14 results on '"Sunny C"'
Search Results
2. Application of unstructured kinetic models to predict microcystin biodegradation: Towards a practical approach for drinking water treatment
- Author
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Manheim, Derek C., Detwiler, Russell L., and Jiang, Sunny C.
- Published
- 2019
- Full Text
- View/download PDF
3. Evaluation of the dry and wet weather recreational health risks in a semi-enclosed marine embayment in Southern California
- Author
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Lim, Keah-Ying, Shao, Stella, Peng, Jian, Grant, Stanley B., and Jiang, Sunny C.
- Published
- 2017
- Full Text
- View/download PDF
4. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell
- Author
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Huang, Xiao, Qu, Yan, Cid, Clément A., Finke, Cody, Hoffmann, Michael R., Lim, Keahying, and Jiang, Sunny C.
- Published
- 2016
- Full Text
- View/download PDF
5. Reevaluation of health risk benchmark for sustainable water practice through risk analysis of rooftop-harvested rainwater
- Author
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Lim, Keah-Ying and Jiang, Sunny C.
- Published
- 2013
- Full Text
- View/download PDF
6. Shifts in dissolved organic matter and microbial community composition are associated with enhanced removal of fecal pollutants in urban stormwater wetlands
- Author
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Stanley B. Grant, Brandon K. Winfrey, Sunny C. Jiang, Andrew S. Mehring, Xiao Huang, and Megan A. Rippy
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Chlorophyll ,Time Factors ,Environmental Engineering ,Victoria ,Microbial Consortia ,0208 environmental biotechnology ,Stormwater ,Indicator bacteria ,Wetland ,02 engineering and technology ,010501 environmental sciences ,Cyanobacteria ,01 natural sciences ,California ,Feces ,Proteobacteria ,Microbial community ,Dissolved organic carbon ,Dissolved organic matter ,Ecosystem ,Water pollution ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Stormwater wetland ,geography ,geography.geographical_feature_category ,Pathogen ,Chlorophyll A ,Ecological Modeling ,Water Pollution ,food and beverages ,Pollution ,020801 environmental engineering ,Water quality ,Microbial population biology ,Fecal indicator bacteria ,Wetlands ,Environmental chemistry ,Environmental science ,Environmental Pollutants ,Enterococcus - Abstract
Constructed stormwater wetlands provide a host of ecosystem services, including potentially pathogen removal. We present results from a multi-wetland study that integrates across weather, chemical, microbiological and engineering design variables in order to identify patterns of microbial contaminant removal from inlet to outlet within wetlands and key drivers of those patterns. One or more microbial contaminants were detected at the inlet of each stormwater wetland (Escherichia coli and Enterococcus > Bacteroides HF183 > adenovirus). Bacteroides HF183 and adenovirus concentrations declined from inlet to outlet at all wetlands. However, co-removal of pathogens and fecal indicator bacteria only occurred at wetlands where microbial assemblages at the inlet (dominated by Proteobacteria and Bacteriodetes) were largely displaced by indigenous autotrophic microbial communities at the outlet (dominated by Cyanobacteria). Microbial community transitions (characterized using pyrosequencing) were well approximated by a combination of two rapid indicators: (1) fluorescent dissolved organic matter, and (2) chlorophyll a or phaeophytin a fluorescence. Within-wetland treatment of fecal markers and indicators was not strongly correlated with the catchment-to-wetland area ratio, but was diminished in older wetlands, which may point to a need for more frequent maintenance.
