2.5.2. Temperature and conductivity
Schilperoort et al. (2006) used conductivity together with
temperature measurements for detecting wastewater dilution by
stormwater, but their methodology could be applied for detecting
stormwater contamination by wastewater addressed herein.
Simultaneous on-line measurements of conductivity and temperature,
during both dry and wet weather, showed that: (i) conductivity
fluctuated more sharply than temperature during dry
weather, and (ii) In wet weather, conductivity dropped distinctly to
relatively low values indicating wastewater dilution by stormwater
inflow (Schilperoort et al., 2006). Therefore, it can be assumed that
a sharp increase in flow conductivity in storm sewers may indicate
illicit wastewater connections, providing that there are sufficient
inflows of wastewater with elevated conductivity.