COD balance and nitrogen removal in a biofilter pilot plant

Abstract

Biological nitrogen removal from wastewater depends on nitrogen incorporation and on denitrification. Both processes strongly depend on the degradation of COD. On the hand of operational data from a biofilter pilot plant, the relation between COD-removal and nitrogen removal is shown. Mass balances for the two parameters COD and N are the base of this consideration, as they are excellent tools for the evaluation of WWTPs (large scale plants as well as pilot plants) in order to estimate the fluxes of these substances and to draw conclusions of general validity. When applying the results from the pilot scale investigation to the whole treatment process (which includes sludge stabilisation), reject water must be taken into account. Therefore, the N removal efficiency was calculated both for the process with and without return liquor.

Optimization of a full‐scale site to achieve total nitrogen removal through implementation of a denitrification‐submerged anoxic filter

“…Others studies present significantly higher nitrate loading rates for higher strength wastewaters, between 4.3 and 5.7 kg NO 3 /m 3 day for high C:N ratio of 10, that is, with an average influent BOD of 414 mg/L (Nikolavcic et al . ) and critical nitrate loading rates of 9 kg NO 3 /m 3 day for C:N ratios between 3 and 3.9 using methanol dosing (Oh et al . ).…”

“…The maximum loading rate could not be determined in this study but others investigating predenitrification submerged filters recommend nitrate loading rates between 0.6 and 1.2 kg NO 3 /m 3 day (Pujol & Tarallo 2000), 1.9 kg NO 3 /m 3 day (Dee et al 1994) for feed wastewater with COD < 450 mg/L, similar to the study here presented. Others studies present significantly higher nitrate loading rates for higher strength wastewaters, between 4.3 and 5.7 kg NO 3 /m 3 day for high C:N ratio of 10, that is, with an average influent BOD of 414 mg/L (Nikolavcic et al 2000) and critical nitrate loading rates of 9 kg NO 3 /m 3 day for C:N ratios between 3 and 3.9 using methanol dosing (Oh et al 2001).…”

Biological Fixed Film Systems

“…Nitrification rates were lower in the biofilm airlift reactor. COD and N fluxes were used to evaluate pilot-and full-scale biofilter performance (Nikolavcic et al, 2000). Recycle rates were known to be important; N removal efficiencies were calculated for the process with and without recycle.…”