Premium
High‐rate volatile fatty acid (VFA) production by a granular sludge process at low pH
Author(s) -
Tamis J.,
Joosse B.M.,
Loosdrecht M.C.M.van,
Kleerebezem R.
Publication year - 2015
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.25640
Subject(s) - effluent , chemistry , sequencing batch reactor , chemical oxygen demand , volatile suspended solids , bioreactor , pulp and paper industry , chromatography , yield (engineering) , anaerobic digestion , settling , granulation , wastewater , waste management , methane , organic chemistry , environmental engineering , materials science , engineering , metallurgy , composite material
Volatile fatty acids (VFA) are proposed platform molecules for the production of basic chemicals and polymers from organic waste streams. In this study we developed a granular sludge process to produce VFA at high rate, yield and purity while minimizing potential operational costs. A lab‐scale anaerobic sequencing batch reactor (ASBR) was fed with 10 g l −1 glucose as model substrate. Inclusion of a short (2 min) settling phase before effluent discharge enabled effective granulation and very high volumetric conversion rates of 150–300 gCOD l −1 d −1 were observed during glucose conversion. The product spectrum remained similar at the tested pH range with acetate and butyrate as the main products, and a total VFA yield of 60–70% on chemical oxygen demand (COD) basis. The requirement for base addition for pH regulation could be reduced from 1.1 to 0.6 mol OH − (mol glucose) −1 by lowering the pH from 5.5 to 4.5. Solids concentrations in the effluent were 0.6 ± 0.3 g l −1 but could be reduced to 0.02 ± 0.01 g l −1 by introduction of an additional settling period of 5 min. The efficient production of VFA at low pH with a virtually solid‐free effluent increases the economic feasibility of waste‐based chemicals and polymer production. Biotechnol. Bioeng. 2015;112: 2248–2255. © 2015 Wiley Periodicals, Inc.