Abstract:

The designed capacity of second phase project of a wastewater treatment plant in Tianjin is 4.5×104m3/d. A2O process for denitrification and desulfurization is adopted in the biological treatment process. The effluent quality meet the primary standard grade A of 〖WTBX〗Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant 〖WTBZ〗(GB 18918—2002).The upgrading and reconstruction project improves the effluent quality to meet the Tianjin local primary standard,〖WTBX〗Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant 〖WTBZ〗(DB 12/599—2015).As the capacity remains unchanged，the original A2O tank was modified to AAOAO process (fivestage biological process). Furthermore, carbon source addingand bioselectors devices were installed into the biological process. After reconstruction, denitrification and desulfurization were significantly promoted, and the effluent quality meet the discharge standard steadily. The fivestage biological process has great popularization and application value in upgrading and reconstruction of urban wastewater treatment plant due to its advantages of no additional land occupation, short reconstruction period, low investment cost and stable effluent quality.

Key words:

upgrading and reconstruction, urban wastewater, fivestage biological process, denitrification and desulfurization, A2O