【设计总说明】本设计对该市的用水、供水现状进行了调查,了解了该市的人口、地形及工业企业分布情况。根据当地地形气候等条件,选择B市北面一条自西向东流淌的河流作为该市的取水水源,以保证稳定有效的取水。并通过分析原水水质,并结合当地其他水厂净水工艺处理经验,探究取水构筑物形式和净水工艺流程并对所采用的每一个构筑物进行了仔细的计算和校核;对不同的给水管网方案进行经济技术比较,权衡其经济可行性以及可操作性,选用最优方案作为B市的给水管网系统,。
(1)设计背景
B市为二类城市,分为三个区:一区有人口10万,平均楼层高度为6层;二区有人口35万,平均楼层高度为7层;三区有人口20万,平均楼层高度有8层。B市地势中间高,四周低,采用吴淞高程系,水厂所在地的绝对标高为+300.00m。B市共有两个企业,一个是化工厂,一个是电视机厂。化工厂的日产量是20000吨,单位产品用水量为0.7吨水/吨,电视机厂日产量2000台,单位产品用水量为4.5吨水/台。
B市土壤种类为粘土,地下水位深9.0m,城市最高温度为42℃,最低温度为0℃,平均温度为20℃;主导风向为西北风。
B市取水水源最大流量为10000m3/s,最小流量为6000m3/s。最大流速为8m/s,最高水位(1%)为297m,常水位为292m,最低水位为(97%)282m,取水点河床断面最低标高为296.0m,最低水位时河宽70m。该河流为输送木材的河流,通航河流。水源水质较好。所以净水厂采用常规处理工艺对水源水进行处理。
(2)处理工艺简介
B市用水量为21.3万吨/日,水源为城市北部的一条河流,主流近岸,地质条件较好,同时考虑到取水量大、安全性要求较高,故选择合建式岸边式取水构筑物。取水泵房包括进水室、吸水室和泵房三部分,土建一次建成。根据流量和扬程选择500S35型水泵五台,四用一备。
折板絮凝池与平流式沉淀池合建,共三座。折板絮凝池分为三段:异波折板段、同波折板段及平行直板段,以使原水的到更好的絮凝效果。每座絮凝池长12.24m,宽17.15m。平流式沉淀池共设10根放空管,采用虹吸式刮泥机进行机械排泥;单座沉淀池长111.5m,宽17.15m。
V 型滤池由法国德利满公司在20 世纪70 年代发展的一种重力式快滤池,适用于大、中型水厂,现在V型滤池在中国的使用广泛。其属于等水位等速过滤;采用均质滤料,滤层厚度比普通快滤池厚,截污量也比普通快滤池大,故滤速较高,过滤周期长,出水效果好;冲洗采用空气、水反冲洗和表面扫洗,提高了冲洗效果并节约冲洗用水。本设计设滤池两座,每座滤池中滤池个数N=8,布置成对称双行排列,每个滤池分左右两格,每格宽3.5m,长10.0m,实际每个滤池过滤面积70.0m2。
设计主要参数有:滤速8m/h,过滤周期24h,允许最大水头损失2.0m。
本设计设置四座矩形钢筋混凝土清水池。根据管网计算得出清水池的调节容积为处理水量的12.07%,即为24480m3。清水池总容积为37580 m3。单座清水池体积为37580÷4=9395 m3,设清水池有效水深4.40m,则单格清水池占地面积为2136 m2,尺寸设为B×L=39.6m×54m,则实际面积为2139 m2,实际水深为4.40m。
水厂采用液氯消毒,滤后水加氯量为1.0mg/L。氯与水接触时间不小于30min。加氯点在清水池前。
二级泵房前设5.8m×41.8m 的吸水井一座,泵房土建一次建成。本设计用水量时变化系数为1.27。B市的给水管网采用并联分压式给水管网系统,所以二级泵房有高压泵五台,四用一备;低压泵三台,两用一备。每台高压泵流量为630.66L/s,扬程为69.82m,用水高峰期全部开启,用水低峰期可以减少开启的台数来进行调节;每台低压泵流量为229.34L/s,扬程为52.44m。
(3)预期效果
由于在设计前对该市的水量和原水水质进行了详细的调查,并有相近水厂作为参照,从原水水质及本次设计的工艺上分析,水厂能够较好地满足当地居民对水质水量的要求。
【关键词】常规水处理工艺;折板絮凝池;平流式沉淀池;V型滤池;氯消毒
Graduation Design of City B’s Water Supply Project
Water & Wastewater Engineering Chunfang Wang Teacher Shuili Yu
【General Information Design】 According to the survey with the water supply status of city B, we grasp the city’s population, topography and distribution of industrial enterprises. According to the local terrain and climate conditions, we select a river in the north of city B flowing from west to east as the water sources. By analyzing the raw water quality and combining with other water plants’ water purification process, we choose the best water purification forms and structures and choose the best solution as the water supply network of city B.
(1)background of the design
As a second-class city , city B is divided into three zones. Zone one has a population of 100,000 and the average floor height is 6 layers; Zone two has a population of 350,000 and the average floor height is 7 layers; Zone three has a population of 200,000 and the average floor height is 8 layers. City B has two companies, one is chemical plant and another is a TV factory. The daily output of the chemical plant is 20,000 tons and the TV factory is 2000 units .
The largest flow of the source water is 10,000 m3/s and the minimum flow of the river is 6,000 m3/s. The maximum flow rate is 8 m/s,. The highest level (1%) is 297.00m. The average level of the river is 292.00m and the lowest level is 282.00m.
(2)Introduction of the water treatment process
Taking the experience of other water plants and water condition into consideration, the typical water treatment process –coagulation, sedimentation, filtration, disinfection-can purify the row water to the Sanitary Standard for Drinking Water Quality. The raw water is pumped by first-stage pump house to the folded plate flocculator. The flocculator can form the flocs. We select the advection sedimentation tanks and V-shaped filter to purify the water.
(3)The expected results
We carried out a detailed investigation of raw water quality before the design. So we can purify the row water to the Sanitary Standard for Drinking Water Quality.
【Keywords】 conventional water treatment processes; folded plate flocculator; advection sedimentation tanks; V-shaped Filtration; Disinfection with Chlorine
目 录
3.3.8冲洗水泵设计计算
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