Effects of discharged water from the sewage plant and dynamic behavior of pollutants in Hori-River

Hori-River是流经名古屋市的一条受潮汐影响的河流。一座污水处理厂位于这条河的上游。在沿河的多个地点采集了河水和沉积物的样本。通过对几项水质和底泥水质的测定，研究了污水处理厂排放水对河水水质的影响以及河水中污染物的动态行为。并对污水和河水中镍的去除进行了研究。主要研究结果如下：(1)霍里河水体中高浓度的Ni和NH4-N主要来源于污水处理厂排放的水。可以看出，这些污染是由污水厂排放造成的。(2)从名古屋港入侵的海水对Hori-River中观察到的高浓度Se和Cr值有贡献。可以看出，这些污染是由位于名古屋港海边的几家工厂的排放造成的。(3)疏浚作业导致了几种重金属的高浓度。(4)位于污水厂下游数百处的樱桥附近经常观测到高浓度的Ni和NH4-N。分析了造成这一结果的原因。最后指出，胶体污染物(Ni和NH4-N)从淡水层向海水层迁移的抑制是造成Hori-River中Ni浓度分布的原因。(5)对Hori-River中Ni最有效的吸附剂是活性碳。(6)吸附实验结果表明，在Hori-River中，Ni以胶体粒子的形式存在。对历时三年的研究进行总结，并以书面式报告的形式发表。

Hori-River is a tide affected river running in Nagoya City. A sewage plant locates at the upper stream of the river. River water and sediment were sampled at many points along the river. Several items of water and sediment quality were measured to investigate the effects of discharged water from sewage plant and dynamic behavior of pollutants in Hori-river. And the investigations about removal of Ni from sewage or river water were carried out. The results can be summarized as follows :(1) Discharged water from the sewage plant contributes the high concentrations of Ni and NH4-N observed in Hori-River. It can be seen that these pollution were caused by the discharge from sewage plant.(2) Seawater intruded from Nagoya harbor contributes the high concentrations of Se and Cr observed in Hori-river. It can be seen that these pollution were caused by the discharge from several factory located seaside of Nagoya harbor.(3) Dredging operation contributes the high concentrations of several heavy metals.(4) The high concentrations of Ni and NH4-N were often observed around Sakurabashi that is located in the several hundreds of downstream from sewage plant. The reasons of this results were investigated. Finally, it was pointed out that the restraint of colloidal pollutants (Ni and NH4-N) movement from the layer of fresh water to the layer of seawater would contribute such a concentration profile in Hori-River.(5) The most effective adsorbent for Ni in the Hori-River was activated charcoal.(6) From the results of adsorption experiment, it was suggested that Ni existed as colloidal particle in the Hori-River. The study for three years was summarized and published as the book-style report.