尾水导流工程是解决徐州市区域尾水出路问题、保证南水北调东线工程输水水质的重要工程。本文以正在建设中的徐州市尾水导流工程为研究对象,通过资料统计与分析、现场勘探与监测、遥感解译、数值模拟与计算等,对尾水导流工程方案、工程区域内重点控制单元治污方案、区域尾水资源化尾水导流工程的水环境影响等关键问题进行了系统研究。主要结论如下:(1)规划了“截流、蓄存、回用、导流”的尾水资源化工程,提出了以专线渠道为主的导流方案一和以利用现有河道为主的方案二。方案一线路全长172.61km,其中新开渠道109.39km,利用现状河渠63.22km;方案二线路全长172.69km,其中新开渠道31.16km,利用现状河渠141.53km。两个方案全线基本能实现尾水自流,同时能保证南水北调东线工程清水廊道的建设。方案二能利用现状河道实现尾水的调蓄,有利于尾水的资源化利用和尾水调度,而且方案二工程量小、配套建筑物少、工程投资少。方案一预计总投资为8.9998亿元,方案二为7.3008亿元,因此优选方案二。(2)分析了尾水导流工程区内重点控制单元污染物排放清单,阐明了区域水环境问题,规划设计了重点控制单元制污方案:①京杭运河不牢河段、京杭运河邳州段和房亭河是尾水导流工程区内的重点控制单元,生活废水和工业废水是造成单元内氨氮和COD超标的主要原因;②京杭运河不牢河段控制单元的治污重点是建设荆马河污水处理厂(三期工程)、桃源河污水处理厂和贾汪大吴污水处理厂;京杭运河邳州段和房亭河控制单元的治污重点建设邳州污水处理厂三期工程和三八河污水处理厂三期工程。(3)建立了尾水资源化利用规划:①2010年尾水导流工程控制范围内污水集中处理量为49.23×104m3/d;②综合分析了尾水水质、农业灌溉水质、区域灌溉定额和作物灌溉制度,结果表明灌溉期间尾水可全部用于农业灌溉;③制定了尾水工业回用方案,即按尾水与京杭运河水3:7的比例回用于电厂冷却水,回用规模为8.14×104 m3/d;④规划设计了4个尾水工业回用工程,并进行了尾水回用费用分析,结果表明尾水回用的成本为0.340-0.444元/m3。(4)构建了尾水导流工程输水干渠水质模型,预测了尾水导流对输水干渠的影响,结果表明导流尾水会造成输水干渠的水质恶化。非汛期降雨时,各预测断面的预测水质结果均劣于所利用河道的水质现状,预测输水干渠水质均为劣Ⅴ类水。(5)以Visual Modflow数值模拟软件为平台,研究了尾水导流对输水沿线地下水环境的影响。结果表明:①预测期内,各评价单元五年地下水水位升幅0.77～4.04m,五年渗漏量24.87～136.25×104 m3;总体上来说,河渠渗漏对地下水影响范围相对较小,五年的影响范围275～3110m;②第一、第二、第三和第七评价单元可能发生盐碱化,发生盐碱化的范围为距河渠50～190m;③河渠渗漏尾水COD的影响范围较小。(6)尾水完全能满足旱作、水作的灌溉用水水质要求,但不满足蔬菜的灌溉用水要求。镉是尾水灌溉的控制性指标,预测在20年后可能会产生镉超标的问题。(7)提出了水环境风险预案体系。
工业羊毛毡
Water diversion project is an important project which can resolve the tail water’s future and assure the water quality of water transfer from south to north. The tailing water diversion project of Xuzhou city was studied through statistical data and analysis, spot survey. and monitoring,remote sensing interpretation, numerical simulation and calculation and so on. Some key issues such as water diversion project proposal, key control unit’s treatment proposal, regional tail water recycling was studied systematically. Main conclusions are followed :(1) Two proposals were proposed which according to four principles of“interception, storage, reuse and diversion”. The route one was special channel about 172.61 kilometers long, which composed by the present river about 63.22 kilometers and newly opened river about 109.39 kilometers. The route two was to make full use of presented river, and was composed by the present river about 141.53 kilometers and newly opened river about 31.16 kilometers. Two proposals can meet the needs of transferring the tail water to the Xinyi river ecological treatment system and flow autotically, attain the goal of agro-irrigation reuse.The Route two can store tail water by the present rivers, which is benefical for tail water reuse.The total investment of the route two is 0.73008 billion RMB, the route one is about 0.89998 billion RMB. So the route two was choosed.(2) The list of pollutant items of key control unit in the tail water diversion area were analyzed, water environment problems were clarified. Some key control units was designed:①Bulao river unit, Pizhou section unit and Fangting river unit of the Grand Canal are key control units in the tail water diversion area. Sewage and industrial wastewater were the two main contributors which can make ammonium and COD overstandard.②the key pollution solution was to build a Jingma river wastewater treatment plant (the third stage of the project), Taoyuan river wastewater treatment plant and Jiawang Dawu wastewater treatment plant. The pollution management of Pizhou section and Fangting river unit of the Grand River were to build Pizhou wastewater treatment plant (the third stage of the project) and Sanba river wastewater treatment plant (the third stage of the project).(3)Tail water reuse plan was established.①the quantity of wastewater treatment was centralized treated which can attain the 49.23×104 m3/d.②tail water quality, agricultural irrigation water quality and irrigation regime was analyzed. The results showed tail water quality can meet the agricultural irrigation.③tail water recycling was proposed. The tail water and the Grand River water were used according to the ration three to seven by electricity-generated plant as cool water. (4) Water quality model of tail water diversion project was proposed and the impact of tail water on the main water diversion channel was forecasted. Results showed tail water diversion can worsen the water quality, water quality of all the monitoring sections were worse than the presented water quality during non-flood season and raining time. The water quality of main water distribution are below the Grade-fifth.(5) The impact of tail water diversion on the groundwater environment which based on the Visual Modeflow software was studied. Results showed①during the forecasted time, groundwater level will rise from 0.77 to 4.04 meter in all evaluated unit. The quantity of leakage will be from 24.87×104 to 136.25×104 m3, the impact area of channel leakage on the groundwater is relatively small, the impact length is from 275 meters to 3110 meters.②The first and second and third and seventh evaluated area maybe salinization-alkalization, whose length is from 50 to 190 meters.③the impact area of COD which seep from the channel is small.(6)Tail water’s quality can meet the quality of drying farming and wet farming, but cannot meet the need for vegetable. Cd is the main control element of tail water. It will be the pollution problem in the twenty years.(7)Water environment risk emerging plan was proposed