Banana stem as a waste-derived bio-sorbent to remove organics and nutrients from rice mill wastewater

Abstract

The discharge of organics and nutrients rich rice mill wastewater into an aquatic ecosystem ultimately affects ecosystem functioning. Bio-sorption is a viable technique for rice mills for onsite wastewater treatment. This study aimed to produce waste derived bio-sorbent from banana stem to treat rice mill wastewater. The banana stem was washed thoroughly, shade dried and ground using a kitchen blade grinder and sieved using 500μm siever. The feed water was collected from a rice mill functioning in the Vavuniya town area and the initial COD, phosphates and nitrates were determined as 840.87±23.32 ppm, 12.32±0.11 ppm and 5.63±0.23 ppm respectively. Adsorption isotherm was conducted for varying dose of biosorbent(1- 6 g/L) and the adsorption kinetics was conducted for different contact times (30 -180 min). The bio-sorbent reduced 61.6 % COD, 52.1 % nitrates and 22.2 % phosphates at the dosage of 4 g/L biosorbent at 150 min. Based on the t-test, banana stem is effective in reducing organics, nitrate, and phosphate (p-value < 0.05). This study emphasizes that the banana stem has the potential to remove contaminants from wastewater.