- Published
- 2018
7. Evaluation of the dry and wet weather recreational health risks in a semi-enclosed marine embayment in Southern California
- Author
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Jian Peng, Stanley B. Grant, Keah-Ying Lim, Sunny C. Jiang, and Stella Shao
- Subjects
0301 basic medicine ,Engineering ,Environmental Engineering ,030106 microbiology ,Stormwater ,Indicator bacteria ,010501 environmental sciences ,01 natural sciences ,Bathing Beaches ,California ,Feces ,03 medical and health sciences ,Environmental monitoring ,Humans ,Weather ,Waste Management and Disposal ,Recreation ,Nonpoint source pollution ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Hydrology ,business.industry ,Ecological Modeling ,Pollution ,Human waste ,Water quality ,Water Microbiology ,business ,Water resource management ,Risk assessment ,geographic locations ,Environmental Monitoring - Abstract
For many coastal regions around the world, recreational beach water quality is assessed using fecal indicator bacteria (FIB). However, the utility of FIB as indicators of recreational water illness (RWI) risk has been questioned, particularly in coastal settings with no obvious sources of human sewage. In this study we employed a source-apportionment quantitative microbial risk assessment (SA-QMRA) to assess RWI risk at a popular semi-enclosed recreational beach in Southern California (Baby Beach, City of Dana Point) with no obvious point sources of human sewage. Our SA-QMRA results suggest that, during dry weather, the median RWI risk at this beach is below the U.S. EPA recreational water quality criteria (RWQC) of 36 illness cases per 1000 bathers. During wet weather, the median RWI risk predicted by SA-QMRA depends on the assumed level of human waste associated with stormwater; the RWI risk is below the EPA RWQC illness risk benchmark 100% of the time provided that
- Published
- 2017
8. Balancing carbon, nitrogen and phosphorus concentration in seawater as a strategy to prevent accelerated membrane biofouling
- Author
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Sunny C. Jiang, Nikolay Voutchkov, and Siqian Huang
- Subjects
Osmosis ,Environmental Engineering ,Biofouling ,Nitrogen ,0208 environmental biotechnology ,chemistry.chemical_element ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Desalination ,Water Purification ,RNA, Ribosomal, 16S ,Seawater ,Reverse osmosis ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Fouling ,Ecological Modeling ,Phosphorus ,Biofilm ,Membranes, Artificial ,Pollution ,Carbon ,020801 environmental engineering ,Membrane ,chemistry ,Environmental chemistry ,Biofilms - Abstract
Membrane biofouling remains a significant challenge in seawater reverse osmosis desalination for drinking water production. This study investigated nutrient imbalance as the cause of biofouling in lab-scale experiments and carried out a year-long field-testing at a seawater desalination pilot plant. Lab experiments showed that growth medium with excess of organic carbon (C) but with low nitrogen (N) and phosphorus (P) accelerated the formation of bacterial biofilm. Balancing C to N and P ratios by adding N and P to growth medium increased the proliferation of free-living cells but reduced attached form of bacteria as biofilm. The cell excretion of excess C in the form of extracellular polysaccharides (EPS) was considered as a strategy for nutrient storage for future use. Cell enzyme activity assays indicated some of the bacteria had enhanced enzyme activities to degrade polysaccharides in the absence of organic C in growth medium, possibly using EPS in the biofilm. A year-long field study indicated that accelerated biofouling of seawater reverse osmosis (SWRO) membranes was associated with the elevated content of total organic carbon (TOC) in the intake seawater. Adding N and P to the intake seawater to balance the increase of TOC resulted in reduction of membrane biofouling. Microbial community analysis of the biofouling layer using 16S rRNA gene sequencing indicated biofouling communities varied with seasonal changes. Dosing of N and P did not induce dramatic changes in the fouling microbial community growing on the membrane surface. The outcome of this work implies that membrane biofouling associated with the elevated concentration of TOC in intake seawater is caused by imbalance of C:N:P in the source seawater which occurs often during algal blooms. Addition of N and P to rebalance the nutrients can prevent accelerated SWRO membrane biofouling.
- Published
- 2019
9. Assessing the water quality impacts of two Category-5 hurricanes on St. Thomas, Virgin Islands
- Author
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Sunny C. Jiang, Srikiran Chandrasekaran, Yingcong Fang, Christina A. Kellogg, and Muyue Han
- Subjects
Environmental Engineering ,Legionella ,Rain ,0208 environmental biotechnology ,Indicator bacteria ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Article ,Enterococcus faecalis ,Feces ,United States Virgin Islands ,Disaster area ,Next generation sequencing ,Virgin Islands ,Water Quality ,Humans ,Rain cistern ,14. Life underwater ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Islands ,biology ,Cyclonic Storms ,Cistern ,Ecological Modeling ,Disaster management ,biology.organism_classification ,Pollution ,6. Clean water ,020801 environmental engineering ,Fishery ,Geography ,Microbial population biology ,13. Climate action ,Water quality ,Water Microbiology ,Surface runoff - Abstract
Managing waterborne and water-related diseases is one of the most critical factors in the aftermath of hurricane-induced natural disasters. The goal of the study was to identify water-quality impairments in order to set the priorities for post-hurricane relief and to guide future decisions on disaster preparation and relief administration. Field investigations were carried out on St. Thomas, U.S. Virgin Islands as soon as the disaster area became accessible after the back-to-back hurricane strikes by Irma and Maria in 2017. Water samples were collected from individual household rain cisterns, the coastal ocean, and street-surface runoffs for microbial concentration. The microbial community structure and the occurrence of potential human pathogens were investigated in samples using next generation sequencing. Loop mediated isothermal amplification was employed to detect fecal indicator bacteria, Enterococcus faecalis. The results showed both fecal indicator bacteria and Legionella genetic markers were prevalent but were low in concentration in the water samples. Among the 22 cistern samples, 86% were positive for Legionella and 82% for Escherichia-Shigella. Enterococcus faecalis was detected in over 68% of the rain cisterns and in 60% of the coastal waters (n = 20). Microbial community composition in coastal water samples was significantly different from cistern water and runoff water. Although identification at bacterial genus level is not direct evidence of human pathogens, our results suggest cistern water quality needs more organized attention for protection of human health, and that preparation and prevention measures should be taken before natural disasters strike., Graphical abstract Image 1, Highlights • Rain cistern, coastal ocean and surface runoff waters were sampled post hurricanes. • Microbial community composition was dramatically different in each type of water. • Fecal indicator bacteria and Legionella were prevalent in all water samples. • The concentrations of Legionella and fecal indicator bacteria were generally low.
