Md. Shahidul Islam*
Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
Saleha Khan
Department of Fisheries Management, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
Shrimp and fish processing; Waste loading; Effluents; Coastal and marine pollution; Environment
Risk Management in Agriculture
Waste output and loading in fish and shrimp processing. The main inputs in a processing plant are whole fresh or iced fish and shrimp, water, ice, calcium hypochlorite and other chemicals, packaging materials and electricity plus liquid soap used during cleaning. The outputs are the fresh chilled fillet exported or consumed; swimbladders, removed from fish carcasses and processed separately into valuable product; skins of fishes like sharks and rays are processed into leather; remaining fats, red meat carcasses (with swim bladders removed), and fillets rejected on quality grounds that are either used for human consumption or made into fish meal or silage; wastewater of varying strengths, especially from the filleting and trimming processes, contains fat, oil and grease (FOG) with blood, small pieces of fish and protein; waste heat from ice manufacture, chilling, and the cold room (to atmosphere). The outputs of the processing industries usually contain a large bulk of waste products. Generally, the head, hardcover, and tail portions of shrimp are removed during processing and these account for approximately 50% of the volume of raw materials. Increasing production of inedible parts of shrimp, such as heads, hardcovers and tails, is causing environmental problems as a result of uncontrolled dumping. The wastewater from seafood processing plants contains large amounts of organic matter, small particles of flesh, breading, soluble proteins, and carbohydrates. Mauldinand Szabo (1974) reported that as much as 65% of the tuna is wasted in the canning process. The average daily waste flow was over 27,000 l ton1of fish, varying from500–1550 mg l1of BOD; 1300–3250 mg l1of COD; and 17,000 mg l1of TSS of which 40% was organic. Steven (1981) surveyed the North Carolina seafood industry and stated that unloading, washing and separating ice, sorting grading and re-icing before shipping all constitute handling and sources of contamination from personnel. Results of the survey found that the average values for TSS were 2.4, ash 1.11, organic solids1.30 and BOD 0.23 g kg1while water use was 1.5 l kg1of fish handled. hardcovers and appendages may drop off during unload-ing, contributing large amounts of settleable solids to the waste load. Slime and body fluids and sand were also found to be part of the wastewater. The average BOD of rinse tank wastewaters was 251 mg l1. Scales seemed to constitute the bulk of the solids in the effluent from the wash tanks surveyed. Scott et al. (1978) and Carawan(1991) reported effluents loading at all stages of processing raw materials with a very high final bulk of wastes and the average value of waste loads. Information provided by the Mississippi shrimp industry (Mississippi State University, 1998) indicates that Mississippi shrimp processors processed about 17,255tons of shrimp in different months in 1998 with a corresponding production of 6277 tons of wet waste through all seasons of a year. On average, the waste bulk constituted 35% of the raw materials. An even higher volume of waste production was reported by Yorio and Caille (in press) in the fish processing industry in Argentina (Fig. 3). They reported that the total waste generated in fish processing plants at five coastal cities in Argentina during the last decade (from1989 to 2001) ranged 37,186–76,880 tons (average49,786 tons) against total landings ranging 64,114–132,552 tons (average 85,838 tons); on average, waste bulk constituted 58% of the total landings.
Marine Pollution Bulletin 49 (2004) 103–110
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