Ndiongue S, Huck P M, Slawson R M
Department of Civil Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
Water Res. 2005 Mar;39(6):953-64. doi: 10.1016/j.watres.2004.12.019.
This study used annular reactors (AR) to investigate, under controlled laboratory conditions, the effects of temperature and biodegradable organic matter (BOM) on the free chlorine residual needed to control biofilm accumulation, as measured by heterotrophic plate count (HPC) bacteria. Biofilm was grown on PVC coupons, initially in the absence of chlorine, at 6, 12, and 18 degrees C, in the presence and absence of a BOM supplement (250 microg C/L) added as acetate. During the early stages of chlorine addition, when no measurable free chlorine residual was present, a reduction in biofilm HPC numbers was observed. Subsequently, once sufficient chlorine was added to establish a residual, the biofilm HPC numbers expressed as log CFU/cm2 fell exponentially with the increase in free chlorine residual. Temperature appeared to have an important effect on both the chlorine demand of the system and the free chlorine residual required to control the biofilm HPC numbers to the detection limit (3.2 Log CFU/cm2). For the water supplemented with BOM, a strong linear correlation was found between the temperature and the free chlorine residual required to control the biofilm. At 6 degrees C, the presence of a BOM supplement appeared to substantially increase the level of free chlorine residual required to control the biofilm. The results of these laboratory experiments provide qualitative indications of effects that could be expected in full-scale systems, rather than to make quantitative predictions.
本研究使用环形反应器（AR），在可控的实验室条件下，研究温度和可生物降解有机物（BOM）对控制生物膜积累所需的游离氯残留量的影响，生物膜积累通过异养平板计数（HPC）细菌来衡量。生物膜在PVC试片上生长，最初在无氯条件下，于6℃、12℃和18℃，在添加和不添加作为乙酸盐添加的BOM补充剂（250μg C/L）的情况下生长。在添加氯的早期阶段，当不存在可测量的游离氯残留时，观察到生物膜HPC数量减少。随后，一旦添加足够的氯以建立残留量，以log CFU/cm2表示的生物膜HPC数量随着游离氯残留量的增加呈指数下降。温度似乎对系统的氯需求量以及将生物膜HPC数量控制到检测限（3.2 Log CFU/cm2）所需的游离氯残留量都有重要影响。对于添加了BOM的水，发现温度与控制生物膜所需的游离氯残留量之间存在很强的线性相关性。在6℃时，BOM补充剂的存在似乎大幅增加了控制生物膜所需的游离氯残留量水平。这些实验室实验的结果提供了在全尺寸系统中可能预期的效果的定性指示，而非进行定量预测。
