About
58
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Introduction
I am an associate professor of Civil Engineering and Environmental and Ecological Engineering at Purdue University. My research focuses on the application of biotechnologies in engineering systems, such as development of molecular microbiology techniques to evaluate antibiotic resistant bacteria in natural and urban environments, production of cost-effective biofuels, and nanomaterials for water purification.
More information can be found in http://environbiotechnology.com.
Current institution
Publications
Publications (58)
With the extensive detection of antibiotics and antibiotic resistance genes (ARGs) in drinking water treatment plants, the safety of drinking water has received increased attention. Therefore, the distribution and removal of antibiotics and ARGs in drinking water systems require further investigation. In this study, nine typical antibiotics, nine A...
Complete autotrophic nitrogen removal over nitrite (CANON) is used in wastewater treatment. However, the performance of the CANON system significantly decreases at low temperatures; thus, a new strategy to improve the resistance of the CANON system is required. To investigate the impact of sludge ratio control (high-granule, equivalent, and high-fl...
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Adenovirus is among the most UV-resistant waterborne human pathogens. There is a need to identify nonpathogenic surrogates for adenovirus for the water treatment industry. In this study, the feasibility of using the algal virus Paramecium bursaria chlorella virus (PBCV-1) as an adenovirus surrogate for validation of UV reactors was evaluated. The U...
Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment are of great concern for their potential risk to human health. The effluents from wastewater treatment plants and livestock production are important sources of ARB and ARGs. Chlorination, UV irradiation and ozone disinfection could not remove ARGs complete...
Algal biofuel has been advocated as a sustainable and environmentally friendly renewable energy source. However, intensive chemical usage, high energy consumption, and high operation and maintenance costs associated with current cell disruption methods have been identified as main challenges to cost-effective production of algal biofuel. Viral infe...
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Recent, partial nitrification/anammox process has received increasing attention in water nitrogen removal. And denitrification process might also play an indispensable role to enhance nitrogen removal performance. In this study, the symbiosis of heterotrophic denitrification bacteria (HDB) and anaerobic ammonium oxidation bacteria (AAOB) was observ...
In this study, antibiotic resistance to macrolide-lincosamide-streptogramin B (MLS B )antibiotics in total microbial community in surface water in a coastal urban city was measured using a modified fluorescence in situ hybridization (FISH)technique. This FISH technique quantified the rate of antibiotic resistance to MLS B antibiotics through target...
Recently, a flocculent-granular hybrid reactor was reported as a novel nitrogen removal system; however, the mechanisms of stable operation in the system remain unclear. In this study, the mechanisms of the stable nitrogen removal performance in a flocculent-granular hybrid system were investigated with temperature reduction. The operational period...
Understanding the dynamics of biofilm development in response to chemical cues and signals is required toward the development of controllable biofilm‐mediated bioprocesses. In this study, we report a new biofilm growth system that integrates a microfluidic gradient mixer with a biofilm growth chamber. The biofilm growth system allows biofilms to gr...
The occurrence of environmental antibiotic resistance genes (ARGs) are often attributed to selective pressure from antibiotics from point source pollution. However, the potential effects of natural production of antibiotics, environmental factors, and anthropogenic pressure on the development and spread of ARGs have not been fully investigated. Thi...
Electro-Fenton process is an emerging treatment technology for water and wastewater treatment. Electro-Fenton utilizes hydroxyl radicals to oxidize hazardous contaminants and is especially useful to treat recalcitrant compounds that are not easily degraded in conventional water and wastewater treatment plants. This paper reviews the mechanism of el...
Residential plumbing is critical for the health and safety of populations worldwide. A case study was conducted to understand fixture water use, drinking water quality and their possible link, in a newly plumbed residential green building. Water use and water quality were monitored at four in-building locations from September 2015 through December...
Microbial electrosynthesis has been a prominent technique to convert electricity and CO2 to multicarbon extracellular compounds without producing a large-scale crop based biomass. Variety of modified strains and limited wild pure cultures has been used in microbial electrosynthesis cells. Few of the pure cultures successfully produced multicarbon c...
