Assessment of energy recovery potential and analysis of environmental impacts of waste to energy options using life cycle assessment

Effective waste management such as energy recovery from waste is not very successful in many cities of India. The present study is carried out in the Dhanbad city, India where all the generated wastes are managed unscientifically through open dumping. Most of the reported life cycle assessment-based studies for Indian cities have focussed on the common waste management options such as composting and recycling. This study aimed to evaluate the energy recovery potential and environmental impacts of mainly waste to energy options namely; anaerobic digestion, landfill gas to energy, mass incineration and refuse derived fuel incineration based on the characteristics and composition of wastes of the study area. The selection of waste to energy options is done based on the composition of waste suitable for the respective options, thus making it helpful in reproducing the present work in other cities as well. Anaerobic digestion technology is evaluated based on the biogas generation potential of total food waste generated in the study area using laboratory-scale batch experiments. Similarly, landfill gas to energy is evaluated based on the estimated landfill gas generation (using LandGEM model) from the existing landfill of the study area. While incineration (mass and refuse derived fuel) is evaluated based on the heating value of combustible waste fractions. For the comparison of energy recovery potential and environmental impacts, six scenarios are developed. The maximum energy recovery potential of 602 kWh/tonne of dry waste is found for the scenario mass incineration of combustible waste fractions (72%) and landfilling of remaining wastes (28%). This scenario also showed the maximum net environmental savings due to avoided electricity production. The sensitivity analysis revealed that the collection efficiency of generated landfill gas for electricity conversion significantly impacts the change in global warming and photochemical ozone creation potential. The outcomes of this study will help the concerned authorities in developing the efficient waste to energy system.