船舶饮用水消毒试验研究及方案设计

Experimental Study and Scheme Design on Disinfection of Ship Drinking Water

船舶饮用水主要有二种:市政自来水和海水淡化水。船舶淡水舱内的水储存超过一定时间,水中的消毒剂衰减完,细菌重新繁殖,导致水质难以达到GB5749-2006《生活饮用水卫生标准》,因此必须对其进行持续消毒处理。本研究采用次氯酸钙、次氯酸钠、紫外线消毒等几种最常用方式对船舶淡水进行消毒,分析它们的适用性。使用次氯酸钙法进行消毒试验时,发现密闭环境下,其余氯自然衰减比较缓慢,当余氯初始浓度为0.64 mg/L时,保存半月后余氯含量仍在0.3 mg/L以上;对含有105 CFU/100 mL大肠杆菌的贮水箱进行消毒,初始余氯为3.82 mg/L时,有良好的消毒效果;进行14 d的贮水箱循环消毒试验时,其副产物浓度远低于GB5749-2006要求,表明消毒处理的饮用水长期存储饮用是安全的。使用次氯酸钠进行消毒试验,结果表明其同样具有良好的消毒效果。采用紫外线消毒,发现其在一定流速内具有较好的杀菌效果,但没有持续消毒功能。根据试验研究结果,船舶上不同位置饮用水应采用不同的消毒方式,对船舶给水、反渗透淡化水及水舱淡水消毒推荐使用次氯酸钙(钠)法,对终端用水推荐使用紫外线消毒法。

There are two main types of ship drinking water:municipal tap water and desalination water.When the water stores in the ship’s water tank for some time,the disinfectant has decayed in the water and bacteria reproduction,resulting in water quality is difficult to meet Standards for drinking water quality(GB5749-2006).Therefore,it must be continuously sterilized.In this study,calcium hypochlorite,sodium hypochlorite,and ultraviolet disinfection were used to sterilize the ship fresh water,and their applicability was analyzed.When using calcium hypochlorite to sterilize water,it was found that the natural attenuation of residual chlorine was slow in a closed en-vironment.When the initial concentration of residual chlorine was 0.68 mg/L,the residual chlorine content was still larger than 0.3 mg/L after half a month.The experiment of sterilizing water containing 105 CFU/100 mL Escherichia coli in the water storage tank and the disinfection showed a good effect when the initial residual chlorine content was 3.82 mg/L.The disinfection by-product(DBP)concentration was much lower than the limits in GB5749-2006 when doing the 14-day circulating disinfection test of water storage tank,which indicated that the drinking water treated by calcium hypochlorite was safe for long-term storage and drinking.The results showed that the sodium hypochlorite also had a good disinfection effect.When testing ultraviolet disinfection,it was found that ultraviolet(UV)had better disinfection effect in a certain velocity,but without continuous disinfection function.According to the result of the experiments,the different disinfection methods should be chosen based on the different spots of the drinking water on ships.The water feeding the ship,desalinated by reverse osmosis,and storage in the water tank should be disinfected by calcium(or sodium)hypochlorite,and the terminal water should be disinfected by ultraviolet ray.