The reference to minus 30 Celsius as mentioned in the ann. could be a little misleading. The air temp I guess can dip down to that temperature at times however as far as I know water turns to ice at zero degrees celsius, unless the Chinese pour anti freeze down the toilet with each flush.
Therefore I assume that, in any piped sewerage system, the pipes would have to be buried or otherwise insulated and the treatment plant as well be sheltered so that the effluent temperature does not drop below zero degrees. As water expands when it freezes I imagine all sorts of damage could occur if that happened.
