What Is the Suitable Sampling Frequency for Water Quality Monitoring in Full-Scale Constructed Wetlands Treating Tail Water?

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 sampling frequency (SF). The modified coefficient variation (CVm) average rate (VRa) calculated monitor dynamics annual performance, respectively. It was found that (1) under CVm 5%, VRa VRm intervals (SI) can be set as 1.19 h, 526.5 110.1 respectively, SI should 4.51 66.3 26.8 respectively; (2) 10%, monitoring 11.92 1401.7 233.5 30.73 139.3 50.5 Therefore, meet need dynamic changes in data, 4 h SIs recommended evaluation, when it is necessary consider operation maintenance costs at same time, 11 30 methods proposed this study could provide reference improve management evaluation level CWs.