Abstract
Denitrification of nitrified wastewater was investigated by using a bioelectro reactor which consisted of immobilized denitrifying bacteria electrode as cathode and carbon electrode as anode.
Experiments were performed to investigate the effects of electric current, influent nitrate concentration, HRT and ORP on the denitrification rate, nitrite production and hydrogen utilization.
The denitrification rate and hydrogen utilization were varied with mol ratio (λ) of hydrogen and nitrate which were supplied to the bio-electro reactor, and those muximum values were observed at λ=1.4. Nitrate remained under λ=1.4 in the effluent, and residual hydrogen occurred upper λ=1.4.
The nitrite production was not effected by change of λ value and ORP and DO have to control in the proper values because nitrite production was enhanced in the higher value ranges of ORP and DO.
