<p>Traditional research often focuses on the single dimension of water quality improvement, while ignoring the comprehensive assessment of dimensions such as ecosystems, human health, economic costs, and social acceptance. Through on-site investigation and automatic sampling, this paper uses various analytical techniques to detect organic matter, inorganic matter, and heavy metals in wastewater, monitors water quality indicators, energy consumption, and by-products after treatment, and establishes a comprehensive data set of the wastewater treatment process. In addition, a water quality model, an air diffusion model, and an ecological model are established to simulate the diffusion, dilution, and long-term environmental impacts of wastewater discharge on water bodies, air, and ecosystems to assess the environmental impact and verify the accuracy of the model. Exposure assessment, toxicity parameters and dose–response models are used to evaluate the risks of treated wastewater and air pollutants to human health and ecosystems, and multi-criteria decision analysis and sensitivity analysis are used to weigh risks and quantify uncertainties. The experimental results show that the quality of wastewater is significantly improved after treatment. The environmental impact model is accurate in prediction, with correlation coefficients above 0.9 and small errors. The treatment process has a positive impact on ecology, economic cost–benefit, and social acceptance. Multi-stage wastewater treatment processes can effectively improve water quality and achieve lower industrial environmental impact.</p>