Several natural indicators of radial well ageing at the Belgrade Groundwater Source, part 2

2011 ◽  
Vol 63 (11) ◽  
pp. 2567-2574 ◽  
Author(s):  
M. Dimkić ◽  
M. Pušić ◽  
V. Obradović ◽  
D. Djurić
Keyword(s):  
Population Growth ◽  
Redox Potential ◽  
Microbial Population ◽  
Iron Concentration ◽  
Hydraulic Losses ◽  
Research Outcomes ◽  
Groundwater Source ◽  
Kinetics Of ◽  
Radial Well

From 2005 to 2009, research was conducted at the Belgrade Groundwater Source (BGWS) to investigate the process of clogging of wells with horizontal lateral screens (radial wells). The clogging process was monitored via the kinetics of the increase in hydraulic losses at the laterals. A correlation of this process with the redox potential, the iron concentration in water, and the microbial population growth at the laterals and in their immediate vicinity was established. Research outcomes are presented here from a study of five wells where laterals were replaced between 2006 and 2008. Derived dependencies were later used to define the preferred approach to the installation and maintenance of well laterals at the BGWS. Results contribute to the study of well ageing caused by biochemical clogging.

The effect of certain biochemical factors on well clogging under suboxic and mildly anoxic conditions

2012 ◽  
Vol 65 (12) ◽  
pp. 2206-2212 ◽  
Author(s):  
M. Dimkić ◽  
M. Pušić ◽  
V. Obradović ◽  
S. Kovačević
Keyword(s):  
Redox Potential ◽  
Hydraulic Resistance ◽  
Iron Concentration ◽  
Research Project ◽  
Anoxic Conditions ◽  
Rate Of Increase ◽  
Well Clogging ◽  
Groundwater Source ◽  
Shed Light

Research conducted at the Belgrade Groundwater Source in Serbia has shown that significant well screen clogging processes take place under reduced oxic and initial anoxic conditions. Criteria for the prevention, or deceleration, of clogging are becoming more relevant to well ageing, compared with classical, mechanical clogging criteria and the permissible entrance velocities derived from them. The research project was later expanded to encompass other alluvial sources, which feature distinct oxic conditions. This paper presents some of the outcomes of this project, which shed light on the correlation between certain important indicators of well screen clogging (such as the redox potential and iron concentration) and the rate of increase in local hydraulic resistance at the wells.

Several natural indicators of radial well ageing at the Belgrade Groundwater Source, part 1

2011 ◽  
Vol 63 (11) ◽  
pp. 2560-2566 ◽  
Author(s):  
M. Dimkić ◽  
M. Pušić ◽  
D. Vidovic ◽  
A. Petković ◽  
Dj. Boreli-Zdravković
Keyword(s):  
Structural Characteristics ◽  
Iron Concentration ◽  
Total Iron ◽  
Operating Efficiency ◽  
Microbiological Parameters ◽  
Groundwater Source ◽  
Selection Of ◽  
Radial Well ◽  
The Sava River

Over time, the radial collector wells of the Belgrade Groundwater Source, located in the alluvial sediments of the Sava River, exhibit a decline in discharge and a reduction in operating efficiency due to well ageing. An increase in hydraulic losses at the lateral screens, due to chemical and biochemical clogging, has been identified as the primary cause. Certain hydrogeological, hydrochemical and microbiological parameters reflect the well-ageing process and can, therefore, be considered as its indicators. An indicator-based determination of scale is an important aspect in the selection of appropriate well locations, structural characteristics, and maintenance approaches. Well ageing was studied over a period of 5 years (2005–2009). The objective was to investigate the causes of well ageing. The correlations established between the groundwater redox potential, the total iron concentration in groundwater, the grain-size distribution of the aquifer, and well discharge, are presented in the paper.

scholarly journals Analysis of kinetics of local hydraulic losses on the laterals of radial wells at Belgrade groundwater source

