Winward G P, Avery L M, Stephenson T, Jefferson B
Centre for Water Sciences, Cranfield University, Bedfordshire, MK43 0AL, United Kingdom.
Environ Technol. 2008 Feb;29(2):235-44. doi: 10.1080/09593330802030069.
The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from < 1 to > or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.
针对城市中水回用，研究了水质对中水紫外线（UV）消毒的影响。由于存在粒径范围从小于1微米到大于或等于2000微米的颗粒物，中水的直接紫外线消毒不符合加利福尼亚州第22号法规中关于无限制城市中水回用的严格标准。通过沉淀对中水进行处理，以产生具有不同粒径分布的组分，并在消毒后采用混合方法来提取与颗粒相关的大肠菌群（PACs）。发现紫外线消毒的效果与中水组分的粒径有关。观察到平均粒径为262微米及以上的较大粒径组分比平均粒径低于119微米的较小颗粒能使更多大肠菌群免受紫外线照射。在紫外线剂量（通量）为260 mJ.cm(-2)后，较大粒径组分中高达70%的总大肠菌群与颗粒相关，并且用标准大肠菌群计数技术将无法检测到这些菌群。讨论了对城市中水回用的影响，并就中水的处理提出了建议，以确保在紫外线消毒之前去除与颗粒相关的指示细菌和病原体。
