Presenter
Dr. Siyuan Song, PowerChina Huadong Engineering Corporation Limited
Co-author(s)
Dr. Sheng Sheng, PowerChina Huadong Engineering Corporation Limited
Mr. Jianqiang Xu, PowerChina Huadong Engineering Corporation Limited
Prof. Dehua Zhao, PowerChina Huadong Engineering Corporation Limited
Sub-theme
2. Promoting Water Efficiency, Productivity and Services
Topic
2-4. Wastewater treatment and reuse
Body
As an economic and environmentally friendly type of technology for wastewater treatment, constructed wetlands have developed rapidly worldwide in recent decades, especially in China, with increasing requirements for surface water environmental quality improvement. Currently，although some studies have shown the importance of high-frequency and continuous monitoring as well as the problems of sporadic sampling for constructed wetlands, only a few studies have evaluated the effect of the sampling frequency (SF) on the estimation accuracy of water quality or removal efficiency (RE) and the proper SF for full-scale CWs.Three years of hourly COD and NH4+-N measurements for two full-scale integrated constructed wetlands (CWs) treating secondary effluents from sewage treatment plants (STPs) were used to quantify the proper SF. The modified coefficient of variation (CVm) and average variation rate (VRa) were calculated to monitor the dynamics and annual average performance, respectively. It was found that (1) under CVm 5%, VRa 5%, and VRm 5%, the sampling intervals (SI) of COD can be set as 1.19 h, 526.5 h, and 110.1 h, respectively, and the SI of NH4+-N should be 4.51 h, 66.3 h, and 26.8 h, respectively; (2) under CVm 10%, VRa 10%, and VRm 10%, the monitoring intervals of COD can be set as 11.92 h, 1401.7 h, and 233.5 h, respectively, and the monitoring intervals of NH4+-N should be 30.73 h, 139.3 h, and 50.5 h, respectively. Therefore, to meet the need of monitoring the dynamic changes in data, hourly and 4 h SIs were recommended for COD and NH4+-N evaluation, respectively, when it is necessary to consider the operation and maintenance costs at the same time, 11 h and 30 h SIs were proper for COD and NH4+-N evaluation, respectively. The methods proposed in this study could provide reference to improve the management and evaluation level of full-scale constructed wetlands.