ORCID Profile
0000-0003-0025-3537
Current Organisation
University of Technology Sydney
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Publisher: Elsevier
Date: 2022
Publisher: Springer International Publishing
Date: 2020
DOI: 10.1007/698_2020_550
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 06-2022
DOI: 10.1016/J.JHAZMAT.2022.128688
Abstract: The presence of micropollutants in water, wastewater and soil are a global problem due to their persistent effect on ecosystems and human health. Although there are many methods of removal of environmental pollutants, they are often ineffective for degradation of pharmaceuticals, including estrogens. In presented work we proposed fabrication of electrospun material from polyacrylonitrile olyethersulfone (PAN/PES) as a support for laccase immobilization by covalent binding. Oxidoreductase was attached to the electrospun fibers using polydopamine as a linker and produced system was used for degradation of two estrogens: 17β-estradiol (E2) and 17α-ethynylestradiol (EE2). It was shown that 92% of E2 and 100% of EE2 were degraded after 24 h of the process. Moreover, the effect of surfactants, metal ions and mediators on conversion efficiencies of estrogens was investigated and it was confirmed that immobilized enzyme possessed higher resistance to inhibitory agents as well as thermal and storage stability, compared to its native form. Finally, estrogenic activities of E2 and EE2 solutions decreased around 99% and 87%, respectively, after enzymatic conversion, that corresponds to significant reduction of the total organic carbon and formation of low-toxic final products of estrogens degradation.
Publisher: Elsevier BV
Date: 04-2022
Publisher: Informa UK Limited
Date: 14-12-2017
Publisher: MDPI AG
Date: 31-10-2020
DOI: 10.3390/MATH8111904
Abstract: The implied volatility index is a forward-looking indicator of fear among stock market participants. We examine the extent to which the connectedness of fear among global stock markets is driven by the cross-country connectedness of economic policy uncertainty (EPU). We use data on stock market fear and EPU indices for 13 countries, which spans from January 2011 to December 2018. To measure the connectedness among stock market fear and EPU of our s le countries, we employ two connectedness models. A cross-sectional regression model is further employed to ascertain the extent to which EPU connectedness between two countries explains the connectedness of fear between their stock markets, while controlling for bilateral linkage and country-specific factors. We find that EPU connectedness between any two partner countries significantly drives the connectedness of fear between their stock markets. The driving potential not only holds for short- and long-term connectedness, but also after controlling for bilateral linkages (bilateral trade, geographical distance, common language) and country-specific (trade and financial openness of the transmitter country) factors indicating robustness in our results.
Publisher: Springer International Publishing
Date: 2016
DOI: 10.1007/698_2014_318
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.JENVMAN.2019.02.043
Abstract: Chlorhexidine (CHX) is a broad-spectrum antimicrobial, which may pose environmental health risks. This study examined the removal potential and the mechanisms regulating the fate of CHX in activated sludge (AS). Bioreactors inoculated with AS removed 74 ± 8% and 81 ± 6% of CHX at steady state while receiving 0.5 and 1 mg/L CHX, respectively. Analysis of the removal pathways showed that biosorption, rather than biological breakdown or other abiotic losses, largely (>70%) regulated the removal of CHX. 16S rRNA gene-based analysis revealed that CHX selected for Luteolibacter (4.3-10.1-fold change) and Runella (6.2-14.1-fold change) with potential multi-drug resistance mechanisms (e.g., efflux pumps). In contrast, it significantly reduced core members (Comamonadaceae and Flavobacteriaceae) of AS, playing a key role in contaminant removal and floc formation directly associated with the performance of WWTPs (e.g., wastewater effluent quality). Antimicrobial susceptibility testing showed that 0.4-1.3 mg/L of CHX can be sublethal to AS. Our work provided new insights into the fate of CHX in urban waste streams and the potential toxicity and effects on the structure and function of AS, which has practical implications for the management of biological WWTPs treating CHX.
