Chemical and Bacteriological Studies on the Water of Swimming-place. IV : On the Quality of Water of Swimming-pool with Recirculation System (No. 1)

Abstract

Turbidity, value of COD, contents of NH₃-N, NO₂^--N, NO₃^--N and Cl^- were measured on the water of several swimming pools with recirculation system, and the significance and variation of the results of each test and their mutual relationship were discussed. Any significant mutual relationship was not observed among them. The values of turbidity, COD and NO₂^--N were very changeable, though the value of COD were always under 3 ppm (12 ppm as for KMnO₄ consumption value) owing to the control of recirculation system. The relation between turbidity and value of COD showed that there are two different KMnO₄ consuming factors in the pool water, one of them is suspended material to be removed by recirculation and another one is soluble and not removed by recirculation. The results of successive tests showed that NH₃-N, NO₂^--N and Cl^- had a tendency to accumulate, except one swimming pool where NH₃-N and NO₂^--N were not detected at all times.