UNEP和IGES发布《堆肥指南》_45页_2mb

Summary of Composting Guideline

Core Content

This guideline provides an overview of composting as an intermediate municipal solid waste (MSW) treatment technology, particularly focusing on its application in developing Asian cities. It outlines the objectives, benefits, and challenges of composting, along with the pre-conditions necessary for sustainable implementation.

Main Objectives of Composting

1. To treat organic waste such as food waste, garden waste, livestock excreta, and other types of waste through aerobic or anaerobic processes, deactivating harmful bacteria, viruses, and weed seeds.
2. To produce organic fertilisers that improve soil conditions and serve as a partial substitute for chemical fertilisers.

Benefits of Composting

• Environmental Benefits: Reduces greenhouse gas (GHG) emissions from landfills, mitigates odours, vermin, and water pollution, and prevents fires and smoke.
• Soil Improvement: Enhances soil structure, nutrient retention, and microbial activity. Compost contributes to sustainable agriculture by improving soil conditions biologically, physically, and chemically.
• Economic Benefits: Reduces transportation and operational costs, and supports local agriculture, food, and tourism industries.
• Resource Perspective: Compost can supply essential nutrients like nitrogen, phosphorus, and potassium, and promote the formation of a sustainable soil and food recycling system.

Opportunities and Challenges for Developing Countries

• Opportunities: Composting is a viable option for cities seeking to reduce landfill reliance, manage organic waste effectively, and support local agriculture.
• Challenges: Cities must have the capacity to collect quality organic waste, secure compost demand, and maintain a budget for long-term operations. Additionally, they need institutional support and manpower to implement and sustain composting projects.

Pre-conditions for Sustainable Composting

The guideline outlines six key areas for evaluating the feasibility of composting projects:

1. Social Conditions

   • There must be adequate demand for compost products.
   • Composting plants should be located near farmland to facilitate distribution.
   • Storage units are necessary due to seasonal variations in demand.
   • Compost can also be used in home gardening and municipal green spaces.

2. Public Awareness & Cooperation of Residents

   • Residents must be aware of the benefits of composting and motivated to participate in source separation.
   • Involvement of local communities is crucial for the success of composting projects.

3. Institutional Aspects

   • Clear institutional arrangements are required for the planning, development, and implementation of composting projects.
   • Local governments and stakeholders must collaborate to ensure effective project management.

4. Governance Capability

   • Governance capacity is essential for ensuring the proper functioning of composting projects.
   • Strong governance structures help in monitoring and maintaining project standards.

5. Financial Aspects

   • A sufficient budget must be allocated for the design, construction, and operation of composting plants.
   • Grants or loans can support local governments in launching composting initiatives.

6. Technological Aspects

   • Appropriate composting technologies must be selected based on local conditions.
   • Effective processes such as fermentation, mechanical separation, and deodorisation are critical for successful composting.

Key Evaluation Criteria

• Mandatory Key Criteria (Pink): Adequate demand for compost.
• Strongly Advisable Key Criteria (Yellow): Local farmers must be involved from the planning stage.
• Advisable Key Criteria (Green): Public awareness and cooperation, institutional support, and financial planning.

Main Technology and Composting Processes

• Waste Suitable for Composting: Organic waste including food waste, garden waste, livestock excreta, and sewage sludge.
• Composting Systems: Decentralised and centralised systems.
• Processes: Fermentation, mechanical separation, and deodorisation.
• Requirements: Moisture content, temperature, oxygen supply, pH, C/N ratio, particle size, and compaction must be maintained within appropriate ranges.

Case Studies

• Surabaya City, Indonesia: Demonstrates successful composting implementation.
• Kuliyapitiya Urban Council, Sri Lanka: Highlights community-based composting efforts.
• Hanoi City, Vietnam: Shows the integration of composting in urban waste management.
• Nagai City, Japan: Provides insights into long-term composting strategies and practices.

Conclusion and Recommendations

• Composting is a key element in a functioning MSW system but should be part of an integrated waste management plan.
• Composting should be introduced only after evaluating all necessary conditions and ensuring that the project is feasible and sustainable.
• Collaboration between local governments, stakeholders, and residents is essential for the success of composting initiatives.
• Continuous monitoring and improvement are necessary to ensure the long-term viability of composting projects.

Message for the Busy Reader

• Chapter 1 provides a general overview of composting.
• Use Fig. 3 to check pre-conditions at the planning stage.
• Chapter 3 details the composting technologies and processes involved.

Historical Context (Box 1)

• Japan has a long history of using compost for agriculture, dating back to the Edo period.
• After the Meiji era, the use of compost declined due to urbanisation and increased use of chemical fertilisers.
• Composting practices have seen a revival in recent years, with a focus on source separation and community involvement.

Stages of Composting Projects (Box 2)

1. Planning Stage: Assess local interest, develop composting systems and technologies, estimate waste and compost quantities, and secure demand.
2. Setup and Operating Stage: Secure budget, design and construct the facility, and begin waste collection and compost distribution.
3. Upgrading Stage: Shift focus from waste management to enhancing local agriculture, creating a recycling loop in the food supply chain.

Key Takeaways

• Composting is an effective and sustainable method for managing organic waste.
• It requires a combination of technical and non-technical factors to be successful.
• Community involvement, institutional support, and financial planning are critical for the implementation of composting projects.
• Composting can significantly reduce environmental impacts and support sustainable agriculture.