Publisher: IWA Publishing
Date: 15-07-2022
Publisher: Springer Science and Business Media LLC
Date: 07-07-2020
Publisher: Springer Science and Business Media LLC
Date: 27-03-2020
Publisher: Elsevier
Date: 2020
Publisher: Elsevier BV
Date: 12-2022
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.CHEMOSPHERE.2018.08.004
Abstract: Ciprofloxacin (CIP) is an antibiotic that is widely used to treat bacterial infections and is poorly biodegraded during wastewater treatment. In this study, a CIP-degrading bacterial strain (GLC_01) was successfully retrieved from activated sludge by enrichment and isolation. The obtained bacterial strain shares over 99% nucleotide identity of the 16S rRNA gene with Bradyrhizobium spp. Results show that Bradyrhizobium sp. GLC_01 degraded CIP via cometabolism with another carbon substrate following a first-order kinetics degradation reaction. CIP degradation by Bradyrhizobium sp. GLC_01 increased when the concentration of the primary carbon source increased. The biodegradability of the primary carbon source also affected CIP degradation. The use of glucose and sodium acetate (i.e. readily biodegradable), respectively, as a primary carbon source enhanced CIP biotransformation, compared to starch (i.e. relatively slowly biodegradable). CIP degradation decreased with the increase of the initial CIP concentration. Over 70% CIP biotransformation was achieved at 0.05 mg L
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.BIORTECH.2021.126408
Abstract: This study develops and applies the PROMETHEE-GAIA method as a new tool to select microalgae strains for aviation fuel production. Assessment involves 19 criteria with equal weighting in three aspects, namely biomass production, lipid quality, and fatty acid methylester properties. Here, the method is demonstrated for evaluating 17 candidate microalgae strains. Chlorella sp. NT8a is assessed as the most suitable strain for aviation fuel production. The results also show that unmodified biofuel from the most suitable strain could not meet all jet fuel standards. In particular, microalgae-based fuel could not satisfy the required density, heating value and freezing points of the international jet fuel standards. These results highlight the need for a broad action plan including improvement in the processing or modification of biofuel produced from microalgae and revision of the current jet fuel standards to facilitate the introduction of microalgae-based biofuel for the aviation industry.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.BIORTECH.2013.08.142
Abstract: The degradation of 30 trace organic contaminants (TrOC) by a white-rot fungus-augmented membrane bioreactor (MBR) was investigated. The results show that white-rot fungal enzyme (laccase), coupled with a redox mediator (1-hydroxy benzotriazole, HBT), could degrade TrOC that are resistant to bacterial degradation (e.g. diclofenac, triclosan, naproxen and atrazine) but achieved low removal of compounds (e.g. ibuprofen, gemfibrozil and amitriptyline) that are well removed by conventional activated sludge treatment. Overall, the fungus-augmented MBR showed better TrOC removal compared to a system containing conventional activated sludge. The major role of biodegradation in removal by the MBR was noted. Continuous mediator dosing to MBR may potentially enhance its performance, although not as effectively as for mediator-enhanced batch laccase systems. A ToxScreen3 assay revealed no significant increase in the toxicity of the effluent during MBR treatment of the synthetic wastewater comprising TrOC, confirming that no toxic by-products were produced.
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.BIORTECH.2019.122707
Abstract: High concentrations of antibiotics in swine wastewater pose potentially serious risks to the environment, human and animal health. Identifying the mechanism for removing antibiotics during the anaerobic treatment of swine wastewater is essential for reducing the serious damage they do to the environment. In this study, batch experiments were conducted to investigate the biosorption and biodegradation of tetracycline and sulfonamide antibiotics (TCs and SMs) in anaerobic processes. Results indicated that the removal of TCs in the anaerobic reactor contributed to biosorption, while biodegradation was responsible for the SMs' removal. The adsorption of TCs fitted well with the pseudo-second kinetic mode and the Freundlich isotherm, which suggested a heterogeneous chemisorption process. Cometabolism was the main mechanism for the biodegradation of SMs and the process fitted well with the first-order kinetic model. Microbial activity in the anaerobic sludge might be curtailed due to the presence of high concentrations of SMs.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.WATRES.2021.117871
Abstract: This study examined the removal and enantio‑specific fate of a suite of eleven chiral 2-arylpropionic acids (2-APAs) during biological wastewater treatment simulated in a laboratory-scale membrane bioreactor (MBR). Using pure (R)- and (S)- enantiomers in the MBR influent, chiral inversion was determined through the increase in the concentration of the non-dominant enantiomer and changes in the enantiomeric fraction (EF) between the two enantiomers during the treatment process. Effective (>90%) and similar removal rates between (R)- and (S)- enantiomers were confirmed for eight 2-APAs. In this study, 2-APAs exhibited erse and distinctive chiral inversion behaviours: two 2-APAs showed (R→S) unidirectional inversion, three 2-APAs showed (S→R) unidirectional inversion, and six 2-APAs showed bidirectional inversion. This is the first study to report chiral inversion behaviours of a comprehensive suite of 2-APAs with a variety of functional groups substituted onto the aryl ring. A decrease in effluent EF over time was observed for two 2-APAs. This study shows that chiral inversion of 2-APAs varies significantly from compound to compound, despite the high similarity in their chemical structures.
