Premium
Microalgal bacterial floc properties are improved by a balanced inorganic/organic carbon ratio
Author(s) -
Van Den Hende Sofie,
Vervaeren Han,
Saveyn Hans,
Maes Guy,
Boon Nico
Publication year - 2011
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.22985
Subject(s) - chemistry , photobioreactor , wastewater , bicarbonate , total inorganic carbon , carbon fibers , total organic carbon , sewage treatment , sucrose , nitrogen , settling , sequencing batch reactor , dissolved organic carbon , autotroph , environmental chemistry , biomass (ecology) , bioreactor , chemical oxygen demand , chromatography , carbon dioxide , environmental engineering , bacteria , food science , organic chemistry , materials science , biology , environmental science , ecology , genetics , composite number , composite material
Microalgal bacterial floc (MaB‐floc) reactors have been suggested as a more sustainable secondary wastewater treatment. We investigated whether MaB‐flocs could be used as tertiary treatment. Tertiary influent has a high inorganic/organic carbon ratio, depending on the efficiency of the secondary treatment. In this study, the effect of this inorganic/organic carbon ratio on the MaB‐flocs performance was determined, using three sequencing batch photobioreactors. The MaB‐flocs were fed with synthetic wastewater containing 84, 42, and 0 mg L −1 C‐KHCO 3 supplemented with 0, 42, 84 mg L −1 C‐sucrose, respectively, representing inorganic versus organic carbon. Bicarbonate significantly decreased the autotrophic index of the MaB‐flocs and resulted in poorly settling flocs. Moreover, sole bicarbonate addition led to a high pH of 9.5 and significant lower nitrogen removal efficiencies. Sucrose without bicarbonate resulted in good settling MaB‐flocs, high nitrogen removal efficiencies and neutral pH levels. Despite the lower chlorophyll a content of the biomass and the lower in situ oxygen concentration, 92–96% of the soluble COD‐sucrose was removed. This study shows that the inorganic/organic carbon ratio of the wastewater is of major importance and that organic carbon is requisite to guarantee a good performance of the MaB‐flocs for wastewater treatment. Biotechnol. Bioeng. 2011; 108:549–558. © 2010 Wiley Periodicals, Inc.