Abstract—The main environmental problems of fish canning industries are high water consumption and high organic matter, oil and grease and salt content in their wastewaters. This work aims to analyze the situation of different plants located north of Douro river, in Portugal, in order to propose various solutions to their problems. Thus, initially it was made an identification and implementation of prevent and control pollution measures within the industrial units in order to reduce water consumption, minimize the wastewater production and reduce the pollutant load to treat. Then, the wastewater treatability was evaluated through a sedimentation and coagulation-flocculation process and through an aerobic biological degradation. In the sedimentation and coagulation-flocculation process two organic coagulants (RIPOL 070 and RIFLOC 1815), commonly used in wastewater treatment, were tested, leading to good results, especially in terms of oil and grease and total suspended solids removals. The best suspended solids removal efficiencies were 53% and 79%, using 400 mg/L of RIPOL 070 and 150 mg/L of RIFLOC 1815, respectively. At these dosages, both coagulants demonstrated excellent oil and grease removals, about 99% for RIFLOC 1815 and 88% for RIPOL 070. The aerobic biological treatment with activated sludge proved to be very adequate to organic matter removal. Two feed flow rates were tested and the highest TOC removal efficiency (96%) was verified with the lowest one (0.75 L/h), corresponding to a longer hydraulic retention time (8 h). So, the proposed sequential treatment, combining physico-chemical and biological processes, proved to be an effective alternative to start the fish canning wastewaters treatment for further reuse in the industrial process.

Index Terms—Biological treatment, coagulation-flocculation, integrated pollution prevention and control (IPPC), fish canning wastewater treatment.

R. O. Cristóvão and C. M. S. Botelho, and R. A. R. Boaventura are with the Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE/LCM, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua do Dr. Roberto Frias, 4200-465 Porto, Portugal (e-mail: raquel.cristovao@fe.up.pt, rmartins@ipb.pt. bventura@fe.up.pt).
R. J. E. Martins is with the Department of Chemical and Biological Technology, Superior School of Technology, Polythecnic Institute of Bragança, Campus de Santa Apolónia, 5301-857 Bragança, Portugal (e-mail: rmartins@ipb.pt).

Cite: Raquel O. Cristóvão, Cidália M. S. Botelho, Ramiro J. E. Martins, and Rui A. R. Boaventura, "Chemical and Biological Treatment of Fish Canning Wastewaters," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 2, no. 4, pp. 237-242, 2012.