Characterization of Urban Stormwater Runoff in Tianjin

Characterization of urban stormwater runoff was carried out in commercial, residential and cultural and educational zones during 2009 rainy season in Tianjin. The pH, DO, BOD₅, COD, TOC, TSS, TN, TP, NH₃-N, As, Pb, Zn, Cd, LAS and fecal coliforms in stormwater runoff were analyzed. The ranges of arithmetic mean concentration of COD, TSS, TN, LAS and fecal coliforms were 67-331 mg/L, 134-480 mg/L, 4.00-4.69 mg/L, 1.53-11.12 mg/L, 3.03×10⁸-6.46×10⁹ cfu/100mL respectively, depending on the type of land using . In conclusion, COD, TSS, TN, LAS and fecal coliforms were the major runoff pollutants. The sequence of surface runoff pollution was in the following order: commercial zone > residential zone > cultural and educational zone in terms of the major pollutants. On the meantime, the results indicated that the urban non-point source pollution played an important part in the decreasing of water quality after analyzing the changes of quality in receiving waters.