Water quality management of heavily contaminated urban rivers using water quality analysis simulation program

Precisely management of water quality in urban rivers is of significant and water environmental capacity provide a useful tool. This study presented a water quality analysis simulation program modelbased approach for dynamical load reduction in Ashi River, highly contaminated tributaries of Songhua River, China. The actual and surplus dynamic environmental capacity of CODCr and NH3N, as the two controlling endpoints, were computed based on “segmentendcontrol” method for monthly or seasonal management. The dynamic pollution control scheme and monthly to annual control strategies were produced based on calculated results. Results show that CODCr and NH3N need to be cut down to approximately 462.47t/a and 5.2t/a at ZhujiaAcheng down reach and 282.42 t/a and 9.25t/a Acheng downChenggaozi town reach, respectively under 90% hydrological design reliability to keep the water quality at classIV. The CODCr and NH3N of three ditches should be strictly controlled throughout the year. Some interesting temporalspatial characteristics of surplus environmental capacity were also found in the study. This study provides local governments with technical measurements and policy recommendations for highly contaminated water body treatment. In the future, the river water quality management in the winter season should take into particular consideration.