A preliminary pan-European assessment of pollution loads from urban runoff

Acknowledging the difficulty of modelling pollution conveyed by urban runoff, this contribution presents a first pan-European quantification of loads from this diffuse source. We estimate annual loads of 5-days biochemical oxygen demand (BOD5), nitrogen (N), phosphorus (P) and total suspended solids (TSS) using a simple event mean concentration (EMC) model initially proposed by Heaney et al., 1976. On a European scale, this yields discharges corresponding to untreated wastewater of about 31 million population equivalents (PE) for BOD5, about 18.5 million PE for N and P and about 280 million for TSS. These represent 51% of the pollution coming from treated wastewater for BOD5, 15% for N and P and 461% for TSS. Although the model applied for the assessment was developed more than 40 years ago, the results are consistent with those obtained using more recent parameterizations, except for a tendency to underestimate P loads. Although lack of data on pollution from urban runoff makes model verification impossible, and the uncertainty on EMC models is known to be very high, urban runoff emerges as a significant source of pollution, and should be properly addressed as such. Reducing runoff volume from urban areas through improved water retention can not only be key to pollution control, but also a no-regret option thanks to its co-benefits, especially when incorporated at early stages of planning and design.

PISTOCCHI Alberto; 

2020-02-04

ACADEMIC PRESS INC ELSEVIER SCIENCE

JRC119568

0013-9351 (online),   

https://www.sciencedirect.com/science/article/pii/S0013935120300219,    https://publications.jrc.ec.europa.eu/repository/handle/JRC119568,   

10.1016/j.envres.2020.109129 (online),