The effect of operating parameters on the performance of a biosand filter: a statistical experiment design approach

2015 ◽  
Vol 16 (3) ◽  
pp. 775-782 ◽  
Author(s):  
Krutika Rajesh Tundia ◽  
M. Mansoor Ahammed ◽  
Duithy George
Keyword(s):  
Pore Volume ◽  
Microbiological Quality ◽  
Pause Time ◽  
Operating Parameters ◽  
Optimum Conditions ◽  
Box Behnken Design ◽  
Biosand Filter ◽  
Bacterial Removal ◽  
The Ideal

The influence of three important parameters, namely, pause time, charge volume and influent turbidity on the performance of a biosand filter (BSF) was assessed by employing response surface methodology with a Box-Behnken design. Fifteen runs were conducted in triplicate using a full-scale BSF with a pore volume of 19.6 L, and the performance of the filter was assessed by monitoring total coliforms, Escherichia coli and turbidity of the effluent. Results showed that there was a significant improvement in the microbiological quality of filtered water when the pause time was increased from 12 to 36 h, while it deteriorated as charge volume was increased from 10 to 30 L. The effluent microbiological quality was unaffected by changes in the influent turbidity in the range of 10–50 NTU. Further, effluent turbidity was not significantly affected by the changes in any of the operating parameters, and it remained below 1.5 NTU in all the runs. At optimum conditions of pause time 23 h, charge volume 19.4 L and influent turbidity 32 NTU, bacterial removal exceeded 99.4%. The results show that charging of the filter with about one pore volume of water once a day would be the ideal operating strategy for a BSF.

scholarly journals Optimization of Operating Parameters on Dry Grinding of Calcite in a Stirred Media Mill Using the Box-Behnken Design

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 251
Author(s):  
Diler Katircioglu-Bayel
Keyword(s):  
Mass Fraction ◽  
Filling Ratio ◽  
Operating Parameters ◽  
Stirrer Speed ◽  
Solid Mass ◽  
Optimum Conditions ◽  
Box Behnken Design ◽  
Dry Grinding ◽  
Grinding Time ◽  
Stirred Media Mill

The optimization of the operating parameters of a stirred media mill in the dry grinding of calcite was investigated. A three-level Box-Behnken design was used for the purpose of examining the impact of four independent factors, the stirrer speed (SS), grinding time (GT), media filling ratio (MFR), and solid mass fraction (SMF), on the product particle size (d50). For the purpose of establishing an empirical correlation between operating parameters and responses, a series of experiments were carried out. Variance analysis showed a reasonably good value for d50 (R2 = 0.965). According to the software solutions, the optimum conditions for minimizing the d50 size were found to be 573 rpm stirrer speed, 11.18 min grinding time, 63% media filling ratio, and 11.52% solid mass fraction, with 3.78 µm for the d50 size. To verify the improvement of grinding, verification tests were performed using the above-mentioned optimum conditions and the average d50 size and standard deviation were found to be 3.83 µm and 0.025, respectively. The average d50 value obtained was smaller than those obtained in the 27 tests. Furthermore, when the optimum result obtained from the experiments was compared with the result obtained using the software, a 22% energy saving was achieved. The impacts of grinding on the structural characteristics of calcite particles were characterized by XRD analysis. XRD measurements indicated that no change was observed in the peak areas of ground calcite specimens compared to the untreated calcite specimen.

Microbiological quality of ready to hang enteral formulas

2005 ◽  
Vol 30 (03) ◽  
Author(s):  
J Kehr ◽  
B Morales ◽  
P Contreras ◽  
L Castillo ◽  
W Aranda
Keyword(s):  
Microbiological Quality ◽  
Enteral Formulas

La Formación Continua y el Desarrollo de Competencias en los Docentes en Ejercicio del Nivel Secundario

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Leonor Alexandra Rodríguez Álava
Keyword(s):  
Teaching Practice ◽  
Training And Development ◽  
Middle Level ◽  
Teaching Skills ◽  
Practicing Teachers ◽  
Active Subject ◽  
Continuous Preparation ◽  
Analysis And Synthesis ◽  
The Ideal

Este artículo está encaminado a caracterizar el proceso de formación continua del docente del nivel medio en ejercicio asociado a la formación y desarrollo de sus competencias docentes, para lo que fueron utilizados métodos como   el análisis y síntesis, inducción y deducción, abstracción y concreción, la entrevista, la encuesta y  el cuestionario, donde a partir de sus resultados se  llega a la consideración de que la formación continua es la vía idónea para la formación y desarrollo de competencias docentes en los profesores en ejercicio, donde se debe asumir un modelo que propicie la reflexión sobre la propia práctica del docente, un clima de colaboración   y el profesor como sujeto activo de ese proceso.   Palabras claves: calidad educativa,   competencias docentes,   educador, estudio, preparación continua,  ABSTRACT   This article aims to characterize the process of education for teachers of middle level associated with exercise training and development of their teaching skills, for which methods were used as analysis and synthesis, induction and deduction, abstraction and concreteness, interview and questionnaire survey, where from their results leads to the consideration that the training is the ideal way for the formation and development of teaching skills in practicing teachers, where they must assume a model that encourages reflection on own teaching practice, a climate of collaboration and the teacher as an active subject of that process Keywords: quality of education, teaching skills, teacher, study, continuous preparation

