Modelling and evaluation of nitrogen removal performance in subsurface flow and free water surface constructed wetlands

Abstract

With the aim of protecting drinking water sources in rural regions, pilot-scale subsurface water flow (SSF) and free water surface flow (FWS) constructed wetland systems were evaluated for removal efficiencies of nitrogenous pollutants in tertiary stage treated wastewaters (effluent from the Pasaköy biological nutrient removal plant). Five different hydraulic application rates and emergent (Canna, Cyperus, Typhia sp., Phragmites sp., Juncus, Poaceae, Paspalum and Iris) and floating (Pistia, Salvina and Lemna) plant species were assayed. The average annual NH4-N, NO3-N and organic-N treatment efficiencies were 81, 40 and 74% in SSFs and 76, 59 and 75% in FWSs, respectively. Two types of the models (first-order plug flow and multiple regression) were tried to estimate the system performances. Nitrification, denitrification and ammonification rate constants (k20) values in SSF and FWS systems were 0.898 d-1 and 0.541 d(-1), 0.486 d(-1) and 0.502 d(-1), 0.986 d(-1) and 0.908, respectively. Results show that the first-order plug flow model clearly estimates slightly higher or lower values than observed when compared with the other model.

Study on nitrogen removal enhanced by shunt distributing wastewater in a constructed subsurface infiltration system under intermittent operation mode

“…NH 3 -N concentration in the effluent increased owing to the wastewater being directly introduced to the depth of 50 cm. This result suggested that shorter path of the sewage would result in the incomplete nitrification, which was in agreement of other studies [19,31]. Zhang et al [32] noted that NO 2 -N concentration in the effluent would be between 0.1 and 0.5 mg/L, thus indicating nitrification-denitrification process performed successfully in the subsurface infiltration system.…”

Post-treatment of UASB reactor effluent in waste stabilization ponds and in horizontal flow constructed wetlands: a comparative study in pilot scale in Southeast Brazil

“…Also, as noticed for BOD and TSS, CW5 did not provide any remarkable additional TKN removal (Figure 4). Removal coefficients (K NT20 ) were calculated (data not included) based on (Brix 1997;Kadlec 2004;Sousa et al 2004;Tunç siper et al 2006). In general, the CW showed 2 -4 log unit of E. coli reduction, producing effluents with 10 2 -10 4 E. coli per 100 mL (geometric means), however in a much less stable rate than the ponds ( Figure 5).…”

Modeling Subsurface Upflow Wetlands Systems for Wastewater Effluent Treatment

“…Kadlec and Knight (1996) had summarized the nitrogen removal equations of modeling the constructed wetland (Table 2). Tunçsiper et al (2006) simulated removal efficiencies of nitrogenous pollutants in SSF and FWS constructed wetland systems. Two types of the models (first-order plug flow and multiple regressions) were used to evaluate the system performances.…”