Role of Wooden Charcoal in Indigenous Household Iron Filters used in Assam (India)

Ground water, the major source of drinking water in rural and semi-urban areas of Assam (India), contains an excessive amount of iron (1 to 10 mg/L). In order to reduce the amount of iron from water, people use household iron filter units – indigenously developed using wooden charcoal as one of the filter media. The present work evaluates role of wooden charcoal in reducing the dissolved iron. The experiments were carried out at a fixed pH of 5.5 and zero DO levels. Batch kinetic studies indicated rapid Fe(II) uptake in the first 40 min. and yielded a rate constant of 0.0136 min $^{-1}$ . The adsorption process seemed to be governed by diffusion within the pores of wooden charcoal and the mechanism of Fe(II) removal appeared to be complex. The Fe(II) adsorption data fitted into Langmuir isotherm (R $^{2}$ = 0.9952) indicating favourable adsorption process. The breakthrough column studies with 5 and 10 cm bed depths yielded 66 and 82 number of bed volumes respectively of treated water containing Fe(II) concentration ⩽ 0.3 mg/L at a fixed flow rate of 1.4 mL/min. Overall wooden charcoal seemed to have good potential for Fe(II) removal from the water.