RECYCLING WASTE POLYETHYLENE MATERIALS TO USEFUL PRODUCTS VIA PYROLYSIS
INTRODUCTION
1.1 Background of study
Recycling is a process of changing waste materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, energy usage, water and air pollution (from incineration), and lower greenhouse gas emissions as compared to plastic production. Recycling is a key component of modern waste reduction and is the third component of the “Reduce, Reuse and Recycle” waste hierarchy (lajeunesse,sara 2004).
The rate of consumption of plastic materials in the world is greatly expanding, more waste plastics are generated. In recent years, their generation amount in Korea becomes about four million per year, according to data from the National Institute of Environmental Research (Lajeunesse, Sara 2004). The disposal of waste plastic is mostly achieved by conventional ways such as landfill or incineration. However, these methods have a problem of a social resistance due to the air pollution, soil contamination, and the economical resistance caused by an increase of space and disposal cost. Thus, the recycling of plastic wastes as a cheap source of raw materials has become a predominant subject over all countries (Roach, John 2003). The development of technologies acceptable from the environmental and economical fields is one of the most important key factors. (Roach, John.2003). Plastic materials used for food storage, visible in all supermarkets, preserves freshness and flavor due to the ability to seal out contaminants. Polyethylene materials are useful over a wide temperature range, from frozen foods to microwavable packages1. Due to these benefits, plastics have become widely used. (lajeunesse,sara 2004).
Polyethylene plastic bags are petroleum-based so the manufacturing process releases harmful pollutants into the atmosphere. Some speculate that these emissions and other smog-related types of pollution accumulate over time in the atmosphere.
Countries and large corporations are beginning to realize the threat that these plastic bags pose to our planet. Many are proposing or have already enacted laws and taxes to decrease the use of polyethylene plastic bags. Many grocery stores are even rewarding customers for bringing reusable grocery bags as an alternative to these polyethylene plastic bags. Customers choosing not to use alternatives to plastic bags either find the alternatives are inconvenient or are simply unaware of the problem at hand.
Polyethylene recycling bags are currently being used all over the world but there is currently no environmentally friendly way to dispose of them.
