Removal of Toxic Chemicals and Biological Pollutants from Groundwater Wells Using Modified Downflow Hanging Sponge Reactor

Abstract

Water pollution is one of the most important environmental problems in the world. In developing countries, contaminated water has frequently caused water diseases. Today, water borne toxic chemicals (anions and heavy metal ions) and biological pollutants pose a great threat to the safety of water supplies. Currently, the quality of groundwater with respect to pollutants is of great concern. Modified Downflow Hanging Sponge (DHS) reactor will be a good groundwater treatment technology in the near future, it is used for excellent removal of heavy metals, anions, organic pollutants and harmful microbes, and also the reactor has advantages like low cost, easy to apply and satisfaction level. In order to achieve these objectives, treatment scheme has been investigated. It consists of mixing organic chelator with impure groundwater in different concentrations followed by a downflow hanging sponge (DHS) reactor. In the presence of 0.5 g/L of the chelator, the average removal of total NO3 and NO2 and (total dissolved solids) TDS are respectively 72%, 62% and 75%. The results show that, when Cd treated with chelator, the amount decreases from 0.0063 to 0.0 mgL -1 (100%) after 1 h, Cu decreases from 0.0023 to 0.0 mgL -1 (100%) after 1 h, Fe decreases from 0.4 to 0.0 mgL -1 (100%) after 1 h, Mn decreases from 0.3 to 0.0 mgL -1 (100%) after 1 h and Zn decreases from 0.012 to 0.0 mgL -1 (100%) after 1 h. Also, the results show removal of fecal coliform . Decreased from 50 to 0 and the overall removal efficiency of fecal coliform is (100%).