Hydrochar Derived from Sewage Sludge and Water Hyacinth and Its Characterization

Abstract

Population and urbanization increase the sewage generation. Sewage treatment plant (STP) generates the sewage sludge. Agricultural runoff and sewage water discharge into water bodies proliferates the growth of water hyacinth and creates environmental issues. Managing the sewage sludge and water hyacinth are difficult task because of high water content, environmental concerns, regulatory measures and high operational cost. Hydrothermal carbonization (HTC) converts the wet biomass into condensed solid product called hydrochar at moderate temperature range of 180 – 250°C under auto generated pressure. Through HTC process, the sewage sludge and water hyacinth were mixed and converted into hydrochar @ temperature of 200℃ and 4h resident time with L/S ratio of 9:1. The produced hydrochar showed desired functional groups viz., CH – methyl groups, C-O-C – alcohol groups, esters, ethers and Oxygenic functional groups (-C=O, -OH, -CO-O, C-O-C) with particle size of 494.8 nm, BET surface area of 369.70 m2 g-1, Zeta Potential of -27.9 mV. The hydrochar recorded slightly acidic pH (5.8) with appreciable levels of C (24.4%), N (2.51%), P (0.44%), K (0.98%), Ca (1.24%), Mg (0.68%). These properties of sewage sludge and water hyacinth derived hydrochar exhibits its potential use in agricultural and environmental applications.