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Singapore
Date: 08-11-2019
Publisher: MDPI AG
Date: 29-05-2020
DOI: 10.3390/PR8060648
Abstract: Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 µM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 µM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a erse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals.
Publisher: Elsevier
Date: 2022
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier
Date: 2020
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.BIORTECH.2021.126634
Abstract: Hydrogen sulphide (H
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 2021
Publisher: American Society of Civil Engineers
Date: 27-06-2016
Publisher: Elsevier BV
Date: 2022
DOI: 10.2139/SSRN.4098825
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.BIORTECH.2016.01.014
Abstract: Laccase was immobilized on granular activated carbon (GAC) and the resulting GAC-bound laccase was used to degrade four micropollutants in a packed-bed column. Compared to the free enzyme, the immobilized laccase showed high residual activities over a broad range of pH and temperature. The GAC-bound laccase efficiently removed four micropollutants, namely, sulfamethoxazole, carbamazepine, diclofenac and bisphenol A, commonly detected in raw wastewater and wastewater-impacted water sources. Mass balance analysis showed that these micropollutants were enzymatically degraded following adsorption onto GAC. Higher degradation efficiency of micropollutants by the immobilized compared to free laccase was possibly due to better electron transfer between laccase and substrate molecules once they have adsorbed onto the GAC surface. Results here highlight the complementary effects of adsorption and enzymatic degradation on micropollutant removal by GAC-bound laccase. Indeed laccase-immobilized GAC outperformed regular GAC during continuous operation of packed-bed columns over two months (a throughput of 12,000 bed volumes).
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9EW00851A
Abstract: A hybrid process combining a single compartment aerobic membrane bioreactor (MBR) and a membrane microalgal reactor (MMR) was evaluated for nutrient removal and microalgal biomass production.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 05-2017
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.BIORTECH.2014.05.125
Abstract: The removal of four recalcitrant trace organic contaminants (TrOCs), namely carbamazepine, diclofenac, sulfamethoxazole and atrazine by laccase in an enzymatic membrane reactor (EMR) was studied. Laccases are not effective for degrading non-phenolic compounds nevertheless, 22-55% removal of these four TrOCs was achieved by the laccase EMR. Addition of the redox-mediator syringaldehyde (SA) to the EMR resulted in a notable dose-dependent improvement (15-45%) of TrOC removal affected by inherent TrOC properties and loading rates. However, SA addition resulted in a concomitant increase in the toxicity of the treated effluent. A further 14-25% improvement in aqueous phase removal of the TrOCs was consistently observed following a one-off dosing of 3g/L granular activated carbon (GAC). Mass balance analysis reveals that this improvement was not due solely to adsorption but also enhanced biodegradation. GAC addition also reduced membrane fouling and the SA-induced toxicity of the effluent.
