Reduction of COD from Corrugated Box Manufacturing Plant Wastewater using Chemical Coagulation

Abstract

In this study, the treatment of the corrugated cardboard box manufacturing plant wastewater by coagulation method was examined. The wastewater used in this work was provided from a local corrugated box plant located in the city of Eskişehir (Turkey). The COD concentration of the used wastewater was 4206 mg/L, and the pH was 8.3. The effects of operation parameters such as coagulant type and concentration, pH, amount of coagulant aid on COD removal and sludge generation quantities were investigated.  Aluminum sulfate (50 mg/L to 1000 mg/L), aluminum chloride (50 mg/L to 1000 mg/L), ferric chloride (12.5 mg/L to 300 mg/L) and starch (100 mg/L to 1500 mg/L) were used as coagulants. A commercial polyelectrolyte (5 mg to 25 mg) was used as a coagulant aid in the experiments.  Optimum COD removal was obtained as 78.6% in the experiments that the alum was used as coagulant.  More than 60% removal was realized from the experiments that ferric chloride, aluminum chloride and starch were used. The effect of coagulant aid on COD removal was also investigated. It was seen that COD removal was increased to 82.5% by adding the coagulant aid to the wastewater in the flocculation step of the experiments that alum was used as the coagulant. The use of coagulant aid resulted in lower sludge production levels.