Microbial electrosynthesis (MES) offers a promising approach to sustainable biofuel production by combining microbial metabolism with electrochemical processes. This study aims to improve the effectiveness of biofuel generation using microbial electrolysis cells (MES) by optimizing important elements such as microbial consortia, electrode materials...
Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore were examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by LC-MS/MS, antibiotic resistant bacteria (ARB), class 1 integrase gene ( int1 ), and 16 antibiotic resistant genes (...
Methane production by methanogens in mangrove sediments is known to contribute significantly to global warming, but studies on the shift of methanogenic community in response to anthropogenic contaminations were still limited. In this study, the effect of anthropogenic activities in the mangrove sediments along the north and south coastlines of Sin...
Methanococcus maripaludis is a rapidly growing, fully sequenced, genetically tractable model organism among hydrogenotrophic methanogens. It has the ability to convert CO2 and H2 into a useful cleaner energy fuel (CH4). In fact, this conversion enhances in the presence of free nitrogen as the sole nitrogen source due to prolonged cell growth. Given...
Biological activated carbon (BAC) filter has been widely used as an effective water treatment but regenerations of BAC are costly. Ultrasound has been successfully applied for regeneration of activated carbon but has been less frequently applied to the regenerate the BAC. In this study, bench-scale and pilot-scale experiments were conducted to eval...
Electrochemically active carbon nanotube (CNT) filters have been developed as a highly efficient technology for water and wastewater treatment during the last few years. CNT filters have been widely used to adsorb chemical and biological contaminants due to their high stability, great flexibility, and large specific surface area. Electrochemically...
M. maripaludis, a hydrogenotroph, is capable of reducing CO2 to methane in the presence of electron donors such as H2 or formate. To explore the metabolic potential of M. maripaludis for CO2 conversion to methane, it is crucial to quantify its substrate uptake and methane production rates. In this work, we perform a dynamic cell growth study in a b...
Diazotrophs in the mangrove rhizosphere play a major role in providing new nitrogen to the mangrove ecosystem and their composition and activity are strongly influenced by anthropogenic activity and ecological conditions. In this study, the diversity of the diazotroph communities in the rhizosphere sediment of five tropical mangrove sites with diff...
A solid-phase extraction/liquid chromatography/electrospray ionization/multi-stage mass spectrometry (SPE-LC-ESI-MS/MS) method was optimized in this study for sensitive and simultaneous detection of multiple antibiotics in urban surface waters and soils. Among the seven classes of tested antibiotics, extraction efficiencies of macrolides, lincosami...
Background:
The rapidly growing mesophilic methanogen Methanococcus maripaludis S2 has a unique ability to consume both CO2 and N2, the main components of a flue gas, and produce methane with H2 as the electron donor. The existing literature lacks experimental measurements of CO2 and H2 uptake rates and CH4 production rates on M. maripaludis. Furt...
Electrochemically active carbon nanotube (CNT) filters can effectively adsorb and oxidize chemical compounds in the anode, but the role of a cathode in electrochemical filters beyond a counter electrode has not been thoroughly investigated. In this study, a novel wastewater treatment system was developed to combine both adsorption and oxidation in...
In this work, a carbon nanotube (CNT) electrochemical filter was investigated for treatment of aqueous antibiotics using tetracycline (TC) as a model compound. Electrochemical filtration of 0.2 mM TC at a total cell potential of 2.5 V and a flow rate of 1.5 mL min-1 (hydraulic residence time <2 s) resulted in an oxidative flux of 0.025±0.001 mol hr...
Research has been focused on bioelectrocatalytic CO2 reduction due to the rising levels of atmospheric carbon dioxide (CO2) and the growing need for sustainable alternatives to traditional chemical synthesis. This study explores the capacity of mixed cultures consisting of acetogens and acetate-utilizing Clostridium strains to convert CO2 into high...