Publisher: Informa UK Limited
Date: 08-03-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8EW00663F
Abstract: This study examines the changes in microbial community ersity and structure in response to anaerobic co-digestion (AcoD) between sewage sludge and a carbon-rich organic waste.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 11-2020
Publisher: CSIRO Publishing
Date: 2021
DOI: 10.1071/AJ20089
Abstract: This study evaluates the feasibility of an emerging technology – a concentrated solar multi-effect distiller (CSMED) – to supply high quality water for beneficial use at Eromanga, which is located in a remote and dry region of Australia. Produced water from the Kenmore oil field is the only reliable water source at Eromanga and has been approved for livestock watering. The process utilises concentrated solar technology to drive a multi-effect distiller, making the process ideal for the Australian outback. Historical water parameters of the produced water were assessed against the water guidelines for irrigation, livestock watering, municipal and potable use. The proposed treatment will further improve key water quality parameters to exceed guideline requirements for unrestricted water uses mentioned above. The CSMED produces a high-quality distillate (i.e. treated water) free of all mineral salts that can be mixed with the produced water to increase the final product water volume. An Excel based model was developed to determine suitable blending ratios while maintaining the water quality for each beneficial use. For production of livestock watering and potable use, a blending ratio (of at least 19% v/v) between the CSMED distillate and produced water can be applied, significantly increasing the final water volume. The Excel based model could also indicate chemical addition for adjustment of sodium absorption ratio in the case of irrigation application. The brine from the CSMED can potentially be used to prepare drilling mud for oil field operation. An on-site performance study of the CSMED system has been planned to validate these results.
Publisher: American Chemical Society (ACS)
Date: 08-06-2022
Abstract: This work examined the chiral inversion of 2-arylpropionic acids (2-APAs) under anaerobic conditions and the associated microbial community. The anaerobic condition was simulated by two identical anaerobic digesters. Each digester was fed with the substrate containing 11 either pure (
Publisher: Informa UK Limited
Date: 27-02-2021
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 03-2014
Publisher: IWA Publishing
Date: 20-06-2017
DOI: 10.2166/WST.2017.331
Abstract: This study demonstrates continuous enantiomeric inversion and further biotransformation of chiral profens including ibuprofen, naproxen and ketoprofen by an enzymatic membrane bioreactor (EMBR) dosed with laccase. The EMBR showed non-enantioselective transformations, with high and consistent transformation of both (R)- and (S)-ibuprofen (93 ± 6%, n= 10), but lower removals of both enantiomers of naproxen (46 ± 16%, n= 10) and ketoprofen (48 ± 17%, n= 10). Enantiomeric analysis revealed a bidirectional but uneven inversion of the profens, for ex le 14% inversion of (R)- to (S)- compared to 4% from (S)- to (R)-naproxen. With redox-mediator addition, the enzymatic chiral inversion of both (R)- and (S)-profens remained unchanged, although the overall conversion became enantioselective except for (S)-naproxen, the addition of redox mediator promoted the degradation of (R)-profens only.
Publisher: Wiley
Date: 09-07-2021
Publisher: Springer Science and Business Media LLC
Date: 27-02-2022
DOI: 10.1007/S11356-022-19322-8
Abstract: The skyrocketing demand and progressive technology have increased our dependency on electrical and electronic devices. However, the life span of these devices has been shortened because of rapid scientific expansions. Hence, massive volumes of electronic waste (e-waste) is generating day by day. Nevertheless, the ongoing management of e-waste has emerged as a major threat to sustainable economic development worldwide. In general, e-waste contains several toxic substances such as metals, plastics, and refractory oxides. Metals, particularly lead, mercury, nickel, cadmium, and copper along with some valuable metals such as rare earth metals, platinum group elements, alkaline and radioactive metal are very common which can be extracted before disposing of the e-waste for reuse. In addition, many of these metals are hazardous. Therefore, e-waste management is an essential issue. In this study, we critically have reviewed the existing extraction processes and compared among different processes such as physical, biological, supercritical fluid technologies, pyro and hydrometallurgical, and hybrid methods used for metals extraction from e-waste. The review indicates that although each method has particular merits but hybrid methods are eco-friendlier with extraction efficiency > 90%. This study also provides insight into the technical challenges to the practical realization of metals extraction from e-waste sources.
