Natural Water Environment Research Articles

Lysis to Kill: Evaluation of the Lytic Abilities, and Genomics of Nine Bacteriophages Infective for Gordonia spp. and Their Potential Use in Activated Sludge Foam Biocontrol.

Nine bacteriophages (phages) infective for members of the genus Gordonia were isolated from wastewater and other natural water environments using standard enrichment techniques. The majority were broad host range phages targeting more than one Gordonia species. When their genomes were sequenced, they all emerged as double stranded DNA Siphoviridae phages, ranging from 17,562 to 103,424 bp in size, and containing between 27 and 127 genes, many of which were detailed for the first time. Many of these phage genomes diverged from the expected modular genome architecture of other characterized Siphoviridae phages and contained unusual lysis gene arrangements. Whole genome sequencing also revealed that infection with lytic phages does not appear to prevent spontaneous prophage induction in Gordonia malaquae lysogen strain BEN700. TEM sample preparation techniques were developed to view both attachment and replication stages of phage infection.

Quantification of the water, energy and carbon footprints of wastewater treatment plants in China considering a water–energy nexus perspective

Water and energy are closely connected and both are very important for human development. Wastewater treatment plants (WWTPs) are central to water–energy interactions as they consume energy to remove pollutants and thus reduce the human gray water footprint on the natural water environment. In this work, we quantified energy consumption in 9 different WWTPs in south China, with different treatment processes, objects, and capacities. The energy intensity in most of these WWTPs is in the range of 0.4–0.5kWh/m3 in 2014. Footprint methodologies were used in this paper to provide insight into the environmental changes that result from WWTPs. A new indicator “gray water footprint reduction” is proposed based on the notion of gray water footprint to better assess the role of WWTPs in reducing human impacts on water resources. We find that higher capacity and appropriate technology of the WWTPs will result in higher gray water footprint reduction. On average, 6.78m3 gray water footprint is reduced when 1m3 domestic sewage is treated in WWTPs in China. 13.38L freshwater are required to produce the 0.4kWh electrical input needed for treating 1m3 domestic wastewater, and 0.23kg CO2 is emitted during this process. The wastewater characteristics, treatment technologies as well as management systems have a major impact on the efficiency of energy utilization in reducing gray water footprint via these WWTPs. The additional climate impact associated with wastewater treatment should be considered in China due to the enormous annual wastewater discharge. Policy suggestions are provided based on results in this work and the features of China's energy and water distribution.

Biodegradation of Polyhydroxyalkanoates in Natural Water Environments

Biodegradation of Polyhydroxyalkanoates in Natural Water Environments

Optimization of wastewater reclamation and reuse system using membrane filtration and oxidation processes: removal of pharmaceuticals

In a wastewater reclamation and reuse system, even though reverse osmosis (RO) or forward osmosis (FO) membrane is utilized as a main process, micropollutants, especially non-biodegradable matters, such as pharmaceuticals, endocrine disrupting compounds, and cancer causing matters, can give menaces to natural water environment and human. Initially, in this study, pharmaceuticals were measured present in both wastewater effluent and brackish water to investigate how much the pharmaceuticals remain after naturally degraded in water stream. Through the filtration with RO and FO, the concentrations of pharmaceuticals in permeate and retentate were observed. For the elimination of pharmaceuticals, the possibility of ultraviolet (UV) alone and UV/H2O2 processes for the integration with the membrane filtrations (RO and FO) was explored by observing the removal efficiencies of pharmaceuticals in feed and retentate.

Effects of hydrodynamic conditions on the sorption behaviors of aniline on sediment with coexistence of nitrobenzene.

The sorption behaviors of pollutants affected by hydrodynamic conditions were confirmed in natural water environment. The effects of hydrodynamic conditions on the sorption behaviors of aniline on sediment with coexistence of nitrobenzene were investigated. The particle entrainment simulator (PES) was used to simulate varied bottom shear stresses. The batch equilibrium method was applied to the experiments with the stress levels and the action time controlled at 0.2-0.5 N/m(2) and 24 h, respectively. The findings indicated that apparent partition coefficient of aniline on sediment increased with the shear stress significantly, while decreased with nitrobenzene concentration. On the contrary, both the sorption amount of aniline on suspended particulate matter (Q s) and the effect of nitrobenzene concentration on Q s declined as the shear stress increased. The sorption kinetic results showed that the sorption process followed the pseudo-second-order kinetics equation, and the process included two stages: fast sorption stage and slow sorption stage, among which the average sorption rate of fast stage was 7.5-9.5 times that of slow one. The effect of shear stress on the average sorption rate of aniline was enhanced with the increase of nitrobenzene concentration. And shear stress weakened the disturbance of cosolute on main solute sorption process. In addition, experiment results of sorption kinetic show that only the initial sorption rate was affected by shear stress and cosolute concentration. In the first 5 min, shear stress had positive effects on the sorption rate. After that, the sorption rate barely changed with shear stress and cosolute concentration.

