To address the challenges associated with industrial-domestic mixed wastewater treatment,including significant fluctuations in influent quality and stringent requirements for nitrogen and phosphorus removal,a municipal wastewater treatment plant with a design capacity of 3×104 m3/d was investigated.The performance of a combined process combining"pretreatment+CASS+high-efficiency sedimentation+denitrification deep bed filter"was analyzed.By optimizing the operational phase configuration of the CASS process and carbon source dosing strategy,a synergistic control mechanism of"temporal sequencing-carbon source matching"was established,which enhanced nitrogen removal stability under low C/N conditions from a mechanistic perspective.Meanwhile,a water reuse strategy was incorporated to promote the transition from pollutant removal to water resource recycling.Based on the evaluation of 20 months'continuous operation data,the system showed good removal effect on CODCr,NH3-N,TN and TP under the condition of average treatment water volume of 2.2×104 m3/d,and the long-term stability of effluent quality was better than the Grade A standard of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918－2002).The treatment cost was approximately 1.15 yuan/m3.The results demonstrate that the proposed process exhibits strong adaptability and operational stability for complex mixed wastewater,and its control strategy and resource-oriented design provide valuable references for similar applications.