Publisher: Elsevier
Date: 2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 07-2014
Publisher: Elsevier BV
Date: 2022
DOI: 10.1016/J.BIORTECH.2021.126201
Abstract: Enzymatic conversion of micropollutants into less-toxic derivatives is an important bioremediation strategy. This paper aims to critically review the progress in water and wastewater treatment by both free and immobilized enzymes presenting this approach as highly efficient and performed under environmentally benign and friendly conditions. The review also summarises the effects of inorganic and organic wastewater matrix constituents on enzymatic activity and degradation efficiency of micropollutants. Finally, application of enzymatic reactors facilitate continuous treatment of wastewater and obtaining of pure final effluents. Of a particular note, enzymatic treatment of micropollutants from wastewater has been mostly reported by laboratory scale studies. Thus, this review also highlights key research gaps of the existing techniques and provides future perspectives to facilitate the transfer of the lab-scale solutions to a larger scale and to improve operationability of biodegradation processes.
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.BIORTECH.2022.127433
Abstract: The effects of microalgae harvesting methods on microalgal biomass quality were evaluated using three species namely the freshwater green alga Chlorella vulgaris, marine red alga Porphyridium purpureum and marine diatom Phaeodactylum tricornutum. Harvesting efficiencies of polyacrylamide addition, alkaline addition, and centrifugation ranged from 85 to 95, 59-92 and 100%, respectively, across these species. Morphology of the harvested cells (i.e. compromised cell walls) was significantly impacted by alkaline pH-induced flocculation for all three species. Over 50% of C. vulgaris cells were compromised with alkaline pH compared to < 10% with polyacrylamide and centrifugation. The metabolic profiles varied depending on harvesting methods. Species-specific decrease of certain metabolites was observed. These results suggest that the method of harvest can alter the metabolic profile of the biomass amongst the three harvesting methods, polyacrylamide addition showed higher harvesting efficiency with less compromised cells and higher retention of industry important biochemicals.
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.SCITOTENV.2019.135279
Abstract: Recent developed sequencing techniques have resulted in a new and unprecedented way to study biological wastewater treatment, in which most organisms are uncultivable. This review provides (i) an insight on state-of-the-art sequencing techniques and their limitations (ii) a critical assessment of the microbial community in biological reactor and biofouling layer in a membrane bioreactor (MBR). The data from high-throughput sequencing has been used to infer microbial growth conditions and metabolisms of microorganisms present in MBRs at the time of s ling. These data shed new insight to two fundamental questions about a microbial community in the MBR process namely the microbial composition (who are they?) and the functions of each specific microbial assemblage (what are their function?). The results to date also highlight the complexity of the microbial community growing on MBRs. Environmental conditions are dynamic and erse, and can influence the ersity and structural dynamics of any given microbial community for wastewater treatment. The benefits of understanding the structure of microbial communities on three major aspects of the MBR process (i.e. nutrient removal, biofouling control, and micropollutant removal) were symmetrically delineated. This review also indicates that the deployment of microbial community analysis for a practical engineering context, in terms of process design and system optimization, can be further realized.
Publisher: Elsevier BV
Date: 03-2022
Publisher: Wiley
Date: 08-11-2022
Abstract: Solar steam generator (SSG) systems have attracted increasing attention, owing to its simple manufacturing, material abundance, cost‐effectiveness, and environmentally friendly freshwater production. This system relies on photothermic materials and water absorbing substrates for a clean continuous distillation process. To optimize this process, there are factors that are needed to be considered such as selection of solar absorber and water absorbent materials, followed by micro/macro‐structural system design for efficient water evaporation, floating, and filtration capability. In this contribution, we highlight the general interfacial SSG concept, review and compare recent progresses of different SSG systems, as well as discuss important factors on performance optimization. Furthermore, unaddressed challenges such as SSG's cost to performance ratio, filtration of untreatable micropollutants/microorganisms, and the need of standardization testing will be discussed to further advance future SSG studies.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.JENVMAN.2019.109526