- Published
- 2020
10. Application of unstructured kinetic models to predict microcystin biodegradation: Towards a practical approach for drinking water treatment
- Author
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Sunny C. Jiang, Derek C. Manheim, and Russell L. Detwiler
- Subjects
Specific growth ,Environmental Engineering ,Microcystins ,0208 environmental biotechnology ,02 engineering and technology ,Microcystin ,010501 environmental sciences ,Bacterial growth ,01 natural sciences ,Water Purification ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,chemistry.chemical_classification ,Ecological Modeling ,Model selection ,Bayesian optimization ,Bayes Theorem ,Biodegradation ,Pollution ,6. Clean water ,020801 environmental engineering ,Kinetics ,Biodegradation, Environmental ,chemistry ,13. Climate action ,Water treatment ,Biochemical engineering ,Energy source - Abstract
Biological drinking water treatment technologies offer a cost-effective and sustainable approach to mitigate microcystin (MC) toxins from harmful algal blooms. To effectively engineer these systems, an improved predictive understanding of the bacteria degrading these toxins is required. This study reports an initial comparison of several unstructured kinetic models to describe MC microbial metabolism by isolated degrading populations. Experimental data was acquired from the literature describing both MC removal and cell growth kinetics when MC was utilized as the primary carbon and energy source. A novel model-data calibration approach melding global single-objective, multi-objective, and Bayesian optimization in addition to a fully Bayesian approach to model selection and hypothesis testing were applied to identify and compare parameter and predictive uncertainties associated with each model structure. The results indicated that models incorporating mechanisms of enzyme-MC saturation, affinity, and cooperative binding interactions of a theoretical single, rate limiting reaction accurately and reliably predicted MC degradation and bacterial growth kinetics. Diverse growth characteristics were observed among MC degraders, including moderate to high maximum specific growth rates, very low to substantial affinities for MC, high yield of new biomass, and varying degrees of cooperative enzyme-MC binding. Model predictions suggest that low specific growth rates and MC removal rates of degraders are expected in practice, as MC concentrations in the environment are well below saturating levels for optimal growth. Overall, this study represents an initial step towards the development of a practical and comprehensive kinetic model to describe MC biodegradation in the environment.
- Published
- 2018
11. Shifts in dissolved organic matter and microbial community composition are associated with enhanced removal of fecal pollutants in urban stormwater wetlands
- Author
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Huang, Xiao, primary, Rippy, Megan A., additional, Mehring, Andrew S., additional, Winfrey, Brandon K., additional, Jiang, Sunny C., additional, and Grant, Stanley B., additional
- Published
- 2018
- Full Text
- View/download PDF
12. Evidence for groundwater and surface marine water contamination by waste disposal wells in the Florida keys
- Author
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Joan B. Rose, John H. Paul, Samual Farrah, Sunny C. Jiang, Jordan B. Kang, Christina A. Kellogg, Dale W. Griffin, Jerzy Lukasik, Xingting Zhou, and Pamela K. Cochran
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Hydrology ,geography ,Environmental Engineering ,geography.geographical_feature_category ,Ecological Modeling ,Bedrock ,Environmental engineering ,Pollution ,Wastewater ,Environmental science ,Seawater ,Water quality ,Water pollution ,Waste Management and Disposal ,Injection well ,Groundwater ,Water Science and Technology ,Civil and Structural Engineering ,Waste disposal - Abstract
One of the methods for domestic wastewater disposal in the Florida Keys is injection of partially treated wastewater into the highly porous limestone bedrock using waste disposal or injection wells. In an effort to understand the transport and fate of wastewater, we utilized bacteriophages as tracers in a 12.2-m deep, simulated injection well in Key Largo and an active (27.4 m deep) class V disposal well in the Middle Keys. The latter is the currently permitted type of injection well used for multi-unit domestic waste disposal in the Keys. Surface waters and groundwater at several sites were monitored for 5 days after seeding of the injection wells. In both environments, viral tracers appeared after short periods of time in groundwater (8 h after injection) and surface marine waters (10 h and 53 h for Key Largo and the Middle Keys, respectively). Estimated rates of tracer movement were greatest in Key Largo (2.5–35 m/h), where tidal pumping was implicated in tracer movement. In the Middle Keys, the pattern of movement showed little evidence of tidal pumping, and migration rates were slower (0.12–2 m/h). Collectively these results indicate that wastewater injected into the subsurface can make its way rapidly to surface marine waters, where it may contribute to water quality deterioration.
