Dehghani Mohammad Hadi, Jahed Gholam-Reza, Zarei Ahmad
Dept. of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran ; Tehran University of Medical Sciences, Center for Solid Waste Research (CSWR), Institute for Environmental Research (IER), Tehran, Iran.
Iran J Public Health. 2013 Mar 1;42(3):314-9. Print 2013.
Rhabditidae is a family of free-living nematodes. Free living nematodes due to their active movement and resistance to chlorination, do not remove in conventional water treatment processes thus can be entered to distribution systems and cause adverse health effects. Ultraviolet radiation (UV) can be used as a method of inactivating for these organisms. This cross sectional study was done to investigate the efficiency of ultraviolet lamp in the inactivation of free living nematode in water.
The effects of radation time, turbidity, pH and temperature were invistigated in this study. Ultraviolet lamp used in this study was a 11 W lamp and intensity of this lamp was 24 μw / cm(2).
Radiation time required to achieve 100% efficiency for larvae nematode and adults was 9 and 10 minutes respectively. There was a significant correlation between the increase in radiation time, temperature rise and turbidity reduction with inactivation efficiency of lamp (P<0.001). Increase of turbidity up 25 NTU decreased inactivation efficiency of larvae and adult nematodes from 100% to 66% and 100% to 64% respectively. Change in pH range from 6 to 9 did not affect the efficiency of inactivation. With increasing temperature inactivation rate increased. Also the effect of the lamp on inactivation of larvae nematod was mor than adults.
It seems that with requiring the favorable conditions low-pressure ultraviolet radiation systems can be used for disinfection of water containing Rhabitidae nematode.
小杆线虫科是一类自由生活的线虫。自由生活的线虫由于其活跃的移动性和耐氯化性,在传统水处理过程中无法去除,因此可能进入供水系统并对健康造成不利影响。紫外线辐射(UV)可作为灭活这些生物的一种方法。本横断面研究旨在调查紫外线灯对水中自由生活线虫的灭活效率。
本研究考察了辐射时间、浊度、pH值和温度的影响。本研究中使用的紫外线灯是一盏11瓦的灯,其强度为24微瓦/平方厘米。
使线虫幼虫和成虫达到100%灭活效率所需的辐射时间分别为9分钟和10分钟。辐射时间的增加、温度的升高和浊度的降低与灯的灭活效率之间存在显著相关性(P<0.001)。浊度增加到25 NTU时,线虫幼虫和成虫的灭活效率分别从100%降至66%和从100%降至64%。pH值在6至9范围内的变化不影响灭活效率。随着温度升高,灭活率增加。此外,灯对幼虫线虫的灭活作用比对成虫的作用更大。
似乎在具备有利条件时,低压紫外线辐射系统可用于对含有小杆线虫科线虫的水进行消毒。