Rich microbial communities inhabit water treatment biofilters and are differentially affected by filter type and sampling depth

2010 ◽  
Vol 10 (2) ◽  
pp. 145-156 ◽  
Author(s):  
S. A. Wakelin ◽  
D. W. Page ◽  
P. Pavelic ◽  
A. L. Gregg ◽  
P. J. Dillon
Keyword(s):  
Microbial Community ◽  
Water Treatment ◽  
Small Particle Size ◽  
Sampling Depth ◽  
Sand Filters ◽  
Filter Function ◽  
Urban Catchment ◽  
Factors Affecting ◽  
Filter Type

Factors affecting microbial diversity (richness) and community structure in biofilter columns were investigated. At a pilot filtration plant, granular activated carbon (GAC), anthracite and sand-based filters were used to treat stormwater from an urban catchment. After 12 weeks operation, sand media filters clogged (hydraulic conductivity declining by 90%) and all filters were destructively sampled. All biofilters had similar levels of polysaccharide in the surface layer, however only the sand columns clogged. This clogging may have been due to a combination of polysaccharide and small particle size, the development of a sand-specific microbial community, or other biogeochemical interactions. DNA fingerprinting was used to show that bacterial, archaeal and eukaryotic communities were present in all filter types and at all sampling depths (to 45 cm). The bacterial community was far richer (Margalefs index, d, 1.5–2) than the other groups. This was consistent across filter types and sampling depths. The structure of the bacteria and archaea communities in sand filters differed to those in GAC and anthracite filters (P<0.05). In contrast, eukaryotic communities were similar in surface biofilm layers, irrespective of filter type. As such, physicochemical properties of filters differentially influence the microbial community. Furthermore, we have established that archaea are distributed throughout biofilters; the role of these microorganisms in water treatment and filter function, particularly clogging, requires attention.

scholarly journals Application of Polyaluminium Chloride Coagulant in Urban River Water Treatment Influenced the Microbial Community in River Sediment

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1791
Author(s):  
Siyu Liu ◽  
Xuchao Zhuang ◽  
Chuandong Wang
Keyword(s):  
Microbial Community ◽  
Water Treatment ◽  
River Flow ◽  
River Sediments ◽  
Urban River ◽  
Factors Affecting ◽  
Eukaryotic Diversity ◽  
Bacterial Function ◽  
The Impact ◽  
Polyaluminium Chloride

Polyaluminium chloride (PAC) has been widely used as a chemical coagulant in water treatment. However, little is known about the impact of PAC performance on the microbial community in sediments. In this study, the archaeal, bacterial, and fungal communities in urban river sediments with and without PAC treatment were investigated. Prokaryotic diversity decreased at the PAC addition site (A2) and increased along with the river flow (from A3 to A4), while eukaryotic diversity was the opposite. The abundance of core microbiota showed a similar trend. For example, the dominant Proteobacteria presented the highest relative abundance in A1 (26.8%) and the lowest in A2 (15.3%), followed by A3 (17.5%) and A4 (23.0%). In contrast, Rozellomycota was more dominant in A2 (56.6%) and A3 (58.1%) than in A1 (6.2%) and A4 (16.3%). Salinity, total dissolved solids, and metal contents were identified as the key physicochemical factors affecting the assembly of core microorganisms. The predicted functions of archaea and fungi were mainly divided into methane cycling and saprotrophic nutrition, respectively, while bacterial function was more diversified. The above findings are helpful to enhance our understanding of microorganism response to PAC and have significance for water treatment within the framework of microecology.

