China Water Supply and Drainage Design Experience Shenzhen Zhilin Village's Pipeline Drinking Water Design Experience Liu Qixiang, Chen Hua (Liyuan Water Supply Design Consulting Co., Ltd., Shenzhen, Guangdong 518031) combined with the design of the direct drinking water design of the main residential area in Shenzhen Meilinfeng, introduced some experiences And experience.

The Meilin Village residential community was developed and built by the Shenzhen Municipal Housing Bureau. It covers an area of ​​about 44X 104m2. It plans to build 65 multi-storey residential buildings and 31 medium- and high-rise residential buildings, with a total of more than 7,000 households. It plans to accommodate about 30,000 people.

1 Introduction to Design 1. Water quota and water consumption The quota of drinking water is different for buildings of different regions and different natures. The state has not clearly defined the quota of drinking water for houses. According to relevant information, about 0.5% to 2% of urban water supply is used for cooking and drinking, while the water consumption standards for direct drinking water in other cities in China are as follows: q=5L/(person.d) direct drinking water Quantity: average day is Q flat = 150m3 / d highest day is Q high = kdQ level = 1.3X 150 = 195m3 / d community direct drinking water system water supply design scale: Q = 200m3 / d high daily variation coefficient: d = 1.3 high Coefficient of variation: h=4.0 1.2 The water treatment process is based on the characteristics of the tap water quality of the Shenzhen Special Economic Zone and the proposed drinking water quality test standard. Through the research and analysis of multiple schemes (microfiltration, ultrafiltration and reverse osmosis), the treatment process of the project is determined. .

In the process of water purification treatment process, several membrane filtration technologies such as microfiltration, ultrafiltration and reverse osmosis were compared and determined to adopt ultrafiltration. Ultrafiltration can remove residual organic matter and harmful substances in tap water, and retain trace elements beneficial to the human body in water. This is where high-quality drinking water is different from pure water.

Each treatment process is designed according to the highest daily average flow rate, and based on the characteristics of the system allowing intermittent water supply, the treatment process adopts a single set design.

1.3 System design system design process The system adopts centralized treatment, and the water supply mode is unified by the pipeline. The water purification station is established in the community. According to the different water pressure required by the user, the water supply of the partial pressure system is also considered. Through comparison of energy consumption, cost, operation management, etc., the direct drinking water in the community is divided into three independent water supply pipe network systems: multi-layer system, middle and high-level system and high-level system. In order to protect the water quality, the entire system does not need to have secondary water tanks and water tanks with secondary pollution. The production and transportation are all closed design, and the circulating pipe network system is designed like the hot water supply system to further ensure the user's water use. Safe, reliable and high quality, this is also the most prominent feature of the design of the direct drinking water system.

1. Pipe network design The designed direct drinking water for drinking water is only for dietary water. Each household only considers installing a drinking faucet in the kitchen. The indoor and outdoor pipes are calculated and checked according to the designed second flow rate and maximum time flow. While complying with the design specifications of the water supply pipeline, the layout of the pipeline network should be carried out in accordance with the principle of short, straight, simple and smooth, and coordinated with other pipelines. Under the premise of safety and reliability, the accessories with secondary pollution such as accessories and interfaces should be reduced as much as possible. In particular, the remote metering water meter is adopted to minimize the length of the branch pipe after the water meter, to ensure complete circulation, and to ensure the water quality is fully guaranteed.

In view of the special nature of the direct drinking water, in order to ensure that the water quality remains unchanged during the transportation process, in addition to the fully closed circulation type of the conveying pipeline system, higher requirements are also placed on the material of the pipeline. After comprehensive comparison, the following pipes were selected in this project.

Outdoor pipeline: PVC-U pipe for circulating pipe and multi-layer system; domestic stainless steel pipe for middle and high-rise and high-rise system: aluminum-plastic composite pipe for multi-layer system and its circulating pipe; middle and high-rise system and high-rise system and its circulating pipe Imported thin-walled stainless steel tubes.

1.5 Circulating system design system designed into a circular type is the biggest feature of the direct drinking water design, but also the most fundamental difference between the design of the tap water supply system. According to the characteristics of direct drinking water, after extensive discussion and certification by experts, it is considered that to meet the requirements of water quality standards, the system must be designed in a circular manner.

The design of the direct drinking water system uses two sets of circulating pipe networks, that is, the multi-layer system is separately provided with a circulating pipe network, and the middle and high-rise systems and the high-rise system are jointly arranged with a circulating pipe network. The two circulating pipe networks are independent of each other, and do not interfere with each other, and the circulating pumps are separately grouped. Form a small circulation system or called a sub-circulation system (see).

The circulating water volume is designed according to 50% of the total water volume of the pipe network, that is, the user's water is produced within 12 hours (except the water in the branch pipe after the water meter).

Sub-circulation system. 6 System operation management system operation management mainly includes the management of water purification station and water supply pipe network. The water treatment system implements linkage control of effluent water quality, water volume and water pressure, and is fully automated.

The operation and management of the water supply network is mainly for the operation and management of the circulation system implemented to ensure the water quality. Since the circulation system is composed of the group sub-circulation system, the system does not have to implement the 24h cycle throughout the day, but is determined according to the water quality of the drinking water tap. The operation law of the cycle, the quantitative circulation of the sub-circulation system is implemented in batches and batches to achieve the principle that the drinking water meets the standard, which is also the characteristic of the operation of the circulation system.

