Comparison of Carbon Emissions in Different Sludge Treatment Pathways - a Case Study of Jiaxing, China

Abstract

Sludge management strategy is essential to future carbon reduction in wastewater plants since the treatment and disposal of sludge contribute significantly to the carbon emissions. Using the method proposed by intergovernmental Panel on Climate Change(IPCC), the three sludge treatment paths of a typical wastewater treatment plant in Jiaxing were investigated. The result showed that net carbon emission is negative at -588kgCO2/tDS thanks to R3 which is characterized by centrifugal dehydrator, coal blending incineration with combined heat and power generation and cement substitute by slag is the rout with lowest carbon missions. The carbon emission of R1 is the highest at 699.87 kgCO2/tDS because of the chemical reagents. Process unit with larger carbon emissions was identified to be dewatering in which chemical reagent contributed the most. The main carbon offsets was the combined heat and power cogeneration which should be widely advocated.