The effect of alternating influent carbon source composition on activated sludge bioflocculation

Abstract

which has been archived on the university repository Lirias (https://lirias.kuleuven.be/) of the Katholieke Universiteit Leuven.The content is identical to the content of the published paper, but without the final typesetting by the publisher.When referring to this work, please cite the full bibliographic info:Van Dierdonck, J., Van den Broeck, R., Vervoort, E., Van Impe, J., Smets, I. (2013). Effect of alternating influent carbon source composition on activated sludge bioflocculation. Journal of Biotechnology, 167 (3),[225][226][227][228][229][230][231][232][233][234] The journal and the original published paper can be found at: http://www.journals.elsevier.com/journal-of-biotechnology http://dx.doi.org/10.1016/j.jbiotec.2013.07.012 The corresponding author can be contacted for additional info.Conditions for open access are available at: http://www.sherpa.ac.uk/romeo/ Postprint version of paper published in Journal of Biotechnology 2013, vol. 167, issue 3, p. 225--234. The content is identical to the published paper, but without the final typesetting by the publisher. AbstractThe impact of alternating influent carbon sources, i.e., glucose and starch, on activated sludge bioflocculation was investigated. To this end, four lab-scale reactors were operated during a long-term experiment. During this period the influent carbon source ratio (glucose/starch) was alternated every 7 or 35 days (i.e., a fast and slow switching frequency). Bioflocculation was monitored throughout the entire experiment using an extensive set of parameters, including macroscopic and microscopic activated sludge characteristics. Sludge hydrophobicity remained high (> 80%) throughout the experiment indicating good bioflocculation. However, sludge settleability decreased for all four reactors after a 60 day adaptation period to the applied alternation in influent carbon source. During this adaptation period, floc size decreased due to the release of microcolonies. The subsequent period was characterized by a decrease in settleability, coinciding with a release of primary particles and an increase in floc size. The observed phenomena could be linked with the protein concentration near the floc surface. This fraction mainly consists of hydrolytic enzymes necessary for the degradation of starch and is responsible for a progressive deterioration of the EPS matrix. The results of this specific study indicate to be independent of the influent carbon source ratio or switching frequency.

Organic substrate transformation and sludge characteristics in the integrated anaerobic anoxic oxic–biological contact oxidation (A2/O–BCO) system treating wastewater with low carbon/nitrogen ratio

“…Sludge settleability of activated sludge is greatly related to the EPS properties [47]. Although EPS is essential to sludge floc formation, excessive EPS will weaken cell attachment and deteriorate floc structure, resulting in poor solid-liquid separation [48].The main components of proteins (PN) and polysaccharides (PS) contents in the three processes were contrasted where DNA content was ignored due to small quantity (Fig.…”

Bioindication assessment of activated sludge Adaptation in a Lab-Scale Experiment

“…A majority of papers published on this subject deal with activated sludge adaptation to the influence of various toxic substances. In a number of papers, the aspects of adaptation of activated sludge microorganisms to the effect of phenol [6,7], high concentrations of ammonium [8], organic solids accumulated in the system [9], toxic organic micro-pollutants [10], bisphenol-A [11] and other [12][13][14][15][16] are examined. In the work of Bajenov and Kanunnikova [17], adaptation of activated sludge to low oxygen concentrations was also studied.…”

Filamentous and non-filamentous bulking of activated sludge encountered under nutrients limitation or deficiency conditions

“…Sludge settleability of activated sludge is greatly related to its EPS properties [32,33]. 271 Therefore, the main components of EPS including carbohydrates, proteins and DNA 272 were quantified in order to identify any correlation between SVI and the amount and 273 composition of EPS ( Figure 5 and Table S3).…”