How the hydro-gel flocculation microstructure changes

Abstract Microstructural investigations were conducted to better understand the poor settling and dewatering of a clay mineral-rich slurry. Investigations of the flocculated microstructure in a 2.5 wt% smectite clay suspension in a moderately salty aqueous solution were conducted with the aid of a synchrotron-powered transmission X-ray microscope and a cryo-transmission electron microscope. These investigations enabled the study of the clay particles’ mutual configuration in three-dimensional arrangements within natural water environments without drying the samples. The observed microstructure was similar to that observed in Wyoming smectite suspensions. A transition was observed from the “net of flakes” in monovalent cations in solution to the “Bander” model, when bivalent cations were present in the solution. As these structural models differ significantly from each other, the physical properties of the resulting gel also demonstrated remarkable diversities. These findings may play a crucial role in understanding smectite gel behaviour and its aggregating nature, which are of interest across many industries and are important in designing the most suitable technology to deal with colloidal stability.

Transformation products of antibiotic and cytostatic drugs in the aquatic cycle that result from effluent treatment and abiotic/biotic reactions in the environment: An increasing challenge calling for higher emphasis on measures at the beginning of the pipe

Pharmaceuticals may undergo transformation into new products during almost all possible processes along their life-cycle. This could either take place in the natural water environment and/or during water treatment processes. Numerous studies that address the issue of such transformation products (TPs) have been published, describing selected aspects of TPs in the environment and their formation within effluent and water treatment processes. In order to exemplify the number and quality of information published on TPs, we selected 21 active pharmaceutical ingredients from the groups of antibiotics and antineoplastics, and assessed the knowledge about their TPs that has been published until the end of May 2012. The goal of this work was to demonstrate, that the quality of data on pharmaceutical TPs greatly differs in terms of the availability of chemical structures for each TP, rather than to provide an exhaustive database of available TPs. The aim was to point out the challenge going along with so many TPs formed under different treatment and environmental conditions. An extensive review in the form of a table showing the existing data on 158 TPs for 15 compounds, out of 21 investigated, was presented. Numerous TPs are the result of different treatments and environmental processes. However, also numerous different TPs may be formed within only one type of treatment, applied under sometimes even very similar treatment conditions and treatments times. In general, the growing number of elucidated TPs is rationalized by ineffective removal treatments. Our results demonstrate a severe risk of drowning in much unrelated and non-assessable data, both from a scientific and from a technical treatment-related point of view. Therefore, limiting the input of pharmaceuticals into effluents as well as improving their (bio) degradability and elimination behavior, instead of only relying on advanced effluent treatments, is urgently needed. Solutions that focus on this “beginning of the pipe” approach should minimize the adverse effects of parent compounds by reducing and formation of TPs and their entrance into the natural environment.

The formation of a structural framework in gelled Wyoming bentonite: Direct observation in aqueous solutions

HypothesisParticle space arrangement is a very important factor that determines the physico-mechanical properties of soil. Formations of three-dimensional (3D) structured networks within gelled or flocculated suspension may prevent clay particles and aggregates from settling under gravity force and by encapsulate water within such a network, lead to poor sludge dewatering. To better understand this phenomenon, a microstructural investigation of a smectite clay (SWy2) suspension was conducted. ExperimentsSWy-2 was diluted in water and a moderately salty aqueous solution and was studied with the aid of a synchrotron-powered transmission X-ray microscope (TXM) and cryogenic transmission electron microscope (Cryo-TEM). Observations of mutual particle arrangement in 3D spaces were conducted within a natural water environment after vitrification without drying. FindingsA new type of micro-architecture in particle space arrangement was observed. Smectite flakes were mostly in edge-to-edge (EE) contact and formed a 3D network, confirming a “net of flakes” structural model. Clay particles form a complex and multi-hierarchic flocculated structure with characteristic cellular chained networking. Chained aggregates build cellular elements, encapsulating water inside closed voids. Increasing ionic strength results in the development of multi-hierarchic voids categories, with most water retained within nano-pores.