Abstract: Hospital wastewater contains acetaminophen (ACT) and nutrient, which need adequate removal and monitoring to prevent impact to environment and community. This study developed a pilot scale vertical flow constructed wetland (CW) to (1) remove high-dose ACT and pollutants in hospital wastewater and (2) identify the correlation of peroxidase enzyme extruded by Scirpus validus and pollutants removal efficiency. By that correlation, a low-cost method to monitor pollutants removal was drawn. Plants, such as Scirpus validus, generated peroxidase enzymes to alleviate pollutants' stress. Results showed that the CW removed 3.5 to 6 logs of initial concentration 10 mg ACT/L to a recommended level for drinking water. The CW eliminated COD, TKN and TP efficiently, meeting the wastewater discharged standards of Thailand and Vietnam. By various multivariable regression models, concentrations of ACT in CW effluent and enzymes in S. validus exhibited a significant correlation (p < 0.01, R
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier
Date: 2022
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.SCITOTENV.2018.12.094
Abstract: This study evaluated the removal of diclofenac (DCF) in activated sludge and its long-term exposure effects on the function and structure of the microbial community. Activated sludge could remove <50% of 50 μg/L DCF. The removal decreased significantly to below 15% when DCF concentrations increased to 500 and 5000 μg/L. Quantitative assessment of the fate of DCF showed that its main removal routes were biodegradation (21%) and adsorption (7%), with other abiotic removals being insignificant (<5%). The biodegradation occurred through cometabolic mechanisms. DCF exposure in the range of 50-5000 μg/L did not disrupt the major functions of the activated sludge ecosystem (e.g. biomass yield and heterotrophic activity) over two months of DCF exposure. Consistently, 16S rRNA gene-based community analysis revealed that the overall community ersity (e.g. species richness and ersity) and structure of activated sludge underwent no significant alterations. The analysis did uncover a significant increase in several genera, Nitratireductor, Asticcacaulis, and Pseudacidovorax, which gained competitive advantages under DCF exposure. The enrichment of Nitratireductor, Asticcacaulis, and Pseudacidovorax genus might contribute to DCF biodegradation and emerge as a potential microbial niche for the removal of DCF.
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.BIORTECH.2012.11.131
Abstract: The removal efficiency of 22 selected trace organic contaminants by sequential application of granular activated carbon (GAC) and simultaneous application of powdered activated carbon (PAC) with membrane bioreactor (MBR) was compared in this study. Both sequential application of GAC following MBR treatment (MBR-GAC) and simultaneous application of PAC within MBR (PAC-MBR) achieved improved removal (over 95%) of seven hydrophilic and biologically persistent compounds, which were less efficiently removed by MBR-only treatment (negligible to 70%). However, gradual breakthrough of these compounds occurred over an extended operation period. Charged compounds, particularly, fenoprop and diclofenac, demonstrated the fastest breakthrough (complete and 50-70%, in MBR-GAC and PAC-MBR, respectively). Based on a simple comparison from the long-term performance stability and activated carbon usage points of view, PAC-MBR appears to be a better option than MBR-GAC treatment.
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.BIORTECH.2015.10.054
Abstract: Redox-mediators such as syringaldehyde (SA) can improve laccase-catalyzed degradation of trace organic contaminants (TrOCs) but may increase effluent toxicity. The degradation performance of 14 phenolic and 17 non-phenolic TrOCs by a continuous flow enzymatic membrane reactor (EMR) at different TrOC and SA loadings was assessed. A specific emphasis was placed on the investigation of the toxicity of the enzyme (laccase), SA, TrOCs and the treated effluent. Batch tests demonstrated significant in idual and interactive toxicity of the laccase and SA preparations. Reduced removal of resistant TrOCs by the EMR was observed for dosages over 50μg/L. SA addition at a concentration of 10μM significantly improved TrOC removal, but no removal improvement was observed at the elevated SA concentrations of 50 and 100μM. The treated effluent showed significant toxicity at SA concentrations beyond 10μM, providing further evidence that higher dosage of SA must be avoided.
