Dr Luong Nguyen was trained at University of Wollongong in Environmental Engineering. His Master and PhD focused on the treatment of trace organic contaminants (i.e. PPCPs, pesticides, industrial chemicals) in biological processes, including activated sludge, membrane bioreactor, enzymatic membrane reactor and fungal bioreactor.
He held a postdoctoral research position at the Advanced Environmental Biotechnology Centre in Nanyang Technological University, Singapore. He investigated the impact of PPCPs on activated sludge microbial community and developed enrichment and isolation methods to retrieve bacterial strains from activated sludge with capability to degrade PPCPs.
Dr. Nguyen’s overall aim is to improve sustainability through research and technology development in the areas of waste and wastewater treatment with a focus on the recovery of water and the production of renewable energy and chemical precursors.
His current research is to disentangle the complexities of microbiomes in anaerobic digestion and co-digestion systems to facilitate genome-driven process design. This effort will enhance our understanding and control of biological wastewater and sludge treatment processes.
- Member of Waste Management & Resource Recovery Association Australia
- Microbiology Society
- Associate Member of The Royal Society of Chemistry
- Engineer Australia
- Membrane Society of Australasia
Can supervise: YES
- Anaerobic digestion and co-digestion
- Microbial ecology in wastewater treatment process
- Genomic driven process design
- Bioreactor design and operation
- Environmental Biotechnology
- Water and wasteater treatment processes
Labeeuw, L, Commault, AS, Kuzhiumparambil, U, Emmerton, B, Nguyen, LN, Nghiem, LD & Ralph, PJ 2021, 'A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting', Science of the Total Environment, vol. 752.View/Download from: Publisher's site
© 2020 Elsevier B.V. Flocculation is a low-cost harvesting technique for microalgae biomass production, but flocculation efficiency is species dependent. In this study, we investigated the efficacy of two synthetic (polyacrylamide) and one natural (chitosan) flocculants against three algal species: the cyanobacterium Synechocystis sp., the freshwater Chlorella vulgaris, and the marine Phaeodactylum tricornutum at laboratory and pilot scales to evaluate harvesting efficiency, biomass integrity and media recycling. Growth phase affected the harvesting efficiency of the eukaryotic microalgae. The flocculation was optimal at stationary phase with high flocculation efficiency achieved using polyacrylamides at 24–36 mg/g dry weight. The effect of the flocculants on the harvested biomass was investigated. The flocculated Synechocystis sp. showed a higher proportion of compromised cells compared to C. vulgaris and P. tricornutum likely due to differences in cell walls composition. Compromised cells could lead to the release of valuable products into the surrounding growth media during flocculation. The residual culture media was recycled once with no impact on cell growth for all treatments and algal species. The flocculation technique was demonstrated at pilot-scale using 350 L microalgal suspension, showing an efficiency of 82–90% at a polyacrylamide dosage of 6.5–10 mg/L. This efficiency and the biomass quality are comparable to the laboratory-scale results. Overall, results indicate that polyacrylamide flocculants work on a wide range of species without the need for pre-treatment. The information generated in this study can contribute to making the microalgae industry more competitive.
Vu, HP, Nguyen, LN, Vu, MT, Labeeuw, L, Emmerton, B, Commault, AS, Ralph, PJ, Mahlia, TMI & Nghiem, LD 2021, 'Harvesting Porphyridium purpureum using polyacrylamide polymers and alkaline bases and their impact on biomass quality', Science of the Total Environment, vol. 755.View/Download from: Publisher's site
© 2020 Elsevier B.V. This study aims to examine the flocculation efficiency of Porphyridium purpureum (i.e. a red marine microalga with high content of pigments and fatty acids) grown in seawater medium using polyacrylamide polymers and alkaline flocculation. Polymers Flopam™ and FO3801 achieved the highest flocculation efficiency of over 99% at the optimal dose of 21 mg per g of dry biomass through charge neutralisation and bridging mechanism. The addition of sodium hydroxide, potassium hydroxide, and sodium carbonate also achieved flocculation efficiency of 98 and 91%, respectively, but high doses were required (i.e. > 500 mg per g of dry biomass). Calcium hydroxide was not as effective and could only achieve 75% flocculation efficiency. Precipitation of magnesium hydroxide was identified as the major cause of hydroxide-induced flocculation. On the other hand, sodium carbonate addition induced flocculation via both magnesium and calcium carbonate co-precipitation. The large mass of precipitates caused a sweeping effect and enmeshed the microalgal cells to trigger sedimentation. Cell membrane integrity analysis of flocculated P. purpureum indicated that polyacrylamide polymers led to significant compromised cells (i.e. 96%), compared to the alkaline bases (70–96% compromised cells). These results appear to be the first to demonstrate the high efficiency of polyacrylamide polymer and alkaline flocculation of P. purpureum but at the expense of the biomass quality.
