Tao Lyu
Nottingham Trent University
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Featured researches published by Tao Lyu.
Water Research | 2018
Liang Zhang; Tao Lyu; Yang Zhang; Mark Button; Carlos A. Arias; Kela P. Weber; Hans Brix; Pedro N. Carvalho
Microbial degradation is an important pathway during the removal of pharmaceuticals in constructed wetlands (CWs). However, the effects of CW design, plant presence, and different plant species on the microbial community in CWs have not been fully explored. This study aims to investigate the microbial community metabolic function of different types of CWs used to treat ibuprofen via community-level physiological profiling (CLPP) analysis. We studied the interactions between three CW designs (unsaturated, saturated and aerated) and six types of mesocosms (one unplanted and five planted, with Juncus, Typha, Berula, Phragmites and Iris) treating synthetic wastewater. Results show that the microbial activity and metabolic richness found in the interstitial water and biofilm of the unsaturated designs were lower than those of the saturated and aerated designs. Compared to other CW designs, the aerated mesocosms had the highest microbial activity and metabolic richness in the interstitial water, but similar levels of biofilm microbial activity and metabolic richness to the saturated mesocosms. In all three designs, biofilm microbial metabolic richness was significantly higher (pu202f<u202f.05) than that of interstitial water. Both the interstitial water and biofilm microbial community metabolic function were influenced by CW design, plant presence and species, but design had a greater influence than plants. Moreover, canonical correlation analysis indicated that biofilm microbial communities in the three designs played a key role in ibuprofen degradation. The important factors identified as influencing ibuprofen removal were microbial AWCD (average well color development), microbial metabolic richness, and the utilization of amino acids and amine/amides. The enzymes associated with co-metabolism of l-arginine, l-phenyloalanine and putrescine may be linked to ibuprofen transformations. These results provide useful information for optimizing the operational parameters of CWs to improve ibuprofen removal.
Environmental Pollution | 2018
Tao Lyu; Keli He; Renjie Dong; Shubiao Wu
This study investigated the treatment performance and nitrogen removal mechanism of highly alkaline ammonia-stripped digestate effluent in horizontal subsurface flow constructed wetlands (CWs). A promising nitrogen removal performance (up to 91%) was observed in CWs coupled with intensified configurations, i.e., aeration and effluent recirculation. The results clearly supported that the higher aeration ratio and presence of effluent recirculation are important to improve the alkalinity and pollutant removal in CWs. The influent pH (>10) was significantly decreased to 8.2-8.8 under the volumetric hydraulic loading rates of 0.105 and 0.21 d-1 in the CWs. Simultaneously, up to 91% of NH4+-N removal was achieved under the operation of a higher aeration ratio and effluent recirculation. Biological nitrogen transformations accounted for 94% of the consumption of alkalinity in the CWs. The significant enrichment of δ15N-NH4+ in the effluent (47-58‰) strongly supports the occurrence of microbial transformations for NH4+-N removal. However, relatively lower enrichment factors of δ15N-NH4+ (-1.8‰ toxa0-11.6‰) compared to the values reported in previous studies reflected the inhibition effect of the high pH alkaline environment on nitrifiers in these CWs.
Environmental Pollution | 2018
Tao Lyu; Liang Zhang; Xiao Xu; Carlos A. Arias; Hans Brix; Pedro N. Carvalho
Constructed wetlands (CWs) are a promising technology to treat pesticide contaminated water, but its implementation is impeded by lack of data to optimize designs and operating factors. Unsaturated and saturated CW designs were used to compare the removal of triazole pesticide, tebuconazole, in unplanted mesocosms and mesocosms planted with five different plant species: Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta. Tebuconazole removal efficiencies were significantly higher in unsaturated CWs than saturated CWs, showing for the first time the potential of unsaturated CWs to treat tebuconazole contaminated water. An artificial neural network model was demonstrated to provide more accurate predictions of tebuconazole removal than the traditional linear regression model. Also, tebuconazole removal could be fitted an area-based first order kinetics model in both CW designs. The removal rate constants were consistently higher in unsaturated CWs (range of 2.6-10.9xa0cmxa0d-1) than in saturated CWs (range of 1.7-7.9xa0cmxa0d-1) and higher in planted CWs (range of 3.1-10.9xa0cmxa0d-1) than in unplanted CWs (range of 1.7-2.6xa0cmxa0d-1) for both designs. The low levels of sorption of tebuconazole to the substrate (0.7-2.1%) and plant phytoaccumulation (2.5-12.1%) indicate that the major removal pathways were biodegradation and metabolization inside the plants after plant uptake. The main factors influencing tebuconazole removal in the studied systems were system design, hydraulic loading rate and plant presence. Moreover, tebuconazole removal was positively correlated to dissolved oxygen and all nutrients removal.