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.BIORTECH.2011.10.051
Abstract: The removal of trace organics by a membrane bioreactor-granular activated carbon (MBR-GAC) integrated system were investigated. The results confirmed that MBR treatment can be effective for the removal of hydrophobic (log D>3.2) and readily biodegradable trace organics. The data also highlighted the limitation of MBR in removing hydrophilic and persistent compounds (e.g. carbamazepine, diclofenac, and fenoprop) and that GAC could complement MBR very well as a post-treatment process. The MBR-GAC system showed high removal of all selected trace organics including those that are hydrophilic and persistent to biological degradation at up to 406 bed volumes (BV). However, over an extended period, breakthrough of diclofenac was observed after 7320 BV. This suggests that strict monitoring should be applied over the lifetime of the GAC column to detect the breakthrough of hydrophilic and persistent compounds which have low removal by MBR treatment.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.CHEMOSPHERE.2019.04.159
Abstract: This study investigated the production of biogas, volatile fatty acids (VFAs), and other soluble organic from lignocellulosic biomass by two microbial communities (i.e. rumen fluid and anaerobic sludge). Four types of abundant lignocellulosic biomass (i.e. wheat straw, oaten hay, lurence hay and corn silage) found in Australia were used. The results show that rumen microbes produced four-time higher VFAs level than that of anaerobic sludge reactors, indicating the possible application of rumen microorganism for VFAs generation from lignocellulosic biomass. VFA production in the rumen fluid reactors was probably due to the presence of specific hydrolytic and acidogenic bacteria (e.g. Fibrobacter and Prevotella). VFA production corroborated from the observation of pH drop in the rumen fluid reactors indicated hydrolytic and acidogenic inhibition, suggesting the continuous extraction of VFAs from the reactor. Anaerobic sludge reactors on the other hand, produced more biogas than that of rumen fluid reactors. This observation was consistent with the abundance of methanogens in anaerobic sludge inoculum (3.98% of total microbes) compared to rumen fluid (0.11%). VFA production from lignocellulosic biomass is the building block chemical for bioplastic, biohydrogen and biofuel. The results from this study provide important foundation for the development of engineered systems to generate VFAs from lignocellulosic biomass.
Publisher: Springer Science and Business Media LLC
Date: 20-04-2021
DOI: 10.1007/S40726-021-00183-7
Abstract: In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.SCITOTENV.2022.155871
Abstract: The ersity of microalgae and bacteria allows them to form a complementary consortium for efficient wastewater treatment and nutrient recovery. This review highlights the potential of wastewater-derived microalgal biomass as a renewable feedstock for producing animal feed, biofertilisers, biofuel, and many valuable biochemicals. Data corroborated from this review shows that microalgae and bacteria can thrive in many environments. Microalgae are especially effective at utilising nutrients from the water as they grow. This review also consolidates the current understanding of microalgae characteristics and their interactions with bacteria in a consortium system. Recent studies on the performance of only microalgae and microalgae-bacteria wastewater treatment are compared and discussed to establish a research roadmap for practical implementation of the consortium systems for various wastewaters (domestic, industrial, agro-industrial, and landfill leachate wastewater). In comparison to the pure microalgae system, the consortium system has a higher removal efficiency of up to 15% and shorter treatment time. Additionally, this review addresses a variety of possibilities for biomass application after wastewater treatment.
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.JENVMAN.2013.01.037
Abstract: This study investigated the removal of trace organic contaminants by a combined membrane bioreactor - granular activated carbon (MBR-GAC) system over a period of 196 days. Of the 22 compounds investigated here, all six hydrophilic compounds with electron-withdrawing functional groups (i.e., metronidazole, carbamazepine, ketoprofen, naproxen, fenoprop and diclofenac) exhibited very low removal efficiency by MBR-only treatment. GAC post-treatment initially complemented MBR treatment very well however, a compound-specific gradual deterioration of the removal of the above-mentioned problematic compounds was noted. While a 20% breakthrough of all four negatively charged compounds namely ketoprofen, naproxen, fenoprop and diclofenac occurred within 1000-3000 bed volumes (BV), the same level of breakthrough of the two neutral compounds metronidazole and carbamazepine did not occur until 11,000 BV. Single-solute isotherm parameters did not demonstrate any discernible correlation in idually with any of the parameters that may govern adsorption onto GAC, such as log D, number of hydrogen-bond donor/acceptor groups, dipole moment or aromaticity ratio of the compounds. The isotherm data, however, could differentiate the breakthrough behaviour between negatively charged and neutral trace organic contaminants.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 16-08-2019
DOI: 10.1007/S10653-019-00392-6
Abstract: This study investigated the effects and fate of the antibiotic ciprofloxacin (CIP) at environmentally relevant levels (50-500 µg/L) in activated sludge (AS) microbial communities under aerobic conditions. Exposure to 500 µg/L of CIP decreased species ersity by about 20% and significantly altered the phylogenetic structure of AS communities compared to those of control communities (no CIP exposure), while there were no significant changes upon exposure to 50 µg/L of CIP. Analysis of community composition revealed that exposure to 500 µg/L of CIP significantly reduced the relative abundance of Rhodobacteraceae and Nakamurellaceae by more than tenfold. These species frequently occur in AS communities across many full-scale wastewater treatment plants and are involved in key ecosystem functions (i.e., organic matter and nitrogen removal). Our analyses showed that 50-500 µg/L CIP was poorly removed in AS (about 20% removal), implying that the majority of CIP from AS processes may be released with either their effluents or waste sludge. We therefore strongly recommend further research on CIP residuals and/or post-treatment processes (e.g., anaerobic digestion) for waste streams that may cause ecological risks in receiving water bodies.
