Assessment of Moringa-functionalized carbon based biofilter for disinfection through column experiments

The lack of infrastructure for water treatment and distribution remains a major problem in many low-income regions across the globe. Many available water treatment technologies may not be successfully implemented due to economic constraints and low social acceptability. In this study, we test the extent to which Moringa oleifera (MO)-functionalized carbon biofilter columns can effectively remove bacterial contamination in water. MO proteins were adsorbed onto two carbon adsorbents, granular activated carbon (GAC) and rice husk ash (RHA), and were then used as packing materials for a biofilter column. Synthetic contaminated water (non-pathogenic E. coli in water) was fed at the top of the column at fixed flow rates, and coliform removal in the column was evaluated by monitoring the coliform breakthrough in the filtered water. A semi-factorial experimental design was adopted to evaluate the influence of column bed height, type of adsorbent, and contact time on the E. coli removal efficiencies. As a control, parallel experiments using bare carbon adsorbents were also performed. The effectiveness of MO-functionalized adsorbents was evaluated through ANOVA comparison of the breakthrough data from the experimental and control columns. Results show that the MO-functionalized adsorbents effectively remove E. coli from contaminated water. Generally, E. coli removal rates were higher in MO-functionalized RHA than in MO-functionalized GAC. These findings suggest the potential use of MO-based biofilters in water disinfection. Due to the low cost and availability of MO in many low-income regions, MO-functionalized adsorbents can be used as an inexpensive water treatment alternative in these areas.