Estimation of stochastic colored noise signal driving DNAPLs degradation kinetics in the natural water environment

Little attention has been devoted to the characterization of colored noise in stochastic modeling systems. This study aims to propose an integrated numerical-simulation and statistical-inference method for the characterization of individual and mixed colored noises driving the DNAPL degradation kinetics. Through the method, the properties of colored noise (i.e. intensity and time correlation) can be identified statistically. Results for the estimations indicate that the method is useful for identifying the colored noise since the regression equations have high R square values and most of the relative errors of the estimates are below 40%. It is also found that (i) the more the repeated experiments, the higher the estimation accuracy; (ii) the larger the true value, the higher the estimation accuracy; (iii) a large number of statistical samples does not always imply high estimation accuracy. Moreover, the increase in both number of samples and interval of sampling is not helpful in enhancing the estimation accuracy. Results from the estimation of the mixed multiplicative colored-noise also show that the estimates can be regarded to be acceptable. Future studies will be needed for estimation of other types of mixed additive and multiplicative colored noises.

Kinetics and Equilibrium Biosorption of Nano-ZnO Particles on Periphytic Biofilm under Different Environmental Conditions

As engineered nanoparticles (ENPs) were widely used in industry and commerce, increasing amounts of ENPs are expected to enter aquatic environment where their fate and potential impacts are unknown. Understanding the interaction between ENPs and periphytic biofilm, ubiquitous in the natural water environment, will help to better predict the behavior and fate of ENPs in aquatic media. This study focuses on ZnO NPs biosorption mechanism by periphytic biofilm dominated by bacteria and diatoms. Batch experiments were performed, in which the effect of pH, natural organic matter (NOM), extracellular polymeric substances (EPS) and temperature on the biosorption were investigated. The biosorption of ZnO NPs were found to be pH dependent, and more biosorption was observed under neutral and acidic conditions. Increasing concentration of NOM negatively affected on the biosorption of ZnO NPs onto periphytic biofilm due to the adsorption of NOM molecules on the surface of nanoparticles and the resulting steric stabilization of the particles suspension. The removal of loosely bound EPS enhanced the biosorption capacity of periphytic biofilm. The biosorption of nano-ZnO on the biofilm was related to electrostatic force of attraction, confirmed from the zeta potential study. The biosorption of ZnO NPs on biofilm was correlated better with Langmuir isotherms as compared to Freundlich isotherms under the concentration range studied. The biosorption process was thermodynamically feasible and spontaneous. The present study shows that periphytic biofilm can be employed for an environmentally benign and effective biosorbent for removal of ZnO NPs.

Екологічні загрози будівництва каскаду міні-ГЕС на території басейну р. Черемош

The article coverage the development issues Carpathian cascade mini-hydro-plants for example basin Cheremosh. It was the influence of existing hydro power plants in natural (water) environment and proved inappropriate, unprofitable and environmental threat. Available mini water plants violate hydrologic regime (water content of the river) and stimulates the development of erosion-accumulative processes, endangered species and benthic organisms integral component of aquatic ecosystems. Operation of small hydropower plants also contributes to shallowing of rivers and creation of artificial barriers for migration and gene pool exchange between populations of aquatic animals. The construction of mini hydro cascade prevents alloys of the river (rafting). In addition there is a threat of ecological security of the region and the development tourism and recreation, social and economic potential of the basin, the Cheremosh. Key words: mini-hydro, river Cheremosh, water quality, environmental hazards, hydrology, hydroecology.

Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process

The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometry. Various byproducts identified indicated three common reaction pathways: hydroxyl addition (+16 Da), alcoholic oxidation or dehydrogenation (-2 Da), and elimination of sulfate (-80 Da). The initiation of the degradation was observed at the hydroxymethyl uracil and tricyclic guanidine groups; uracil moiety cleavage/fragmentation and further ring-opening of the alkaloid were also noted at an extended reaction time or higher UV fluence. The degradation rates of CYN decreased and less byproducts (species) were detected using natural water matrices; however, CYN was effectively eliminated under extended UV irradiation. This study demonstrates the efficiency of CYN degradation and provides a better understanding of the mechanism of CYN degradation by hydroxyl radical, a reactive oxygen species that can be generated by most AOPs and is present in natural water environment.

