Operators in NL try to offset the
lack of water treatment by applying higher chlorine doses to ensure
adequate microbiological quality. In addition, the lack of physical treatment
prior to chlorination in NL systems leads to a higher concentration
of NOM in the DS, which could be one important reason for high chlorine
consumption all along the DS. Such treatment conditions (lack of
filtration, higher NOM and higher chlorine concentrations) also explain
why DBPs in drinking water, namely THMs and HAAs, occur in
significantly higher concentrations in NL systems than in QC systems
(Fig. 2b and c).