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Batch treatment of liquid fraction of pig slurry by intermittent aeration: process simulation and microbial community analysis
Author(s) -
Magrí Albert,
Guivernau Miriam,
Baquerizo Guillermo,
Viñas Marc,
PrenafetaBoldú Francesc X,
Flotats Xavier
Publication year - 2009
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2158
Subject(s) - nitrobacter , aeration , denitrifying bacteria , nitrification , anoxic waters , pulp and paper industry , bioreactor , temperature gradient gel electrophoresis , nitrosomonas , microbial population biology , sequencing batch reactor , nitrifying bacteria , environmental chemistry , denitrification , nitrospira , bioprocess , wastewater , chemistry , environmental engineering , environmental science , biology , nitrogen , ecology , bacteria , paleontology , biochemistry , genetics , 16s ribosomal rna , organic chemistry , gene , engineering
BACKGROUND: Manure treatment in intensive livestock farming is required to reduce the risk of negative environmental impacts by nitrogen disposal. Biological removal through intermittent aeration in a single bioreactor is a suitable method for this purpose. The characteristic operation based on the alternation of oxic/anoxic phases confers these systems with certain particularities in terms of process modelling and of understanding the microbial interactions. RESULTS: The performance of a sequencing batch reactor (SBR) treating raw liquid fraction of pig slurry (LFPS) under loading rates of 0.13 g N L −1 d −1 was studied. Three different aeration strategies were applied: (1) constant airflow; (2) dissolved oxygen (DO) set‐point; and (3) DO‐based real‐time control. The comparatively low aeration intensity applied throughout the third strategy resulted in the process being performed mainly via nitrite, implying a reduction on the requirements of organic carbon and oxygen. However, a decrease in the nitrification rate was observed under those conditions. Experimental results were satisfactorily simulated by a mathematical model focused on organic carbon and nitrogen removal. Microbial community structure analysis through denaturing gradient gel electrophoretic profiling of 16S rDNA genes showed that the aeration exerted a strong influence on the dominant microbial populations. The presence of the ammonia‐oxidizing species Nitrosomonas europaea , and of denitrifying bacteria related to Thauera sp. and Ralstonia sp., was detected in the strategy at low DO. CONCLUSION: Dependence of model statement and parameter values on the bioreactor operational patterns and piggery wastewater composition was evidenced. Oxygen limitation was responsible for a significant microbial shift in SBR treating LFPS. Copyright © 2009 Society of Chemical Industry