Assessment of carbon footprint emissions and environmental concerns of solid waste treatment and disposal techniques; case study of Malaysia

Abstract

Malaysian authorities has planned to minimize and stop when applicable unsanitary dumping of waste as it puts human health and the environment at elevated risk. Cost, energy and revenue are mostly adopted to draw the blueprint of upgrading municipal solid waste management system, while the carbon footprint emissions criterion rarely acts asa crucial factor. This study aims to alert Malaysian stakeholders on the uneven danger of carbon footprint emissions of waste technologies. Hence, three scenarios have been proposed and assessed mainly on the carbon footprint emissions using the 2006 IPCC methodology. The first scenario is waste dumping in sanitary landfills equipped with gas recovery system, while the second scenario includes anaerobic digestion of organics and recycling of recyclable wastes such as plastic, glass and textile wastes. The third scenario is waste incineration. Besides the carbon footprint emissions criterion, other environmental concerns were also examined. The results showed that the second scenario recorded the lowest carbon footprint emissions of 0.251t CO₂ eq./t MSW while the third scenario had the highest emissions of 0.646t CO₂ eq./t MSW. Additionally, the integration between anaerobic digestion and recycling techniques caused the highest avoided CO₂ eq. emissions of 0.74t CO₂ eq./t MSW. The net CO₂ eq. emissions of the second scenario equaled -0.489t CO₂ eq./t MSW due to energy recovery from the biogas and because of recycled plastic, glass and textile wastes that could replace usage of raw material. The outcomes also showed that the first scenario generates huge amount of leachate and hazardous air constituents. The study estimated that a ton of dumped waste inside the landfills generates approximately 0.88m³ of trace risky compounds and 0.188m³ of leachate. As for energy production, the results showed that the third scenario is capable of generating 639kWh/t MSW followed by the second scenario with 387.59kWh/t MSW. The first scenario produced 296.79kWh/t MSW. In conclusion, the outcomes of this study recommend an integrated scenario of anaerobic digestion and recycling techniques to be employed in Malaysia.

Keywords: Anaerobic digestion; Carbon footprint emissions; Incineration; Landfills; Recycling; Waste to energy.