Prospect of managing factory tea waste as biochar

Abstract

A comprehensive experiment was carried out in the year 2021 under the Department of Biochemistry and Agricultural Chemistry and Department of Agricultural Engineering, Assam Agricultural University, Jorhat, Assam to study the prospect of managing factory tea waste from a selected Tea Garden of Assam as Biochar. In this present study, factory tea waste was collected from Cinamara Tea Estate, Jorhat and biochar was produced from the waste material by two methods i.e., by using charring device and by using muffle furnace. Other physical and chemical properties of tea waste and biochar prepared from above two methods were determined following standard procedure proposed by earlier workers. Each estimation was replicated thrice and the data obtained from laboratory analysis were examined statistically under Completely Randomized Design (CRD). The yield of biochar was recorded to be 71.07% (charring device) and 77.21%, (muffle furnace), respectively. Among the physical properties, moisture content of tea waste biochar and factory tea waste were 6.10% (method 1-charring device), 3.34% (method 2-muffle furnace) and 6.98%, respectively. The bulk density of biochar and factory tea waste were 0.19 g/cm3 (method 1-charring device), 0.21 g/cm3 (method 2-muffle furnace) and 0.09 g/cm3, respectively. Whereas, carbon content (%) was found maximum in tea waste biomass (65.11%) followed by method 2 (60.24%) and method 1 (50.9%). Overall, higher bulk density and water holding capacity were observed in biochar produced by second method i.e., muffle furnace besides its higher values for ash content, carbon content, mineral content (nitrogen, potassium, phosphorus) and cation exchange capacity. Thus, factory tea waste can be profitably converted to biochar using charring device and muffle furnace and thereby contributing to carbon sequestration. Furthermore, the biochar produced from tea waste can be effectively used to improve soil health.