Researching the factors influencing the satisfaction of master students at VNU School of Interdisciplinary Studies

2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Do Huy Thuong ◽  
Nguyen Thi Phuong Hong
Keyword(s):  
Service Industry ◽  
Interdisciplinary Studies ◽  
Number Of Solutions ◽  
Factors Affecting ◽  
Training Institutions ◽  
Market Needs ◽  
Market Strategies ◽  
Students Satisfaction ◽  
Training Service

Improving the quality in order to keep up with the trend in the world is the vital task of training institutions today. Training institutions need to grasp market needs and satisfy the requirements of customers - learners. Nadiri, H., Kandampully, J & Hussain, K. (2009) argue that the managers in education need to apply market strategies that are being used by manufacturing and business enterprises and need to be aware that the role of training institutions is a service industry which is responsible for satisfying learner needs (Elliott & Shin, 2002). Currently, there have been many researches on students’ satisfaction. However, each research has its own objectives and is conducted on different scales. This study is implemented to provide information about the factors affecting master students’ satisfaction with the training service at VNU School of Interdisciplinary Studies (VNU SIS). Through it, the research offers a number of solutions to improving the satisfaction level of the master students at VNU SIS in the coming time.

Business Aviation in Russia: Specific Features and Prospects of Development

2020 ◽  
Vol 26 (1) ◽  
pp. 86-93
Author(s):  
D. V. Slivinsky ◽  
I. A. Fomina ◽  
D. G. Menshikh
Keyword(s):  
Systems Approach ◽  
National Policy ◽  
Civil Aviation ◽  
Economic Growth Rate ◽  
Factors Affecting ◽  
Organization And Management ◽  
Transport Services ◽  
Business Aviation ◽  
Wide Range

The presented study determines the role of business aviation in the modern economy and examines the specific features of its development in Russia.Aim. The study aims to analyze the development of business aviation in Russia and its correlation with economic development in general.Tasks. The authors determine the benefits of business aviation as a business tool, examine the specific features of the Russian business aviation market and problems of its development, and identify factors that affect the development of business aviation in Russia.Methods. This study uses the methods of comparative and retrospective analysis, cross-country comparison, systems approach, and expert analytics.Results. Business aviation is a new segment of civil aviation for Russia. Therefore, it is advisable to rely on foreign practices in the management of its development. In many countries, business aviation is a separate industry that specializes in providing transport services to a wide range of corporate clients and/or individuals. The development of this industry is associated with the economic growth rate and the development level of the national economy, and also depends on the national institutional specifics. This study describes the specific features of development of business aviation in Russia and problems arising in the organization and management of this type of business.Conclusions. The authors develop a system of factors affecting the development of business aviation in Russia, describe the major problems of this industry, and propose solutions. The results of this study can be used in the development (adjustment) of business aviation development strategies in Russia both at the industrial and corporate level, and in the implementation of the national policy in this field.

The methodology of experimental research of the feed components extrusion process in order to improve its energy performance

2020 ◽  
pp. 147-152
Author(s):  
E. M. Ratnikov ◽  
D. O. Milko
Keyword(s):  
Experimental Studies ◽  
Energy Performance ◽  
Extrusion Process ◽  
Mathematical Methods ◽  
Screw Extruder ◽  
Mathematical Planning ◽  
Factors Affecting ◽  
Extrusion Processing ◽  
Definition Of

Annotation Purpose. Development of a program and methods for conducting experimental studies of the extrusion process with the definition of parameters and modes of operation of the extruder to improve its energy performance. Methods. Methods of mathematical statistics, synthesis, analysis, description and modeling were used. Results. The application of mathematical methods, in particular mathematical planning, reduces the number of experiments several times, and allows to evaluate the role of influencing factors, obtain a mathematical model of the process and determine the optimal conditions for its parameters and modes, etc. Conclusions. The methodology for experimental studies of a screw extruder is presented with the necessary equipment and methodology for processing the obtained experimental data. A mathematical method of planning, which reduces the number of experiments several times, allows us to evaluate the role of factors affecting productivity and energy intensity is presented. Keywords: extruder, auger, nutrients, research methodology, extrusion, processing, feed.

