title: Characteristics of change in water quality along reclaimed water intake area of the Chaobai River in Beijing, China.
abstract: To reveal the basic characteristics and controlling factors of water quality change in the project Wenyu to Chaobai reclaimed water diversion, the water quality in the study area was monitored for one year at seven monitoring sites. Inverse geochemical models of the statistical groups were developed using PHREEQC to elucidate the hydrochemistry characteristics of reclaimed water and the factors. The monitoring results indicated that nitrogen and phosphorus contents were significantly reduced along the river mainly caused by seasonal and location variation. The pH ranged from 7.44 to 9.81. Photosynthesis of algae and denitrification in anaerobic microenvironment ultimately led to a sudden pH increase after the Jian River and the Chaobai River confluence. Mg2+and SO42-levels dropped obviously in the summer and increased in winter seasons after intersection. Na+and Cl-are relatively stable, and marked drop in the concentration only after the two rivers meet. And there is a decrease of Ca2+and HCO3-and increase in CO32-during monitoring period. As a whole, the primary ions and nutrient components, including nitrogen and phosphorus, had high levels in winter. Algae's photosynthesis and respiration were observed to have an impact on the river water quality; there was precipitation-dissolution of minerals and denitrification from upstream to downstream. Inverse geochemical PHREEQC modeling confirmed that there was precipitation of aragonite or calcite, and gypsum or anhydrite in summer, and dissolution in winter; as well as precipitation of dolomite in winter, and cationic exchange and denitrification along the river.
authors.affiliation: Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China. Electronic address: yangleiangela@126.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China. Electronic address: jthe@cugb.edu.cn.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: He
authors.affiliation: Beijing Xinguohuan Environmental Technology Development Co., Ltd., Beijing 100044, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Liu
authors.affiliation: East China University of Technology, Nanchang 330013, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Jiangxi Institute of Geo-Environment Monitoring, Nanchang 330012, China.
authors.forename: Lie
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China.
authors.forename: Guangcai
authors.initials: G
authors.lastname: Wang
mesh_terms: D000068476:Beijing; D004784:Environmental Monitoring; D045483:Rivers / Q000737:chemistry; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*; D060753:Water Quality / Q000592:standards
chemical_list: D062065:Wastewater; D014873:Water Pollutants
keywords: Chaobai River; PHREEQC; Reclaimed water; Water quality