【设计总说明】某市位于江西省中偏东部，抚河中游，南赣公路通过境内，向乐铁路纵贯市西，交通便利。中心城区是该市的政治、经济、文化和科技、信息、物资流通中心，由文昌桥区和上顿渡、抚北镇、红桥镇一区三镇组成。该市处于赣抚平原向武夷山区过渡地带，地形为南北长，东西窄，地势南高北低，地震少发，气候温和，日照充足。
该市自来水公司现有五个水厂，总供水能力达到10.5万m3/d，加上部分工业自备水8万m3 /d，城市供水总能力达到18.5万m3/d。尽管如此，该市供水事业仍存在诸多问题，如工艺落后；五座水厂运行时间均在十五年以上，事故隐患多；水安全性难以保证；配水管网有待优化；城市供水普及率低等问题。
为满足城区经济发展，改善市民用水现状，以及提高供水安全性，扩大供水能力，现新建供水规模为20万m3/d的水厂，分两期建成。新建水厂以抚河为水源，水源水质达到生活饮用水水源水质二级标准，仅需常规处理即可达到生活饮用水水质要求。经方案比较,南区水厂扩建工程采用岸边式取水构筑物取水，处理工艺采用高密度澄清池加V型滤池，消毒剂采用氯消毒。
该新建水厂水源为地表水，水位变化幅度小，岸边水质和地质条件好，适宜用岸边式取水构筑物取水。为使取水泵房布置紧凑，减小占地面积，减短吸水管路的长度，将进水间与泵房合建。进水间设置上、下两层格栅，以便在不同水位时取得水质较好的原水。泵房土建按远期考虑，水泵按近期考虑，泵房为半地下式的矩形泵房。
考虑到新建水厂用地限制，采用占地面积较小的高密度澄清池。高密度澄清池是由法国得利满公司研制的一种采用斜管沉淀及污泥循环方式的高速澄清池，具有处理效果高、单位面积产水量大、适应性强、处理效果稳定等优点。高密度澄清池的工作原理是基于原始概念上整体化的絮凝反应池、推流式反应池至沉淀池之间的慢速传输、泥渣的外部再循环、斜管沉淀机理以及采用混凝剂加助凝剂这五点之上。高密度澄清池在国内运用的实例较少，在上海市杨树浦水厂的扩建工程以及在乌鲁木齐石墩子山水厂中有运用，设计参数资料较少，因此本设计主要参考这两个水厂的设计参数以及相关文献。高密度澄清池分为预混合区、快速混合区、絮凝区、预沉-浓缩区组成，前三者的停留时间分别取1.92min、2min、5min，斜管上升流速取22.5m/h。混凝剂采用碱式硫酸铝，加药点在快速混合区；助凝剂采用PAM，加药点在絮凝区。
V型滤池也是由法国得利满公司开发的一种重力式快滤池，通过出水阀门的不断调节可保证滤池的恒水位等速过滤。V型滤池采用均粒石英砂滤料，滤层厚度大、滤速高、过滤周期长、出水水质好。同时，V型滤池反冲洗采用气冲、水冲及表面扫洗，滤层保持微膨胀状态，提高了反冲效果。本设计近期采用8座双格滤池，反冲洗泵房和鼓风机泵房与滤池合建。滤速采用8m/h，过滤周期为24h，单格滤池面积为35m2，滤池高度为4.25m。反冲洗过程分为气冲、气水冲、水冲三个阶段，每个阶段持续时间为4min。气冲强度为16L/(s·m2)，气水同冲时水冲强度为4 L/(s·m2)，单水冲时水冲强度为5 L/(s·m2)，表面扫洗强度为1.8 L/(s·m2)，持续时间为8min。
近、远期各造一座清水池，水池容积按最高日用水量10%设计。由于厂区占地有限，因此水厂平面布置采用折角型，折角选在清水池。吸水井为独立式，这种吸水井的优点是调度管理方便、吸水管道短，提高水泵运行的安全程度。本设计的加氯点设置在V型滤池至清水池的出水管上。
调节池收集V型滤池的反冲洗废水，需进一步处理；高密度澄清池的排放污泥由污泥调节池收集后送至污泥脱水机房直接脱水。
厂区内道路均为6m的双车道，转弯半径为10m。厂区绿化率为35.9%。由于采用了高密度澄清池，单位处理水量的占地面积仅为0.15m2/(m3/d)。
【关键词】一级泵房；高密度澄清池；V型滤池；消毒；反冲洗
20×104 m3/d Water Works Process Design
Water & Wastewater Engineering Huang Ling
Teacher Deng Huiping
【General Specification】X city is located on the middle reaches of Fu River, eastern centre of Jiangxi Province. Nangan highway going through the city together with the Xiangle railway running from the north to the south forms a convenient transportation system. The centre town is the political, economy, culture and technology center of X city, which includes Wenchang Bridge District, Wubei Town, Hongqiao Town. X city lies in the transforming area from Ganfu Plain to Wuyi Mountain area and has a landform of long north-south border line and narrow line west-east. X city rarely has earthquakes and enjoys a mild climate and a sufficient sunlight.
Presently, there are five waterworks in X city, which have a total water supply of 105,000 cubic meters per day. Along with the industrial water reserve of 80,000 cubic meters per day, the capability of water supply in X city reaches 185,000 cubic meters per day. However, there remain a lot of problems in the water supply system. For example, the techniques are out of time; all the present waterworks have ran for over fifteen years, which means a high risk of accident; no guarantee is available for water safety; water distributing systems need to be optimized; the popularity rate of water supply is low; etc.
In order to meet the requirements of economic development, ameliorate the current situation of the water use, as well as enhance the safety of water supply and scale-up the water supply capability, this project is meant for expansion of the former Nanqu Water Works. This project has a water supply ability of 20,000 cubic meters per day and is planned to be built in two stages. This new water works collects raw water from Fu River, which meets the second grade standard of drinking water resource. Only conventional treatments are able to produce qualified drinking water. After comparing several plans, this new water works employs the shore type water collection structure for collecting water and Densadeg plus V-type filter as the main treatment process. Chlorine is used for disinfection.
As the water level doesn’t change much and with good water quality near the bank and good geological conditions, it is advantageous to employ the shore type water collection structure. In order to decrease the footprint of the pump station and shorten the length of suction pipe, intake structure is built in combination with the pump station. In consideration of the land limitation, Densadeg (developed by Degremont Company), is employed to substitute the conventional folded plate coagulation tank and rectangular sedimentation tank. As a result, the ratio of occupied area to treated water quality is only 0.15m3/(m2·d), which is quite low compared with other waterworks. Because Densadeg is only employed by two water works domestically, the key parameters of this project are much based on former operating experience. Densadeg is composed of reactor zone, presettling/thickening zone and clarification zone. Part of the sludge is reused for coagulation. V-type filter is also developed by Degremont Company. The advantages of this type of filter are as followings: high thickness of filter layer; high filtration rate; long filtration period; satisfactory effluent quality; etc. Moreover, air backflushing and surface sweep washing used in the backwashing process keep the filtration layer in slight expansion state, which improves the flushing effect. In this project, chlorine is added in the pipe connecting the V-type filtration and clean water tank.
This new water works covers an area of about 30,000 square meters and has a green ratio of approximate 36%.
【Keywords】Raw water pump station；Densadeg；V-type filter；Disinfection；Back flush
目 录
3.4.1 清水池设计水量
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