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PART I INTRODUCTION
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PART II INSTITUTIONAL AND REGULATORY FRAMEWORK
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2.INSTITUTIONAL, POLICY, REGULATORY FRAMEWORK FOR RURAL SANITATION AND WASTEWATER MANAGEMENT
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2.1 Overview
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2.2.Institutional Arrangement
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2.3.Policies and Regulations
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2.4 Discharge Standards
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2.5.Sources of funds
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2.6.Typical provincial cases
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2.7.Conclusions and recommendations
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PART III TECHNICAL BASIS
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3 Overview of Rural Sanitation and Wastewater Management
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3.1 Domestic Wastewater
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3.2 Rural Toilets in China – Source of Black Water
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3.3 Decentralized vs. Centralized Rural Wastewater Management
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4 Rural Wastewater Treatment Technology
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4.1 Preliminary Treatment
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4.2. Primary Treatment
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4.3 Secondary Treatment
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4.3.1 Attached Growth Process
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4.3.2 Suspended growth Process
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4.3.3 Waste Stabilization Pond
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4.3.4 Constructed Wetlands
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4.3.5 Subsurface Wastewater Infiltration Systems
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5 Wastewater Treatment Process Design
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5.1 General Design Consideration
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5.2 Sewage Collection Alternatives
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5.3 Wastewater Treatment Process Design
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5.4 Water Reuse
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5.5 Sludge Management
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PART IV PROJECT PLANNING AND DESIGN
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6 Project Planning and Design
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6.1 Diagnosis for Project Villages – Initial Community Assessment
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6.2 Establishment of Stakeholder Group
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6.3 Assessment on Existing Conditions and Community’s Capacity
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6.3.1 Physical Conditions Assessment
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6.3.2 Community’s Capacity Assessment
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6.4 Baseline Engineering Survey and Assessment
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6.5 Project Feasibility Study and Environmental Impact Assessment
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6.6 Selection of Operation Model
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6.7 Project Cost Estimate
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7 Community Participation
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7.1 Why Need Community Participation?
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7.2 Principles of Community Participation
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7.3 Community Participation Activities
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PART V PROJECT FINANCING
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8 Financing, Subsidies, and Cost Recovery
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8.1 Programmatic Costs
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8.2 Project Implementation Costs
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8.3 Project Financing
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8.4 Subsidies
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8.5 Cost Recovery
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PART VI PROJECT IMPLEMENTATION AND MANAGEMENT
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9 Procurement and Implementation
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9.1 Procurement Principles
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9.2 Procurement Alternatives
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9.3 Procurement Planning
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10 System Adminstration, Operation, Maintenance and Monitoring
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10.1 Introduction
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10.2 Management and Administration Arrangement
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10.3 Operation and Maintenance
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10.4 Reporting and Monitoring
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10.5 Operator Training and Support
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Appendix: Case Studies – Rural Wastewater Management in Zhejiang, Shanxi, and Jiangsu Province
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1.Zhejiang Province
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2.Shanxi Province
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3.Jiangsu Province
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4.Summary
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REFERENCES
5.3.4 Suspended Growth Process + Construction Wetland/Stabilization Pond Treatment System
- Categories: 5.3 Wastewater Treatment Process Design
- Time of issue: 2022-04-28 18:38:13
- Views: 0
A. Description of the system
The system consists of a septic tank, a suspended growth process unit (activated sludge process or SBR), and a construction wetland or stabilization pond (Figure 5.6). The effluent from the aeration tank will go through a secondary clarifier before flowing to the constructed wetland or stabilization pond. The clarified sludge will either be returned to the aeration tank or disposed of as waste. System effluent complied with applicable standard is discharged to surface water. It is applicable for large communities.
Figure 5.6 Flow chart of suspended growth and constructed wetland/stabilization pond process
B. Design Consideration
- The compressor or air blower must be located on a stable foundation to prevent movement and should not in an area subjected to flooding.
- The number of fittings that change direction must be minimized to avoid excess friction loss in the air supply pipes.
- The sludge return lines must be directed to either the aeration chamber or the septic tanks. Sludge return outlets should be located in or above the inlet junction of these zones, not directly into the tank.
- The sludge return pump is located at critical points, where sludge settles, usually specified by the manufacturer of a proprietary system.
Design of a septic tank, activated sludge process, SBR, constructed wetland or stabilization pond refers to Section 4.2.1, Section 4.3.2.1, Section 4.3.2.2, Section 4.3.4, and Section 4.3.3, respectively.
C. Construction and Commissioning/testing
- The control panel must be watertight with all connections sealed to prevent moisture or sewer gases from entering. The control panel must be easily accessible and located where audible or visual alarms can be seen and heard by the owner of the premises.
- Carefully follow the manufacturer’s instruction for equipment installation.
- All electrical components should be tested by an appropriately qualified technician.
- All pumps should be clean water tested before commissioning and pressure tested to ensure the desired pressure can be achieved for the pumps’ specific purpose.
D. Operation management
- The plant should be inspected quarterly by the designated operator. This detailed maintenance inspection should include:
- checking that pumps, motors and blower assemblies are operating correctly. If the system includes a standby pump, motor or blower, it should be alternated with the operating piece from time to time to ensure that the work hours on both are approximately equal.
- checking the sludge return lines and skimmers are working properly and excess sludge and scum does not accumulate in the secondary clarifier. It is important to maintain an appropriate balance of air supply for aeration and operation of air-lift sludge return lines and skimmers.
- a suitably qualified person servicing the pump and control system according to any schedule set by the manufacturer. Pump(s) should be serviced at least once a year.
- ensuring a continuous power supply is provided to the system.
- ensuring that the service provider is contacted as soon as practicable if an alarm activates.