TITLE:
Commercial Laundry Water Characterisation
AUTHORS:
J. K. Braga, M. B. A. Varesche
KEYWORDS:
Greywater; Linear Alkylbenzene Sulphonate; Legislation; Xenobiotic Organic Compound; Heavy Metal
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.5 No.1,
January
10,
2014
ABSTRACT:
Surfactants are the
major active ingredients of laundry detergents. Therefore, special attention
should be focused on the treatment and disposal of laundry wastewater. The aim
of this study was to characterise the wastewater from a commercial laundry over
30 days. Physicochemical analyses were performed, monitoring the content of
nitrogen, phosphate, heavy metals, linear alkylbenzene sulphonate (LAS),
volatile organic acids and alcohols. The pH was approximately 5.6 and the COD approximately
4800 mg·L－1.
The average concentrations of sulphate, sulphide, N-ammoniacal organic nitrogen
compounds and heavy metals were below the maximum limit, in accordance with
local and national environmental legislation, and the average total suspended
solids was 0.08 g·L－1. Among the metals analysed, iron
was observed with the highest
concentrations (0.037 mg·L－1 and 0.72 mg·L－1).
Phosphate was detected in 93% of samples (94.65 mg·L－1 average). LAS was
detected in all samples (12.24 mg·L－1 to 1023.7 mg·L－1).
Thirty-three different xenobiotic organic compounds were identified in the
laundry wastewater with the qualitative screening. The major groups of the
compounds were fragrances, preservatives, solvents and some surfactants.
Although the characterisation indicated low values for many parameters, this
does not eliminate the need for specific treatment before its disposal at the
sewage system.