Composting Solid Organic Waste from Municipal Sources in West Asia – A Technical Guide for Decision Makers and Practitioners

Approximately one billion tonnes of municipal organic waste are generated globally every year, although only a small fraction of this is currently recycled, with the remaining factions being either burnt or dumped in landfill sites. Composting is one of a number of different ways in which organic wastes can be converted into valuable products such as compost. Composting helps to alleviate pressures on land management, encourage sustainable farming practices and reduce fugitive emissions of methane gas from dumpsites and landfills.
 

Although composting harnesses natural micro-organisms to decompose organic materials under controlled conditions, the planning and management of a composting facility is complex. It requires a unique blend of knowledge and understanding spanning a number of disciplines, including amongst others, engineering, biology, chemistry, physics, marketing and occupational safety and health. It is particularly challenging when municipal sources of organic waste, such as food and green/garden wastes, are composted. Understanding how to prevent problems, and troubleshooting when they do occur, takes skill and technical know-how.

The purpose of this guide is to provide decision makers and waste managers with sufficient technical information to plan, design and operate a composting facility. It is aimed at developing Asian countries where access to high-cost capital infrastructure may not be possible. It focuses on medium- to large-scale composting operations, although the principles described apply equally to smaller scale operations. It is split into different chapters as follows:

• Waste Mapping: Chapter 2 provides background information on the history of composting, why it is used to treat municipal organic wastes and some of the different composting technologies that have been developed globally. Examples of composting facilities in a selected number of Asian countries have been summarised. 
• The Composting Process: Chapter 3 explains the main composting parameters and the key composting stages that form essential background information for all composting practitioners. 
• Composting Feedstocks: Chapter 4 discusses why organic waste needs to be managed effectively in order to prevent problematic emissions and the importance of effective source segregation to minimise contamination. 
• Planning a Composting Facility: Chapter 5 sets out important information that should be considered when planning a composting facility, irrespective of its size. The failings of many facilities have their root cause in inadequate sizing, poor design and inappropriate sourcing of feedstocks. Fundamentals, such as site location and compliance with regulatory requirements, need to be understood by all stakeholders during the planning and commissioning stages. The information in this chapter should lead to effective planning of a new composting facility.
• Operating a Composting Facility: Chapter 6 provides step-by-step instructions on how to develop an effective site management system, including compost monitoring, contaminant management, worker health and safety, and training. Good site management can also prevent problems occurring, such as generating odours and starting fires; problems that may cause a facility to cease operations and potentially close permanently. This chapter therefore sets out essential information that should be incorporated into a site’s standard operating procedures. 
• Compost Products and Markets: Chapter 7 provides background information on the properties of compost, its benefits when applied to soil and the different types of products that can be manufactured. However, compost products do not sell themselves; hence a comprehensive marketing strategy should be developed as part of the planning process before the site becomes operational. As compost is a relatively new product to many people, product awareness and practical demonstrations may be necessary to build consumer demand. Without an effective sales strategy, the organic waste-to-compost-to-soil circle cannot be connected. 
• Awareness Raising: Chapter 8 provides some suggestions about how a composting company can target its three main stakeholders: technical professionals; farmers, agricultural advisers, landscapers and marketing professionals; and citizens. Communicating with each target group before operations begin should help build trust and understanding, as well as create market demand for compost. 
• Worked Examples: Information about four differently sized composting facilities, including site infrastructure, equipment and operational steps, are set out in Appendix 1. This is intended to illustrate how some of the principles described in the previous chapters have been put into practise. 
• Personal Requirements: Finally, Appendix 2 lists specimen job descriptions and desirable attributes of the different employees or volunteers needed at a successful composting operation.