The high standards of drinking water are very important in drinking water treatment plants (DWTPs). The presence of visible aquatic invertebrates as suspended pollutants in the DWTPs can affect human health and decrease consumer confidence and psychological discomfort. The occurrence and mass development of chironomids in the clarifier parts is a critical issue in DWTP of Sanandaj city (capital of Kurdistan province in Iran). Therefore, during the research, the chironomid communities and their biology were monitored in the DWTP. Six SLAM malaise traps were established to monitor and assess the presence and peak emergence of chironomid adults in the clarifier parts of the DWTP from early spring to mid-autumn in 2019. The traps were visited every week, and the trapped chironomid individuals were collected. The collected adults were sorted and determined in the laboratory. A total of 3626 chironomid individuals were collected. The only detected species also was Chironomus riparius (Meigen, 1804). The results of the assessment of the species emergence also showed that the species was multivoltine. Three generations were observed in the DWTP annually, so the first adults were trapped on June 21st, and the flight peaks took place on July 29th and October 7th, respectively; finally, the last adults were trapped on October 27th. The occurrence of three generations per year demonstrated the very high reproduction potential of C. riparius in the DWTP. The study helps to make a more accurate assessment of C. riparius in the DWTP and improves our ability to manage it to support the supply of clean drinking water
