By Jeffrey R. Seay, PhD, PE
In developing countries, the lack of robust infrastructure makes managing plastic waste difficult. Municipal solid waste management requires disposal, collection, transfer and ultimately, sequestration in a properly designed and maintained landfill. All of these steps require management and infrastructure. A breakdown in any of these steps can lead to plastic waste entering the ecosystem, where it stays, essentially forever. A potential solution can be found in the application of appropriate technology.
Appropriate technology (AT) is a design philosophy first described by E.F. Schumacher in his book Small is Beautiful (1973). AT is simply technology suitable for a specific region, designed to meet specific needs of certain individuals or communities. It differs from industrial scale processes in the sense that AT is specifically intended to be used in rural or underdeveloped regions. AT is low-cost, small-scale, easy to construct, and can be operated by individuals with limited formal technical education. The purpose of AT is not to reproduce industrial technology on a small scale; instead, it is to design specific solutions based upon the resources available in a given region or for a given community. Therefore, AT based solutions often require trading industrial scale efficiency for simpler approaches that still meet the overall goals of the projects.
An AT solution for plastic waste can be found in a process called “thermal decomposition”. This is basically a type of slow pyrolysis where plastic polymers are heated, melted and broken down into smaller and smaller lengths, until they become a liquid, similar to No. 1 or No. 2 diesel fuel. This process is useful for a class of plastics called polyolefins – polypropylene and high and low density polyethylene are the most common types. Polyolefins are easily distinguishable from other plastics because polyolefins float in water, whereas other plastics will sink. The process of thermal decomposition is energy efficient and produces a sulfur-free fuel oil product.
Our mission at Engineers for Sustainable Energy Solutions is to enable communities in developing countries to use AT to manage their plastic waste locally in a way that benefits the local community.