The article presents research carried out on a sand/anthracite filter in a water treatment plant in Cracow in the south of Poland. These studies show that shutting down the filter after only three hours of operation, setting it aside for four hours and restarting without backwashing did not cause any visible deterioration in the quality of the produced filtrate. Stopping the same filter for four hours, however, after 68 h of operation, visible deterioration in the quality of the filtrate can be observed. After a significant initial deterioration, the quality of the filtrate slowly improved and after a few hours, it reached a level comparable to that before the filter was taken out of service. This was probably the result of characteristic changes in shear stress at the boundary of the deposit and flowing water in the capillaries, which accompanied changes of filtration rate. Decrease in the removal efficiency of coarser particles lasted longer and was greater than that of finer particles. Decrease in particle removal efficiency after restarting the dirty filter was difficult to identify by turbidity measurements, but clearly identifiable by measuring suspended solid concentration and the number of coarser particles. Interrupting the operation of a rapid filter shortly after it has been backwashed should not significantly reduce its efficiency, but after prolonged operation, it may adversely affect the quality of the filtrate.

本文介绍了在波兰南部克拉科夫的一家水处理厂中对沙子/无烟煤过滤器进行的研究。这些研究表明，仅在运行三小时后关闭过滤器，将其放置四小时，然后在不进行反冲洗的情况下重新启动，不会导致产生的滤液质量出现任何明显的劣化。停止相同的过滤器四个小时，然而，在运行 68 小时后，可以观察到滤液质量的明显恶化。经过最初的显着恶化，滤液的质量慢慢提高，几个小时后，它达到了与过滤器停止使用前相当的水平。这可能是沉积物边界处剪切应力和毛细管中流动水的特征变化的结果，伴随着过滤速率的变化。粗颗粒去除效率的下降持续时间更长，并且大于细颗粒。重新启动脏过滤器后颗粒去除效率的下降很难通过浊度测量来识别，但通过测量悬浮固体浓度和粗颗粒数可以清楚地识别出来。快速过滤器在反冲洗后立即中断运行不会显着降低其效率，但长时间运行后，可能会对滤液质量产生不利影响。重新启动脏过滤器后颗粒去除效率的下降很难通过浊度测量来识别，但通过测量悬浮固体浓度和粗颗粒数可以清楚地识别出来。快速过滤器在反冲洗后立即中断运行不会显着降低其效率，但长时间运行后，可能会对滤液质量产生不利影响。重新启动脏过滤器后颗粒去除效率的下降很难通过浊度测量来识别，但通过测量悬浮固体浓度和粗颗粒数可以清楚地识别出来。快速过滤器在反冲洗后立即中断运行不会显着降低其效率，但长时间运行后，可能会对滤液质量产生不利影响。