© 2020 Elsevier B.V. This study evaluated the potential of extracting acetic acid from rumen fluid by forward osmosis (FO). Unlike other FO applications to extract water and reduce the feed water volume, this research used FO to mimic the ruminant intestines for extracting acetic acid from rumen fluid to a clean matrix with a minimum water flux. The FO extraction of acetic acid was optimised with a synthetic solution using cellulose triacetate (CTA) and thin film composite (TFC) polyamide membranes under different operating parameters (e.g. membrane orientation and stripping solution pH ). Under the same operating conditions the CTA membrane showed higher acetic acid transport than the TFC polyamide membrane. Increasing the stripping solution pH from 5.5–6.5 to 9.0–10.0 increased the acetic acid transport through both CTA and TFC membranes. On the other hand, the membrane orientation had no discernible effect on the transport of acetic acid. Under the optimum conditions, the FO process using the CTA membrane exhibited negligible water flux and extracted 27% of the maximum attainable acetic acid from the synthetic solution within 8 h of operation. The optimised conditions were used to elaborate the FO extraction of acetic acid from a real rumen fluid. Considerably lower extraction rate from the real rumen fluid was observed compared to the synthetic solution, suggesting the need for further research to address the complexity of the rumen matrix.
Kim, D, Nguyen, LN & Oh, S 2020, 'Ecological impact of the antibiotic ciprofloxacin on microbial community of aerobic activated sludge.', Environmental geochemistry and health.View/Download from: Publisher's site
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 diversity 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.
Nguyen, AQ, Nguyen, LN, Johir, MAH, Ngo, H-H, Chaves, AV & Nghiem, LD 2020, 'Derivation of volatile fatty acid from crop residues digestion using a rumen membrane bioreactor: A feasibility study', BIORESOURCE TECHNOLOGY, vol. 312.View/Download from: Publisher's site
Nguyen, LN, Vu, MT, Johir, MAH, Pathak, N, Zdarta, J, Jesionowski, T, Semblante, GU, Hai, F, Hong, KDN & Nghiem, LD 2020, 'A Novel Approach in Crude Enzyme Laccase Production and Application in Emerging Contaminant Bioremediation', PROCESSES, vol. 8, no. 6.View/Download from: Publisher's site
Truong, MV, Nguyen, LN, Li, K, Fu, Q, Johir, MAH, Fontana, A & Nghiem, LD 2020, 'Biomethane production from anaerobic co-digestion and steel-making slag: A new waste-to-resource pathway', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 738.View/Download from: Publisher's site
Vu, HP, Nguyen, LN, Lesage, G & Nghiem, LD 2020, 'Synergistic effect of dual flocculation between inorganic salts and chitosan on harvesting microalgae Chlorella vulgaris', ENVIRONMENTAL TECHNOLOGY & INNOVATION, vol. 17.View/Download from: Publisher's site
Vu, HP, Nguyen, LN, Zdarta, J, Nga, TTV & Nghiem, LD 2020, 'Blue-Green Algae in Surface Water: Problems and Opportunities', CURRENT POLLUTION REPORTS, vol. 6, no. 2, pp. 105-122.View/Download from: Publisher's site
Vu, MT, Vu, HP, Nguyen, LN, Semblante, GU, Johir, MAH & Nghiem, LD 2020, 'A hybrid anaerobic and microalgal membrane reactor for energy and microalgal biomass production from wastewater', Environmental Technology and Innovation, vol. 19.View/Download from: Publisher's site
© 2020 Elsevier B.V. In the concept of a circular economy, wastewater is no longer waste but a resource for water, energy and nutrients. In this study, a hybrid system containing an anaerobic membrane bioreactor (AnMBR) and a microalgal membrane reactor (MMR) was developed to harvest energy, nutrients, and microalgal biomass from food and agribusiness industrial wastewater. The AnMBR removed over 97% of chemical oxygen demand (COD) and generated 4.7 ± 0.15 L (n=80) of biogas equivalent to 2.4 kWh kg−1 COD (feed) d−1. Through anaerobic metabolism, the microorganism in AnMBR generated NH4+ and PO43− -rich effluent. Their effluent concentrations were 1.9 and 1.4 times of that in the influent, respectively. NH4+ and PO43−-rich effluent was directly used (i.e. without filtration or sterilization) to culture microalgae Chlorella vulgaris in the MMR. . Microalgal biomass production reached up to 700 mg/L after 6 days of operation and nutrient removal rates of above 75% were achieved. However, biomass production and nutrient removal declined towards the end of experiment. The generated biomass was completely harvested using cationic polyacrylamide at the dose of 36 mg g−1 dry weight. Overall, the AnMBR has great potential to produce energy. Future research is needed to intensify the microalgal growth (e.g. genetic modification of strains, addition of plant hormones) in the MMR for continuous operation of the hybrid system.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Shan, X, Nghiem, LD & Nguyen, LN 2020, 'Removal process of antibiotics during anaerobic treatment of swine wastewater.', Bioresource Technology, vol. 300, pp. 1-8.View/Download from: Publisher's site
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.
