Sep 21, 2006. /Lesprom Network/. A discolouration of water was noticed at UPM Kaukas mill's effluent treatment plant on Tuesday 19 September 2006. Water flow to the treatment plant and into Lake Saimaa was stopped immediately. As the effluent lagoons reached reportable levels, production was ceased at the paper mill on Wednesday 20 September. No discoloured water was released into Lake Saimaa. The mill's emission permission conditions have not been exceeded. The reason for the discolouration was soap which was discharged to the effluent treatment plant during a maintenance break at the pulp mill. Corrective measures have been taken and the situation is estimated to get back to normal in 1-3 days.