Hydrothermal Carbonization of Paper Mill ETP Sludge and Assessing its Potential Application in Agriculture

Abstract

Effluent Treatment Plant Sludge (ETPS) from pulp and paper mill is produced in larger quantities and its disposal has the major problem faced by the industries. The conversion of paper mill sludge into hydrochar through the process of Hydro Thermal Carbonization (HTC) has wider opportunities in agriculture. This study explored the optimization processes which influence the preparation of hydrochar from ETPS through the approaches of Response Surface Methodology (RSM). The optimized temperature and time were 220 °C and 4 hours, respectively for hydrochar production based on higher carbon and nitrogen content. The hydrochar and ETPS was characterized using Scanning Electron Microscopy (SEM), Brunauer Emmett Teller (BET) surface area and Fourier Transform Infra-Red Spectroscopy (FTIR) for its structural morphology. Based on the optimized parameters, the hydrochar was produced and used in the pot culture experiment to study the impact of the hydrochar on bhendi (Abelmoschus esculentus) crop growth. Different concentrations of hydrochar were applied as basal in the pot. The treatment with 4% hydrochar germinated first show the good shoot and root length and 11% increase in germination percentage and 22% increase in vigour index when compared with control due to its higher nutritives which is on par with the results of 5% hydrochar.