Ahmed, MB, Johir, MAH, McLaughlan, R, Nguyen, LN, Xu, B & Nghiem, LD 2020, 'Per- and polyfluoroalkyl substances in soil and sediments: Occurrence, fate, remediation and future outlook', Science of the Total Environment, vol. 748.View/Download from: Publisher's site
© 2020 Elsevier B.V. Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are contaminants of great concern due to their wide-spread occurrence and persistence in the environments (i.e., in water, soil and sediment) and potential toxicology even at very low concentration. The main focus of this review is on the PFASs in soil and sediments. More specifically, this review systematically examines the occurrence and toxicological effects with associated risks, fate (i.e., PFASs adsorption by soil and sediment, transportation and transformation, and bioaccumulation), and remediation practices of PFASs in soil and sediment. Various models and equations such as fugacity-based multimedia fate and hydrodynamic models are used to study the fate, transport, and transformation of PFASs. Among different remediation practices, sorption is the dominant process for the removal of PFASs from soil and sediments. Results also indicate that PFASs adsorption onto activated carbon decrease with the increase of carbon chain length in the PFASs. The longer-chain PFASs have larger partition coefficient values than shorter-chained PFASs. Sorption of PFASs to soil and sediments are mainly governed by different electrostatic interactions, hydrogen bonds formation, hydrophobic interactions, organic content in soil and sediments, and ligand exchange. Other technology such as thermal treatment might be potential in the removal of PAFSs, but need further study to elucidate a conclusion. Finally, the associated challenges and future outlook have been included.
Vu, HP, Nguyen, LN, Vu, MT, Johir, MAH, McLaughlan, R & Nghiem, LD 2020, 'A comprehensive review on the framework to valorise lignocellulosic biomass as biorefinery feedstocks', Science of the Total Environment, vol. 743.View/Download from: Publisher's site
© 2020 Elsevier B.V. An effective pretreatment is the first step to enhance the digestibility of lignocellulosic biomass – a source of renewable, eco-friendly and energy-dense materials – for biofuel and biochemical productions. This review aims to provide a comprehensive assessment on the advantages and disadvantages of lignocellulosic pretreatment techniques, which have been studied at the lab-, pilot- and full-scale levels. Biological pretreatment is environmentally friendly but time consuming (i.e. 15–40 days). Chemical pretreatment is effective in breaking down lignocellulose and increasing sugar yield (e.g. 4 to 10-fold improvement) but entails chemical cost and expensive reactors. Whereas the combination of physical and chemical (i.e. physicochemical) pretreatment is energy intensive (e.g. energy production can only compensate 80% of the input energy) despite offering good process efficiency (i.e. > 100% increase in product yield). Demonstrations of pretreatment techniques (e.g. acid, alkaline, and hydrothermal) in pilot-scale have reported 50–80% hemicellulose solubilisation and enhanced sugar yields. The feasibility of these pilot and full-scale plants has been supported by government subsidies to encourage biofuel consumption (e.g. tax credits and mandates). Due to the variability in their mechanisms and characteristics, no superior pretreatment has been identified. The main challenge lies in the capability to achieve a positive energy balance and great economic viability with minimal environmental impacts i.e. the energy or product output significantly surpasses the energy and monetary input. Enhancement of the current pretreatment techno-economic efficiency (e.g. higher product yield, chemical recycling, and by-products conversion to increase environmental sustainability) and the integration of pretreatment methods to effectively treat a range of biomass will be the steppingstone for commercial lignocellulosic biorefineries.
McCauley, JI, Labeeuw, L, Jaramillo-Madrid, AC, Nguyen, LN, Nghiem, LD, Chaves, AV & Ralph, PJ 2020, 'Management of Enteric Methanogenesis in Ruminants by Algal-Derived Feed Additives', CURRENT POLLUTION REPORTS, vol. 6, no. 3, pp. 188-205.View/Download from: Publisher's site
Nguyen, LN, Commault, AS, Kahlke, T, Ralph, PJ, Semblante, GU, Johir, MAH & Nghiem, LD 2020, 'Genome sequencing as a new window into the microbial community of membrane bioreactors - A critical review.', Science of the Total Environment, vol. 704, pp. 135279-135279.View/Download from: Publisher's site
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 sampling. 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 diverse, and can influence the diversity 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.
