Sterols: a tracer of organic matter in combined sewers

Abstract

The important organic pollution of combined wet weather flows (WWF), its acute impact on receiving waters have been widely demonstrated. The main three possibly origins for this organic pollution are: runoff water (streets and roofs), wastewater and erosion of sewer sediments in combined sewer system. This work, for tracing the origin of organic particles bound in combined sewer system, has been focused on the innovative use of sterols. So, eight sterols have been selected and analysed for each kind of sample. Results are represented in contents of sterols (microg g(-1)) and in sterol profiles (%). The comparison of contents and profiles leads the separation between two groups: runoff water, characterized by the total absence of coprostanol, epicoprostanol and coprostanone, and the group of sewer deposits (gross bed sediment (GBS), organic layer (OL), biofilms) and wastewater. Moreover, sewer deposits and wastewater can be distinguished by their sterol contents and profiles. To evaluate their contribution to WWF a comparison between sterol signatures is done which shows that these effluents have a strong similarity in profiles and in contents of sterols to the organic layer.

Quantitative Evaluation of Tracers for Quantification of Wastewater Contamination of Potable Water Sources

“…In particular, X-ray contrast agents − , human-specific antibiotics, and pharmaceuticals , attracted attention, since they are biorefractory by design and are mostly specific for human consumption. Health care products , , human steroidal hormones , , caffeine and its metabolites , , and more recently even artificial sweeteners , were all considered as wastewater markers.…”

Where Did That Pollution Come From? A Review of Chemical and Microbial Markers of Organic Pollution

“…The sterol profile of wastewater was found to be slightly different from that of in-sewer deposits [18]. It is characterized by similar abundances of cholesterol (30-49%) and coprostanol (34-52%), and a low percentage of other sterols.…”

“…Zgheib et al present a very innovative example of using chemical source markers to study organic matter in combined wet weather flows containing domestic wastewater and runoff storm water in Paris [18]. This water contains organic particles from three main sources: runoff water, domestic wastewater and erosion of an organic in-sewer deposit.…”

“…As in other studies utilizing these markers, principal component analysis (PCA) was applied to help interpret the rather complex results of the sterol profiles [18]. This analysis found both sterol profiles to be similar between the combined wet weather flows, wastewater and the organic layer deposits, while gross bed sediment and runoff clusters are far apart.…”