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

Microbiological quality of residues from drinking water preparation

1995 ◽  
Vol 31 (5-6) ◽  
pp. 75-79 ◽  
Author(s):  
M. Würzer ◽  
A. Wiedenmann ◽  
K. Botzenhart
Keyword(s):  
Waste Water ◽  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Drinking Water ◽  
Water Treatment ◽  
Pathogenic Bacteria ◽  
Waste Water Treatment ◽  
Microbiological Quality ◽  
Detection Limits

In Germany the application of procedures such as flocculation and filtration in the preparation of drinking water results in the annual production of an estimated 500,000 t of sediments and sludges. Some of these residues have a potential for being reused, for example in agriculture, forestry, brickworks or waste water treatment. To assess the microbiological quality of residues from waterworks methods for the detection of enterobacteria, Escherichia coli, Salmonella, Pseudomonas aeruginosa, Legionella, poliovirus, Ascaris suis eggs and Cryptosporidium have been evaluated regarding their detection limits and were applied to various residues from German waterworks. Results show that sediments and sludges may contain pathogenic bacteria, viruses and protista. When residues from waterworks are intended to be reused in agriculture or forestry the microbiological quality should therefore be considered.

Impacts of Vending Practices on the Microbiological Quality of Bread in the Ojoo Area of Ibadan, Oyo-State, Nigeria

2019 ◽  
Vol 15 (1) ◽  
pp. 31-39
Author(s):  
Oluwadara Oluwaseun Alegbeleye ◽  
Wasiu Akinloye Oyebisi Afolabi ◽  
Beatrice Oluwatoyin Opeolu ◽  
Amin Mousavi Khaneghah
Keyword(s):  
Food Safety ◽  
Microbiological Quality ◽  
Bacillus Species ◽  
Potential Hazard ◽  
Safety Regulations ◽  
Bacillus Flexus ◽  
Microbiological Methods ◽  
Key Factor ◽  
Quality Of Food

Background: Bacterial counts in ready-to-eat foods are a key factor in assessing the microbiological quality and safety of food. Periodic assessment of the microbiological quality of food is necessary to develop a robust database and help to ensure food safety. </P><P> Methods: The bacterial contamination of a total of 336 bread samples collected from two bakeries and 10 vendors in Ojoo Area of Ibadan, Oyo-State, Nigeria (December 2014 -June 2015) was evaluated. The microbiological quality of the bread loaves was investigated using standard microbiological methods (morphological, phenotypic and molecular characterization). </P><P> Results: The results showed that the number of contaminated samples among the vended bread samples was higher than the bakery bread samples and can be summarized as Bacillus megaterium (4.30%), Staphylococcus arlettae (0.005%), Staphylococcus saprophyticus (2.78%), Citrobacter freundii (2.40%), Bacillus flexus (1.64%), Bacillus species (49.59%), Pseudomonas aeruginosa (4.12%), Pseudomonas fluorescens (0.92%), Pseudomonas species (0.045%), Escherichia coli (30.44%) Klebsiella sp. (0.040%) and Aeromonas hydrophila (3.72%). </P><P> Conclusion: The findings demonstrate that the bread samples which become contaminated after transport and handling can be considered a potential hazard to human health in the area. More stringent adherence to food safety regulations should be encouraged and enforced by the appropriate authorities. The findings of this study may be adopted to improve the hygienic conditions of bread distribution chain in the area as well as in other regions of the World.

Humanism and the Human

2020 ◽  
Author(s):  
Joseph Winters
Keyword(s):  
Critical Theory ◽  
Michel Foucault ◽  
Karl Marx ◽  
Black Studies ◽  
Black Feminism ◽  
Working Through ◽  
A Site ◽  
The Ideal ◽  
Sylvia Wynter

This chapter engages humanism and its fundamental assumptions by working through critical theory, black feminism, and black studies. It contends that there is a tension at the heart of humanism—while the ideal human appears to be the most widespread and available category, it has been constructed over and against certain qualities, beings, and threats. To elaborate on this tension, this chapter revisits the work of authors like Karl Marx and Michel Foucault. Marx acknowledges that the human is a site of conflict and antagonism even as his thought betrays a lingering commitment to progress and humanism. Foucault goes further than Marx by underscoring the fabricated quality of man and the ways in which racism functions to draw lines between those who must live and those who must die. In response to Marx and Foucault’s tendency to privilege Europe, this chapter engages black feminism and Afro-pessimism—Sylvia Wynter, Hortense Spillers, and Frank Wilderson—who show how the figure of the human within humanism is defined in opposition to blackness.

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