Nguyen, LN, Truong, MV, Nguyen, AQ, Johir, MAH, Commault, AS, Ralph, PJ, Semblante, GU & Nghiem, LD 2020, 'A sequential membrane bioreactor followed by a membrane microalgal reactor for nutrient removal and algal biomass production', Environmental Science: Water Research and Technology, vol. 6, no. 1, pp. 189-196.View/Download from: Publisher's site
© 2019 The Royal Society of Chemistry. 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. When operated without biomass extraction, the microalgal biomass in the MMR reached 920 mg L-1 on day 18 and then collapsed, rendering nutrient removal ineffective. Stable operation of the MMR was achieved by regular biomass extraction (i.e. 1/30 of the microalgal biomass in the reactor daily). The biomass production at steady state was approximately 26 g m-3 d-1. The NO3- and PO43- uptake values by microalgae were 4.0 ± 1.1 and 1.5 ± 0.9 g m-3 d-1, respectively. A facile flocculation and separation technique capable of recovering 98% microalgal biomass was demonstrated. Although the hybrid process can significantly enhance nutrient removal and biomass production, further research is needed to intensify the microalgal growth rate. At the current microalgal growth rate, a large MMR volume (37 times that of the MBR) is necessary for synchronous operation.
Nguyen, LN, Nghiem, LD, Pramanik, BK & Oh, S 2019, 'Cometabolic biotransformation and impacts of the anti-inflammatory drug diclofenac on activated sludge microbial communities', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 657, pp. 739-745.View/Download from: UTS OPUS or Publisher's site
Keerthisinghe, TP, Luong, NN, Kwon, EE & Oh, S 2019, 'Antiseptic chlorhexidine in activated sludge: Biosorption, antimicrobial susceptibility, and alteration of community structure', JOURNAL OF ENVIRONMENTAL MANAGEMENT, vol. 237, pp. 629-635.View/Download from: Publisher's site
Nguyen, LN & Oh, S 2019, 'Impacts of antiseptic cetylpyridinium chloride on microbiome and its removal efficiency in aerobic activated sludge', International Biodeterioration & Biodegradation, vol. 137, pp. 23-29.View/Download from: Publisher's site
This study evaluated short- and long-term exposure of activated sludge (AS) microbiome to cetylpyridinium chloride (CPC), a quaternary ammonium compound widely used as biocidal additive or cationic surfactant. Toxicity assay in batch mode showed that CPC (50 μg L−1) inhibited cell growth. However, in a continuous reactor, CPC concentration in the range of 50–500 μg L−1 did not result in any observable impact on the biological activities of the AS microbiome. Similarly, 16S rRNA gene-based community profiling revealed that CPC had no observable impact on microbial diversity. At the phylogenetic structure, Rhodobacter (15 ± 7% of the total) and Asticcacaulis (9 ± 3%) were the only two phyla with increasing population in the 500 μg L−1-exposed reactors. This was also supported by an observation of no major change in the community structure. The reactors could remove >60% of CPC at initial concentrations of 50–500 μg L−1, primarily by adsorption and biodegradation. The enrichment of Rhodobacter and Asticcacaulis genus might contribute to CPC biodegradation and emerge as a potential microbial niche for the removal of CPC.
Vo, HNP, Koottatep, T, Chapagain, SK, Panuvatvanich, A, Polprasert, C, Nguyen, TMH, Chaiwong, C & Nguyen, NL 2019, 'Removal and monitoring acetaminophen-contaminated hospital wastewater by vertical flow constructed wetland and peroxidase enzymes.', Journal of Environmental Management, vol. 250.View/Download from: Publisher's site
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, R2 = 68.3%). These findings suggested that (i) vertical flow CW could remove high-dose ACT and nutrient and (ii) peroxidase enzymes generated in S. validus, such as soluble and covalent ones, could track ACT removal efficiency. This would help to reduce facilities and analytical cost of micro-pollutants.
