Study of Constructed Wetland Configurations for Wastewater Treatment

Abstract

Improving the removal efficiency of organic matter and nitrogen from constructed newlinewetland (CW) is very important in today s world. In this research work wastewater newlinewas treated by using four different constructed wetland models planted with Typha sp. newlineTreatment performance of CW was judged based on the removal efficiency for newlinebiochemical oxygen demand (BOD5), chemical oxygen demand (COD), total newlinesuspended solids (TSS), Ammonium-Nitrogen (NH4-N), Nitrate Nitrogen (NO3-N), newlineNitrite Nitrogen (NO2-N) and total nitrogen (TN). newlineFirst model was a modified approach of recirculated horizontal subsurface flow newlineconstructed wetland (CW), is studied for three different filter media packing namely newlineincreased size filter (ISF), decreased size filter (DSF) and uniformed size filter (USF) newlinemedia packing. The pathway of main CW reactor was increased from 1 m to 5 m by newlineproviding a baffle wall in it. The sample was monitored after 24 hours, 48 hours and newline72 hours from feeding. Recirculation of wastewater provided in three modes i.e. I-C-I, newlineC-I-C and C mode (I idle phase, C continuous recirculation phase). Results newlineindicated average removal efficiency for the entire system of 89.09% for BOD5, newline84.88% for COD, 89.50% for TSS, 97.58% for NH4-N, 94.54% for NO3-N, 66.99% newlinefor NO2-N and 96.16% for TN. I-C-I mode has given more removal efficiency for newlineUSF media packing, only NO2-N is removed in maximum level by USF media newlinepacking of I-C-I mode. This model shows that the partial recirculation of wastewater newlineand use of uniform filter media size of 4-5 mm (and#981; - effective diameter) is effective for newlinethe removal of organic matter, solids and nitrogen. newlineThe second model was two stage tidal flow constructed wetland (TSTFCW), with newlinethree different ratios for Hydraulic Retention Time (HRT) 1:1, 1:2 and 1:3 in Phase-I newlineand 1:1, 2:1 and 3:1 in Phase-II, is used to treat domestic wastewater. It was newlinedemonstrated that the maximum removal efficiencies of BOD5, COD, TSS, NH4-N, newlineNO2-N and TN were 46.09 %, 46.05 %, 77.25 %, 86.40 %, 50.47 % and 82.38 % newlinerespectively in Phase-