2021 ◽  
Author(s):  
David Mitrinović ◽  
Milenko Pušić ◽  
Miodrag Popović ◽  
Srđan Kovačević ◽  
Milan Dimkić
Keyword(s):  
Water Level ◽  
Square Root ◽  
Constant Flow ◽  
Hydraulic Losses ◽  
Operating Modes ◽  
Software Model ◽  
Bivalent Iron ◽  
Groundwater Source ◽  
Kinetics Of ◽  
Good Agreement

Abstract An analysis of the dynamics of the process of biochemical colmation of laterals of radial wells at the Belgrade Groundwater Source is presented. A very good correlation between the rate of forming of the colmations and the concentration of bivalent iron was obtained, on the basis of which the maximum recommended flows and velocities were defined, which are in good agreement with the values from previous articles and studies. The effects of regenerations on yield and the total volume of extracted water (up to 2 times higher than in the case of no regeneration) were investigated using a mathematical and software model. A correlation was developed linking the ratio of the amounts of water extracted with and without regeneration, to the aquifer hydraulic resistance, the coefficient of local hydraulic losses reduction due to regeneration, and the number of regenerations. The factor equal to the square root of the number of regenerations increased by one was added to the expressions for the maximum recommended values of inlet velocities and flows per lateral. The differences in flows and extracted volumes between operating modes with constant flow between regenerations and a constant, minimal water level were also examined using the model. The ratio between the total extracted volumes when the drawdown is kept equal to maximum and when the flow between the regenerations is kept constant reaches up to 1.25.

scholarly journals Effect of Iron Concentration on the Growth Rate of Pseudomonas syringae and the Expression of Virulence Factors in hrp-Inducing Minimal Medium

2009 ◽  
Vol 75 (9) ◽  
pp. 2720-2726 ◽  
Author(s):  
Beum Jun Kim ◽  
Joon Ho Park ◽  
Tai Hyun Park ◽  
Philip A. Bronstein ◽  
David J. Schneider ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Virulence Factors ◽  
Minimal Medium ◽  
Iron Concentration ◽  
Medium Components ◽  
Iron Oxalate ◽  
Limiting Nutrient ◽  
Essential Nutrient ◽  
Virulence Factor Gene ◽  
Kinetics Of

ABSTRACT Although chemically defined media have been developed and widely used to study the expression of virulence factors in the model plant pathogen Pseudomonas syringae, it has been difficult to link specific medium components to the induction response. Using a chemostat system, we found that iron is the limiting nutrient for growth in the standard hrp-inducing minimal medium and plays an important role in inducing several virulence-related genes in Pseudomonas syringae pv. tomato DC3000. With various concentrations of iron oxalate, growth was found to follow Monod-type kinetics for low to moderate iron concentrations. Observable toxicity due to iron began at 400 μM Fe3+. The kinetics of virulence factor gene induction can be expressed mathematically in terms of supplemented-iron concentration. We conclude that studies of induction of virulence-related genes in P. syringae should control iron levels carefully to reduce variations in the availability of this essential nutrient.

Modelling of microbial processes that govern degradation of organic substrates in soil, with special reference to pesticides

1990 ◽  
Vol 329 (1255) ◽  
pp. 369-373 ◽  
Keyword(s):  
Microbial Population ◽  
Large Fraction ◽  
Organic Substrates ◽  
High Concentration ◽  
Deterministic Models ◽  
Soil Microbial ◽  
Low Concentrations ◽  
Biokinetic Parameters ◽  
Soil Microbial Population ◽  
Kinetics Of

We tried to develop deterministic models for kinetics of 2,4-D breakdown in the soil based on the following considerations: (i) at low concentrations degradation results from maintenance consumption by a large fraction of the soil microbial population; (ii) at high concentration in addition to the maintenance consumption there is a growth-associated carbon incorporation by a small specific microbial population. Values for the biokinetic parameters are consistent with those commonly found in the literature. Comparison between observed and simulated curves suggests that a non-negligible part of the pesticidal carbon exists as microbial by-products.

