Abstract
Fish canning industry is one of the top priority industries in Indonesia that is competitive in international market and essential to food security. It is also an industry with high water consumption due to its water-intensive processes such as thawing and washing that produces large amount of wastewater containing very high load of organic pollutants which must be treated properly before disposal into the environment. This study was conducted using wastewater characteristics from one of the fish canning plants in Bali, Indonesia, that already implemented wastewater treatment using a combination of aerobic treatments with trickling filter and activated sludge. The treatment system has difficulty to achieve a good and stable effluent quality, especially during high load production season. It is necessary to find a better system that can treat the high load of organic content in wastewater and produce a cleaner effluent that can be recycled back into the production process. This study is aimed to develop a model of integrated system comprised of sedimentation, coagulation-flocculation, Upflow Anaerobic Sludge Blanket (UASB) and Modified Ludzack-Ettinger (MLE) that can be used as a base design for further implementation in pilot-scale facility. The integrated system was designed to remove 99 % of BOD, 99 % of oil and grease, 98 % of TSS and 87.8 % of total nitrogen achieving effluent quality of 59.9 mg/L BOD, 0.6 mg/L oil and grease, 27.4 mg/L TSS, and 30.0 mg/L total nitrogen in nitrates form. Compared to the existing treatment system with effluent quality of 351.4 mg/L BOD, 337 mg/L TSS and 111.1 mg/L ammonia, this system could improve the effluent quality significantly by maintaining a hydraulic retention time (HRT) of 55.3 h. Combining constructed wetland with HRT of 28.8 h as water reclamation system to refine the water quality, the nitrogen content could be reduced to less than 10 mg/L to meet the requirement as raw water for clean water production process. The design in this study could be used to replace the existing aerobic treatment system and enable the industry to solve the environmental problems of wastewater disposal and water conservation and expand further the production capacity simultaneously.
