The effects of Cl on the removal efficiency werestudied at 819, 1500, 2000, 2500
and 3000 mg/L levels. As is seen in Fig. 6, An increase in the concentration of Cl
from 819 mg/L to 2500 mg/L yield an increase in the efficiency of COD removal from 29.8 to 38.9% and the NH3-N removal from 23.5 to 32.6%,
it does not change significantly after 2500mg/l. With the Cl
concentration increases, the passivation of the electrode
can be relief and the ability of electric conduction can beimprove[16]. During the coagulation process, the Cl
will
be discharged at the anode to generate Cl2, then the Cl2 can be chemically convert to ClO
which can oxidize the
pollutants effectively[17]. To take into account the cost, the optimum concentration of Cl
is 2000 to 2500 mg/L.