Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 9 3 2023 09 01 Effect of influent load fluctuation on the efficiency of vertical constructed wetlands treating dairy farm wastewater 227 241 1307 10.22104/aet.2023.6224.1716 EN Pradeep Kumar Sharma Department of Environmental Science, Graphic Era (Deemed to be) University, Dehradun, Uttarakhand, India Anju Rani Department of Microbiology, Graphic Era (Deemed to be) University, Dehradun, Uttarakhand, India Deepa Minakshi Department of Environmental Science, Graphic Era (Deemed to be) University, Dehradun, Uttarakhand, India Piyush Malaviya Department of Environmental Science, University of Jammu, Jammu and Kashmir, India Journal Article 2023 04 18 Three vertical sub-surface flow (VSSF) constructed wetland (CW) systems (CW-1, CW-2 and CW-3) filled with different filter media, each 4 m2 in area, planted with Arundo donax was operated for 4 years for treating dairy farm wastewater. The vertical CW systems received high fluctuations in influent concentration and loads i.e. BOD (26 to 619 mg L-1 and 1.5 to 34 g m-2 d-1), TSS (165 to 643 mg L-1 and 9.1 to 24 g m-2 d-1), TP (16 to 49.9 mg L-1 and 1.2 to 2.7 g m-2 d-1) and NH4-N (24.5 to 76.2 mg L-1 and 1.3 to 4.2 g m-2 d-1) during the assessment period. Average annual removal rates showed fluctuations in removal of BOD (70.5 to 92.9%), TSS (82.5 to 97.5%), TP (51.1 to 91.9%) and NH4-N (34.6 to 69%). This shows that the removal of BOD is very sensitive to inlet load fluctuations in CWs. High inlet loads may confine good nitrification that affects ammonium-nitrogen removal while TP removal rate reduced when inlet TP loads reduced. The average concentration of the pollutants (BOD, TSS, TP and NH4-N) in the treated effluent showed noticeable decrease: 43.4 to 16.1 mg L-1 for BOD; 43.3 to 11.7 mg L-1 for TSS; 17.9 to 3.1 mg L-1 for TP and 33.2 to 22.7 mg L-1 for NH4-N. Thus from the outcomes of the current study, it can be concluded that the VSSF CW system may provide promising outcomes despite there is fluctuations in the influent loads. https://aet.irost.ir/article_1307_fdaa7796273fcc66a251168c7f2c2ccb.pdf