The aim of this study was to evaluate the nitrogen transformations in horizontal and vertical flow
constructed wetlands (HFCW and VFCW), working in parallel and applied for dairy cattle wastewater
treatment. Both HFCW (26.50 m2 of surface area) and VFCW (14.30 m2 of surface area) were filled up with
sand (d10 of 0.3 mm and uniformity coefficient of 2.50) as bed media and planted with Typha domingensis
Pers. HFCW and VFCW worked with an influent flow rate of 3.98 m3 week1 and 4.50 m3 week1
,
respectively. Applying an average loading rate of 151.4 gCOD m2 week1
, 10.3 gTKN m2 week1 and
8.2 gNH4
+
-N m2 week1 in HFCW, it was possible to achieve 59% of TN and 58% of NH4
+
-N removals. In
VFCW an average loading rate of 317.2 gCOD m2 week1
, 21.6 gTKN m2 week1 and 13.7 gNH4
+
-N m2
week1 were applied and was obtained 23% of TN and 80% NH4
+
-N removals, where 73% of ammonia
removal was due to nitrification process. The macrophytes removed 5.1% and 0.88% of influent N loading
rate in HFCW and VFCW, respectively