Tainan’s Guantian District turned water chestnut shells into black gold through local-private cooperation.
The water chestnuts produced in Guantian, Tainan, account for 70-80% of Taiwan's market share. After the water chestnuts are processed, nearly 500 tons of water chestnut shells remain in Guantian. In the past, farmers used to burn water chestnut shells at the edges of fields. However, in recent years, initiatives for air quality and carbon reduction have led locals to reflect on how to increase the value of these water chestnut shells in a way that is environmentally friendly and that takes into account circular sustainability.
Water chestnut shells become black gold
Learning from the experience of making biochar from rice husks, the local government, private organizations, and local demonstration factories in Guantian worked with research institutions to develop technologies to convert water chestnut shells into biochar, in hopes of establishing brand characteristics through the reuse of waste chestnut shells. Due to their efforts, water chestnut shells that were usually abandoned on the roadside could now be transformed into a material with moisture-absorbing and deodorizing properties, giving new life to the water chestnut shells.
A cooperative division of labor system
In Guantian District, a specialized divisional system has been implemented, enabling each community to participate in the Guantian Wujin Community Cooperative. This cooperative oversees decentralized processing tasks across multiple community "satellite factories," including recycling, drying, carbonization, and packaging. Together, these activities focus on producing charcoal from rice husks, contributing to the development of a unique local production enterprise.
Uncovering the diverse application value of water chestnut shells
In cooperation with rehabilitation buses, water chestnut shell biochar is made into adsorption sachets that help purify the air on buses. In addition, farmers in Guantian are also provided guidance to practice the crop rotation of water chestnuts and rice. By using rice husk charcoal instead of traditional lime to purify the water in water chestnut fields, we aim to reduce soil calcification. Subsequently, planting rice improves rice quality and contributes to carbon sink.
Benefits
- Recycling approximately 1,200 metric tons of discarded water chestnut husks annually results in the production of 36 metric tons of biochar from water chestnut husks, effectively reducing emissions by 105.6 metric tons of CO2e.