| Weihe basin has a profound effect on the development of Shaanxi. Weihe is the mainriver in Guanzhong region and it is the main surface water sources for Guanzhong region.However, with the rapid development of regional economy and population growth, industrialand agricultural water consumption increases year by year, the water environment isdeteriorating and highlights the growing problem (including water shortage, water pollutionand the middle and lower reaches of Weihe river sedimentation), which has seriouslyrestricted the development of social economy and people’s normal life. As the majortributaries of the Yellow River, Weihe raised60%population of Shaanxi, assuming70%farmland irrigation area, ensure65%commissariat production of Shannxi province and morethan80%industrial output, its revenue in GDP province accounted for more than70%. Morethan70%wastewater of industrial and domestic wastewater through Weihe excretion makesWeihe become the largest polluted river in Guanzhong region. Because of the lack of effectivewater pollution control facilities, a large number of industrial waste water and city sewagedischarged into the Weihe, Chromium (VI) of Guanzhong section (especially Xianyang-Xi’an section of river) has worse than" surface water quality standard"(GB3838-2002) of Vtype water quality requirements.This paper takes Weihe River as the research object, through determination the content ofchromium (VI) in water,suspended matter and sediment in Weihe dry season water,researchon influence factors on chromium (VI) absorption, calculation and derivation decay indexand mathematical model of transfer and preliminary verification of chromium (VI), toprovide a scientific basis on resources optimization and management of Weihe water.In this paper, in order to study the distribution characteristics of chromium (VI) and tounderstand the water quality situation along the middle and lower reaches of Weihe, usingthree point three line method of acquisition in middle and lower reaches of Weihe in themiddle of March in2011, the water and sediment samples near13hydrological monitoringstation (include Wolong Lin village temple bridge, Guo town bridge, Chang Xingqiao,Xingping, South Camp, Xianyang bridge, Jiang Rendu, Geng Zhenqiao, new Fengzhen bridge, sand bridge suspension bridge in Tongguan, grove). In order to research on pollution sourceson chromium (VI) content change, monitoring and control15main outfall include Jiangriver, Baoji eighteen hole bridge sewage outlet, Guo Town Bridge Chencang area sewagedischarge outlet, west of Caijiapo Weihe Bridge Industrial outfall, Xingping, South Camp,Xianyang City Bridge sewage outfall, soap River, Lintong district sewage discharge outlet,Weibei Weinan Industrial Park sewage outfall, Weinan economic development zone sewageexport, harmonic river outfall, Shi Di river, Luo Fu River, Liuye river; at the same time, inorder to understanding the change of water content affected on sediment sorption onchromium (VI), selecting the Guo Town Bridge Town, Xinfeng bridge and Tongguan bridgeas representative section to take sediment samples, analysis the change of sediments ofchromium (VI) content. Throught analysis monitoring data of Cr (VI) conten of differentmonitoring section in the study area, the chromium (VI) distribution along the middle andlower reaches of Weihe River initial is grasped and analysis the relation on sediment andchromium (VI) migration process to each other. According steady water quality model tosimulate chromium (VI) distribution and migration along the middle and lower reaches ofWeihe River, calculate the reach of chromium (VI) integrated attenuation index the totalsewage outfall of Guo Town, Caijiapo industrial outfall, Xingping and Xianyang City Bridgesewage outfall and use the principle of least square method by means of the computersimulation to determine the reasonable parameter estimation; Derived for chromium (VI)migration in3D and2D control equation according to water dynamics model with sedimentmotion control equations. Based on hypothesis of the specific conditions, water and sedimentenvironment of chromium (VI) transfer and transformation model is simplified andundertook initial exploration for the analytic solution, obtain the result of analytical solutionsof one-dimensional model for the two specific conditions that the simple herpes depositionand erosion, and to simulation the effect of sediment on chromium (VI)’s migration processby putative data that meet the specific conditions, to make clear that silt is the main carrier ofmigration and transformation of chromium (VI). |
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