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Document type:
Article
Author(s):
Liebig, T; Wagner, M; Bjerrum, L; Denecke, M
Title:
Nitrification performance and nitrifier community composition of a chemostat and a membrane-assisted bioreactor for the nitrification of sludge reject water
Abstract:
Nitrification performance of a chemostat and a membrane-assisted bioreactor (MBR) was assessed at pilot scale for the treatment of sludge reject waters with NH4+-N concentrations up to 600 mg/L and low organic content (COD<200 mg/L). To prevent nitrifier washout the 1-m(3) chemostat was operated at 20degreesC with minimum hydraulic retention time of tau=2 days. At the 0.71 m(3) MBR, tau was successively reduced to 6.2 h. Complete sludge retention was achieved by means of a 2-m(2) 100,000-Dalton PES ultrafiltration membrane. Operation in crossflow mode with flow velocities from v(F)=2.4-3.7 m/s and transmembrane pressures Deltap=0.5-1.2 bar yielded a long-term permeate flux, of 110 L/(m(2)xh). In the MBR, nitrification rates up to 2,500 g N/(m(3)xd) were measured with biomass concentrations between 4 and 15 g TSS/L. Despite low TSS values, about 0.2 g/L of the chemostat was able to nitrify 180 g N/(m(3)xd). The microbial community composition differed considerably between the two reactors as determined by fluorescent in situ hybridisation (FISH) with rRNA-targeted oligonucleotide probes. For both reactors, the relative abundance of ammonia and nitrite oxidisers measured by FISH was consistent with results from dynamic simulation of the nitrification process.
Journal title abbreviation:
Bioprocess Biosyst Eng
Year:
2001
Journal volume:
24
Journal issue:
4
Pages contribution:
203-210
Language:
eng
Print-ISSN:
1615-7591
TUM Institution:
Fachgebiet Neuroradiologie (Prof. Zimmer)
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