Day 1 :
Keynote Forum
Josef Winter
Karlsruhe Institute of Technology, Germany
Keynote: Microbial growth and biofilm formation in the capillary fringe above the groundwater table
Biography:
Josef Winter is a Chemist and Microbiologist with research experience of more than 30 years in the Field of Aerobic and Anaerobic Wastewater and Waste Treatment, Soil Remediation and Groundwater Pollution. He has published more than 100 articles in peer-reviewed journals and is a member of different professional NGOs. He retiered in the year 2016
Abstract:
Soil and groundwater are naturally inhabited by a vast variety of prokaryotes. It was estimated that 2.5 x 1029 microorganisms live in the top 8 m of the terrestrial subsurface and at least 2.5 x 1030 microorganisms below 8 m depth, either suspended in the water phase or immobilized as a biofilm on organic and mineral compounds. Capillary fringes (CFs) form the interface between groundwater-saturated soil and the unsaturated underground and may be as thin as a few centimetres but can also span over more than one meter above the water table. Microbial life in the vadose zone (zone above permanent water saturation) requires adaptive strategies to cope with unfavorable conditions such as dryness, growth-limiting moisture content or inadequate supply of carbonaceous compounds and oxygen or other electron acceptors. Human activity may cause severe local pollution associated with surplus substrate supply, toxicity or other harmfull effects for the soil bacteria. As a consequence of the highly variable presence of water that is essential for bacterial growth and a variable supply of growth substrates, surface-attached growth and life in biofilms is an appropriate strategy for survival. Biofilm formation in an oligotrophic, groundwater-saturated underground and in the capillary fringe (CF) above the water table is however a very slow process due to severe nutrient limitation. Because of low groundwater flow rates, non-motile and motile bacteria have sufficient time to passively or actively attach to mineral surfaces at places or in the vicinity of a growth-supporting environment to form a stationary and permanent biofilm. The thickness of a biofilm depends on the continuity of nutrient supply, the nutrient concentration and the electron availability for aerobic, anoxic or anaerobic respiration/fermentation. The formation of a biofilm may cause changes in the flow behavior of the groundwater due to narrowing of pore diameters or changes of surface properties of the overgrown soil minerals. Bacteria in the biofilm at the surface of soil particles are surrounded by a thick layer of extracellular polymeric substances (EPS) which form a hydrogel. EPS functions as absorbant for nutrients and supplies moisture for the bacteria in the biofilm when the CF is dehydrated during long-lasting droughts with decreasing groundwater levels. Part of it may slowly be degraded when no ohter carbon sources are available. Harmless soil bacteria in biofilms of groundwater-saturated soil may mutate and get antibiotic-resistant when exposed to antibiotic resistence bacteria or antibiotic resistence genes that were found in polluted groundwater and are absorbed by EPS of biofilms.
Keynote Forum
Karina Gin
National University of Singapore, Singapore
Keynote: Antibiotic resistance in urban environmental waters
Biography:
A/P Karina Gin is an Associate Professor with the Department of Civil and Environmental Engineering, National University of Singapore (NUS). She received her Bachelor degree in Civil Engineering from the University of Melbourne in 1988 and Doctor of Science (ScD) jointly from the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution in 1996. Her research specialisation is in the area of water quality and ecosystem processes. She has been a Principle Investigator of research projects totalling more than $16m and is a Dean’s Chair at the Faculty of Engineering, NUS. A/P Gin’s research and professional experience includes Member, WHO Expert Working Group on Antimicrobial Resistance and Water Safety & Hygiene and Chairman, National Committee of Future Earth (formerly known as International Geosphere-Biosphere Programme (IGBP)).
