As the number of climbers increased in the past few decades, human waste became the biggest problem of Mount Fuji. When the amount of waste exceeded the disposal capacity of the mountain's toilet system, undecomposed toilet papers were discharged on the mountain, which people called "White River".
To solve this problem, which is essential to become a UNESCO World Heritage, the mountain's toilets have been dramatically improved. The types of high-technology toilets installed on Mount Fuji include Incineration-method toilet, oyster-shell-method toilet, and biotoilet.
Recently I found a news saying that this eco-friendly biotoilet was donated to Mount Rainier National Park by a Japanese environmental group that is active on Mount Fuji. According to the article, it's the first biotoilet installed in the United States. ( http://www.katu.com/home/related/19695814.html )
I was glad to hear that Japanese technology can be useful for the conservation of world's nature.