Exploring long-term retention and reactivation of micropollutant biodegradation capacity.

The factors limiting micropollutant biodegradation in the environment and how to stimulate this process have often been investigated. However, little information is available on the capacity of microbial communities to retain micropollutant biodegradation capacity in the absence of micropollutants or to reactivate micropollutant biodegradation in systems with fluctuating micropollutant concentrations. This study investigated how a period of 2 months without the addition of micropollutants and other organic carbon affected micropollutant biodegradation by a micropollutant-degrading microbial community.

Biostimulation with oxygen and electron donors supports micropollutant biodegradation in an experimentally simulated nitrate-reducing aquifer.

The availability of suitable electron donors and acceptors limits micropollutant natural attenuation in oligotrophic groundwater. This study investigated how electron donors with different biodegradability (humics, dextran, acetate, and ammonium), and different oxygen concentrations affect the biodegradation of 15 micropollutants (initial concentration of each micropollutant = 50 μg/L) in simulated nitrate reducing aquifers. Tests mimicking nitrate reducing field conditions showed no micropollutant biodegradation, even with electron donor amendment.

Effect of dissolved organic carbon on micropollutant biodegradation by aquifer and soil microbial communities.

Groundwater, a major source of drinking water worldwide, is often contaminated with micropollutants. Although microbial communities in aquifers and soils have the capability to biodegrade some micropollutants, this process is limited in situ. Biostimulation with dissolved organic carbon (DOC) is known to promote micropollutant biodegradation, but the role of DOC biodegradability is still poorly understood.

Influence of redox condition and inoculum on micropollutant biodegradation by soil and activated sludge communities.

Micropollutant biodegradation is selected by the interplay among environmental conditions and microbial community composition. This study investigated how different electron acceptors, and different inocula with varying microbial diversity, pre-exposed to distinct redox conditions and micropollutants, affect micropollutant biodegradation. Four tested inocula comprised of agricultural soil (Soil), sediment from a ditch in an agricultural field (Ditch), activated sludge from a municipal WWTP (Mun AS), and activated sludge from an industrial WWTP (Ind AS).

Micropollutant removal from black water and grey water sludge in a UASB-GAC reactor.

The effect of granular activated carbon (GAC) addition on the removal of diclofenac, ibuprofen, metoprolol, galaxolide and triclosan in a up-flow anaerobic sludge blanket (UASB) reactor was studied. Prior to the reactor studies, batch experiments indicated that addition of activated carbon to UASB sludge can decrease micropollutant concentrations in both liquid phase and sludge. In continuous experiments, two UASB reactors were operated for 260 days at an HRT of 20 days, using a mixture of source separated black water and sludge from aerobic grey water treatment as influent.

Biodegradation of persistent organics can overcome adsorption-desorption hysteresis in biological activated carbon systems.

In Biological Activated Carbon (BAC) systems, persistent organic pollutants can be removed through a combination of adsorption, desorption and biodegradation. These processes might be affected by the presence of other organics, especially by the more abundant easily-biodegradable organics, like acetate. In this research these relations are quantified for the removal of the persistent pharmaceutical metoprolol.

Anaerobic bioleaching of metals from waste activated sludge.

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents.

Growth of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a high-pressure membrane capsule bioreactor.

Communities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.

Kinetics modelling of Cu(II) biosorption on to coconut shell and Moringa oleifera seeds from tropical regions.

Adsorption kinetic studies are of great significance in evaluating the performance of a given adsorbent and gaining insight into the underlying mechanism. This work investigated the sorption kinetics of Cu(II) on to coconut shell and Moringa oleifera seeds using batch techniques. To understand the mechanisms of the biosorption process and the potential rate-controlling steps, kinetic models were used to fit the experimental data.

Enrichment of ANME-1 from Eckernförde Bay sediment on thiosulfate, methane and short-chain fatty acids.

The microorganisms involved in sulfate-dependent anaerobic oxidation of methane (AOM) have not yet been isolated. In an attempt to stimulate the growth of anaerobic methanotrophs and associated sulfate reducing bacteria (SRB), Eckernförde Bay sediment was incubated with different combinations of electron donors and acceptors. The organisms involved in AOM coupled to sulfate reduction (ANME-1, ANME-2, and Desulfosarcina/Desulfococcus) were monitored using specific primers and probes.

Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis.

Trace methane oxidation and the methane dependency of sulfate reduction in anaerobic granular sludge.

This study investigates the oxidation of labeled methane (CH(4)) and the CH(4) dependence of sulfate reduction in three types of anaerobic granular sludge. In all samples, (13)C-labeled CH(4) was anaerobically oxidized to (13)C-labeled CO(2), while net endogenous CH(4) production was observed. Labeled-CH(4) oxidation rates followed CH(4) production rates, and the presence of sulfate hampered both labeled-CH(4) oxidation and methanogenesis.

Effect of environmental conditions on sulfate reduction with methane as electron donor by an Eckemförde Bay enrichment.

Sulfate reduction (SR) coupled to anaerobic oxidation of methane (AOM) is meditated by marine microorganisms and forms an important process in the global sulfur and carbon cycle. In this research, the possibility to use this process for the removal and recovery of sulfur and metal compounds from waste streams was investigated. A membrane bioreactor was used to enrich for a community of methane-oxidizing sulfate-reducing microorganisms from Eckernförde Bay sediment The AOM and SR rate of the obtained enrichment were 1.

Microbial diversity and community structure of a highly active anaerobic methane-oxidizing sulfate-reducing enrichment.

Anaerobic oxidation of methane (AOM) is an important methane sink in the ocean but the microbes responsible for AOM are as yet resilient to cultivation. Here we describe the microbial analysis of an enrichment obtained in a novel submerged-membrane bioreactor system and capable of high-rate AOM (286 mumol g(dry weight)(-1) day(-1)) coupled to sulfate reduction. By constructing a clone library with subsequent sequencing and fluorescent in situ hybridization, we showed that the responsible methanotrophs belong to the ANME-2a subgroup of anaerobic methanotrophic archaea, and that sulfate reduction is most likely performed by sulfate-reducing bacteria commonly found in association with other ANME-related archaea in marine sediments.

Enrichment of anaerobic methanotrophs in sulfate-reducing membrane bioreactors.

Anaerobic oxidation of methane (AOM) in marine sediments is coupled to sulfate reduction (SR). AOM is mediated by distinct groups of archaea, called anaerobic methanotrophs (ANME). ANME co-exist with sulfate-reducing bacteria, which are also involved in AOM coupled SR.

Desulfovibrio paquesii sp. nov., a hydrogenotrophic sulfate-reducing bacterium isolated from a synthesis-gas-fed bioreactor treating zinc- and sulfate-rich wastewater.

A hydrogenotrophic, sulfate-reducing bacterium, designated strain SB1(T), was isolated from sulfidogenic sludge of a full-scale synthesis-gas-fed bioreactor used to remediate wastewater from a zinc smelter. Strain SB1(T) was found to be an abundant micro-organism in the sludge at the time of isolation. Hydrogen, formate, pyruvate, lactate, malate, fumarate, succinate, ethanol and glycerol served as electron donors for sulfate reduction.

Sulfur formation and recovery in a thiosulfate-oxidizing bioreactor.

This work describes the design and performance of a thiosulfate-oxidizing bioreactor that allowed high elemental sulfur production and recovery efficiency. The reactor system, referred to as a Supernatant-Recycling Settler Bioreactor (SRSB), consisted of a cylindrical upflow reactor and a separate aeration vessel. The reactor was equipped with an internal settler and packing material (structured corrugated PVC sheets) to facilitate both cell retention and the settling of the formed elemental sulfur.

Effect of carbon monoxide, hydrogen and sulfate on thermophilic (55 degrees C) hydrogenogenic carbon monoxide conversion in two anaerobic bioreactor sludges.

The conversion routes of carbon monoxide (CO) at 55 degrees C by full-scale grown anaerobic sludges treating paper mill and distillery wastewater were elucidated. Inhibition experiments with 2-bromoethanesulfonate (BES) and vancomycin showed that CO conversion was performed by a hydrogenogenic population and that its products, i.e.