Chapple, A, Nguyen, LN, Hai, FI, Dosseto, A, Rashid, MHO, Oh, S, Price, WE & Nghiem, LD 2019, 'Impact of inorganic salts on degradation of bisphenol A and diclofenac by crude extracellular enzyme from Pleurotus ostreatus', Biocatalysis and Biotransformation, vol. 37, no. 1, pp. 10-17.View/Download from: Publisher's site
© 2017 Informa UK Limited, trading as Taylor & Francis Group This study investigated the influence of inorganic salts on enzymatic activity and the removal of trace organic contaminants (TrOCs) by crude laccase from the white-rot fungus Pleurotus ostreatus. A systematic analysis of 15 cations and anions from common inorganic salts was presented. Laccase activity was not inhibited by monovalent cations (i.e. Na + , NH 4 + , K + ), while the presence of divalent and trivalent cations showed variable impact – from negligible to complete inhibition – of both laccase activity and its TrOC removal performance. Of interest was the observation of discrepancy between residual laccase activity and TrOC removal in the presence of some ions. Mg 2+ had negligible impact on residual laccase activity but significant impact on TrOC removal. Conversely, F − showed greater impact on residual laccase activity than on TrOC removal. This observation indicated different impacts of the interfering ions on the interaction between laccase and TrOCs as compared to that between laccase and the reagent used to measure its activity, implicating that residual laccase activity may not always be an accurate indicator of TrOC removal. The degree of impact of halides was in the order of F − > I − > Br − > Cl − . Particularly, the tolerance of the tested laccase to Cl − has important implications for a range of industrial applications.
Nguyen, AQ, Nguyen, LN, Phan, HV, Galway, B, Bustamante, H & Nghiem, LD 2019, 'Effects of operational disturbance and subsequent recovery process on microbial community during a pilot-scale anaerobic co-digestion', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 138, pp. 70-77.View/Download from: Publisher's site
Nguyen, LN, Commault, AS, Johir, MAH, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Application of a novel molecular technique to characterise the effect of settling on microbial community composition of activated sludge.', Journal of environmental management, vol. 251.View/Download from: Publisher's site
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.
Nguyen, LN, Johir, MAH, Commault, A, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Impacts of mixing on foaming, methane production, stratification and microbial community in full-scale anaerobic co-digestion process.', Bioresource technology, vol. 281, pp. 226-233.View/Download from: Publisher's site
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 samples from the digester.
Nguyen, LN, Nghiem, LD, Pramanik, BK & Oh, S 2019, 'Cometabolic biotransformation and impacts of the anti-inflammatory drug diclofenac on activated sludge microbial communities', Science of the Total Environment, vol. 657, pp. 739-745.View/Download from: Publisher's site
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 diversity (e.g. species richness and diversity) 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.
Nguyen, LN, Nguyen, AQ, Johir, MAH, Guo, W, Ngo, HH, Chaves, AV & Nghiem, LD 2019, 'Application of rumen and anaerobic sludge microbes for bio harvesting from lignocellulosic biomass.', Chemosphere, vol. 228, pp. 702-708.View/Download from: Publisher's site
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.
Nguyen, LN, Labeeuw, L, Commault, AS, Emmerton, B, Ralph, PJ, Johir, MAH, Guo, W, Ngo, HH & Nghiem, LD 2019, 'Validation of a cationic polyacrylamide flocculant for the harvesting fresh and seawater microalgal biomass', Environmental Technology and Innovation, vol. 16.View/Download from: Publisher's site
© 2019 Elsevier B.V. A simple, efficient, and fast settling flocculation technique to harvest microalgal biomass was demonstrated using a proprietary cationic polyacrylamide flocculant for a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal culture at their mid-stationary growth phase. The optimal flocculant doses were 18.9 and 13.7 mg/g of dry algal biomass for C. vulgaris and P. tricornutum, respectively (equivalent to 7 g per m3 of algal culture for both species). The obtained optimal dose was well corroborated with changes in cell surface charge, and culture solution optical density and turbidity. At the optimal dose, charge neutralization of 64 and 86% was observed for C. vulgaris and P. tricornutum algal cells, respectively. Algae recovery was independent of the culture solution pH in the range of pH 6 to 9. Algal biomass recovery was achieved of 100 and 90% for C vulgaris and P. tricornutum respectively, and over 98% medium recovery was achievable by simple decanting.
