Guantian is the primary producing region of water caltrops; however, the massive amount of waste water caltrop shells generated as a result has become a major environmental headache for the local area. To breathe new life into waste in an environmentally friendly and sustainable, circular manner, we have combined the strengths of industry, government, academia, and the community to launch "Guantian Black Gold," a brand centered on the circular economy. This brand transforms water caltrop shells into "black gold"—water caltrop shell charcoal—and has introduced a series of daily-use products made from it. Meanwhile, the patented charcoal-making system within our park not only generates products but also serves as a prime exemplar of circular economy applications, as it is equipped with a comprehensive "heat source reuse system" and a "solar power system." Beyond commercial operations, we also promote the concepts of earth-friendliness and the circular economy through a diverse range of guided tours within the park.