Abstract:
In recent years, the emergence of antimicrobial resistance has drawn heightened global concern because of the severe ramifications on the treatment of microbial infections. In particular, the issue of antibiotic resistance arises due to the overuse and misuse of antibiotics in both developed and developing countries. Bacteria develop antibiotic resistance in the presence of residual levels of antibiotics and these antibiotic resistant bacteria in turn, are able to spread their resistance to other bacteria through mechanisms such as horizontal gene transfer, mediated by mobile genetic elements (e.g. plasmids, integrons) or co-selecting agents such as biocides and toxic metals. There is a worrying trend that pathogens are developing antibiotic resistance to a degree where last resort antibiotics are no longer effective. This, in turn, has severe implications on public health and healthcare costs. In an effort to better understand the rising levels of antimicrobial resistance, surveillance studies have been undertaken to explore the occurrence of antimicrobial resistance in both clinical and natural environments. Implementing such initiatives through assessing the types of antibiotics used, antibiotic resistant bacteria (ARB) present and associated antibiotic resistant genes (ARG) in microbiomes enables better understanding of the impact of antibiotics and the growth of antibiotic resistance, especially for last resort antibiotics. Aquatic environments harbour diverse freshwater bacterial communities which may be subjected to anthropogenic pressures, while domestic wastewaters receive direct loads of antibiotics and pathogenic bacteria from human excretion. The nature of these environments allows them to function as hotspots for resistance through the selection of ARB and circulation of ARG through stimulation of horizontal gene transfer between members of the microbiome. In this keynote, I will present findings from our studies of antibiotic resistance in diverse environmental waters in Singapore, ranging from hospital effluents, surface waters and treated effluents, with specific reference to the detection and occurrence of antibiotics, antibiotic resistant bacteria, antibiotic resistant genes and resistomes. Such knowledge would be needed to assist in the management and control of antimicrobial/antibiotic resistance and ultimately, the protection of public health.
- Drinking Water Microbiology and Wastewater Treatment, |Water Borne Disease, Water Safety
Chair
Claudia Gallert
University of Applied Science Emden Leer, Germany
Session Introduction
Xiaohui Bai
Shanghai Jiao Tong University, China
Title: The drinking water treatment process as a potential source of affecting the bacterial antibiotic resistance
Biography:
Xiaohui Bai has completed his PhD from Harbin Institute of Technology and Post-doctoral studies from Zhejiang University School of Environment and Resources. He is the Director and Associate Professor of lab of water biology and process technology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, China. He has published more than 10 papers in Wat. Res., Sci. Total Environ., J Water Health, Wat. Sci. Tech. and 4 books related to Ecological Engineering, Water Quality in Distribution System, Digital Water Quality and Drinking Water Quality Guideline.
Abstract:
Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 μg/mL were studied. Multi-drug resistance was also analyzed using drug sensitivity tests. The results indicated that bacteria derived from water treatment plant effluent that used the Huangpu River rather than the Yangtze River as source water exhibited higher antibiotic resistance rates against AMP, STR, RFP and CM but lower antibiotic resistance rates against KAN. When the antibiotic concentration levels ranged from 1 to 10 μg/mL, the antibiotic resistance rates of the bacteria in the water increased as water treatment progressed. Biological activated carbon (BAC) filtration played a key role in increasing the antibiotic resistance rate of bacteria. Chloramine disinfection can enhance antibiotic resistance. Among the isolated ARB, 75% were resistant to multiple antibiotics. Ozone oxidation, BAC filtration and chloramine disinfection can greatly affect the relative abundance of bacteria in the community. Ozone oxidation can give a great effect on ARGs removal. Relative abundances of ARGs, transposases, and integrons increased significantly after biological activated carbon filtration. The final chloramine disinfection can’t guarantee the deactivation of ARGs.
Yu-Zhong Zhang
Shandong University, China
Title: Kinetically regulated utilization and detoxification of acrylate is a key mechanism for marine bacterial DMSP metabolism
Time : 14.10-15.40
Biography:
Yu-Zhong Zhang is a Professor of the State Key Laboratory of Microbial Technology, Shandong University, China. He obtained his PhD degree in Marine Biology from Institute of Oceanography, Chinese Academy of Sciences in 1995. He has been In-charge of several important projects in China, such as 863 key projects and NSFC key projects. He has published over 150 peer-reviewed scientific papers, some of which are published in well-known international journals, such as PNAS, the ISME Journal, Molecular Microbiology and Journal of Biological Chemistry etc. He is now an Editor of FEMS Microbiology Letters and an Editor in Board of Applied and Environmental Microbiology.
