Design of an Underground MBR Wastewater Treatment Plant in Qingdao

The design scale of an underground MBR wastewater treatment plant in Qingdao was 4×10⁴ m³/d with the area coverage of 1.31 hm². The combination treatment process of aeration oil removal sedimentation tank+fine grille+biological treatment tank+MBR was adopted. Domestic sewage was the main part of influent. The design effluent quality was required to meet the relevant requirements of the first class A standard of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), the recreational landscape environment water standard in the Reuse of Urban Recycling Water—Water Quality Standard for Scenic Environment Use (GB/T 18921-2002), and the Letter of Qingdao Environmental Protection Bureau on Clarifying the Water Quality Improvement Target of Provincial River Section in 2015. The land of the plant was small and irregular. In order to ensure the sufficient hydraulic retention time of the biological tank for the treatment requirements, the effective depth of the biological tank in this design was 8.5 m. The actual operation showed that the effluent quality had completely reached the design goal. Its design experience could be used as a reference for other similar projects.