Up-flow roughing filtration: rehabilitation of a water treatment plant in Tarata, Bolivia

1998 ◽  
Vol 37 (9) ◽  
pp. 105-112 ◽  
Author(s):  
Ana María Ingallinella ◽  
Luis María Stecca ◽  
Martin Wegelin
Keyword(s):  
Water Treatment ◽  
Pilot Plant ◽  
Laboratory Tests ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Horizontal Flow ◽  
Design Parameters ◽  
Sand Filters ◽  
Chemical Products ◽  
Made In

This paper presents the methodology used for the rehabilitation of the pretreatment stage in a water treatment plant for a village located in Bolivia which has 3500 inhabitants. The treatment plant was initially composed by horizontal-flow roughing filters and slow sand filters, but due to the high contents of colloidal turbidity of the providing source, it did not work properly. A plan of rehabilitation was made which comprised laboratory tests, pilot tests and proposal of modifications based on the results of previous stages. The laboratory tests were made in order to find the optimum conditions to coagulate the raw water. It was found that horizontal-flow roughing filters must be turned into up-flow roughing filters, so a pilot plant was built and was operated for three months in order to find suitable design parameters. The results obtained obtained during the operation of the pilot plant and the proposal of modifications are presented. The results of operation of the final plant, which are also reported, demonstrated the advantages of the up-flow roughing filtration as a pretreatment stage when it is necessary to add chemical products in small treatment plants.

scholarly journals Assessing the Impact of Bank Concentration and Liquidity of Refah Bank Branches on Profitability during the Period1383-190

2014 ◽  
Vol 4 (1) ◽  
pp. 248
Author(s):  
Hossin Ostadi ◽  
Nastran Monsef
Keyword(s):  
Commercial Banks ◽  
Bank Capital ◽  
Factors Affecting ◽  
Bank Branches ◽  
Independent Variables ◽  
Bank Deposits ◽  
The Impact ◽  
Bank Concentration ◽  
Research Period

Profitability is an important factor to show this articledoeswhat is the role of the intermediary bank to collect your savings and allocation of loans.  Given the importance of profitability indicators in this study, the factors affecting the profitability of commercial banks in Iranare analyzedwith emphasis on the degree of centralization and bank deposits. Dependent variable is indicators of profitability (ROE, ROA) and bank deposits, bank size, bank capital, focus on liquidity and banking requirements are independent variables. Correlation analysis and OLS regression are used and the research period is 1381 to 1390 that the country's territory where bank branches.Our results indicate that the effect of bank size on profitability is positive and the increase in bank size on profitability is increased. Impact on the profitability of bank deposits is positive, ie increasing the profitability of bank deposits increased. Finally, the impact of bank concentration on profitability is positive. Increasing the bank's focus profitability increases. Moreover, the results adversely affect the liquidity of the index is profit. 

scholarly journals Antioxidants in Fish Sperm and the Potential Role of Melatonin

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 36
Author(s):  
Francisca Félix ◽  
Catarina C. V. Oliveira ◽  
Elsa Cabrita
Keyword(s):  
Oxidative Stress ◽  
Fish Cell ◽  
Cell Protection ◽  
Factors Affecting ◽  
Fish Sperm ◽  
Scavenger Activity ◽  
Stress Damage ◽  
Novel Antioxidants ◽  
Aquaculture Production

In recent years, the effects of novel antioxidants have played an important role in the research focusing on fish cell protection. As food demand grows, aquaculture production becomes more intensive, and fish are more exposed to oxidative stress conditions, like high densities, temperature shifting, frequent fish handling and samplings, and prophylactic or disease treatments, which expose fish to a different environment. Particularly in reproduction, germ cells lose antioxidant capacity with spermatogenesis, as spermatozoa are more prone to oxidative stress. Antioxidants have been used in a variety of fish physiological problems including in reproduction and in the establishment of cryopreservation protocols. From the most used antioxidants to natural plant food and herbs, and endogenously produced antioxidants, like melatonin, a review of the literature available in terms of their effects on the protection of fish spermatozoa is presented here in a classified structure. Several direct and indirect approaches to improve gamete quality using antioxidants administration are mentioned (through feed supplementation or by adding in cryopreservation media), as well as factors affecting the efficiency of these molecules and their mechanisms of action. Special attention is given to the unclear melatonin pathway and its potential scavenger activity to prevent and counteract oxidative stress damage on fish spermatozoa.

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