城市污水管网中水质变化特性

以管网中城市污水为研究对象,通过模拟管道的循环流动研究了水质变化特性。结果表明,在水力流动6 h的条件下,因管道沉积和管内微生物作用,城市污水中的TCOD(总有机物)去除率为10.79%,其中,沉积和生物降解作用对TCOD去除的贡献率分别为68.85%和31.15%。而管道中的氮类污染物的去除率为11.15%,管道沉积与生物降解作用各占约50%,其中生物降解引起的氮类污染物的变化主要是水中有机氮转化为NH3-N(NH3-N由35.51 mg/L升至38.38 mg/L),以及反硝化作用造成的NO3-N转变(NO3-N由2.36 mg/L降至0.84 mg/L)。总磷的变化相对较小,与管道内相对稳定的缺氧环境有关。

Characteristics of water quality variation in sewer networks

Simulated sewer networks system was used to study variation of water quality in sewer system. Results showed that under the condition of 6 h of hydraulic flow, the total COD (TCOD) removal efficiency in urban sewage is 10.79% because of sedimentation and biodegradation process. Furthermore, 68.85% of the COD removal is attributed to sedimentation effect while the rest is related to 31.15%. Meanwhile, removal efficiency of TN in sewer is 11.15% and sedimentation and biodegradation process account for 50% respectively. Transformation of nitrogen pollutants caused by biodegradation were mainly conversion of organic nitrogen to NH3-N (NH3-N rises from 35.51 mg/L to 38.38 mg/L) and removal of NO3-N caused by denitrification process(NO3-N drops from 2.36 mg/L to 0.84 mg/L). The elimination of the total phosphorus is relatively small, which is because of stable anaerobic environment in the sewer networks.