Organic micropollutants in raw and treated greywater: a preliminary investigation

Abstract

Effluent and influent of a constructed wetland treating separately collected greywater were subjected to liquid/liquid extraction with dichloromethane as well as to solid phase extraction. Extracts were analysed by gas chromatography/mass spectrometry. More than 80 organics were tentatively identified or roughly characterised in the raw greywater by their mass spectra. A lower number (26) of organic compounds was tentatively identified in the constructed wetland's effluent. Major compounds found in at least one extract of the effluent were an alkane, a squalene isomer, hexadecanoic acid, two not exactly identified phthalates, tris-chloropropyl phosphate, an acephylline derivative and an unidentified nitrogenous heterocycle. The persistent flame retardant tris-chloropropyl phosphate and a couple of phthalates found in the biologically treated greywater are of concern when biologically treated greywater will be reused for high quality demand. Most of the trace organics found in the greywater samples were related to household chemicals, personal care products and foodstuffs.

Keywords:

• constructed wetlands
• greywater
• organic micropollutants
• source control

Acknowledgement

The authors gratefully acknowledge laboratory assistance by Ms S. Eggers and review of the manuscript by Mr T. Maxfield, MSc.