Journal of Environmental Sciences-china | 2018
Gang Pan; Tao Lyu; Robert J.G. Mortimer
Phosphorus (P) reserve, largely derived from phosphate rock, microalgae utilization technologies may greatly accelerate is essential for crop growth to support the growing world population. However, a significant proportion of phosphorus used as a fertilizer runs into natural waters, causing eutrophication and ecological damage. Moreover, most P in the food is eventually discharged as waste after being digested by human and animals. Thus, industrial activities have created a one-way flow of non-renewable P from rocks to farms to lakes, rivers and oceans. It has been suggested that P reserve can only support global food security for up to 125 years (Gilbert, 2009). Due to technological and economic reasons, existing wastewater treatment and environmental stewardship laws permit a relatively high level of P (~0.3 mg/L) to be discharged into natural environment, which will cause eutrophication. Phosphorus recovery has become an important issue for agricultural sustainability and aquatic ecology. Existing technologies for re-capturing P from concentrated wastes still remain unsustainable due to high chemical and energy costs (Zhou et al., 2017; Zhang et al., 2017). We predict that in the near future we have no option but to find cost-effective and sustainable methods to re-capture P from the natural waters where it currently ends up. Harmful algal bloom has become an important issue in eutrophic natural waters, which represent a great threat to public health and cause ecological degradation (Conley et al. 2009). However, microalgae are exceptionally effective in turning low levels of dissolved P into concentrated particulate P, and at very much faster rates than the geological mineralisation processes that created our P reserves. Recent developments have made it possible to remove large scale harmful algal blooms through flocculation using ecologically friendly geo-engineeredmaterials (Pan et al. 2006, 2011; Li and Pan 2013; Li et al. 2015; Shi et al. 2016; Yuan et al. 2016). This principlemakes it possible to harvest algal biomass and take P out of natural waters cost-effectively by combining with conventional air floating technologies. We predict that there will be a tipping point to make it feasible to re-capture from natural waters when the supplying of food, water and energy to the growing global population becomes unsustainable, and
Environmental Science & Technology | 2018
Shubiao Wu; Tao Lyu; Yaqian Zhao; Jan Vymazal; Carlos A. Arias; Hans Brix
Technology for Wastewater Treatment Shubiao Wu,*,†,‡ Tao Lyu, Yaqian Zhao, Jan Vymazal, Carlos A. Arias, and Hans Brix †College of Engineering, China Agricultural University, Beijing 100083, China ‡Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Nottinghamshire NG25 0QF, U.K. Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kymyćka ́ 129, 165 21 Praha 6, Czech Republic Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin, 4, Ireland Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
Science of The Total Environment | 2019
Yang Zhang; Tao Lyu; Liang Zhang; Mark Button; Carlos A. Arias; Kela P. Weber; Jianghong Shi; Zhanghe Chen; Hans Brix; Pedro N. Carvalho
The aim of the present study was to elucidate the microbial community metabolic profiles in saturated constructed wetland (CW) mesocosms planted with five different wetland plant species fed with water individually spiked with 100u202fμgu202fL-1 ibuprofen or iohexol. Community-level physiological profiling (CLPP) using Biolog Ecoplates was performed and coupled with the assessment of water quality parameters (water temperature, pH, DO and TOC, TN, NH4-N, PO4-P removal efficiency). The microbial community metabolic profiles (microbial activity, richness, and carbon source utilization), as well as the water quality parameters revealed similar trends among the control mesocosms and the mesocosms fed with water spiked with iohexol and ibuprofen. Significant differences were observed between the planted and unplanted mesocosms and between seasons (summer and winter) within each of the feeding lines (control, iohexol or ibuprofen). The microbial community metabolic profiles in the saturated CW were shaped by plant presence and plant species, while no negative impact of iohexol and ibuprofen presence was noticed at the 100u202fμgu202fL-1. In addition, the microbial activity and richness were generally higher in planted mesocosms than in the unplanted systems in the summer. For the first time, a positive correlation between iohexol removal and the microbial community metabolic profiles (activity, richness and amines and amides utilization in summer, and carbohydrates utilization in winter) in the saturated mesocosms was observed. Putrescine utilization in the summer and d-cellobiose, d,l-alpha-glycerol phosphate in winter were linked with the metabolic processing of iohexol, while glycogen in summer and l-phenylalanine, Glycyl-l-glutamic acid in winter were linked with ibuprofen removal efficiency in the saturated CW.
Science of The Total Environment | 2018
Honggang Zhang; Tao Lyu; Lei Bi; Grant Wayne Tempero; David P. Hamilton; Gang Pan
Combating hypoxia/anoxia is an increasingly common need for restoring natural waters suffering from eutrophication. Oxygen nanobubble modified natural particles were investigated for mitigating hypoxia/anoxia at the sediment-water interface (SWI) in a simulated column experiment. By adding oxygen nanobubble modified zeolites (ONMZ) and local soils (ONMS), the oxygen nanobubble concentrations (105-107u202fparticles/mL) were several orders of magnitude higher in the water than the original water solution (104u202fparticles/mL) within 24u202fh. In the column experiment, an oxygen-locking surface sediment layer was formed after capping with ONMZ and ONMS particles. The synergy of diffusion of oxygen nanobubbles and retention of oxygen in this layer contributes to both the increase of DO and reversal of hypoxic conditions. The overlying water had significantly higher dissolved oxygen (DO) values (4-7.5u202fmg/L) over the experimental period of 127u202fdays in ONMZ and ONMS compared with the control systems (around 1u202fmg/L). Moreover, the oxidation-reduction potential (ORP) was reversed from -200u202fmV to 180-210u202fmV and maintained positive values for 89u202fdays in ONMZ systems. In the control systems, ORP was consistently negative and decreased from -200u202fmV to -350u202fmV. The total phosphorus (TP) flux from sediment to water across the SWI was negative in the ONMZ and ONMS treated systems, but positive in the control system, indicating the sediment could be switched from TP source to sink. The oxygen-locking capping layer was crucial in preventing oxygen consumption caused by the reduced substances released from the anoxic sediment. The study outlines a potentially promising technology for mitigating sediment anoxia and controlling nutrient release from sediments, which could contribute significantly to addressing eutrophication and ecological restoration.
