金枪鱼罐头生产中节水问题的研究

Research on Water-saving of Canned Tuna Plant

通过对金枪鱼罐头加工项目的耗水量研究,发现金枪鱼罐头生产中每吨原料的耗水量为13.6 m3。废水主要由喷雾冷却过程(4.9 m3/t)及设备和地面的清洗过程(4.2 m3/t)产生。蒸煮过程则是最大的污染源,其废水的化学需氧量(COD)为65 983 mg/L,油脂(O&G)为1 814 mg/L,总固体(TS)为57 276 mg/L,悬浮固体(SS)为6 834 mg/L。在深入调查的基础上提出了节水的主要措施:在喷雾冷却设备上安装压力喷雾嘴;减少罐身缝合以后的清洗用水量,并且用55℃的热水代替冷水;教育工厂的工作人员在设备和地面的清洗过程中节约用水。实验表明节水措施实施后这三个步骤的耗水量分别减少了69%,58%和29%。每吨原料的净耗水量8.4 m3,在总体耗水量上比原来减少了39%。

The common environmental problems of the fish industry are high water consumption and high organic matter content in wastewater. Water consumption in canned tuna （pet food） processing is 13.6 m^3/ton of raw material. The major sources of wastewater are spray cooling process （4.9 m3/ton） and equipment and floor washing （4.2 m3/ton）. The biggest pollution source in wastewater is from precooking, which has the COD 65,983 mg/L, oil and greasel,814 mg/L, TS 57,276 mg/L and SS 6,834 mg/L, respectively.Water conservation measures were attempted at three processing steps. This included the installation of pressure spraying nozzles for spray cooling; the use of hot water（55 ℃） instead of cold water; and educating the plant personnel on water conservation for equipment and floor washing. After the conservation measures were applied, water consumption at the three processing steps was reduced by 69%, 58% and 29%,respectively. The net water consumption was 8.4 m^3/ton of raw material, representing a 39% reduction in overall water consumption.