Abstract:
Dimethylsulfoniopropionate (DMSP) cleavage, yielding dimethyl sulfide (DMS) and acrylate, provides vital carbon sources to marine bacteria, is a key component of the global sulfur cycle and effects atmospheric chemistry and potentially climate. Acrylate and its metabolite acryloyl-CoA are toxic, if allowed to accumulate within cells. Thus, organisms cleaving DMSP require effective systems for both the utilization and detoxification of acrylate. Here, we examine the mechanism of acrylate utilization and detoxification in roseobacters, an abundant group of marine alphaproteobacteria that catabolise DMSP. We propose acrylate-CoA ligase (PrpE) and acryloyl-CoA reductase (AcuI) as the key enzymes involved and through structural and mutational analyses, provide explanations of their catalytic mechanisms. In most cases, the efficiency and substrate affinities of the enzymes involved in DMSP catabolism and acrylate detoxification increases in the order DmdAs≈DMSP lyases˃PrpEs>>AcuIs. We propose a kinetic regulation model for DMSP catabolism and acrylate detoxification in roseobacters. This study provides insight on acrylate metabolism and detoxification and a possible explanation for the high Km values that have been noted for some DMSP lyases. Since acrylate/acryloyl-CoA is probably produced by lactate, propionate, ï¢-alanine and glucose metabolism, and AcuI and PrpE are conserved in many marine and terrestrial organisms across all domains of life, the models proposed here are likely relevant to many metabolic processes and environments just above DMSP catabolism.
Li Gu
Chinese Academy of Fishery Sciences, China
Title: Design and performance of a water treatment system suitable for rice planting
Biography:
Li Gu has completed his PhD from Institute of Hydrobiology, The Chinese Academy of Sciences. He is Professor of Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China. He has been specializing in the research of pond culture facility and ecological engineering technology and has published more than 60 papers in journals.
Abstract:
In this study, a novel water treatment system suitable for rice planting was designed and constructed to treat and recycle wastewater from aquaculture ponds. According to the performance results of the system, the water purification efficiency was optimal when the hydraulic load was 0.29-0.58 m/d and the gas water ratio was 2-4. The removal rates of TAN, TN, TP and CODMn from wastewater were 33.75%-34.31%, 59.21%-64.53%, 68.43%- 73.75% and 71.66%-74.37% respectively when the hydraulic load was 0.58 m/d and the gas water ratio was 2. Meanwhile, rice yield reached 7127.01 kg/hm2. Therefore, this water treatment system which can efficiently reuse nutrients from wastewater and purify water is a new technology for the treatment of aquaculture wastewater in agriculture-aquaculture system in China.
Jin Qian
North western Poly-technical University, China
Title: Sulfur cycle-based bioprocess for co-treatment of wet flue gas desulfurization wastes with fresh sewage
Biography:
Jin Qian has completed his Mphil and PhD from Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology (HKUST). After his PhD degree, he carried out Post-doctoral study in HKUST for 1 year. Currently, he is an Associate Professor in Northwestern Polytechnical University, PR China. He has hosted more than 10 research projects funded by Natural Science Foundation of China (NSFC), Shenzhen Science and Technolgy Novelty Commision, Sichuan Science and Technology Department, etc. and published more than 15 papers in top journals and has been invited as the reviewer by reputed journals.
Abstract:
Seawater toilet flushing has been adopted in Hong Kong for more than half a century, resulted in 22% reduction of freshwater demand. Meanwhile the saline swage containing high content of sulfate enables us to develop a novel sulfate reduction-autotrophic denitrification-nitrification integrated (SANI) process with minimal biowastes production. In this presentation, this sulfur cycle-based biological process for co-treatment of wet flue gas desulfurization wastes with freshwater sewage in inland areas will be discussed, including the organic and nitrogen removal performances, biowaste production, involved microorganisms as well as the optimization of the process.
