Centralized sewage treatment is the main form of urban sewage treatment in China, which has the advantages of good treatment effect, easy management and "scale effect" and plays an important role in urban water environment protection. However, due to the shortcomings of large capital investment and long period in the construction of centralized sewage treatment facilities, urban sewage treatment lags behind, making sewage discharge in the rapidly expanding urban areas an important area to increase the pressure on urban water environment; Decentralized sewage treatment mode can realize sewage treatment nearby, with flexible construction of treatment facilities and less investment. It can be used as a beneficial supplement to the centralized sewage treatment model and has important research significance. This paper takes the urban decentralized sewage treatment model as the research object. Firstly, by analyzing the characteristics and constraints of centralized and decentralized sewage treatment modes, the decentralized sewage treatment area is judged. Secondly, on the basis of analyzing the decentralized treatment technology of sewage, according to different regional characteristics, the decentralized treatment technology model of up-to-standard discharge and the decentralized treatment technology model of sewage resource utilization are constructed; Finally, in view of the restrictive factors of decentralized sewage treatment, the operation management mode and countermeasures of decentralized sewage treatment are formulated, and the following conclusions are drawn: (1) In the process of urbanization development, the sewage treatment mode should focus on centralized treatment, supplemented by decentralized treatment, and realize the effective combination of centralized and decentralized sewage treatment as a whole, improve the urban sewage treatment rate and improve the pressure of the city on the water environment. (2) The determination of decentralized sewage treatment area is the basis of formulating sewage treatment technology model. The decentralized sewage treatment mode is suitable for the following areas: in the sewage discharge area outside the planning of centralized sewage treatment pipe network, permanent decentralized sewage treatment facilities should be built, and according to the requirements of reclaimed water reuse, the decentralized sewage treatment mode is subdivided into two modes: direct discharge after decentralized treatment and reuse after decentralized treatment; In the sewage discharge area, the planning and construction of centralized pipe network and the backward centralized treatment facilities, temporary decentralized sewage treatment facilities should be built, and whether to reuse them should be determined according to the requirements of regional environmental management. (3) For the projects that meet the discharge standards, through the comparison of sewage treatment technology and characteristics, it is concluded that two decentralized sewage treatment processes, biological aerated filter and biological contact oxidation, can be selected when the secondary discharge standard is implemented for sewage discharge under the condition that the occupied area is the main constraint factor; When the first-class discharge standard is implemented for sewage discharge, SBR decentralized sewage treatment process can be selected. In view of the limitation of floor space, it is suggested that the decentralized sewage treatment facilities should be designed underground. The reuse project of sewage treatment in residential areas and universities is analyzed. It is considered that the biological aerated filter process can be used when the reclaimed water in residential areas is reused for urban miscellaneous water. When it is reused as landscape water, SBR process can be used; MBR process can be used as sewage treatment and reuse process in high-grade residential areas. When the construction of sewage treatment facilities in colleges and universities is not limited by land area, underground infiltration sewage treatment technology can be chosen; When the construction of sewage treatment facilities is limited by area, biological oxidation contact method or biological aerated filter treatment technology with low operating cost can be selected. (4) On the basis of selecting the decentralized treatment process mode, it is concluded that the user self-help mode can be applied to the operation and management of sewage treatment systems in hotels, office buildings, commercial clubs and universities; Build-own-operate (BOO) is suitable for the operation and management of sewage treatment and reuse system in small and medium-sized communities. Build-Operate-Transfer (BOT mode for short) is suitable for the operation and management of sewage treatment system in large residential quarters and economic development zones. (5) Some countermeasures and suggestions are put forward to promote the application of decentralized sewage treatment mode, such as speeding up the formulation of decentralized sewage treatment technology system, popularizing preferential policies for decentralized sewage treatment, adjusting sewage treatment charging policies and online monitoring.
Keywords: reclaimed water reuse and decentralized treatment of urbanization sewage
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abstract
The first chapter is introduction.
The research background of 1. 1
1.2 application status of decentralized sewage treatment mode at home and abroad
The research significance of 1.3
1.4 research content and technical route
Research content 1.4. 1
1.4.2 technical route
Chapter II Determination of Applicable Area of Urban Sewage Decentralized Treatment Mode
2. 1 Analysis of centralized treatment mode of urban sewage
2. 1. 1 Analysis of the characteristics of centralized sewage treatment
2. 1.2 Constraints of centralized sewage treatment
2. 1.3 Problems in centralized sewage treatment
2.2 Analysis of decentralized treatment mode of urban sewage
2.2. 1 Analysis of characteristics of decentralized processing mode
2.2.2 Constraints of decentralized sewage treatment
2.3 Determination of Urban Sewage Decentralized Treatment Area
The third chapter is the construction of sewage decentralized treatment technology model.
3. 1 analysis of decentralized sewage treatment technology
3. 1. 1 analysis of manual treatment technology
3. 1.2 analysis of natural treatment technology
3.2 Regional sewage decentralized treatment technology model construction
3.2. 1 Decentralized treatment technology mode for up-to-standard discharge
3.2.2 Decentralized treatment technology mode of sewage treatment and recycling.
Chapter IV Operation Management Mode and Development Countermeasures of Decentralized Sewage Treatment
4. 1 Construction of decentralized sewage treatment operation management mode
4. 1. 1 decentralized sewage treatment market-oriented operation management
4. 1.2 Selection of market-oriented operation management mode for decentralized sewage treatment
4.2 Development Countermeasures of Decentralized Sewage Treatment
4.2. 1 Establish a decentralized sewage treatment technology system.
4.2.2 Formulate preferential policies for decentralized treatment.
4.2.3 Strengthen the functions of government supervision and management.
4.2.4 Improve the charging system
conclusion
refer to
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