Fig 2(a)

Fig 2(b)

Fig 2(c)

Fig. 2(a), Fig.2(b), Fig.2(c) : Nitrite removal by the reactors under varying substrate concentrations (a =2 ppm, b = 5 ppm, c = 10 ppm). R1 to R6 refer to the six reactors that constitute the PBBR.

Fig. 3. Volumetric TAN removal rates by the reactor with flow rate.

The maximum volumetric TAN removal was obtained at its maximum turn over of 2500L/hr was 18 g NH4+-N per day with a HRT of 48 seconds.