Where did the sludge dissolve in the lake winds of Shiga in the late 2000s?

Where did the sludge dissolve in the lake winds of Shiga in the late 2000s?

In the late 2000s, Japan's sewage treatment facilities were aging nationwide, and the cost of renewal was putting pressure on local finances. Water consumption was also declining due to a shrinking population, and the structure of maintaining facilities by a single municipality was showing its limits. In the midst of this nationwide trend, the Kosei Sewage Treatment Center in Otsu City, Shiga Prefecture, also had an aging incineration and melting furnace, and the final disposal facility in Otsu City was nearing its capacity limit. The two cities' circumstances were such that they had to compensate for each other's deficiencies, and the joint disposal of sludge emerged as a rational solution.

In the background, Shiga Prefecture, which is home to Lake Biwa, has a long history of water quality preservation policies. As part of its eutrophication prevention measures and watershed management, sludge treatment has been closely linked to the environmental preservation of the lake. In addition, with 25 million tons of sewage sludge generated annually throughout Japan, and the tightness of final disposal sites becoming an issue, the technology of volume reduction by incineration and melting and reuse of molten slag has been attracting attention. However, the cost of updating facilities is a heavy burden for municipalities to bear alone, and wide-area cooperation was called for.

Shiga Prefecture received an administrative consignment from Otsu City and began partial treatment in phases starting in FY2012, with plans to accept all of the city's sludge from FY2015 onward. Such joint treatment was an initiative to support regional sustainability, born out of the intersection of multiple issues: financial rationality, technological renewal, and environmental preservation.