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Effects of Air Diffusion Turbulent Flow on Nitrification Rate in Fixed‐Film Biofilters: A Comparison Study
Author(s) -
Zhu Songming,
Chen Shulin
Publication year - 2003
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1577/c02-015
Subject(s) - nitrification , biofilter , filtration (mathematics) , environmental engineering , diffusion , mass transfer , recirculating aquaculture system , turbulence , volumetric flow rate , pulp and paper industry , ammonia , environmental science , materials science , nitrogen , aquaculture , biology , chemistry , mechanics , chromatography , mathematics , thermodynamics , physics , engineering , fish <actinopterygii> , fishery , biochemistry , statistics , organic chemistry
The total ammonia nitrogen (TAN) concentration is often a key limiting water quality parameter in intensive aquaculture systems. Removing TAN through biological filtration is a major objective in the design of recirculating aquaculture systems. In this study, the effect of turbulent flow on nitrification rate was investigated using a reactor series system to improve nitrification efficiency by enhancing nutrient mass transfer. Nitrification performance of fixed‐film biofilters was compared between the system with the diffusers placed inside the reactors (D‐in) and that with the diffusers outside the reactors (D‐out). The results indicated that the turbulence caused by diffused air had a substantial impact on the nitrification rate in the biofilters. When TAN concentration was not limited, the TAN removal rate in D‐out reactors was 269 ± 58 mg/(m 2 · d), only about 15% of that in the D‐in reactors. These results suggest that increasing flow turbulence through air diffusion could be an effective way to improve the nitrification efficiency of fixed‐film biofilters.