Determination of colloidal pyrolusite, Eu(III) and humic substance interaction: A combined batch and EXAFS approach

This work determined the role of humic acid (HA) and fulvic acid (FA), which was extracted from the natural soil, in the interaction mechanism and microstructure of Eu(III) with pyrolusite (beta-MnO2) by using batch experiments and extended X-ray absorption fine structure (EXAFS) techniques. We combined macroscopic and spectroscopic approaches to see the evolution of the interaction mechanism and microstructure of Eu(III) with beta-MnO2 in the presence of HA or FA in comparation with that in the absence of HA or FA. The results suggested that Eu(III) interaction with beta-MnO2 was obviously affected by the addition of HA or FA. The interaction of Eu(III) with beta-MnO2 was enhanced at pH 6.5 in the presence of HA or FA. The EXAFS fitting results provided a molecular evidence for the findings from the batch experiments. Adsorption of HA or FA onto beta-MnO2 greatly modified the microstructure of Eu(III) onto beta-MnO2. Only binary surface complexes of Eu(III) can be formed onto beta-MnO2 in the absence of HA or FA, while both binary surface complexes and ternary surface complexes of Eu(III) can be simultaneously formed onto beta-MnO2 in the presence of HA or FA, which was mainly responsible for the enhanced Eu(III) uptake at low pH values. The results observed in this work are important for the evaluation of physicochemical behavior of long-lived radionuclides (lanthanides and actinides) in the natural soil and water environment. (C) 2014 Elsevier B.V. All rights reserved.

The water environment as a source of potentially pathogenic mycobacteria.

Nontuberculous mycobacteria (NTM) are ubiquitous organisms of a wide variety of environmental reservoirs, including natural and municipal water, soil, aerosols, protozoans, animals and humans. Several of these species are potential pathogens which affect human health. The aim of this study was to determine the occurrence of NTM in the water environment. Samples were taken from 13 water-related facilities including fish ponds, storage ponds, drinking water reservoirs and an experimental recirculation system. Altogether, 396 samples of water, sediment and aquatic plants were collected and analysed. All samples were examined using conventional culture methods. Suspected microbial isolates were subjected to polymerase chain reaction analysis and identified using partial sequence analysis of the 16S rDNA gene. The culture revealed 94/396 samples (23.7%) that contained mycobacteria. Among known NTM we identified potentially pathogenic mycobacteria isolated from the fresh water environment for the first time: Mycobacterium asiaticum, M. chimaera, M. interjectum, M. kumamotonense, M. lentiflavum, M. montefiorense, M. nebraskense, M. paraffinicum and M. simiae. Epidemiologic studies suggest that the natural water environment is the principal source of human exposure. Our results indicate that besides the well-known potentially pathogenic mycobacteria it is important to observe occurrence, proliferation and persistence of newly discovered mycobacterial species.

Extraction and Determination of Triclocarban in Aquatic Plants by Homogenate Extraction Combined with HPLC-ESI-MS/MS

A specific, sensitive, and reliable analytical method involving homogenate extraction, solid phase extraction (SPE), and detection by high-performance liquid phase chromatography electrospray tandem mass spectrometry was developed in this study for the determination of triclocarban (TCC) in aquatic plants. Key factors that could affect the extraction, including the extraction solvent and its volume, the length of time of homogenate extraction, were examined and optimised. Under optimum conditions, the linearity of the method ranged from 0.2 ng/g to 200 ng/g, with correlation coefficients (r2) >0.999. The limit of detection was 0.05 ng/g, based on the ratio of the chromatographic signal to baseline noise (S/N = 3). Spiked recoveries of TCC in real aquatic plant samples ranged from 91.8% to 106.1%. The proposed method was successfully applied to analyse TCC in aquatic plant samples collected from a natural water environment.

Pharmaceuticals in the Built and Natural Water Environment of the United States

The known occurrence of pharmaceuticals in the built and natural water environment, including in drinking water supplies, continues to raise concerns over inadvertent exposures and associated potential health risks in humans and aquatic organisms. At the same time, the number and concentrations of new and existing pharmaceuticals in the water environment are destined to increase further in the future as a result of increased consumption of pharmaceuticals by a growing and aging population and ongoing measures to decrease per-capita water consumption. This review examines the occurrence and movement of pharmaceuticals in the built and natural water environment, with special emphasis on contamination of the drinking water supply, and opportunities for sustainable pollution control. We surveyed peer-reviewed publications dealing with quantitative measurements of pharmaceuticals in U.S. drinking water, surface water, groundwater, raw and treated wastewater as well as municipal biosolids. Pharmaceuticals have been observed to reenter the built water environment contained in raw drinking water, and they remain detectable in finished drinking water at concentrations in the ng/L to μg/L range. The greatest promises for minimizing pharmaceutical contamination include source control (for example, inputs from intentional flushing of medications for safe disposal, and sewer overflows), and improving efficiency of treatment facilities.

