We studied on the performance of the treatment of yarn dyeing wastewater. The soluble COD was removed in average in an amount of about 50% in the coagulationprecipitation process, and further removed in an amount of about 70% of the remaining soluble COD in the activated sludge process.
The monthly data of soluble COD, SS and transparency in raw wastewater and treated wastewater during a year were statistically analyzed in terms of non-exceeding probability, and the result was represented as a logarithmic normal distribution. It was found that the wastewater was efficiently treated with this treatment plant, although the satistical figures showed some scatter.
Moreover, the treatment efficiency of COD in the coagulationprecipitation process was investigated by the synthetic dyeing wastewater. As a result, the surfactant, acetic acid and the like were found to be hardly removed in this process. Therefore, it is made evident that when the wastewater with the components to be hardly removed flows into the treatment plant, it is necessary to perform treatments suitable for wastewater components, including chemical and/or biological treatments.

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Chemical characteristics of the sediments in Lake Biwa were analyzed by a concentration correlation matrix method, in which the ratios of the elemental concentrations of the samples are compared with the equivalent ratios of other samples. The core sediment samples were collected from three points of the northern basin and from nine points of the southern basin. The chemical components in the sediments collected at a depth of 15 cm from the bottom surface were quantified by an X-ray fluorometry. The vertical distributions of S, P, Cl, Mn, Cu, Zn, As, Ba and Pb in the sediments showed that these elements were affected by human activities or post-depositional diagenesis, whereas the distributions of Si, Al, Fe, Ti, Na, K, Mg, Ca, Cr, Ni, Rb and Sr showed that the behavior of these elements were not affected thereby. Therefore, the correlation number between the samples was calculated by using the analytical values of these twelve elements. Among the sediments collected from the northern basin and the southern basin of Lake Biwa, high correlation numbers of more than 0.75 were obtained for each of the neighboring locations. On the other hand, relatively low correlations were found between the sediment in the northern site of the northern basin and the sediments of the southern basin. Low correlations were also found between the sediments from the northeast area and those of other locations in the southern basin. The generic correlations among the sediments of Lake Biwa could be explained by the physical and chemical re distributions of chemical constituents during the process in which the sedimentary materials are transported through lacustrine water current. The correlations of the sediments in Lake Biwa could be thus quantitatively evaluated by using a concentration correlation matrix method.

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