Feasibility of waste-to-energy and its role in plastic waste management in Hong Kong

Abstract

Plastic is one of the raw materials for product manufacturing. Due to its advantageous including flexibility, relatively low cost and flexibility, it is widely applied in a wide range of products, such as shopping bags, containers, electronic equipment cases, etc. As plastic products are usually in short-term use, in proportion, a huge amount of plastic waste generates in the world every day, the same case happens in Hong Kong. Landfill expansion in the coming years is a hot social and environmental issue in Hong Kong. Plastic waste, which is a recyclable material, is the second highest component of municipal solid waste (MSW) being disposed into the landfill by weight in 2013.

Plastic recycling business is facing difficulties in high operating cost and low revenue of recycled plastic pellets due to the dropping of oil price in recent years. Besides, the incentives for public to do plastic clean recycling is low. These factors discourage plastic recycling practices in Hong Kong and cause a large proportion of non-recycled plastic waste being dumped into the landfill every day.

Since plastic is derived from petrochemicals, it usually has a comparable heating value with fuels, which is favorable in carrying out waste-to-energy (WTE) process and too valuable to throw away. Overseas countries apply WTE to recover the energy of plastic waste via thermochemical process. In some countries, plastic waste can be 100% recycled and recovered in energy with landfill ban. In this research, the feasibility of WTE and its role in plastic waste management is studied. It was found the application in WTE for the treatment of plastic waste mixed with MSW is technically feasible. It is a significant means in waste management to relieve the space occupying by MSW in landfill and generate energy from waste by energy recovery technologies, for example, incineration, pyrolysis, gasification, etc.

The result of study shows that, WTE is a financially feasible and eco-efficient means in non-recycled plastic waste treatment. WTE fills the gap between recycling and disposal in local plastic waste management. Public accepts the development of WTE for the treatment of non-recycled plastic waste in Hong Kong. Also, citizens welcome such measures to reduce the space of plastic waste occupied in landfill and the generation of energy in terms of electricity from plastic waste. Limitations of development of such facilities in Hong Kong are discussed. Location of the proposed facilities is always a controversial topic. Recommendations are given to deal with the possible difficulties encountered in the development of WTE for the non-separated and non-recycled plastic waste.