Study of Electrocoagulation on removal of coliforms from hospital wastewater

Hospitals, as one of the most important social places, play a basic role in providing, conserving and improving of the individual and community health. Hospital wastewater contain different pathogenic microorganisms, hazardous chemicals, radioactive substances, and organic and inorganic materials. In this research, removal of coliform bacteria from hospital wastewater by electrocoagulation technology has been evaluated. Wastewater samples were collected from Yahianejad hospital wastewater treatment plant belong to Babol Universty of Medical Sciences as a grab sampling before the chlorination unit. Electrocoagulation experiments were carried out in the electrical voltage (10,20,30V), contact time (30,60,90 minutes), and using two types of galvanized iron and aluminum electrodes. Before and after electrocoagulation starting, the samples were taken middle of the reactor and the experiments were conducted multi-tube fermentation method (15 tubes with dilution). The results showed that the maximum removal of coliforms in galvanized iron and aluminum is 99.7% and 95.8% respectively. As well as, with increasing the voltage and contact time, the removal rate of colifirms in the galvanized iron electrode increases. Totally, the galvanized iron electrode has better removal efficiency of coliforms than aluminum electrode in contact time more than 60 min. The results of this study showed that the electrocoagulation process is an effective method for the removal of coliforms from hospital wastewater at pilot scale and can be used as complementary disinfection method.