Bioaugmentation and anaerobic treatment of pharmaceutical effluent in fluidized bed reactor.
01 May 2001-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering (Taylor & Francis Group)-Vol. 36, Iss: 5, pp 779-791
TL;DR: The start-up of an anaerobic fluidized bed reactor was carried out using a single inoculum and later on with multiple inoculum to achieve a faster start- up and the effect of hydraulic retention time (HRT) on COD removal (%) and biogas production was studied.
Abstract: The start-up of an anaerobic fluidized bed reactor was carried out using a single inoculum (supernatant of anaerobic digester) and later on with multiple inoculum (a mixture of supernatant of anaerobic digester and volatile fatty acid (VFA)) to achieve a faster start-up. Then regular experiments were carried out to study the effect of hydraulic retention time (HRT) on COD removal (%) and biogas production. The pharmaceutical effluent with COD of 2000 to 4000 mg/L was treated in a fluidized bed reactor using an enricher-reactor concept with a hydraulic retention times of 3 (Uf = 6 Umf) to 24 (Uf = 1.5 Umf) hr. The maximum COD removal (%) of 91.2 and a maximum biogas production of 5.62 L/d were obtained at 24 hr HRT for a maximum COD concentration of 4000 mg/L corresponding to a fluidization velocity (Uf) of 20 m/hr (1.5 Umf) using a granular activated carbon bed of average size 700 microns.
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27 Oct 2017
TL;DR: FDMB could be developed as a standard inoculum for BMP analyses and to bioaugment anaerobic digesters for improved performance, and results may encourage developing customized, dried methanogenic biomass for specificanaerobic biotechnology applications.
Abstract: In this study, freeze dried methanogenic biomass (FDMB) was used as inoculum in place of conventional, non-dried biomass for biochemical methane potential (BMP) assays and as a bioaugment to improve upset digester recovery. Methanogenic biomass was freeze dried and stored in an air atmosphere. Significant methanogenic activity was preserved in FDMB even with drying and storage in air; specific methanogenic activity (SMA) values were 65 ± 4.5% and 42 ± 10.4% for hydrogen:carbon dioxide (H2:CO2) and acetate, respectively, compared to non-dried biomass. There was no significant difference in BMP results for the four substrates tested (glucose, non-fat dry milk, thin stillage and dog food) when using FDMB and non-dried biomass as inocula. However, BMP assays using FDMB inocula took longer to complete. Methane (CH4) production from digesters exposed to a model toxicant (oxygen [O2]) recovered faster when bioaugmented with FDMB compared to digesters that received autoclaved biomass or no bioaugmentation. Methanogen communities in all digesters before toxicant exposure and bioaugmentation were similar. However, bioaugmented and non-augmented digester communities were significantly different during the recovery phase after toxicant exposure. Sequences similar to Methanospirillum were related to improved performance of the FDMB bioaugmented digesters. FDMB could be developed as a standard inoculum for BMP analyses and to bioaugment anaerobic digesters for improved performance. These results may encourage developing customized, dried methanogenic biomass for specific anaerobic biotechnology applications.
4 citations
01 Jan 2017
TL;DR: This chapter is intended to give a compilation and overview of the various types of bioremediation measures currently being employed or investigated to remove the pharmaceutical pollutants.
Abstract: The astounding increase in the use of pharmaceuticals in the last decade has raised concerns over their occurrence in the soils and wastewaters posing potential dangers to the general public health and environment. Considering the limitations of chemical remediation measures in treatment of recalcitrant xenobiotics, several bioremediation measures are being currently investigated and proposed for removal of pharmaceutical contaminants from the environment. Several bacterial, fungal and plant species have shown promising bioremediation potential with regard to the removal of pharmaceuticals. Varying configurations of anaerobic and aerobic reactors have been utilized for pharmaceutical wastewater treatment. This chapter is intended to give a compilation and overview of the various types of bioremediation measures currently being employed or investigated to remove the pharmaceutical pollutants.
3 citations
01 Jan 2016
TL;DR: A quantitative structure activity relationship (QSAR) between anaerobic microorganism relative abundance values and digester methane production rate is developed and provides an initial step for further research to develop more robust QSAR models to predict the function of anaerobia and other bioprocesses using microbial community descriptors.
