[Technology Selection: How to Choose the Right Organic Waste Treatment System] Population, land, waste composition…….
The selection of the right technology for organic waste management is important for local governments and operators throughout the region. In most cases, technologies are prescribed without any consideration of the local context, and as a result the projects often fail. Municipal officials may also be attracted to the technology that is successfully used in industrial countries, without evaluating its applicability to the local context. Experience shows that more mechanization is required for larger processing plants. Cities can use a combination of technologies such as composting to tackle their vegetable and food waste, biogas digesters for fish and meat waste, and RDF for dry organic waste of high caloric value. More advanced waste treatment systems in Europe use a combined mechanical biological treatment system which is currently nonexistent in South Asia, as it comes at a higher cost and strictly relies on segregated waste, which is more common in Europe. The key criteria to be considered before selecting the type of organic waste treatment system are as follows:
Population size and waste volume.
Based on population size and the daily waste volumes, a city can decide the scale of organic waste-recycling facilities. Larger cities with high waste volumes can consider more mechanical systems, as their higher operational costs may be recovered through increased revenues from the sale of compost, higher tipping fees, and carbon financing. Efforts should be made to find cost-effective solutions.
The physical composition and chemical characteristics of the municipal waste will enable local government officials and private operators to decide which organic waste technology will be most suitable for a particular city. As indicated earlier, a significant portion of waste in the region is biodegradable organic waste, while the rest consists of inorganic recyclables and miscellaneous inert matter. Ratios vary from city to city, with more industrial and economically developed cities possibly containing more hazardous or construction waste material.
Availability of land.
The type of technology selected to cater to the amount of waste volumes will be a factor in determining the amount of land required. However, land scarcity is a major issue throughout the region. Local officials are typically constrained to find available land for waste disposal, which requires large areas typically situated 500 meters from communities. Municipal authorities can play an important role in making suitable land available for current and future waste management disposal and treatment through improved land use planning and regulation.
Availability of workers and capacity.
An abundance of unskilled workers makes labor intensive technology more attractive for South Asian cities. In smaller cities, mechanized approaches should be avoided to minimize investment and operational costs. The health and safety of the workers must be considered, and personal protective equipment (e.g., hard hats, closed shoes, reflective wear, gloves, and masks) and occupational health and safety plans must be basic requirements in all facilities. Facilities should also promote the employment of women, create daycare facilities, and provide healthy meals for workers. These attributes are common in many privately run operations, including in Bangladesh.
Policies conducive to promoting public, private, and community partnerships that also encourage waste reduction, recycling, and reuse are helpful. For example, without proper policy guidelines, source segregation of waste is difficult. Private investment in waste management and the recycling sector should be encouraged with up-front capital subsidies, incentives, and tax breaks, or reduced subsidies on chemical fertilizers or nonrenewable energy sources to create a level playing field for the organic waste product market.
Greenhouse gas reduction.
It is estimated that direct emissions reductions from improved municipal organic waste management are 20%–98% for composting and 60%–100% for anaerobic digestion when compared to landfilling.19 Also, the use of RDF technology for registering such projects for carbon financing through the CDM is on the rise in India.