There is much discussion in the municipal solid waste management sector around what constitutes best practice. In reading industry journals such as Waste Management World, one would learn of the latest machines which are distributed for application in all aspects of waste management from trucks with robotic arms which lift and tip curb-side garbage bins into the truck bed to sorting machines which segregate recyclable materials without anyone having to lift a finger.
Exemplary best practice for everyone to follow?
These capital-intensive solutions have streamlined SWM processes in cities around Europe and the United States, and as such are often mistaken as solutions which should define best practice waste management in cities around the world. Simply importing these western-built solutions to emerging markets, however, often does not respond to the needs and conditions prevalent in developing communities. Below is a closer look at the reasons why.
Physical characteristics of cities
Try getting your compactor through there…
Picture the even, paved streets of New York City, where even the alleys of Chinatown are big enough for a garbage truck to easily drive through and collect the filled bags deposited on the curbside. Now picture the narrow winding roads of Cairo, where many times only bicycles or motorcycles are able to pass each other, and where many of the residents traverse the city by foot. Most developing cities face the issue of a population which is vastly outpacing expansion of the municipal infrastructure. Informal settlements are sprouting up on the edges of cities around the world, with the only access being over narrow, unpaved, and sometimes hilly streets. (I recently paid a visit to a slum in Old Delhi, where ramshackle shelters were perched along the edge of a tiered path up the side of a man-made hill. The only way up to each doorway is by climbing stairs, making it an area impassible to conventional garbage trucks.) In 2003, the UN Habitat report estimated one billion people were living in slums worldwide, or about one third of the world’s urban population. Urban solutions in low-income countries cannot ignore that one third of their city built along hard-to-reach narrow lanes.
Physical characteristics of waste
Waste is rarely segregated at source
Apart from collection, developing countries are performing very limited formal waste processing, if at all, to capture the resource value of the discarded materials. Informally, waste pickers are sorting through rubbish and selecting dry waste in the form of paper, plastics, glass and metal which can be sold into the informal scrap market. However this activity may provide environmental and economic benefits to the cities within which they operate, the majority of the waste which is organic is being left to decay in dumps and along roadsides, releasing methane into the atmosphere. Attempts at mechanized composting projects have failed primarily due to the reliance on an automated pre-processing system rather than any failures in the composting process itself. Municipal governments often regard higher capacity compost facilities as better, building compost sites that have mechanized removal of non-compostable materials. These systems have by and large failed to identify and separate all of the materials that occur in mixed waste. Particularly in developing cities where the waste has large quantities of dust and dirt particles, no existing mechanized systems sort sufficiently to ensure good compost quality.
A question of capital versus labor
60-70% of recyclables in India recovered manually
High-income countries enjoy easy access to equipment and technology, as well as the cash to pay for it. The decision to go the capital intensive route is made simpler by the fact that labor is a more costly alternative to mechanization of processes. Low-income countries, however, face a reverse scenario in which access to capital is restricted but labor is cheap and plentiful, with employment in high demand. It does not make sense for low-income countries to employ capital-intensive solutions in addressing waste management issues.
Rather, appropriate solutions include more effective manual collection with vehicles which can provide door-to-door services such as hand, tricycle, or donkey drawn carts. Door-to-door services make it possible to achieve collection rates near 100%, as well as enabling segregation upon collection. In composting and material recover facilities (MRF’s), manual labor is able to more effectively segregate the waste and ensure higher quality of both compost and recyclable materials. In fact, emerging cities have the opportunity to develop superior integrated solid waste management solutions as the use of labor rather than machines can increase the effectiveness of collection and processing systems.
A working model
To illustrate this point some of the most successful cases of integrated waste management in India has taken these lessons to heart. They have all adopted de-centralized models, primarily built on manual labor and with door-to-door collection using small collection vehicles such as rickshaws. In Suryapet, Namakkal and Vellore such methods have achieved strong community participation and managed to diver 70-80% of the waste from being dumped in open landfills.