Wastewater treatment is a significant part of food engineering and industry, during which a crucial step is to effectively absorb and remove contaminants from the water. To solve this issue, in this study, a series of biochar products were obtained from various food and agricultural byproducts and used as filtering materials for wastewater. Additionally, different approaches for producing large-scale biochar products were developed.

In the preliminary work, one type of biochar was harvested via the pyrolysis of corn cob stalks, and another type was obtained through the gasification of poultry litters. The effects of the experimental conditions on the yields, compositions, and physicochemical properties of the biochar products were investigated in order to optimize the processing products.

In the wastewater treatment application, the biochar products were ground into particles (with an average size of 213.09 μm) and used as filtering material against simulated flowing wastewater that contained ammonia or microplastics, which commonly exist in wastewater in the food processing industry. The preliminary tests demonstrated that the biochar-based filtration systems could effectively absorb the target contaminants and remove them from the water. The results showed that depending the amount of biochar usage and the level of wastewater loading, the removal rate of ammonia could reach up to 73.56%, while the removal rate of microplastics could reach up to 97.39%. Though more investigations are required, the results indicate the great potential capability of biochar as a filter and absorbent for treating wastewater contaminants.