Nguyen, AQ, Wickham, R, Nguyen, LN, Phan, HV, Galway, B, Bustamante, H & Nghiem, LD 2018, 'Impact of anaerobic co-digestion between sewage sludge and carbon-rich organic waste on microbial community resilience', ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY, vol. 4, no. 12, pp. 1956-1965.View/Download from: Publisher's site
Nguyen, L, Nghiem, DL & Oh, S 2018, 'Aerobic biotransformation of the antibiotic ciprofloxacin by Bradyrhizobium sp. isolated from activated sludge', Chemosphere, vol. 211, pp. 600-607.View/Download from: Publisher's site
Ji, C, Nguyen, LN, Hou, J, Hai, FI & Chen, V 2017, 'Direct immobilization of laccase on titania nanoparticles from crude enzyme extracts of P. ostreatus culture for micro-pollutant degradation', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 178, pp. 215-223.View/Download from: Publisher's site
Asif, MB, Nguyen, LN, Hai, FI, Price, WE & Nghiem, LD 2017, 'Integration of an enzymatic bioreactor with membrane distillation for enhanced biodegradation of trace organic contaminants', International Biodeterioration and Biodegradation, vol. 124, pp. 73-81.View/Download from: Publisher's site
© 2017 Elsevier Ltd A novel membrane distillation – enzymatic membrane bioreactor (MD-EMBR) system was developed for efficient degradation of trace organic contaminants (TrOCs). Degradation of five TrOCs, namely carbamazepine, oxybenzone, diclofenac, atrazine and sulfamethoxazole was examined using two commercially available laccases (from Trametes versicolor and Aspergillus oryzae). The MD system ensured complete retention ( > 99%) of both enzyme and TrOCs. Of particular interest was that the complete retention of the TrOCs resulted in high TrOC degradation by both laccases. Oxybenzone and diclofenac degradation in the MD-EMBR ranged between 80 and 99%. Compared to previously developed EMBRs, as much as 40% improvement in the removal of resistant non-phenolic TrOCs (e.g., carbamazepine) was observed. Laccase from A. oryzae demonstrated better TrOC degradation and enzymatic stability. With the addition of redox mediators, namely 1-hydroxybenzotriazole (HBT) or violuric acid (VA), TrOC degradation was improved by 10–20%. This is the first demonstration of a laccase-based high retention membrane bioreactor for enhanced biodegradation of TrOCs.
Nguyen, LN, Hai, FI, McDonald, JA, Khan, SJ, Price, WE & Nghiem, LD 2017, 'Continuous transformation of chiral pharmaceuticals in enzymatic membrane bioreactors for advanced wastewater treatment', WATER SCIENCE AND TECHNOLOGY, vol. 76, no. 7, pp. 1816-1826.View/Download from: Publisher's site
Ashe, B, Nguyen, LN, Hai, FI, Lee, D-J, van de Merwe, JP, Leusch, FDL, Price, WE & Nghiem, LD 2016, 'Impacts of redox-mediator type on trace organic contaminants degradation by laccase: Degradation efficiency, laccase stability and effluent toxicity', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 113, pp. 169-176.View/Download from: Publisher's site
Hai, FI, Nguyen, LN, Nghiem, LD, Liao, BQ, Koyuncu, I & Price, WE 2016, 'Trace Organic Contaminants Removal by Combined Processes for Wastewater Reuse', Handbook of Environmental Chemistry, vol. 45, pp. 39-77.View/Download from: Publisher's site
© 2016 Springer International Publishing Switzerland. The term trace organic contaminant (TrOC) refers to a diverse and expanding array of natural as well as anthropogenic substances including industrial chemicals, chemicals used in households, compounds and their metabolites excreted by people and by-products formed during wastewater and drinking-water treatment processes. Activated sludge-based processes (e.g. membrane bioreactor) are environmentally friendly approaches to wastewater treatment. However, conventional biological treatment alone may not be effective for all TrOCs that are known to occur in municipal and industrial wastewater. The low removal efficiency of biologically persistent and hydrophilic TrOCs necessitates the integration of MBR with other membrane-based and physicochemical processes to ensure adequate removal of TrOCs. Because MBRs can produce effluent with low turbidity and bulk organic content, significant synergy can be realised when it is integrated with other advanced treatment processes. In addition, given the small physical footprint of the MBR process, it is possible to deploy these integrated systems for decentralised water recycling applications. This chapter provides a brief overview of the integration of advanced treatment processes including activated carbon adsorption, advanced oxidation processes and high retention membranes (e.g. nanofiltration and reverse osmosis) with MBR for TrOC removal.