2 Design Discussion 21 Water-based fixed pipe network direct drinking water as a new type of water supply developed in China in recent years, the system design water consumption quota is taken as q = (person.d) This is a small quota for the Shenzhen area. Due to the high temperature throughout the year, and with the further improvement of people's living standards, high-quality water will be used for rice, washing vegetables and even beauty, in addition to being used directly for drinking and cooking. Therefore, in Shenzhen, the direct drinking water is rated at 8~10" (person d), which is only 5%~7% of the current actual household water consumption, which is more in line with the actual situation; from the planning point of view, it is only The living water consumption of residents is about 2%~4%, which is more consistent with the data of 0.5%~2% of the city water supply for cooking and drinking. Therefore, according to the local environment and climate, the actual situation should be determined. The direct drinking water quota for the situation.

22 Regarding the system scale, the direct drinking water consumption is small, and the system scale is generally small. Therefore, in addition to considering technical factors, the operation management and economic feasibility of the system are particularly prominent. Large and medium-sized residential quarters with relatively concentrated housing and large number of households are conducive to the implementation of pipeline drinking water. On the contrary, in the residential areas with scattered houses and fewer households, direct drinking water will be implemented, and the cost per unit of aquatic products and management and operation costs will be greatly increased, which will inevitably decrease. Business Benefits.

Therefore, the author believes that households with less than 1,000 households should not use direct drinking water, otherwise the cost of drinking water will be too high.

The scope of 23 quality water supply is currently implemented in some urban residential communities in China. The 7 water supply is divided into direct drinking water in domestic water. After deep treatment, a separate system is provided for residents to drink water and cook. This type of water supply system Water consumption and scale are generally small, and there are limitations in the implementation process. The author believes that the scope of the quality water supply should be expanded, that is, the living water should be separated from the domestic water. The specific design is to implement the water supply of the kitchen and the bathroom, so as to implement the water supply in a broad sense, which is conducive to the implementation of the quality water supply system. It is beneficial to reduce the cost of the system, especially the water supply system before the water supply, to facilitate the operation and management of the system, and more importantly, it is beneficial to greatly reduce the cost of water production per unit of direct drinking water, making the pipeline drinking water system more economical. Rationality and implementation feasibility.

3 Pipeline drinking water in the conclusion stage is an example. All kinds of "water" in the market not only change people's drinking water concept, but also impact traditional tap water. Although there is still a big gap between China's drinking water quality standards and developed countries, first of all, it should be fully affirmed that tap water that has been strictly tested and meets the national drinking water quality standards is drinkable, and with the development of the economy, China's drinking water quality standards will also continue to increase. As far as the current situation is concerned, it is unrealistic to large-scale and large-scale improvement of the tap water quality of the whole city and to meet the water quality standard requirements for direct raw drinks. Therefore, in the areas where economic conditions permit, secondary purification of tap water can be implemented to form a community. The quality water supply system partially improves the drinking water quality of residents as a transitional measure to improve the quality of tap water. This is also in line with the residents' demand for high-quality drinking water, and its water quality standards, water supply systems, pipe selection, design parameters, etc. Both will be summarized in practice.

° Progress from the recycling and reuse of sewage in Qingdao City is one of the country's severely water-deficient cities. According to the per capita water quantity, the average annual per capita water volume in China is only 2,500 m3, which is only one-fourth of the world's per capita water. The per capita possession of water resources in the city is 375m3, which is less than one-sixth of the national per capita water.

Since the Yellow River Jiqing project was put into operation, the water supply situation in Qingdao has eased. However, with the development of industrial and agricultural production and the improvement of people's living standards, the water consumption is increasing. With the continuous extension of the Yellow River, the shortage of water resources has become a problem that cannot be ignored in the development of Qingdao's cities, even if various measures are taken to tap the potential. In 2000, water supply and demand will remain balanced, but by 2010, urban water supply will still have a serious crisis. Therefore, while saving water, we must establish a water-saving economy, actively open up the use of other water resources, and vigorously promote the recycling of wastewater, which is much more economically justified than the vast project and desalination project of the South-to-North Water Diversion Project.

After the implementation of the modular secondary treatment of sewage in Qingdao, the Fuzhou Road Community in Qingdao will use part of the wastewater for reuse, watering the green area in the area, and the scale of reuse will be 311m3/d, saving 20.5X 104m3 of tap water in one year. Qingdao Haibohe Wastewater Treatment Plant In February 1999, a 4X 104m3/d wastewater reuse project was completed (the secondary treated water is the influent water source for the wastewater reuse project), which is currently in good condition and is available within 13km of the lower reaches of the Haibo River. Water for enterprises, stadiums and Haibo River can save 1 104m3 of water per year. The pre-feasibility study report for the wastewater reuse project in Huangdao Economic and Technological Development Zone has been completed. The development of the Nibuwan Wastewater Treatment Plant in the development zone has started. The treatment scale is 3.5X 104m3/d in the near future. The 7X104m3/d water reuse treatment scale is 2.5. X104m3/d long-term treatment scale 5X104m3/d water is mainly used in the development zone factory enterprises, a small amount for landscaping in the near future can save 912.5X1 tap water (fm3, long-term annual savings of tap water 1 1 (fm3. The price is calculated at 1 yuan/m3, and the tap water price is 1.80 yuan/m3. In the near future, the annual savings of 7.3 million yuan, and the annual savings of 14.6 million yuan.

In terms of economic benefits, the water purification cost of industrial water purification plants with sewage as raw water is lower than or even lower than that of natural water as raw water. This is because water resources fees, water intake and long-distance water transportation are saved. Energy consumption and construction costs. The water treatment cost of Haibohe Wastewater Treatment Plant and Huangdao Economic Development Zone is much cheaper than that of tap water. If the tap water used in Qingdao's current spraying of green land and flushing road surface is changed to medium water, it can receive obvious economic benefits.

(Qingdao Municipal Design and Research Institute Liu Li Qingdao Ocean Shipping Crew Academy Wang Yemin contributed)

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