中文摘要：

废水分类分级处理的再生模式是废水再生的方向，建立和完善该模式的多杂质再生循环水系统的模型具有重要意义。本文从工业实际情况出发，在现有数学模型的基础上，考虑了再生单元进口质量浓度的上下限约束，使得数学模型更加完善。通过实例研究，显示了增加该约束的必要性，并分析了该约束对水网络结构和系统新鲜水目标值的影响。

英文摘要：

The regeneration pattern of classified and stage treatment of wastewater is the tendency of wastewater regeneration and it is of great significance to establish and improve the model of regeneration recycling water systems with such regeneration pattern. In this paper, from the industrial practical situation of regeneration units, the constraints for inlet concentrations of regeneration units are considered to improve the existing models for water systems with wastewater regeneration. The effects of the constraints on the water network structure and the minimum freshwater consumption are analyzed. A case study shows the necessity of the constraints.