Abstract: BIOAUGMENTATION AND CORRELATING ANAEROBIC DIGESTER MICROBIAL COMMUNITY TO PROCESS FUNCTION Kaushik Venkiteshwaran Marquette University, 2016 This dissertation describes two research projects on anaerobic digestion (AD) that investigated the relationship between microbial community structure and digester function. Both archaeal and bacterial communities were characterized using highthroughput (Illumina) sequencing technology with universal 16S rRNA gene primers. In the first project, bioaugmentation using a methanogenic, aerotolerant propionate enrichment culture was investigated as a possible method to increase digester methane production. Nine anaerobic digesters, seeded with different biomass, were operated identically and their quasi steady state function was compared. Before bioaugmentation, different seed biomass resulted in different quasi steady state function, with digesters clustering into high, medium or low methane (CH4) production groups. High CH4 production correlated with neutral pH and high Methanosarcina abundance, whereas low CH4 production correlated to low pH and high Methanobacterium and DHVEG-6 family abundance. After bioaugmentation, CH4 production from the high CH4producing digesters transiently increased by 11±3% relative to non-bioaugmented controls (p <0.05, n=3), whereas no functional changes were observed for medium and low CH4 producing digesters. The CH4 production increase after bioaugmentation was correlated to increased relative abundance of Methanosaeta and Methanospirillum originating from the bioaugment culture. In conclusion, different anaerobic digester seed biomass can result in different quasi steady state function. The bioaugmentation employed can result in a period of increased methane production. In the second project, a quantitative structure activity relationship (QSAR) between anaerobic microorganism relative abundance values and digester methane production rate was developed using 150 lab-scale anaerobic digesters seeded with 50 biomass samples obtained from 49 US states. Although all digesters were operated identically for a minimum of 5 retention cycles, their quasi steady-state performance varied significantly, with the average daily methane production rate ranging from 0.09±0.004 to 0.98±0.05 L-CH4/LR-day (average ± standard deviation). Analysis of over 4.1 million-sequence reads revealed approximately 1300 operation taxonomical units (OTUs) at the genus level across all digesters, with each digester having 158±27 OTUs (mean ± standard deviation). Using Spearman’s rank correlation, 10 OTUs, which included one archaeal OTU, were found to correlate significantly to digester methane production rate. The relative abundance values of the 10 OTUs were used as descriptors to develop a multiple linear regression (MLR) equation, with good statistical prediction of the digester methane production rates. The results are encouraging and provide an initial step for further research to develop more robust QSAR models to predict the function of anaerobic and other bioprocesses using microbial community descriptors.
2 citations
01 Jan 2022
2 citations
Dissertation•
18 Jun 2012
TL;DR: In this paper, the authors evaluate the possibilite de mise en place une ingenierie ecologique des processus microbiens de la digestion anaerobie dans les bioprocedes, differents leviers environnementaux ont ete appliques a des digesteurs de cellulose.
Abstract: Dans le but d'evaluer la possibilite de mise en place une ingenierie ecologique des processus microbiens de la digestion anaerobie dans les bioprocedes, differents leviers environnementaux ont ete appliques a des digesteurs de cellulose. Le premier levier etudie, de nature physico-chimique, etait la temperature. Le deuxieme faisait appel a une adaptation prealable d'une biomasse complexe par incubation avec des molecules simples avant mise en presence de cellulose. Le dernier consistait en la co-inoculation de diverses biomasses exogenes avec une boue anaerobie. Les consequences des perturbations apportees par ces leviers sur les dynamiques metaboliques et ecologiques de bioreacteurs anaerobies degradant de la cellulose ont ete evaluees. Differents indicateurs physico-chimiques ont ete utilises pour caracteriser la degradation de la cellulose (production de molecules intermediaires, production de gaz, etc.). Les outils de la biologie moleculaire ont permis de caracteriser les dynamiques microbiennes a l'echelle des communautes (par fingerprinting ARISA) ou des individus (par pyrosequencage de l'ADNr 16S). L'utilisation d'isotopes stables (cellulose marquee 13C), a permis de realiser un tracage precis des flux de matieres (intermediaires de degradation de la cellulose enrichis en 13C) et des microorganismes impliques dans la chaine de degradation de la cellulose (groupes microbiens fonctionnels identifies par la technique de " stable isotope probing "). Les experiences de changements de temperature ont montrel'influence importante de ce parametre sur les communautes microbiennes, en particulier les archees. Elles ont mis en evidence le caractere asymetrique de l'effet de la temperature sur les communautes microbiennes et les consequences irreversibles du passage par les conditions thermophiles. Ces proprietes ouvrent des perspectives interessantes pour exploiter les chocs de temperature afin de modifier les proprietes de la biomasse. L'experience de fonctionnalisation de la biomasse a l'aide de quatre molecules simples (acide propionique, acide butyrique, glucose et cellobiose) montre qu'un modelage des populations microbiennes par preadaptation est possible. Une fois en contact avec la cellulose, les biomasses fonctionnalisees generent des schemas de degradation et des structures de communautes qui se repartissent de maniere inattendue en deux categories seulement. Ce resultat suggere qu'il est possible d'orienter les etats d'equilibre d'une communaute microbienne complexe par preadaptation fonctionnelle. Enfin, des experiences de co-inoculation ont mis en avant la difficulte d'exploiter directement les proprietes enzymatiques de flores cellulolytiques performantes mais egalement les possibilites de modifier les equilibres de diversite au sein de la biomasse du bioprocede. Ces experiences suggerent qu'un parametre tel que la diversite de la communaute d'un bioprocede pourrait etre manipule par bioaugmentation. Ce travail demontre que nous disposons d'ores et deja d'un certain nombre d'outils pour elaborer une ingenierie ecologique des bioprocedes a travers une nouvelle demarche de gestion qui se place a l'echelle de l'ecosysteme microbien et des services associes.
