The lower winter temperatures in the northern region can affect the microbial activity in the wastewater treatment process and reduce the treatment effect. At the same time, low temperature will also lead to weak sludge activity, which is not conducive to sludge settlement and degradation. Winter temperatures are low, and some industrial enterprises and residential heating facilities may have unauthorized discharge, excessive discharge, etc., resulting in deterioration of intake water quality, increase of pollutant concentration, increase of