Cc. Tseng et al., EFFECT OF INFLUENT CHEMICAL OXYGEN-DEMAND TO NITROGEN RATIO ON A PARTIAL NITRIFICATION COMPLETE DENITRIFICATION PROCESS, Water research, 32(1), 1998, pp. 165-173
A novel single-sludge process for achieving partial nitrification and
complete denitrification (the PN/CD process) was tested at the bench-s
cale over a range of influent ratios of chemical oxygen demand (GOD) t
o total Kjeldahl nitrogen (TKN). Mean ammonia nitrogen concentrations
in PN/CD process effluent varied from 6.5 to 8.4 mg/liter at influent
COD/TKN ratios varying from 3.7 to 9.8. Ammonia nitrogen concentration
s in the influent wastewater had little effect on effluent ammonia lev
els. Bleed-through of COD to the effluent was not observed at influent
filterable COD/ammonia-N ratios between 2 and 11. Denitrification was
nearly complete (mean effluent nitrate plus nitrite N less than or eq
ual to 1.4 mg/liter) at influent COD/TKN ratios of 5.3 or greater, whe
reas nitrate and nitrite accumulation occurred at ratios less than 5.1
. The denitrification performance of the pre-anoxic reactor of the PN/
CD process was consistent with that of other pre-denitrification proce
sses when compared in terms of relative input rates of COD and oxidize
d nitrogen. (C) 1998 Elsevier Science Ltd. All rights reserved.