2 citations
Cites background from "Bioaugmentation and anaerobic treat..."
...Même si la bioaugmentation est définie au sens large comme l’apport de microorganismes spécifiques dans un système dans le but de favoriser un processus du procédé en général (328-330), la plupart des travaux concernant la bioaugmentation en conditions anaérobies trouvés dans la littérature l’utilisent dans des objectifs plus limités : par exemple améliorer le démarrage de nouveaux digesteurs (331-332), réduire les odeurs (238, 333), améliorer la dégradation d’une molécule (236-237) ou faciliter le retour à la normale après des perturbations dans le fonctionnement (234, 334)....
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References
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TL;DR: The metabolism of toluene, phenol, and p-cresol by GS-15 provides a model for how aromatic hydrocarbons and phenols may be oxidized with the reduction of Fe(III) in contaminated aquifers and petroleum-containing sediments.
Abstract: The dissimilatory Fe(III) reducer, GS-15, is the first microorganism known to couple the oxidation of aromatic compounds to the reduction of Fe(III) and the first example of a pure culture of any kind known to anaerobically oxidize an aromatic hydrocarbon, toluene. In this study, the metabolism of toluene, phenol, and p-cresol by GS-15 was investigated in more detail. GS-15 grew in an anaerobic medium with toluene as the sole electron donor and Fe(III) oxide as the electron acceptor. Growth coincided with Fe(III) reduction. [ring-14C]toluene was oxidized to 14CO2, and the stoichiometry of 14CO2 production and Fe(III) reduction indicated that GS-15 completely oxidized toluene to carbon dioxide with Fe(III) as the electron acceptor. Magnetite was the primary iron end product during toluene oxidation. Phenol and p-cresol were also completely oxidized to carbon dioxide with Fe(III) as the sole electron acceptor, and GS-15 could obtain energy to support growth by oxidizing either of these compounds as the sole electron donor. p-Hydroxybenzoate was a transitory extracellular intermediate of phenol and p-cresol metabolism but not of toluene metabolism. GS-15 oxidized potential aromatic intermediates in the oxidation of toluene (benzylalcohol and benzaldehyde) and p-cresol (p-hydroxybenzylalcohol and p-hydroxybenzaldehyde). The metabolism described here provides a model for how aromatic hydrocarbons and phenols may be oxidized with the reduction of Fe(III) in contaminated aquifers and petroleum-containing sediments. Images
463 citations
"Bioaugmentation and anaerobic treat..." refers methods in this paper
...Anaerobic degradation of different constituents of antibiotic and synthetic drug based effluents were recently been carried out, using methanogenic organisms [6–9], sulphate reducing organisms [7, 10–12], nitrate reducing organisms [13–14] and iron reducing organisms [15]....
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TL;DR: Preliminary evidence is presented that the first reaction in anaerobic phenol oxidation is phenol carboxylation to 4-hydroxybenzoate.
Abstract: From various oxic or anoxic habitats several strains of bacteria were isolated which in the absence of molecular oxygen oxidized phenol to CO2 with nitrate as the terminal electron acceptor. All strains grew in defined mineral salts medium; two of them were further characterized. The bacteria were facultatively anaerobic Gram-negative rods; metabolism was strictly oxidative with molecular oxygen, nitrate, or nitrite as electron acceptor. The isolates were tentatively identified as pseudomonads. Besides phenol many other benzene derivatives like cresols or aromatic acids were anaerobically oxidized in the presence of nitrate. While benzoate or 4-hydroxybenzoate was degraded both anaerobically and aerobically, phenol was oxidized under anaerobic conditions only. Reduced alicyclic compounds were not degraded. Preliminary evidence is presented that the first reaction in anaerobic phenol oxidation is phenol carboxylation to 4-hydroxybenzoate.
