Electrochemical Treatment of Cattle Wastewater Samples

Cattle wastewater (CWW) is considered an important source of contamination in the livestock sector. Therefore, electrocoagulation (EC) using Aluminium electrodes and electrooxidation (EO) through Boron Doped Diamond (BDD) electrodes processes, were applied to the liquid fraction of cattle waste (CW) to decrease the levels of certain pollutants such as nitrogen (N-NO3, T-N), phosphates (P-PO4) and organic content (Chemical Oxygen Demand, COD), in order to eliminate their environmental impacts to soil, groundwater and atmosphere. The respective electrochemical methods, were compared with chemical coagulation process by using Al2(SO4)3 and FeCl3 as a coagulant. CWW samples were derived from three cattle farms. As experimentally was revealed, the main parameters strongly affecting the experimental procedure were the solid density of the sample and the high concentration of pollutants. Other operating parameters such as current density, electroprocessing time, dilution ratio and agitation speed were studied and optimised. Results showed an optimal removal efficiency after using the combined EC-EO processes at current density of 200A/m², agitation at 300 rpm, duration time of 2 h for both processes at room temperature, with a 1:5 dilution ratio. The results also showed that P-PO4 were fully removed, COD up to 70%, N-NO3 at 80% and T-N close to 20%. The combined use of EC and EO improved the quality of CWW in regard to P-PO4, COD, N-NO3 and T-N content. Nevertheless, further experiments are needed in order to verify the respective results in a pilot scale.