Innovative upcycling gabions with coal bottom ash for nonpoint source pollution control against climate change

Climate change accelerates extreme temperature fluctuations and rainfall volatility, and shifts in rainfall patterns, rapidly increasing nonpoint source pollution originated from turbid water and soil erosion. The climate changes also pose serious threats to the agricultural environment and food security. This study innovates the conventional control facilities of turbid water and soil erosion in the sloping field, using coal bottom ash as a harmful waste of thermal power generation. Typical gabion and side modified gabion are designed in consideration with geographical characteristics. The adsorption capacity of coal bottom ash for turbidity, suspended solids (SS), total nitrogen (T-N), and total phosphorus (T-P) were increased as the amounts of coal bottom ash increase. At the rate of 20-g coal bottom ash, the turbidity, SS, T-N, and T-P were absorbed by 84.0%, 80.2%, 40.2%, and 53.2%, respectively. The typical gabion (TG) and side modified gabion (SMG) installed in the sloping field also decreased the turbidity, SS, T-N, and T-P by up to 98.1%, 99.4%, 77.6%, and 84.0%, respectively, during the natural rainfall events. The use of coal bottom ash cannot only be an effective upcycling way to control nonpoint source pollution but also be an ecofriendly approach against climate change.