Anabela Rebelo
Portuguese Environment Agency, Portugal
Title: Safety in Water Reuse – Semi-quantitative risk assessment approach for non-potable uses
Biography:
Anabela Rebelo has completed her PhD in 2014 from University of Beira Interior, Portugal. Her PhD studies were related with the chlorination by-products formation in water reuse and related risks. She is a Senior Officer at the Portuguese Environment Agency where she develops works in several areas such as water reuse, water quality, water pollution control and prevention. She is an expert in the ISO TC282 for water reuse and in the working group under the common implementation strategy for the water framework directive. With the same topic, she has published several papers in reputed journals and in international conference proceedings.
Abstract:
On a climate change scenario some alternative water sources are being used to face water scarcity and the increase for water demand. In this context, reclaimed wastewaters are considered a helpful resource for several potable and non-potable purposes, e.g., irrigation, urban or industrial use. However, this kind of uses may present some risks for public health due to its microbiological content and to the environment by the introduction of emergent pollutants (e.g. aquifer recharge). To ensure a safe practice, a risk assessment approach is needed. The World Health Organization published guidelines which defines qualitative and quantitative risk assessment procedures. The Quantitative Microbiological Risk Assessment (QMRA) is very helpful when potable uses and direct intakes may be present. However less attention has being paid for non-potable purposes and for which the dose-response effects are not well known or not determined. For instance, usually drip-irrigation is used on orchards production, where the water does not contact with the fruits and some of these are not also consumed with peel. So, the microbiological pathway from water to the fruit is not easily assessed. Therefore, the development of a semi-quantitative risk assessment methodologies, supported on important scales and in the water microbiological content could present a useful tool when water reuse is in place for non-potable uses, such as orchard drip-irrigation, processed food crops, non-food crops, etc. This kind of methodologies aims to deal with water reuse purposes for which the QMRA is not feasible and a qualitative assessment may give a poor result jeopardizing the public confidence in the practice.
Biography:
Keith McLeroy is a Senior Consultant at Ecolyse, Texas, USA and his research interests are in Bioremediation, Biofilms and Bio fouling: Water System
Abstract:
The Global Petroleum Research Institute (GPRI) at Texas A&M University is distinguished for its high-level assessments of innovative analytical instrumentation and laboratory testing protocols for the chemistry and microbiological examination on various matrices of waters. A Phase 1 laboratory appraisal was performed on the RETEGO TTR-1© Detector portable instrument and on the RETEGO© test assay vial sets categorized as “wet-chemistry”. GPRI evaluated the complete TTR-1 unit, each analyte’s detection ranges, the straightforwardness of written protocols and the quality control/assurance robustness of the software generated data. The test vial sets for hardness/alkalinity, scaling salts, free/total chlorine, iron, and pH were investigated. Laboratory assessments were conducted employing high quality known standards for all analytes. The RETEGO platform utilizes advanced detection and chemical processes that were originally established to provide near real time results for complex matrix industrial water re-use purposes. Liquid samples are added to designated assay testing vials. Each vial contains a stable matrix of chemicals to conduct the colorimetric, turbidimetric or fluorescence test for the analyte. The results of each vial were measured on the TTR-1. The TTR-1 quantifies by conducting a multivariate analysis of a data set obtained through frequencyâ€modulated colorimetric and fluorescence measurements. This quantification is obtained from multiple laser (and other light emitting) diodes having distinctive wavelengths. This presentation will describe the assessments conducted, provide noted outcomes of the protocols, exhibit the assaying results, and detail the QA/QC statistics. The presentation will offer an overall conclusive opinion on both the RETEGO TTR-1 Detector and its wet-chemistry vial sets. Furthermore, discussion about its possible functions for the monitoring and optimization of drinking water distribution systems will also follow and reviewing the use of the TTR-1 as part of a water utility’s infrastructure management program to prevent line scaling, which can lead to possible formation of bacterial bio-filming.