Nguyen, LN, Hai, FI, Dosseto, A, Richardson, C, Price, WE & Nghiem, LD 2016, 'Continuous adsorption and biotransformation of micropollutants by granular activated carbon-bound laccase in a packed-bed enzyme reactor', BIORESOURCE TECHNOLOGY, vol. 210, pp. 108-116.View/Download from: Publisher's site
Nguyen, LN, van de Merwe, JP, Hai, FI, Leusch, FDL, Kang, J, Price, WE, Roddick, F, Magram, SF & Nghiem, LD 2016, 'Laccase-syringaldehyde-mediated degradation of trace organic contaminants in an enzymatic membrane reactor: Removal efficiency and effluent toxicity', BIORESOURCE TECHNOLOGY, vol. 200, pp. 477-484.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Price, WE, Kang, J, Leusch, FDL, Roddick, F, van de Merwe, JP, Magram, SF & Nghiem, LD 2015, 'Degradation of a broad spectrum of trace organic contaminants by an enzymatic membrane reactor: Complementary role of membrane retention and enzymatic degradation', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 99, pp. 115-122.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Kang, J, Leusch, FDL, Roddick, F, Magram, SF, Price, WE & Nghiem, LD 2014, 'Enhancement of trace organic contaminant degradation by crude enzyme extract from Trametes versicolor culture: Effect of mediator type and concentration', JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS, vol. 45, no. 4, pp. 1855-1862.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Nghiem, LD, Kang, J, Price, WE, Park, C & Yamamoto, K 2014, 'Enhancement of removal of trace organic contaminants by powdered activated carbon dosing into membrane bioreactors', JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS, vol. 45, no. 2, pp. 571-578.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Price, WE, Leusch, FDL, Roddick, F, McAdam, EJ, Magram, SF & Nghiem, LD 2014, 'Continuous biotransformation of bisphenol A and diclofenac by laccase in an enzymatic membrane reactor', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 95, pp. 25-32.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Yang, S, Kang, J, Leusch, FDL, Roddick, F, Price, WE & Nghiem, LD 2014, 'Removal of pharmaceuticals, steroid hormones, phytoestrogens, UV-filters, industrial chemicals and pesticides by Trametes versicolor: Role of biosorption and biodegradation', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 88, pp. 169-175.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Price, WE, Leusch, FD, Roddick, F, Ngo, H, Guo, W, Magram, SF & Nghiem, LD 2014, 'The effects of mediator and granular activated carbon addition on degradation of trace organic contaminants by an enzymatic membrane reactor', Bioresource Technology, vol. 167, pp. 169-177.View/Download from: Publisher's site
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, 2255% 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 (1545%) 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 1425% improvement in aqueous phase removal of the TrOCs was consistently observed following a one-off dosing of 3 g/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.
Nguyen, LN, Hai, FI, Kang, J, Price, WE & Nghiem, LD 2013, 'Coupling granular activated carbon adsorption with membrane bioreactor treatment for trace organic contaminant removal: Breakthrough behaviour of persistent and hydrophilic compounds', JOURNAL OF ENVIRONMENTAL MANAGEMENT, vol. 119, pp. 173-181.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Kang, J, Price, WE & Nghiem, LD 2013, 'Removal of emerging trace organic contaminants by MBR-based hybrid treatment processes', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 85, pp. 474-482.View/Download from: Publisher's site
Nguyen, LN, Hai, FI, Yang, S, Kang, J, Leusch, FDL, Roddick, F, Price, WE & Nghiem, LD 2013, 'Removal of trace organic contaminants by an MBR comprising a mixed culture of bacteria and white-rot fungi', BIORESOURCE TECHNOLOGY, vol. 148, pp. 234-241.View/Download from: Publisher's site
Yang, S, Hai, FI, Nghiem, LD, Nguyen, LN, Roddick, F & Price, WE 2013, 'Removal of bisphenol A and diclofenac by a novel fungal membrane bioreactor operated under non-sterile conditions', INTERNATIONAL BIODETERIORATION & BIODEGRADATION, vol. 85, pp. 483-490.View/Download from: Publisher's site
Nguyen, LN, Hai, F, Kang, J, Nghiem, LD, Price, WE, Guo, W, Ngo, H & Tung, K 2013, 'Comparison between sequential and simultaneous application of activated carbon with membrane bioreactor for trace organic contaminant removal', Bioresource Technology, vol. 130, pp. 412-417.View/Download from: Publisher's site
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 (MBRâGAC) and simultaneous application of PAC within MBR (PACâMBR) 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 50â70%, in MBRâGAC and PACâMBR, respectively). Based on a simple comparison from the long-term performance stability and activated carbon usage points of view, PACâMBR appears to be a better option than MBRâGAC treatment.
