Alkylphenols and Phthalates in Greywater from Showers and Washing Machines

Abstract

International audienceParis conurbation is a heavily urbanized but weakly industrialized catchment. Recently, it has been shown at the scale of Paris that alkylphenols (AP) and phthalates (PAE) are not rejected by the industry, but they originate from domestic wastewater at more than 95 %. However, the contribution of the different types of greywater to the pollution by alkylphenols and phthalates was not addressed. This work aims at providing new insights on this particular point. Hence, the concentration of four phthalates (diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), and di(2-ethylhexyl)phthalate (DEHP)) and two alkylphenols (octylphenols (OP) and isomers of nonylphenol (NP)) were followed in greywater. For each sample, analyses were carried out on both the dissolved and particulate phases. Moreover, water quality parameters were also monitored, in order to find out whether or not any correlation exists between the concentration of the investigated contaminants and the quality of water. Water quality parameters studied are pH, total suspended solids (TSS), dissolved and particular organic carbon (DOC and POC), chemical and biochemical oxygen demands (COD and BOD5), total Kjeldahl nitrogen (TKN), and anionic detergents (methylene blue active substance or MBAS). This paper presents the methodology used to monitor two greywater with the most important volumes: showers and washing machines. These greywater showed high variability with regard to water quality parameters. Moreover, AP and PAE concentrations are given for the first time for these two types of greywater. All compounds except OP were observed in almost all samples in at least one of the two monitored phases. The concentrations varied between limit of quantification for OP and 102 μg/l for DEHP. The levels measured in washing machines were higher than those for showers for all compounds. For instance, median NP concentration in washing machines was 3.59 μg/l against 1.09 μg/l in showers, DEHP was observed at 102 μg/l in washing machines against 16.6 μg/l in showers. Variability of the results was explained by habits of individuals (shower time, number of products used…) but also by differences in product composition. However, each type of water exhibited the same distribution. NP was the most abundant AP (about 85 % of the total amount) while DEHP represented the two thirds of the PAE compounds. The partition coefficients (Kd in l/kg) were evaluated. The results showed that log Kd ranged between 2.1 (DEP) and 4.8 (DEHP). Log Koc presented similar trends lying in the 2.4 (DEP)-5.0 (DEHP) range. Finally, with regard to greywater quality, the application for greywater reuse is discussed

Degradation in urban areas

“…Pollutants deriving from urban areas include heavy metals [31], PCBs [47], nutrients [48], pesticides [44], pharmaceuticals [49] and faecal coliforms [50]. Sources of water pollution in urban areas can include (i) industrial processes and spills [51], (ii) untreated solid waste disposal and leachate from landfills [52], (iii) wastewater contamination from septic tanks, leakages in sewage systems and inefficient wastewater treatment [53], (iv) stormwater runoff [31,54], (v) lawns and gardens maintenance due to inappropriate fertilization and irrigation [55], (vi) soil erosion [56], and (vii) atmospheric deposition [30].…”

Interaction between surfactants of different classes and nanofiltration membranes

“…A total of 11 experiments were performed, including a triplicate to assess the experimental error. The minimum and maximum values of the total concentration used (including equal amounts of SDS and CTAB added to the solutions) were selected according to the respective concentrations of anionic and cationic surfactants in laundry effluents [4][5][6][7]. Moreover, equal amounts of CTAB and SDS were added to the solution, to evaluate the simultaneous influence of CTAB and SDS on the performance of NF90, at the same initial concentration.…”

“…Surfactants from different classes are used in laundry detergent formulation, often at concentration ranges varying from 58 to 1,000 mg L −1 [4][5][6][7]. These surfactants are classified into three groups: anionic, cationic and nonionic, from which anionic and nonionic surfactants are the most employed in laundering processes, while cationic surfactants are reported to present bactericide properties [2].…”