Apuss
Assessment of the performance of urban sewer systems
Urban sewer systems (USS) constitute a very significant patrimony
in European cities. Their structural quality and functional efficiency are key
parameters to guarantee the transfer of domestic and trade wastewater to
treatment plants without neither infiltration nor exfiltration.
Infiltration of groundwater is particularly detrimental to treatment
plant efficiency (hydraulic overloading due to the infiltrated volume of water
which can reach up to 100 % of the wastewater volume in some cities, dilution of
pollutant concentrations which leads to a lower pollutant removal efficiency),
while exfiltration of wastewater can lead to groundwater contamination
(especially where groundwater is a water resource for drinking water
production). Both problems are critical on a long-term basis for sustainable
urban water management and have important economic consequences for cities and
sewer systems operators through the EU.
In order to evaluate the
performance of USS, public and private operators need appropriate methods and
techniques. This research project, associating universities, SMEs and
municipalities in 7 European countries, will develop new methods and techniques
based on tracers to assess and quantify infiltration and exfiltration in sewer
systems, at different space scales (from the single pipe to the whole catchment)
and under different conditions (steady and dynamic groundwater levels, seasonal
effects, etc.). The methods will be tested and validated in different catchments
chosen in the associated cities, under various conditions.
Top row: Using natural isotopes to characterize and decompose a diurnal wastewater hydrograph into its elementary components “Foul Sewage” and “Infiltration”
Bottom: Exemplary data set for the
QUEST method to quantify sewer leakage based on the addition of an artificial
tracer