Investigation of treatability of fish processing industry wastewater using various treatment methods

The fish processing industry is a production process that is environmentally important due to high water consumption and variety of raw materials used in the production. Because of high organic matter, salt, and nutrient content, treatment of fish industry wastewater before discharges into the receiving streams or water bodies is of great importance. The aim of this work was to investigate the physico-chemical treatability of the wastewater from fish processing industry by coagulation / flocculation and adsorption methods in terms of COD removal. The isotherm and kinetic evaluations of powdered and granular activated carbon were carried out and the performance in terms of COD removal was investigated. The highest COD removal rates with iron-(III)-chloride (FeCl3.6H2O) and alüm Al2(SO4)3.16H2O were calculated as 74% and 62%, respectively, in the jar test studies carried out with coagulant doses between 50-750 mg/L. When working with powdered and granular activated carbon, their adsorption capacity, isotherm, and kinetic coefficients were determined using adsorbents in different amounts under varying time intervals. It was found that the adsorption capacity of the powdered activated carbon was 14 times greater than the adsorption capacity of the granular activated carbon while the powdered and granular activated carbon were found to conform to the Langmuir (Type 4) and Freundlich Isotherm models, respectively. In the kinetic study, however, it was determined that both adsorbents complied with the Pseudo second order velocity equation.