273 citations
TL;DR: The stoichiometry of sulfate-reduction and substrate depletion by the various enrichment cultures indicated that the parent cresol isomers were completely mineralized, which helps clarify the fate of alkylated aromatic chemicals in anoxic aquifers.
Abstract: Sulfate-reducing bacterial enrichments were obtained from a shallow anoxic aquifer for their ability to metabolize eithero-, m-, orp-cresol. GC/MS and simultaneous adaptation experiments suggested that the anaerobic decomposition ofp-cresol proceeds by the initial oxidation of the aryl methyl group to formp-hydroxybenzoic acid. This intermediate was then converted to benzoic acid. Benzoic acid and a hydroxybenzaldehyde were also found in spent culture fluids from ano-cresol-degrading enrichment culture. This result, in addition to others, suggested thato-cresol may also be anaerobically degraded by the oxidation of the methyl substituent. An alternate pathway for anaerobicm-cresol decomposition might exist. Enrichment cultures obtained with eitherp- oro-cresol degraded both of these substrates but notm-cresol. In contrast, am-cresol enrichment culture did not metabolize theortho orpara isomers. Anaerobic biodegradation in all enrichment cultures was inhibited by molybdate and oxygen, and was dependent on the presence of sulfate as a terminal electron acceptor. The stoichiometry of sulfate-reduction and substrate depletion by the various enrichment cultures indicated that the parent cresol isomers were completely mineralized. This result was confirmed by the conversion of14C-labeledp-cresol to14CO2. These results help clarify the fate of alkylated aromatic chemicals in anoxic aquifers.
54 citations
TL;DR: Results suggested that CO(2) incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas four molecules of acetate product contained a total of eight carbon atoms.
Abstract: The metabolism of m-cresol by methanogenic cultures enriched from domestic sewage sludge was investigated. In the initial studies, bromoethanesulfonic acid was used to inhibit methane production. This led to the accumulation of 4.0 ± 0.8 mol of acetate per mol of m-cresol metabolized. These results suggested that CO2 incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas four molecules of acetate product contained a total of eight carbon atoms. To verify this, [14C]bicarbonate was added to bromoethanesulfonic acid-inhibited cultures, and those cultures yielded [14C]acetate. Of the label recovered as acetate, 89% was found in the carboxyl position. Similar cultures fed [methyl-14C]m-cresol yielded methyl-labeled acetate. A 14C-labeled transient intermediate was detected in cultures given either m-cresol and [14C]bicarbonate or bicarbonate and [methyl-14C]m-cresol. The intermediate was identified as 4-hydroxy-2-methylbenzoic acid. In addition, another metabolite was detected and identified as 2-methylbenzoic acid. This compound appeared to be produced only sporadically, and it accumulated in the medium, suggesting that the dehydroxylation of 4-hydroxy-2-methylbenzoic acid led to an apparent dead-end product.
53 citations
TL;DR: In this article, anaerobic biodegradation of m-cresol was observed in anoxic aquifer slurries kept under both sulfate-reducing and nitrate reducing but not methanogenic conditions.
Abstract: The anaerobic biodegradation of m-cresol was observed in anoxic aquifer slurries kept under both sulfate-reducing and nitrate-reducing but not methanogenic conditions. More than 85% of the parent substrate (300 microM) was consumed in less than 6 days in slurries kept under the former two conditions. No appreciable loss of the compound from the corresponding autoclaved controls was measurable. A bacterial consortium was enriched from the slurries for its ability to metabolize m-cresol under sulfate-reducing conditions. Metabolism in this enrichment culture was inhibited in the presence of oxygen or molybdate (500 microM) and in the absence of sulfate but was unaffected by bromoethanesulfonic acid. The consortium consumed 3.63 mol of sulfate per mol of m-cresol degraded. This stoichiometry is about 87% of that theoretically expected and suggests that m-cresol was largely mineralized. Resting-cell experiments demonstrated that the degradation of m-cresol proceeded only in the presence of bicarbonate. 4-Hydroxy-2-methylbenzoic acid and acetate were detected as transient intermediates. Thus, the parent substrate was initially carboxylated as the primary degradative event. The sulfate-reducing consortium could also decarboxylate p- but not m-hydroxybenzoate to near stoichiometric amounts of phenol, but this reaction was not sulfate dependent. The presence of p-hydroxybenzoate in the medium temporarily inhibited m-cresol metabolism such that the former compound was metabolized prior to the latter and phenol was degraded in a sequential manner. These findings help clarify the fate of a common groundwater contaminant under sulfate-reducing conditions.
52 citations