engleski

THE INFLUENCE OF DIFFERENT PROCESS PARAMETERS ON THE EFFICIENCY OF ORGANIC LOAD REMOVAL FROM OILY WASTEWATER USING ELECTROCHEMICAL TREATMENT

During the treatment process of exhaust gasses produced by gasification of sewage sludge oily wastewater is generated which contains high concentrations of organic load and solid particles created by the contact of the contaminated gas with the liquid through which it passes during its treatment. Sewage sludge was generated as a by-product at the wastewater treatment plant (WWTP) in Zagreb (Croatia). For the purpose of this paper oily wastewater was further treated by hybrid electrochemical process. Applied electrochemical treatment is based on the flow of electric current through electrodes immersed in wastewater. In the process, metals are released from the electrodes and form flocs that coagulate the pollutants present in the wastewater and produce sludge that settles down in the reactor during the sedimentation phase. This research is focused on the influence of different process parameters suh as electrode materials (stainless steel, iron, aluminum), pH of raw wastewater, and current on the efficiency of the treatment process. The objective was to eliminate chemical oxygen demand (COD) and total hydrocarbons (mineral oils) from wastewater below the limits prescribed for discharge to the environment or public sewer system. The laboratory tests were carried out in batches with a wastewater volume of 10 liters in one batch. The wastewater is characterized by a light brown color, fine soot particles, unpleasant odor, slightly alkaline pH (8.95) and high levels of COD (790 mg/L) and total hydrocarbons (14.20 mg/L). The experimental results show that the hybrid electrochemical treatment process that combines electrooxidation and electrocoagulation processes effectively reduces the concentration of COD and total hydrocarbons from wastewater generated during the treatment process of exhaust gas from sewage sludge gasification unit, proving the application of this process for the treatment of this type of oily wastewater.

oily wastewater ; exhaust gas treatment ; electrochemical treatment ; electrodes ; COD ; hydrocarbons ; mineral oil

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