Perturbation‐independent community development in low‐temperature anaerobic biological wastewater treatment bioreactors

Abstract

The reproducibility and stability of low- temperature anaerobic wastewater treatment systems undergoing transient perturbations was investigated. Three identical anaerobic expanded granular sludge bed-based bioreactors were used to degrade a volatile fatty acid and glucose-based wastewater under sub-ambient (15 degrees C) conditions. The effect of a variety of environmental perturbations on bioreactor performance was assessed by chemical oxygen demand removal. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes extracted from sludge granules. Methanogenic activity was monitored using specific methanogenic activity assays. Bioreactor performance and microbial population dynamics were each well replicated between both experimental bioreactors and the control bioreactor prior to, and after the implementation of most of the applied perturbations. Gene fingerprinting data indicated that Methanosaeta sp. were the persistent, keystone members of the archaeal community, and likely were pivotal for the physical stability and maintenance of the granular biofilms. Cluster analyses of DGGE data suggested that temporal shifts in microbial community structure were predominantly independent of the applied perturbations.

Removal of residual dissolved methane gas in an upflow anaerobic sludge blanket reactor treating low-strength wastewater at low temperature with degassing membrane

“…If anaerobic wastewater treatment without heating the reactors can be applied to low-strength wastewater, the cost of anaerobic wastewater treatment can be reduced, thereby making this technology an attractive option for the treatment of a variety of wastewater categories. Improvements in reactor design and operational conditions have helped overcome many of the disadvantages of anaerobic wastewater treatment that limited its application to high-strength wastewater treatment at mesophilic or thermophilic temperatures and have allowed for successful operation of anaerobic wastewater treatment reactors at low temperatures (Dhaked et al, 2010;Lettinga et al, 1999;Lettinga et al, 2001;Trzcinski and Stuckey 2010;Luostarinen and Rintala 2005;Madden et al, 2010;Xing et al, 2009;McKeown et al, 2009). In addition, several studies have focused on anaerobic wastewater treatment of low-strength wastewaters at lower temperatures (Elmitwalli et al, 2003;Angenent et al, 2001;Gomec et al, 2008;Matsushige et al, 1990).…”

Effect of sulfate on low-temperature anaerobic digestion

“…16S rRNA gene fragments were amplified using the Archaea -specific primer set A751F and UA1204R (Baker et al, 2003), and the Bacteria -specific primer set EB341F and UN517R (Muyzer et al, 1993). PCR-amplification of the archaeal and bacterial 16S rRNA genes was performed as described in detail by Madden et al (2010). Dissimilatory sulfite reductase ß-subunit (dsrB) gene fragments were amplified using dsrB-specific primers DSRp2060F (Geets et al, 2006) and DSR4R (Wagner et al, 1998) to yield a dsrB gene fragment of ~350 bp.…”

“…Polyacrylamide gels (8% [w/v]; thickness, 1 mm) with a denaturing gradient consisting of 30–60% urea-formamide for archaeal and dsrB samples, or 30–70% urea-formamide for bacterial samples, were used. DGGE was performed, and bands were excised and re-amplified, as described in detail by Madden et al (2010). PCR amplicons from excised bands were sequenced by MWG (UK) using Sanger sequencing technology.…”

“…Gene sequences from this study were deposited in Genbank under accession numbers FJ535442-FJ535447 for Archaea , FJ535448-FJ535456 for Bacteria and FJ535457-FJ535466 for dsrB genes (Table 2), with the following nomenclature and generic prefixes: ARC-PM1, ARC-PM2 and ARC-PM4 to ARC-PM7 for archaeal sequences; B1-PM to B6-PM and B10-PM to B12-PM for bacterial sequences; and SRB1-PM to SRB-PM10 for dsrB sequences (Table 2). DGGE data were analyzed as described by Madden et al (2010). …”

Anaerobic Membrane Reactors

“…Furthermore, longterm, low-temperature bioreactor operation may act as a selective enrichment for psychrophilic methanogenic activity from mesophilic inocula. Madden et al (2010) investigated the stability of low-temperature UASBs undergoing transient perturbations using COD removal, while microbial ecology was monitored using DGGE. Gene fingerprinting data indicated that Methanosaeta sp.…”