Study of the photochemically generated of oxygen species by fullerene photosensitized CoS2 nanocompounds

Reactive oxygen species (ROS) can be produced by interactions between sunlight and light-absorbing substance in natural water environment and can completely destroy various organic pollutants in wastewaters. In this study, CoS2 and CoS2–fullerene were irradiated by visible light respectively. The generation of reactive oxygen species were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). In comparison with the separate effects of CoS2 and fullerene nanoparticles, the photochemically effect of the fullerene photosensitized CoS2 composites is increased significantly due to the synergetic effect between the fullerene and the CoS2 nanoparticles.

Corrosion Mechanism of Aluminized Steel in Limestone Backfill

Aluminized steel Type 2 (AST2), ASTM A929, has a ~50 μm thick coating with outer and inner layers of Al alloy and Al-Fe intermetallic, respectively. AST2 culvert and drainage pipes are required to have a long service life (e.g., 75 years) in natural soil and water environments; premature pipe failures incur heavy repair and replacement costs. Performance has been adequate in many service conditions, but unexpected early corrosion of AST2 pipes has recently been observed in some Florida inland locations. A recent event with loss of the coating and local penetration of the substrate, after only ~3 years of service, was associated with the use of calcium carbonate (CaCO3)-rich (limestone) backfill. Water in contact with limestone and allowed to equilibrate with carbon dioxide (CO2) in the atmosphere (open system) tends to develop a near-neutral pH, compatible with a stable passive film on Al, so experiments were conducted to determine if the aggressive conditions took place otherwise. Simulated field fresh water conditions were created, where water in a limestone-filled cell was constantly replenished at a slow rate (representing rain-water), while the pH and conductivity were monitored. Under these conditions, a high, steady-state pH > 9 developed that was aggressive to the air-formed aluminum oxide passive film. The higher pH was ascribed to the dissolution of limestone in slowly flowing water that is not given enough time for equilibration with atmospheric CO2 (approaching a closed system). Electrochemical impedance measurements indicated the onset of severe corrosion early in the exposure, confirmed by metal-lographic and scanning electron microscopy (SEM) observation of loss of coating in extracted AST2 specimens. The corrosion rate decreased later as a thick corrosion product layer formed. Corrosion mechanisms are discussed.

Mechanism and microstructure of Eu(III) interaction with γ-MnOOH by a combination of batch and high resolution EXAFS investigation

In this paper, the macroscopic interaction method and high resolution EXAFS technique with a bent crystal analyzer were combined to study Eu(III) interaction mechanism and microstructure with gamma-MnOOH as a function of pH. The results indicated that Eu(III) interaction with gamma-MnOOH was apparently dependent on pH but independent of ionic strength, suggesting the formation of inner-sphere surface complexation for Eu(III) onto gamma-MnOOH. Results of EXAFS analysis indicated that Eu was surrounded by similar to 9.0 O atoms in first coordination shell at R (Eu-O) a parts per thousand 2.40 , and second shell of Mn atoms at R (Eu-Mn) a parts per thousand 3.60 was observed for the three adsorption samples. These findings suggested formation of a bidentate surface complex with Eu(III) bonding by edge sharing to MnO6-octahedron on gamma-MnOOH surface. Both the macroscopic interaction data and the molecular level evidence of Eu(III) microstructure at the gamma-MnOOH-water interface should be factored into better understanding the fate and mobility of Eu(III) and related radionuclides in the natural soil and water environment.

Modeling of power generation from the mixing of simulated saline and freshwater with a reverse electrodialysis system: The effect of monovalent and multivalent ions

A reverse electrodialysis (RED) system utilizes the transport of cations and anions from controlled mixing of saline water (e.g., seawater) and freshwater (e.g., river water) through selective ion exchange membranes for power generation. Sodium chloride alone has been widely used to create power via salinity gradients in lab-scale RED systems. In an effort to simulate realistic salinity conditions in the natural water environment, in this study a new RED model was developed to quantify the power generation with coexisting monovalent and multivalent salt ions. The effects of different flow rate ratios (saline water flow, ØS, over freshwater flow, ØF) and intermembrane distance ratios on power density (amount of power per unit membrane area) were investigated. Our results indicated that magnesium sulfate, sodium sulfate, and magnesium chloride in the feed solutions of the RED system led to a 9–20% lower power density than when sodium chloride was the single ion source, largely because of the higher internal stack resistance of the multivalent ions. Higher power densities could be achieved with higher flow rates in the saline water compartment and shorter intermembrane distances in the freshwater compartment. For example, the power density increased by approximately 11% when the flow rate ratio was 5 compared with 1; similarly, an intermembrane distance ratio of 8 yielded an approximately 85% increase in power density compared with a ratio of 1. The goal of the present work is to advance our understanding of RED systems working in realistic salinity environments.