Biochemical responses of Gammarus pulex to Indigo Carmine solutions treated by electrocoagulation process optimized with response surface methodology

In this thesis, the biochemical responses of Gammarus pulex of indigo carmine solutions treated by electrocoagulation process optimized by response surface method were investigated. Electrocogulation experiments conducted in the first stage were carried out with the response surface method according to the central composite design, and the IK removal efficiency and the amount of sludge formed, electrode consumption and energy consumption were also examined. The effects of changes in pH, current density, dye concentration and time on IK removal efficiency, amount of sludge formed, electrode consumption and energy consumption were investigated. Optimization of process variables that maximize IK removal by electrocoagulation process was carried out by using a second order model within the studied test range of various process variables. According to the optimization results, optimum conditions giving approximately 82.55% maximum IC removal were selected as pH 5.86, current density 13.31 mA/cm2, IK concentration 20.01 mg/L and time 115.80 minutes. Under optimum conditions for IC removal, the amount of sludge formed was 0.928 kg/m3, electrode consumption was 0.0422 kg/m3 and energy consumption was 7.461 kWh/m3. Operating cost was calculated as 6,384 TL/m3 under treatment conditions where optimum IC removal was achieved In the second stage, Gammarus pulex was exposed to purified and unrefined synthetic indigocarmine solutions obtained as a result of the experiments performed according to the optimum conditions obtained according to the optimization results in order to investigate the biochemical response for 24 and 96 hours. Treatment efficiency was evaluated with SOD, KAT, GST and CYP1A1 biomarkers. When the results were evaluated together, it was confirmed that electrocoagulation is an effective method for the treatment of indigo carmine wastewater, but it was found that SOD, KAT, GST, and CYP1A1 biomarkers can be used as indicators of toxicity in the evaluation of the treatment efficiency and are useful biomarkers.