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doi:10.3808/jeil.201900010
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Short-Term Wastewater Influent Prediction Based on Random Forests and Multi-Layer Perceptron

P. Zhou1, Z. Li1 *, S. Snowling2, R. Goel2, and Q. Zhang1,3

  1. Department of Civil Engineering, McMaster University, Hamilton, Ontario, L8S 4L7, Canada
  2. Hydromantis Environmental Software Solutions, Inc., 407 King Street West, Hamilton, Ontario, L8P 1B5, Canada
  3. School of Management, Chengdu University of Information Technology, Chengdu, Sichuan, 610225, China

*Corresponding author. Tel.: +1 (905) 5259140; fax: +1 (905) 5727944. E-mail address: zoeli@mcmaster.ca (Z. Li).

Abstract


Influent flow rate is a crucial parameter closely related to the plant-wide control of wastewater treatment plants (WWTPs). In this study, a random forest (RF) model and a multi-layer perceptron (MLP) model are developed for hourly influent flow rate prediction at a confidential WWTP in Canada. Both models perform well on predicting influent flow rate one-step ahead. The coefficient of determination (R2) values of MLP and RF for the testing data set are 0.927 and 0.925, respectively. Furthermore, the multi-step ahead prediction accuracy of the proposed models is discussed. To improve the multi-step ahead prediction accuracy of the RF model, time-tag information is transformed to numerical values and then fed into the RF model as input. The R2 values of the RF model for the testing data set with and without time-tag information are 0.334 and 0.811, respectively. The results show that the RF model’s performance for multi- step ahead prediction is heavily affected by the time-tag information. Including time-tag information as input could dramatically improve the multi-step ahead prediction accuracy. In this study, the RF model shows more robust performance than the MLP model on solving short-term wastewater influent prediction problems. Influent flow rate is a crucial parameter closely related to the plant-wide control of wastewater treatment plants (WWTPs). In this study, a random forest (RF) model and a multi-layer perceptron (MLP) model are developed for hourly influent flow rate prediction at a confidential WWTP in Canada. Both models perform well on predicting influent flow rate one-step ahead. The coefficient of determination (R2) values of MLP and RF for the testing data set are 0.927 and 0.925, respectively. Furthermore, the multi-step ahead prediction accuracy of the proposed models is discussed. To improve the multi-step ahead prediction accuracy of the RF model, time-tag information is transformed to numerical values and then fed into the RF model as input. The R2 values of the RF model for the testing data set with and without time-tag information are 0.334 and 0.811, respectively. The results show that the RF model’s performance for multi-step ahead prediction is heavily affected by the time-tag information. Including time-tag information as input could dramatically improve the multi-step ahead prediction accuracy. In this study, the RF model shows more robust performance than the MLP model on solving short-term wastewater influent prediction problems.

Keywords: short-term prediction, multi-step ahead, hourly, influent flow, WWTPs


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