Publisher: Elsevier BV
Date: 2022
DOI: 10.2139/SSRN.4126025
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JENVMAN.2019.109594
Abstract: Activated sludge (AS) and return activated sludge (RAS) microbial communities from three full-scale municipal wastewater treatment plants (denoted plant A, B and C) were compared to assess the impact of sludge settling (i.e. gravity thickening in the clarifier) and profile microorganisms responsible for nutrient removal and reactor foaming. The results show that all three plants were dominated with microbes in the phyla of Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, Chloroflexi, Firmicutes, Nitrospirae, Spirochaetae, Acidobacteria and Saccharibacteria. AS and RAS shared above 80% similarity in the microbial community composition, indicating that sludge thickening does not significantly alter the microbial composition. Autotrophic and heterotrophic nitrifiers were present in the AS. However, the abundance of autotrophic nitrifiers was significantly lower than that of the heterotrophic nitrifiers. Thus, ammonium removal at these plants was achieved mostly by heterotrophic nitrification. Microbes that can cause foaming were at 3.2% abundance, and this result is well corroborated with occasional aerobic biological reactor foaming. By contrast, these microbes were not abundant (<2.1%) at plant A and C, where aerobic biological reactor foaming has not been reported.
Publisher: Elsevier
Date: 2021
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.BIORTECH.2019.02.077
Abstract: This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate s les from the digester.
Publisher: Springer Science and Business Media LLC
Date: 18-08-2022
DOI: 10.1007/S40726-022-00230-X
Abstract: Algae cultivation complements wastewater treatment (WWT) principles as the process uptakes nutrients while assimilates CO 2 into biomass. Thus, the application of algae-based WWT is on the upward trajectory as more attention for recovery nutrients and CO 2 capture while reducing its economic challenge in the circular economy concept. However, the complexity of wastewater and algal ecological characteristics induces techno-economic challenges for industry implementation. Algae-based WWT relies totally on the ability of algae to uptake and store nutrients in the biomass. Therefore, the removal efficiency is proportional to biomass productivity. This removal mechanism limits algae applications to low nutrient concentration wastewater. The hydraulic retention time (HRT) of algae-based WWT is significantly long (i.e. 10 days), compared to a few hours in bacteria-based process. Phototrophic algae are the most used process in algae-based WWT studies as well as in pilot-scale trials. Application of phototrophic algae in wastewater faces challenges to supply CO 2 and illumination. Collectively, significant landscape is required for illumination. Algae-based WWT has limited organic removals, which require pretreatment of wastewaters before flowing into the algal process. Algae-based WWT can be used in connection with the bacteria-based WWT to remove partial nutrients while capturing CO 2 . Future research should strive to achieve fast and high growth rate, strong environmental tolerance species, and simple downstream processing and high-value biomass. There is also a clear and urgent need for more systematic analysis of biomass for both carbon credit assessment and economic values to facilitate identification and prioritisation of barriers to lower the cost algae-based WWT. Graphical abstract
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 04-2015
No related grants have been discovered for Luong Ngoc Nguyen.