Polychlorinated Biphenyls in the Centralized Wastewater Treatment Plant in a Chemical Industry Zone: Source, Distribution, and Removal

Figure 1

Flow chart of the centralized WWTP in Zhejiang, China (☆: location of samplings). RW, raw wastewater; PSE, primary sedimentation effluent; AHE, anaerobic hydrolysis effluent; SSE, secondary sedimentation effluent; HCE, high-density clarifier effluent; PSS, primary sedimentation sludge; AS, activated sludge; HCS, high-density clarifier sludge; and FS, final sludge.