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Titel:

Nitrification performance and nitrifier community composition of a chemostat and a membrane-assisted bioreactor for the nitrification of sludge reject water

Dokumenttyp:
Article
Autor(en):
Liebig, T; Wagner, M; Bjerrum, L; Denecke, M
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.
Zeitschriftentitel:
Bioprocess Biosyst Eng
Jahr:
2001
Band / Volume:
24
Heft / Issue:
4
Seitenangaben Beitrag:
203-210
Sprache:
eng
Print-ISSN:
1615-7591
TUM Einrichtung:
Fachgebiet Neuroradiologie (Prof. Zimmer)
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