Environmental Science & Technology | 2018
Honggang Zhang; Yuanyuan Shang; Tao Lyu; Jun Chen; Gang Pan
Switching the dominance from algae to macrophytes is crucial for lake management of human-induced eutrophication. Nutrients from algal sources can be utilized in the process of transition from algal blooms to macrophytes, thereby mitigating eutrophication. However, this process rarely occurs in algal bloom dominated waters. Here, we examined the hypothesis that the transition of algal blooms to macrophytes and the transfer of nutrients from algae at different temperatures (8 and 25 °C) can be facilitated by using a geo-engineering method. The results showed that the combination of flocculation and capping treatment could not only remove Microcystis aeruginosa blooms from eutrophic waters but also facilitate algal decomposition and incorporation into a submerged macrophyte ( Potamogeton crispus) biomass. The flocculation-capping treatment could trigger algal cell lysis. As compared with the control groups, the photosynthesis and respiration rate of algae were inhibited and chlorophyll-a (Chl- a) concentrations were significantly reduced in the flocculation-capping treatment groups. The 15N tracing study revealed that 3.3% and 34.8% of algae-derived nitrogen could be assimilated by Potamogeton crispus at 8 and 25 °C, respectively. The study demonstrated that the flocculation-capping method can facilitate the switchover from algae- to the macrophyte-dominated state, which is crucial for restoring the aquatic ecosystem.
Environmental Pollution | 2018
Liang Zhang; Tao Lyu; Carlos Andrés Ramírez Vargas; Carlos A. Arias; Pedro N. Carvalho; Hans Brix
Constructed wetlands (CWs) are an eco-friendly and cost-effective technology to remove organic micro-pollutants (OMPs) from wastewater. The support matrix is an important component in CWs as it has a primary role in the growth and development of plants and microbes. However, the roles of the support matrix in CWs in removing OMPs have not been systematically studied. Therefore, in this study, six common materials (sand, zeolite, blast iron slag, petcoke, polonite and crushed autoclaved aerated concrete (CAAC)) as support matrixes were firstly investigated by batch tests to explore their adsorption capacities to selected OMPs (ibuprofen, iohexol, tebuconazole and imazalil). Results showed that the adsorption capacities of the materials were low (at the level of μg/g) compared to well-known sorbents (at the level of mg/g), such as activated carbon and carbon nanotubes. Columns packed with the six materials, respectively, were then built up to study the effects of different materials on microbial community. In the medium-term study (66 days), the removal of four OMPs in all the columns increased by 2-58% from day 25 to day 66, and was mainly attributed to microbial degradation. Furthermore, Community-level physiological profiling (CLPP) analysis indicates that material presence shaped the microbial community metabolic function not only in the interstitial water but also in the biofilm. Overall, all the findings demonstrate that although the adsorption capacities of the common materials are low, they may be a driver to improve the removal of OMPs by altering microbial community function in CWs.
ACS Omega | 2018
Lei Wang; Xiaojun Miao; Jafar Ali; Tao Lyu; Gang Pan
Interfacial nanobubbles can exist on various hydrophobic and hydrophilic material interfaces. There are diverse applications for oxygen nanobubbles, which are closely related to their content and long-term stability. However, it remains challenging to determine the amount of nanobubbles loaded in a porous material. In this study, a novel method was used to quantify the total amount of oxygen nanobubbles loaded onto irregular particulate materials. Different materials were evaluated and their oxygen-loading capacities were found to be as follows: activated carbon (AC) > zeolite > biochar > diatomite > coal ash > clay. Significant differences in oxygen-loading capacities were mainly ascribed to differences in the specific surface area and hydrophobic/hydrophilic properties of the materials. The total oxygen loading on AC achieved using the high pressure loading method was higher than that achieved by the temperature variation method. This new quantitative method provides the possibility for the manipulation of oxygen nanobubble materials in practical applications and it is anticipated to be an important supplement to the existing methods of characterizing interfacial oxygen nanobubbles. Our results demonstrate that materials containing oxygen nanobubbles can significantly increase the dissolved oxygen and oxidation reduction potential in anaerobic systems. With the addition of oxygen-loaded materials (such as AC), the survival time of zebrafish was prolonged up to 20 h in a deoxygenated water system, and the germination rate of Vallisneria spiralis was also increased from 27 to 73% in an anaerobic sediment.