Effects of organic matter on the performance of water and wastewater treatment: Electrocoagulation a case study

Abstract

One of the commonly available pollutants in freshwater sources is organic matter (OM) because it is abundantly found in nature and the wastewater, where it is believed all forms of freshwater, soils and wastewaters contain a certain concentration of OM. Although the majority of the OM, especially the natural forms, has no serious impacts on the human health or aquatic environment, its high concentrations or its industrial forms can cause health problems along with severe impacts on the treatability of water or wastewater because it chelates the inorganic matters, reacts with other pollutants or covers them, which makes their removal is difficult. Therefore, a vast number of methods were applied to remove OM from water, such as electrocoagulation. Despite the proven efficiency of the EC in the removal of a vast number of pollutants from solutions, its performance is highly influenced by the content of OM in the solution because the OM covers the electrodes decreasing the dissolution rate, and OM also reacts with inorganic matter such as metals making it difficult to remove them. Some solutions were developed to solve these problems, such as adding chloride that inhibits the formation of the inert layers on electrodes, also adding Mg could improve the removal efficiency by maximising the size of the flocs. Thus, this paper reviews the effects of the OM on the performance of EC and lists a number of recent applications of the EC in OM removal.