Life Cycle Assessment of a Novel Zero Organic-Waste Model Using the Integrated Anaerobic Digester and Oxidation-Ditch Membrane Bioreactor for High-rise Building Application

Abstract

This study aims to develop a prototype of zero-organic waste model using the integrated system of single-stage anaerobic digester (AD) and oxidation-ditch membrane bioreactor (OD-MBR) to convert organic wastes from food waste and sludge from OD-MBR system to biogas for cooking as well as to co-treat liquid digestate from AD with building wastewater in order to produce reclaimed water as a sustainable model for building application. In order to investigate the optimal condition in operating the AD/OD-MBR system to lower organic waste pollution to promote sustainable urban development, LCA with SimaPro 8 software was used to evaluate the environmental impact such as global warming, acidification and eutrophication potentials for six different operating conditions of AD/OD-MBR system for management of food waste and building wastewater. The evaluation by LCA shows that the proposed AD/OD-MBR system can effectively control the environmental impact from liquid digestate and sludge that are discharged into environment. The eutrophication potential of the integrated AD/OD-MBR system is reduced to the lowest value of 4.66 kg PO43−as compared to the values of 713.77 and 75.12 kg PO43− that are obtained from sole OD-MBR and sole AD, respectively. Moreover, global warming potential of AD/OD-MBR is lower than that of AD system. The proposed integrated AD/OD-MBR system can efficiently minimize the impacts from global warming and eutrophication potentials. It can be a model of prototype zero-organic waste for building water and organic waste management with water recycling for garden and landscape use.