Evaluating and modelling the kinetics in a full scale submerged denitrification filter

Abstract

Experimental data in forms of vertical concentration profiles has been provided from a full scale submerged denitrification filter with biocarbone as filter material. Denitrification rates were determined in full scale under different loads of nitrate and methanol with methanol in excess. Vertical concentration profiles of nitrate and methanol have verified kinetics in the half-order region with removal rate constants in the range of k0.5A = 0.13-0.21 g N0.5 m−0.5 d−1 (0.5 order for partial penetration in the 0 order intrinsic concentration range). The removal rates found are low with methanol as carbon source as compared to information from literature. The experience with detailed mathematical modelling is that “best fit” can be achieved by different sets of parameters with the computer program AQUASIM. Full scale experiments have to be supplemented with dedicated laboratory scale experiments to determine all important parameters.

Impact of varying electron donors on the molecular microbial ecology and biokinetics of methylotrophic denitrifying bacteria

“…Consequently, full-scale implementation of heterotrophic denitrification is still guided by a somewhat empirical understanding of its microbial ecology and biokinetics, which in turn limits efforts to optimize denitrification reactor design, monitoring and modeling. Although biokinetic parameters for methylotrophic denitrification in activated sludge have been extensively reported (dos Santos et al, 2004;Gauntlett, 1979;Her and Huang, 1995;Janning et al, 1995;Lee and Welander, 1996;Louzeiro et al, 2002;Mulcahy et al, 1981;Purtschert and Gujer, 1999), the actual abundance and diversity of organisms in activated sludge that actually metabolize methanol and alternate carbon and electron sources has only recently been identified (Ginige et al, 2004(Ginige et al, , 2005Osaka et al, 2006Osaka et al, , 2008. The reason for such sparse data on the identity of bacterial populations denitrifying using specific electron donors is that unlike nitrifying bacteria, which are phylogenetically closely related (Purkhold et al, 2000), denitrifying bacteria are distributed widely across taxonomic groups (Zumft, 1997).…”

Factors Affecting the Design and Operation of Biologically Active Filters

“…Zero-order heterogeneous reactions in a pore that is only partially penetrated by the substrate result in half-order reaction kinetics for nitrate concentration. Half-order reaction kinetics result in the following expressions for a plug flow reactor (Harremoes, 1976;Hultman et al, 1994): Profile sampling conducted at different media depths by Harremoes (1976), Hultman et al (1994), and Janning et al (1995) have shown the half-order kinetic model reasonably correlates to observed values. Half order kinetic constants of 0.25 to 0.9 for temperatures ranging form 6 to 19 0C were reported by Harremoes (1976).…”

Tertiary Denitrification of the Secondary Effluent by Denitrifying Biofilters Packed with Different Sizes of Quartz Sand

“…Wastewater flow along the biofilter depth could be considered as a plug flow, and denitrification could be described with a half-order reaction as follows [27]. [28] found that the half-order coefficient increased with increasing the initial nitrate concentrations. This might be one of the reasons responsible for the increased half-order coefficient at the EBRT of 7.5 min in DNBF S , where the initial nitrate concentration was relatively high.…”