Naturally derived carbon for E. coli and arsenic removal from water in rural India

Low cost solutions for water treatment in rural communities in India are key to improving drinking water quality. Through a social enterprise, selected villagers from Khechare, Maharashtra convert local wood and plant matter into a carbonaceous material (Village carbon, “VC”) which to date has been used for sale as deodorisers in urban areas. This work demonstrates the effectiveness of VC material for bacterial filtering and arsenic adsorption. BET surface area analysis determined that VC is mesoporous with a surface area of around 95 m2 g−1. Scanning electron microscopy revealed that much of the original fibrous features and a wide range of elements from the local environment remain post carbonisation. Bacterial filtering studies using E. coli as model bacteriological contaminant have been demonstrated. Naturally relevant levels of bacteria (110 CFU/100 mL E. coli) were removed from water using a 15 g VC plug while >99%–97% removal of highly contaminated (7 million CFU/100 mL E. coli) were possible to be removed, demonstrating the capacity of the VC material for bacteria filtering. Adsorption of As(V) and As(III) was achieved using VC, which could reduce 200 ppb As(III) to below 50 ppb concentration, and 150 ppb As(V) to 90 ppb concentration. The carbon generated from waste agricultural material used here is an effective material for water purification on site. While its performance compared to other literature carbonaceous materials may be slightly lower, it has great potential for use due to its derivation from available waste products