Koh Phi Phi Island consists of two
mountains connected by a narrow sand strip, about 1.5km long
and 200m wide, creating two U-shaped lagoons and making the
contour of the island similar to the shape of a butterfly. The mountainous
parts of the island are preserved as a part of a national park,
and nearly all the commercial tourist businesses are located on private
land on the narrow sand strip. More than one million tourists
visit the island every year, and the development of an appropriate
wastewater management system for Koh Phi Phi was therefore a
great challenge.