Application of sand- soil- organic matter filter column for removal of Cu, Ni, Zn and Cr heavy metals from industrial waste water

In order to investigate the removal of copper, nickel, zinc and chromium from industrial waste water by a sand–soil–organic matter filter column, this experiment was conducted at a completely randomized design with sixteen treatments and four replications. P.V.C tubes (columns) with 66.5 cm height and 10 cm diameter were chosen and filled from down to top by coarse gravel (15 cm), sand (15 cm), soil (2.5 or 5 cm), organic matter (15 cm) and fine gravel (5 cm), respectively. Then, 1100 ml of electroplating industry waste water was added to the filter and 30 ml of leachate was collected and transferred to the laboratory for measurement of pH and heavy metals concentrations by atomic absorption spectroscopy technique. The action was repeated at nine pore volumes for each filter. The results showed that application of this filter led to increased pH to neutral and low alkaline range and often meaningful decreased heavy metals concentrations in the leachates during nine pore volumes. The probable mechanisms (such as adsorbtion, precipitation, ion exchange and chelation) by which the filter led to changes in the chemical properties of leachate were also discussed. Generally, it seems that the application of sand–soil–organic matter filter column was effective and therefore, could be advisable for the removal of studied heavy metals from industrial waste water.