads to the most reliable measurement of concentrations and removal efficiencies even though, in specific cases, the other modes can also be correctly adopted.

Photo-catalytic dye degradation of methylene blue by using ZrO2/MWCNT nanocomposites

“…The formation of a highly stable, readily storable, compact ZrO 2 /MWCNT composite may provide a new pathway for the purification of effluent (Sharma et al 2018;Serpone 2000;Ramesh & Shivanna 2021). It should be pointed out that from our simulations, the adsorption of dye occurs with ZrO 2 /MWCNT which form hydrogen bonds and weak van der Waals interactions (Verlicchi & Ghirardini 2019). The XRD and SEM characterization provides fundamental evidence of the high yield and purity of composite preparation (Dagar & Narula 2017;Assis et al 2019).…”

Sampling strategies for wastewater surveillance: Evaluating the variability of SARS-COV-2 RNA concentration in composite and grab samples

“…Verlicchi et al [56] evaluated the influence of different sampling strategies in the monitoring of micropollutants in sewage. The sampling methods used were grab sampling, 24-hour time proportional, flow proportional and volume proportional composite sampling.…”

Selection of indicator contaminants of emerging concern when reusing reclaimed water for irrigation — A proposed methodology

“…• the values of the removal efficiencies (R) in the secondary treatment (mainly a conventional activated sludge system) for the listed CECs, based on the literature, but also on the investigations carried out in the reference area, in order to evaluate persistence (P). Also, for these data, quality control must be carried out in order to include only values whose estimation is clearly described according to the considerations on sampling influence, as discussed in (Verlicchi and Ghirardini, 2019);…”