A hybrid evolutionary data driven model for river water quality early warning.
China's fast pace industrialization and growing population has led to several accidental surface water pollution events in the last decades. The government of China, after the 2005 Songhua River incident, has pushed for the development of early warning systems (EWS) for drinking water source protection. However, there are still many weaknesses in EWS in China such as the lack of pollution monitoring and advanced water quality prediction models. The application of Data Driven Models (DDM) such as Artificial Neural Networks (ANN) has acquired recent attention as an alternative to physical models. For a case study in a south industrial city in China, a DDM based on genetic algorithm (GA) and ANN was tested to increase the response time of the city's EWS. The GA-ANN model was used to predict NH3-N, CODmn and TOC variables at station B 2 h ahead of time while showing the most sensitive input variables available at station A, 12 km upstream. For NH3-N, the most sensitive input variables were TOC, CODmn, TP, NH3-N and Turbidity with model performance giving a mean square error (MSE) of 0.0033, mean percent error (MPE) of 6% and regression (R) of 92%. For COD, the most sensitive input variables were Turbidity and CODmn with model performance giving a MSE of 0.201, MPE of 5% and R of 0.87. For TOC, the most sensitive input variables were Turbidity and CODmn with model performance giving a MSE of 0.101, MPE of 2% and R of 0.94. In addition, the GA-ANN model performed better for 8 h ahead of time. For future studies, the use of a GA-ANN modelling technique can be very useful for water quality prediction in Chinese monitoring stations which already measure and have immediately available water quality data.
Tsinghua University - Veolia Environnement Joint Research Center for Advanced Environmental Technology, School of Environment, Tsinghua University, Beijing, China. Electronic address: burchard-levin10@mails.tsinghua.edu.cn.
Alejandra
A
Burchard-Levine
School of Environment, Tsinghua University, Beijing, China. Electronic address: shumingliu@tsinghua.edu.cn.
Shuming
S
Liu
Veolia Environnement, 8 North Dongsanhuan Road, Beijing 100004, China. Electronic address: francois.vince@veolia.com.
Francois
F
Vince
School of Environment, Tsinghua University, Beijing, China. Electronic address: limingming.china@gmail.com.
Mingming
M
Li
Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: ostfeld@tx.technion.ac.il.
Avi
A
Ostfeld
D000641:Ammonia / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D002244:Carbon / Q000032:analysis; D002681:China; D002947:Cities; D060766:Drinking Water; D004784:Environmental Monitoring / Q000379:methods; D008962:Models, Theoretical; D016571:Neural Networks, Computer; D009584:Nitrogen / Q000032:analysis; D045483:Rivers; D013997:Time Factors; D014876:Water Pollution / Q000032:analysis*; D060753:Water Quality
D060766:Drinking Water; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen
Artificial Neural Networks; China; Early warning system; Genetic algorithm; Water quality