Chemical dosage optimization in kitchen wastewater treatment via an integrated bio-chemical model

To address the challenges of achieving organic compliance in kitchen wastewater treatment and the high cost of chemical dosing, this study established a two-stage reactor incorporating both biological and chemical processes and proposed an optimal regulation system. The reactor achieves the effluent COD standard compliance. Additionally, both exceeding-standard and standard-compliant data were collected from the reactor. This avoids the limitation that relying solely on standard-compliant data would prevent chemical dosing optimization from reaching the optimal solution. By adopting the XGBoost algorithm, biological and chemical prediction models for effluent COD are constructed. The R² values of the biological model and the chemical model for accuracy are 0.879 and 0.904, respectively. Subsequently, a chemical dosage optimization method for wastewater treatment processes integrating the Bio-Chemical model and particle swarm optimization (BCPSO) is proposed. After optimization, all the original standard-exceeding COD samples meet the discharge standards. The average effluent COD concentration is reduced by 31.17%, and the average total removal rate is increased by 4.82%. On the premise of ensuring effluent standard compliance, the optimization of originally standard-compliant samples reduces the chemical cost by 22.45%. The BCPSO proposed in this study can be extended to the treatment processes of other refractory organic wastewater, reducing the operating costs without posing a threat to the environment.