Plant-based point-of-use water filtration: A simple solution for potable water in developing countries

Abstract

Rural communities in Africa consistently lack access to safe drinking water, free from chemical contaminants and pathogens. One of the approaches to improve access to drinking water in these areas is point of use treatment, using household water treatment devices. The objective of this work is to demonstrate the applicability of plant xylem filtration, as a water treatment device for households in rural Africa. Pine xylem acted both as a physical filter and a cation exchanger, removing suspended contaminants and positively charged chemicals. For example, Escherichia coli bacteria (E. coli) was completely attenuated during xylem filtration, whereas waterborne viruses (i.e., T4) could not be removed, due to the small size of viruses. Removal of inorganic anion contaminants, i.e., fluoride and nitrate, was ineffective, as was the removal of negatively charged arsenate (removed by merely 40%). On the other hand, removal of six, positively charged, toxic metals was in the range of 70%–100%: Cadmium, copper, lead, chromium, cobalt and nickel. Treatment of natural water was successful principally for groundwaters, which contained low level of suspended material and dissolved organic matter. In this case, filtration could produce 5 L of treated water (for xylem of 1.5 cm diameter), enough to supply the minimum daily consumption required for one person for survival. In conclusion, Pine xylem can serve as an effective household treatment device for groundwater contaminated with bacteria and toxic metals.