Removal of alkylphenols and polybromodiphenylethers by a biofiltration treatment plant during dry and wet-weather periods

Abstract

This paper investigates the occurrence of alkylphenols (APs) and polybromodiphenylethers (PBDEs) in raw wastewater during dry and wet-weather periods, and their removal by physico-chemical lamellar settling and biofiltration techniques. Due to in-sewer deposit erosion and, to a lesser extent, to external inputs, raw effluents exhibit from 1.5 to 5 times higher AP and PBDE concentrations during wet periods compared with dry ones. The lamellar settler obtains high removal of APs and PBDEs under both dry and wet-weather flows (>53% for Σ(6)AP and >89% for Σ(4)PBDE), confirming the insensitivity of this technique to varying influent conditions. Indeed, despite the higher pollutant concentrations observed in raw effluents under wet-weather flows, adjusting the addition of coagulant-flocculent allows for efficient removal. By combining physical and biological processes, the biofiltration unit treats nutrient pollution, as well as Σ(6)AP and Σ(4)PBDE contamination (58 ± 5% and 75 ± 6% respectively). Although the operating conditions of the biofiltration unit are modified during wet periods, the performance in nutrient pollution, APs and light PBDE congeners remains high. Nevertheless, lower efficiency has been noted in nitrogen pollution, i.e. no denitrification occurs, and BDE-209 (not removed during wet-weather periods). In conclusion, this study demonstrates that the combination of both techniques treats AP and PBDE pollution efficiently during dry periods, but that they are also suitable for stormwater treatment.

Priority pollutants in urban stormwater: Part 2 – Case of combined sewers

“…This trend was confirmed by Gilbert et al (2010) for long-chain APnEOs within the Paris sewer network. Although the presence of APEOs in wastewater is now well documented and related to their widespread use as surfactants in numerous industrial and commercial applications or in plastics (Ying et al, 2002), the presence of APEOs in stormwater must be pointed out and these concentrations must be taken into consideration.…”

Micropollutants in urban stormwater: occurrence, concentrations, and atmospheric contributions for a wide range of contaminants in three French catchments

“…All pollutants were quantified using internal standards. Further analytical details are available elsewhere for APnEO and bisphenol A (Cladière et al 2013), pesticides (Schummer et al 2012) and PBDEs (Gilbert et al 2012). To avoid analytical bias, all analyses for a given class of contaminant were conducted by the same reference laboratory, i.e.…”

Contamination des eaux pluviales par les micropolluants : avancées du projet INOGEV

“…Les polluants organiques ont été analysés par chromatographie liquide ou gazeuse couplée avec un détecteur à fluorescence ou avec un spectromètre de masse simple, en tandem ou à temps de vol. Les détails analytiques sont disponibles pour les APnEO et le bisphénol A (Cladière et al 2013), les pesticides (Schummer et al 2012) et les PBDE (Gilbert et al 2012). Toutes les analyses pour une classe de contaminants donnée ont été conduites par un même laboratoire de référence.…”