船舶饮用水消毒试验研究及方案设计(4)
【作者】网站采编
【关键词】
【摘要】4.2.淡水舱余氯补充 船舶水舱淡水在贮存过程中,余氯会随着时间消耗掉,若不及时补充余氯,水舱中可能滋生细菌等微生物,影响饮用安全。通过定期对
4.2.淡水舱余氯补充
船舶水舱淡水在贮存过程中,余氯会随着时间消耗掉,若不及时补充余氯,水舱中可能滋生细菌等微生物,影响饮用安全。通过定期对水舱投加消毒剂可有效抑制水舱中微生物的滋生。采用次氯酸钙(钠)作为余氯补充剂,结合水舱在线余氯监测仪,可以实现淡水舱余氯自动补充功能。
4.3.饮用水终端消毒
当水舱淡水作为饮用水最终使用时,为防止饮用水在管路输送过程中引入细菌等微生物,需在用水终端进行消毒,由于终端处饮用水直接使用,不需要持续消毒效果,同时消毒速度要快,因此采用紫外消毒比较合适。紫外消毒具有消毒速度快、无消毒副产物等优点,同时可有效杀灭的“两虫”—隐孢子虫和贾第鞭毛虫。
5.结论
综合以上不同消毒措施的实验结果可以得出:
1)次氯酸钙(钠)作为传统消毒剂对淡化饮用水消毒效果明显,使用其进行循环消毒时,其副产物浓度远低于GB5749-2006要求,经过了数十年的应用实践,其安全性有保证。
2)紫外线消毒在保证照射强度条件下消毒效果良好的同时,具有无消毒副产物的优点。可有效杀灭隐孢子虫和贾第鞭毛虫。但紫外消毒无持续消毒能力,适用于消毒后直接使用的场合。
3)通过对船舶饮用水系统特点分析,总结了针对性的消毒工艺:对船舶给水、反渗透淡化水及水舱进行消毒时,宜采用具有持续消毒作用的次氯酸钙(钠)法;在终端供水时,可考虑使用紫外线消毒法对饮用水进行消毒。
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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105CFU/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 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 this study, calcium hypochlorite, sodium hypochlorite, and ultraviolet disinfection were used to sterilize the ship fresh water, and their applicability was using calcium hypochlorite to sterilize water, it was found that the natural attenuation of residual chlorine was slow in a closed 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 experiment of sterilizing water containing 105CFU/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 results showed that the sodium hypochlorite also had a good disinfection testing ultraviolet disinfection, it was found that ultraviolet (UV)had better disinfection effect in a certain velocity, but without continuous disinfection to the result of the experiments, the different disinfection methods should be chosen based on the different spots of the drinking water on 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.
文章来源:《船舶工程》 网址: http://www.cbgczzs.cn/qikandaodu/2021/0510/528.html