scholarly journals Biochemical Engineering Parameters for Hydrometallurgical Processes: Steps towards a Deeper Understanding

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. Kundu ◽  
A. Kumar
Keyword(s):  
Redox Potential ◽  
Metal Ion ◽  
Good Control ◽  
Point Of View ◽  
Rate Equations ◽  
Biochemical Engineering ◽  
Mining Operations ◽  
Feasible Option ◽  
Engineering Parameters ◽  
Kinetics Of

Increasing interest in biomining process and the demand for better performance of the process has led to a new insight toward the mining technologies. From an engineering point of view, the complex network of biochemical reactions encompassed in biomining would best be performed in reactors which allow a good control of the significant variables, resulting in a better performance. The subprocesses are in equilibrium when the rate of particular metal ion; for example, iron turnover between the mineral and the bacteria, is balanced. The primary focus is directed towards improved bioprocess kinetics of the first two subprocesses of chemical reaction of the metal ion with the mineral and later bacterial oxidation. These subprocesses are linked by the redox potential and controlled by maintenance of an adequate solids suspension, dilution rate, and uniform mixing which are optimised in bioreactors during mining operations. Rate equations based on redox potential such as ferric/ferrous-iron ratio have been used to describe the kinetics of these subprocesses. This paper reviews the basis of process design for biomining process with emphasis on engineering parameters. It is concluded that the better understanding of these engineering parameters will make biomining processes more robust and further help in establishing it as a promising and economically feasible option over other hydrometallurgical processes worldwide.

scholarly journals Kinetics of Reduction of Fe(III) Complexes by Outer Membrane Cytochromes MtrC and OmcA of Shewanella oneidensis MR-1

2008 ◽  
Vol 74 (21) ◽  
pp. 6746-6755 ◽  
Author(s):  
Zheming Wang ◽  
Chongxuan Liu ◽  
Xuelin Wang ◽  
Matthew J. Marshall ◽  
John M. Zachara ◽  
...  
Keyword(s):  
Redox Potential ◽  
Outer Membrane ◽  
Kinetic Data ◽  
Shewanella Oneidensis ◽  
Reorganization Energy ◽  
Second Order ◽  
Metal Species ◽  
Stopped Flow ◽  
Kinetics Of ◽  
Kinetics Of Reduction

ABSTRACT Because of their cell surface locations, the outer membrane c-type cytochromes MtrC and OmcA of Shewanella oneidensis MR-1 have been suggested to be the terminal reductases for a range of redox-reactive metals that form poorly soluble solids or that do not readily cross the outer membrane. In this work, we determined the kinetics of reduction of a series of Fe(III) complexes with citrate, nitrilotriacetic acid (NTA), and EDTA by MtrC and OmcA using a stopped-flow technique in combination with theoretical computation methods. Stopped-flow kinetic data showed that the reaction proceeded in two stages, a fast stage that was completed in less than 1 s, followed by a second, relatively slower stage. For a given complex, electron transfer by MtrC was faster than that by OmcA. For a given cytochrome, the reaction was completed in the order Fe-EDTA > Fe-NTA > Fe-citrate. The kinetic data could be modeled by two parallel second-order bimolecular redox reactions with second-order rate constants ranging from 0.872 μM−1 s−1 for the reaction between MtrC and the Fe-EDTA complex to 0.012 μM−1 s−1 for the reaction between OmcA and Fe-citrate. The biphasic reaction kinetics was attributed to redox potential differences among the heme groups or redox site heterogeneity within the cytochromes. The results of redox potential and reorganization energy calculations showed that the reaction rate was influenced mostly by the relatively large reorganization energy. The results demonstrate that ligand complexation plays an important role in microbial dissimilatory reduction and mineral transformation of iron, as well as other redox-sensitive metal species in nature.

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