A novel graphene-based electrochemical filter with carbon nanotubes as conductive binders was developed for water purification. Ferrocyanide (Fe(CN)64−) was used as a model compound to study electron transfer mechanisms in the electrochemical filter. A 70%:30% ratio of graphene:carbon nanotube was optimal for electrochemical oxidation of Fe(CN)64−,...
Methane is a major energy source for heating and electricity. Its production by methanogenic bacteria is widely known in nature. M. maripaludis S2 is a fully sequenced hydrogenotrophic methanogen and an excellent laboratory strain with robust genetic tools. However, a quantitative systems biology model to complement these tools is absent in the lit...
The sludge compartment in livestock waste management structures is a potential hotbed for the emergence and proliferation of antimicrobial resistance among bacteria. Little is known about the distribution of antimicrobial resistance genes (ARGs) between the intracellular and extracellular DNA pools in the sludge. The overall objective of this study...
Microbial electrosynthesis (MES) shows potential for generating sustainable methane through the utilization of microbial activity and electrochemical processes. The core focus of MES is the effective production of hydrogen, which plays a crucial role as a primary component for methane synthesis. This study examines the rates of hydrogen production...
Renewable energy sources, which are abundant and cheap but intermittent need to be stored in a more convenient form of energy such as biofuels in the form of chemical bonds through microbial activities, which are called as microbial electrosynthesis. A group of organisms, which can accept or transfer electrons directly to or from electrodes, called...
While environmental engineering students have gained some knowledge of biogeochemical cycles and sewage treatment, most of them haven’t learned microbiology previously and usually have difficulty in learning environmental microbiology because microbiology deals with invisible living microorganisms instead of visible built environment. Many teaching...
Current agricultural practices involve inclusion of antimicrobials in animal feed and result in manure containing antimicrobials
and antimicrobial-resistant microorganisms. This work evaluated the effects of land application of swine manure on the levels
of tetracycline, macrolide, and lincosamide antimicrobials and on macrolide, lincosamide, and s...
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.
A subscription to the Proceedings of the Water Environment Feder...
To investigate the relationship between agricultural antimicrobial use and resistance, a variety of methods for quantification
of macrolide-lincosamide-streptogramin B (MLSB) resistance were applied to organic swine farm manure samples. Fluorescence in situ hybridization was used to indirectly
quantify the specific rRNA methylation resulting in MLS...
The shortage of fresh water is a severe problem for many areas of the world. Water reclamation and reuse provide promising opportunities to ease fresh water shortage problems. However, data and technical information for low-cost treatment technologies for small-scale water reuse projects are often unavailable, especially to communities with limited...
South Florida water utilities are facing some of the largest and most challenging water supply issues they have ever encountered. As a result, South Florida utilities are seeking alternative sources of water. As part of this effort, the City of Plantation and the South Florida Water
Management District entered into a cooperative agreement to evalua...
The supplementation of surface water and groundwater with highly treated wastewater raises environmental and public health concerns. Current research suggests that the microconstituents (often referred to as endocrine disrupting and pharmaceutically active compounds) found in reverse osmosis permeate pose no human health risk, though public concern...
When fluorescence in situ hybridization (FISH) analyses are performed with complex environmental samples, difficulties related to the presence of microbial cell aggregates and nonuniform background fluorescence are often encountered. The objective of this study was to develop a robust and automated quantitative FISH method for complex environmental...
Effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water, Microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. Exogenous 32P was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of differen...
Hexadecyltrimethylammonium (HDTMA)-modified montmorillonite (HMM) has recently been recognized as a potential sorbentto remove organic contaminants from environmental systems. Potential applications of this material highly depend on the efficiency of regenerating contaminant-sorbing HMM. In this study, we investigated a chemical (NaOH solution) and...
Natural montmorillonite was modified with a quaternary ammonium compound, hexadecyltrimethylammonium (HDTMA). The sedimentation capabilities of unmodified and modified montmorillonites were then investigated. The sedimentation velocity of modified montmorillonites increased if the amounts of adsorbed HDTMA were from 0.3 to 1.0 times the cation exch...
