Study On Water Environment Characteristics And Variation Trends Of Reclaimed Water Recharged Chaobai River

This paper took the part of Chaobai River (Shun Yi) supplied by recycled water in Beijing as the research object, through the data and analysis of water quality, zooplankton, phytoplankton and benthonic animal in typical sections, studied the spatial and temporal variations and rules of water quality, water ecosystem. The conclusions of this study are demonstrated as follows:According to the monitoring data of 2013, conclusions are as follows:(1) The results of water quality analysis:the amounts of NH3-N were all meet the criterion, TP, TN,COD, BOD had exceeded the criterion. (2) Plankton analysis results: the dominant species in the monitoring section was the species of Cyanophyta, mainly Microcystis, Anabaena; protozoa and rotifer species were more than cladocerans and copepods in the monitoring sections. It was indicated that the water of the river was rich in nutrition, and was seriously polluted bu organics, reflecting that the Chaobai River (Shun Yi) was already eutrophicated. (3) The result of water quality analyzed by principal component analysis showed that according to pollution degree from heavy to light, the typical section sequenced as follows:Caihong Bridge> Sihao Bridge> Henan rubber dam> Shuangxing Bridge>Jian River inlet. Chaobai River from upstream to downstream was polluted aggravated gradually. (4) The evaluation of lake and reservoir in SL395-2007 was used to evaluate the trophic level of Chaobai River (Shun Yi). The result showed that Chaobai River was severe eutrophication.According to the monitoring results of 2008,2009, and 2013, conclusions are as follows:(1) Spatial variation:from upstream to downstream of Chaobai River (Shun Yi), the water quality change trend was as follows:pH, DO, Chla, CODCr and BOD5 were gradually increased; NH3-N, TN and TP decreased; and the variation of phytoplankton and zooplankton are basically the same, the number of plankton in Shuangxing Bridge was low, the number in Sihao Bridge and Caihong Bridge was much higher than in Shuangxing Bridge, the number in Henan rubber dam was a little lower than in Sihao Bridge and Caihong Bridge. (2) Interannual variations: pH of the monitoring sections wasn’t changed obviously yearly; NH3-N was showing a trend of decreasing year by year; Chlorophyll(a) and COD showed a rising trend; DO, TN and TP showed a downward trend in Jianhe monitoring sections yearly, in Chaobai river monitoring sections showed a rising trend; BOD5 wasn’t changed obviously yearly, and showed rising trend in Chaobai River. The density of phytoplankton in each typical monitoring sections increased year by year, and the density of zooplankton increased in 2009 relative to 2008, and in 2013 was lower than in 2008 and 2009. (3) The plankton annual and seasonal variation:The phytoplankton density showed a rising trend yearly. The density of zooplankton in 2009 was higher than in 2008, and in 2013, the number was decreased. The density of phytoplankton didn’t change obviously in spring, summer, autumn. The density of phytolankton in Sihao Bridge and Caihong Bridge was the highest in summer, and in Henan rubber dam was the highest in autumn; the zooplankton density with the spring, summer, autumn, showed a downward trend in all typical sections except Henan rubber dam, and in Henan rubber dam, the zooplankton density did not change significantly in three seasons, was the highest in autumn.