Nguyen, LN, Hai, FI, Kang, J, Price, WE & Nghiem, LD 2012, 'Removal of trace organic contaminants by a membrane bioreactor-granular activated carbon (MBR-GAC) system', BIORESOURCE TECHNOLOGY, vol. 113, pp. 169-173.View/Download from: Publisher's site
Deng, L, Guo, W, Ngo, HH, Nguyen, LD, Nguyen, LN, Liu, Y & Bui, XT 2020, 'Aerobic membrane bioreactors for municipal wastewater treatment' in Current Developments in Biotechnology and Bioengineering, Elsevier, pp. 103-128.View/Download from: Publisher's site
Nghiem, LD, Nguyen, LN, Phan, HV, Ngo, HH, Guo, W & Hai, F 2020, 'Aerobic membrane bioreactors and micropollutant removal' in Current Developments in Biotechnology and Bioengineering, Elsevier, pp. 147-162.View/Download from: Publisher's site
Song, X, Luo, W, Nguyen, LN, Ngo, HH, Guo, W & Nghiem, LD 2020, 'Anaerobic membrane bioreactors for emerging pollutants removal' in Current Developments in Biotechnology and Bioengineering, Elsevier, pp. 197-218.View/Download from: Publisher's site
Nguyen, LN, Commault, AS, Sutherland, D, Semblante, GU, Oh, S & Nghiem, LD 2020, 'Contemporary Methods for Removal of Nonsteroidal Anti-inflammatory Drugs in Water Reclamations' in The Handbook of Environmental Chemistry.View/Download from: Publisher's site
Global water quantity and quality are anticipated to decrease in the coming decades, as a result of both increasing global populations and the effects of climate change. Reusing and recycling water is a key part of reducing the pressure on our existing water supplies and the aquatic environment. However, the occurrence of nonsteroidal anti-inflammatory drugs (NSAIDs) in secondary, and in some tertiary, treated effluents- and sewage-impacted water bodies is one of the major obstacles for the implementation of water reuse. For several decades, NSAIDs have been extensively used for therapeutic purposes in both humans and domestic livestock. The negative effects of NSAIDs on aquatic biota are just beginning to be realized. Currently, intensive treatments are required to remove effectively NSAIDs from recycled treated effluent in order to minimize or eliminate risks to human health and aquatic environment. In this chapter, we focus the discussion on contemporary methods for NSAID removal including biological, physical, chemical, and combined process that may provide a more effective and efficient alternative.
Nguyen, LN, Nguyen, AQ & Nghiem, LD 2019, 'Microbial Community in Anaerobic Digestion System: Progression in Microbial Ecology' in Bui, X-T, Chiemchaisri, C, Fujioka, T & Varjani, S (eds), Water and Wastewater Treatment Technologies, Springer, Singapore, pp. 331-355.View/Download from: Publisher's site
Anaerobic digestion (AD) is a biochemical process that involves four microorganism groups, namely, hydrolyzers, acidogens, acetogens, and methanogens. These groups function in syntrophy and have intra-dependent metabolic pathways. Changes in one group (e.g., over-/underexpressed population and function) can alter this chain of anaerobic process and consequently AD performance. With recent progress in culture-independent techniques, an array of previously unknown and uncultured microorganisms has been recently uncovered in the AD process. Discoveries on the diversity and structure of the AD microbial community can provide new information on digester stability and performance (e.g., biogas production). This chapter provided a critical analysis of the current knowledge on the AD microbial community, focusing on the factors affecting microbial community and the relationship between microbial community and AD performance. Gaining a better understanding of microbial ecology could be the key for greater AD efficiency and biogas production capacity.
Hai, FI, Alturki, A, Nguyen, LN, Price, WE & Nghiem, LD 2016, 'Removal of trace organic contaminants by integrated membrane processes for water reuse applications' in Green Technologies for Sustainable Water Management, pp. 533-578.View/Download from: Publisher's site
© 2016 American Society of Civil Engineers. This chapter discusses advanced technologies for the removal of emerging trace organic contaminants (TrOCs) from wastewater for reuse purposes. In particular, integrated membrane processes for TrOC removal are delineated. In the environment, TrOCs may be present as a mixture of various compounds and their transformation products. Mixtures of TrOCs may impose a more complicated effect when compared to that of a single compound. Water recycling is a pragmatic approach to mitigate or solve the problems of water supply. There is a growing interest in using nontraditional water resources by means of water reclamation and water recycling for long-term sustainability. This chapter explains the removal of TrOCs by existing and advanced treatment processes. Some of the processes include activated carbon adsorption, high-pressure membrane filtration, advanced oxidation processes, and enzymatic degradation. The biomass feature is an important factor for TrOC removal in membrane bioreactor (MBR).
Nguyen, LN, Hai, FI, Nghiem, LD, Kang, J & Price, WE 2010, 'Coupling powdered activated carbon (PAC) adsorption with membrane bioreactor (MBR) treatment for enhanced removal of trace organics', EUROMEMBRANE CONFERENCE 2012, Euromembrane Conference, ELSEVIER SCIENCE BV, London, ENGLAND, pp. 1410-1411.View/Download from: Publisher's site
- Sydney Water Corporation
- University of Sydney