- Published
- 1997
13. Reevaluation of health risk benchmark for sustainable water practice through risk analysis of rooftop-harvested rainwater
- Author
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Sunny C. Jiang and Keah-Ying Lim
- Subjects
Risk analysis ,Irrigation ,Environmental Engineering ,Agricultural Irrigation ,Rain ,Food Contamination ,Infections ,Risk Assessment ,Rainwater harvesting ,Solanum lycopersicum ,Overhead (business) ,Environmental protection ,Environmental health ,Humans ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering ,Consumption (economics) ,Ecological Modeling ,Drinking Water ,Water ,Lettuce ,Models, Theoretical ,Pollution ,Reclaimed water ,United States ,Relative risk ,Environmental science ,Cucumis sativus ,Risk assessment ,Water Microbiology - Abstract
Health risk concerns associated with household use of rooftop-harvested rainwater (HRW) constitute one of the main impediments to exploit the benefits of rainwater harvesting in the United States. However, the benchmark based on the U.S. EPA acceptable annual infection risk level of ≤1 case per 10,000 persons per year (≤10 −4 pppy) developed to aid drinking water regulations may be unnecessarily stringent for sustainable water practice. In this study, we challenge the current risk benchmark by quantifying the potential microbial risk associated with consumption of HRW-irrigated home produce and comparing it against the current risk benchmark. Microbial pathogen data for HRW and exposure rates reported in literature are applied to assess the potential microbial risk posed to household consumers of their homegrown produce. A Quantitative Microbial Risk Assessment (QMRA) model based on worst-case scenario (e.g. overhead irrigation, no pathogen inactivation) is applied to three crops that are most popular among home gardeners (lettuce, cucumbers, and tomatoes) and commonly consumed raw. The infection risks of household consumers attributed to consumption of these home produce vary with the type of produce. The lettuce presents the highest risk, which is followed by tomato and cucumber, respectively. Results show that the 95th percentile values of infection risk per intake event of home produce are one to three orders of magnitude (10 −7 to 10 −5 ) lower than U.S. EPA risk benchmark (≤10 −4 pppy). However, annual infection risks under the same scenario (multiple intake events in a year) are very likely to exceed the risk benchmark by one order of magnitude in some cases. Estimated 95th percentile values of the annual risk are in the 10 −4 to 10 −3 pppy range, which are still lower than the 10 −3 to 10 −1 pppy risk range of reclaimed water irrigated produce estimated in comparable studies. We further discuss the desirability of HRW for irrigating home produce based on the relative risk of HRW to reclaimed wastewater for irrigation of food crops. The appropriateness of the ≤10 −4 pppy risk benchmark for assessing safety level of HRW-irrigated fresh produce is questioned by considering the assumptions made for the QMRA model. Consequently, the need of an updated approach to assess appropriateness of sustainable water practice for making guidelines and policies is proposed.
- Published
- 2013
14. Evidence for groundwater and surface marine water contamination by waste disposal wells in the Florida keys
- Author
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Paul, John H., primary, Rose, Joan B., additional, Jiang, Sunny C., additional, Zhou, Xingting, additional, Cochran, Pamela, additional, Kellogg, Christina, additional, Kang, Jordan B., additional, Griffin, Dale, additional, Farrah, Samual, additional, and Lukasik, Jerzy, additional
- Published
- 1997
- Full Text
- View/download PDF
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