scholarly journals Concentration of active sludge in the aeration reactors

2018 ◽  
Vol 178 ◽  
pp. 09022
Author(s):  
Nina Zaletova ◽  
Nadezhda Morozova
Keyword(s):  
Enzyme Activity ◽  
Activated Sludge ◽  
Dehydrogenase Activity ◽  
Tap Water ◽  
Experimental Studies ◽  
Aeration Tank ◽  
Active Sludge ◽  
Wastewater Treatment Process ◽  
First Case ◽  
Actual Substrate

The purpose of the paper was to study the dehydrogenase activity (DHA) of activated sludge in aeration tank. The article describes a change in enzyme activity, (dehydrogenase activity of sludge-DHA) of activated sludge while various time of aeration as well as various dose in sludge of aeration tank. Assessment changes enzyme activity were done on two indicators - on DHAor. (original dehydrogenase activity of sludge) and DHAH2O (dehydrogenase sludge activity with tap water). In the first case - DHA with the actual substrate, in the second case - DHA with poorly concentrated substrate. The work was performed on a pilot installation consisting of four models of aeration tanks blocked with sedimentation tanks, on a real city waste water. Working doses of sludge in biological wastewater treatment process was ranged from 2 to 6 g/l, time of aeration in aeration tanks changed from 3.5. up to 0.8 hours. Experimental studies have shown that regardless of the size of working sludge dose in aeration tank character of changes DHA or and DHAH2O is identical.

scholarly journals Modeling and optimizations of mixing and aeration processes in bioreactors with activated sludge

2021 ◽  
Vol 2130 (1) ◽  
pp. 012027
Author(s):  
J Zaburko ◽  
G Łagód ◽  
M K Widomski ◽  
J Szulżyk-Cieplak ◽  
B Szeląg ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Electric Energy ◽  
Active Sludge ◽  
Wastewater Treatment Process ◽  
Sludge Flocs ◽  
Model Studies ◽  
Aeration System ◽  
Pollutants Removal ◽  
Batch Bioreactors ◽  
Exact Amount

Abstract Mixing aimed at homogenization of the volume of bioreactors with the activated sludge is of great importance for the proper course of the wastewater treatment process. It affects both the efficiency of pollutants removal and the properties of the activated sludge related to its sedimentation. The mixing process in bioreactors can be carried out in different ways. In batch bioreactors in the aeration phase or flow bioreactors in aerobic chambers, mixing is carried out through aeration systems. These systems should aerate the activated sludge flocs for efficient biological treating of wastewater, as well as effectively homogenize the volume of the bioreactor. Hence, it is important to choose such a design of the aeration system and its operation settings that provide the amount of air ensuring the exact amount of oxygen for the implementation of technological processes, counteract sedimentation of sludge at the bottom of the reactor, are reliable as well as economical in operation (demand of electric energy). The paper presents the model studies aimed at optimization of the design and settings of aeration and mixing systems used in active sludge bioreactors.

Study on Chemical Wastewater Treatment with Many-Point-Water-Inflow Biological Reaction Tank

2012 ◽  
Vol 518-523 ◽  
pp. 2825-2828
Author(s):  
Fang Li ◽  
Dan Hao
Keyword(s):  
Activated Sludge ◽  
Treatment Effect ◽  
Removal Rate ◽  
Trace Element Content ◽  
Water Inflow ◽  
Good Effect ◽  
Aeration Tank ◽  
Active Sludge ◽  
Cod Removal Rate ◽  
Sludge Concentration

The composition of mixed chemical wastewater is more complex and biodegradability of its is bad, biochemical treatment effect should be further improved. Many-point-water-inflow bioreactor used in this experiment, through controlling hydraulic retention time(HRT), concentration of active sludge of the aeration tank, trace element content and so on, gets a better treatment effect. When water temperature is 25°C, HRT is 5h, 10h, 15h, 20h, 25h,COD removal rate is 60.37%, 82.62%, 89.44% , 91.02%,91.07%. According to the iron content of influent, plus 0.5mg/L ferrous sulfate into influent, the removal rate of COD is increased , activated sludge floc of the sedimentation tank is denser and settling. By changing the activated sludge return ratio to change the activated sludge concentration of the bioreactor, experiments shows that the removal rate of organic matter is better with the activated sludge concentration about 4000-5000mg/L. Influent qualities indicate that this biological treatment has good effect on mixed chemical wastewater.

scholarly journals Bioindication of the metal-containing wastewater treatment process

2020 ◽  
Vol 193 ◽  
pp. 02010
Author(s):  
Albina Salina ◽  
Aleksey Salin
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Dehydrogenase Activity ◽  
Treatment Process ◽  
Activity Measurement ◽  
Redox Processes ◽  
Wastewater Treatment Process

The influence of Nickel (II) and Chronic (VI) ions on the redox processes in activated sludge community is discussed. Toxicity definition is made on the basis of fermentation activity (measurement dehydrogenase activity of sludge)

THE INFLUENCE OF HAEMOGLOBIN-S AND G6PD DEFICIENCY ON THE ACTIVITY OF THE 17β-HYDROXYSTEROID DEHYDROGENASE OF INTACT HUMAN ERYTHROCYTES

1974 ◽  
Vol 75 (4) ◽  
pp. 793-800
Author(s):  
A. O. Sogbesan ◽  
O. A. Dada ◽  
B. Kwaku Adadevoh
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Sex Steroids ◽  
G6pd Deficiency ◽  
Incubation Medium ◽  
Hydroxysteroid Dehydrogenase ◽  
G6pd Activity ◽  
Reverse Transformation ◽  
Oxidative Transformation ◽  
Haemoglobin S

ABSTRACT The 17β-hydroxysteroid dehydrogenase activity in intact erythrocytes of Nigerian patients, in particular with regard to haemoglobin genotypes and G6PD* activity was studied. The G6PD activity of the erythrocyte did not affect the oxidative transformation of testosterone to androstenedione and of oestradiol to oestrone. The reduction (reverse transformation) was inhibited in G6PD-deficient erythrocytes but this inhibition was offset by the addition of 0.025 m glucose to the incubation medium. The per cent oxidation transformation of testosterone was higher in Hb-AA than in Hb-SS erythrocytes. It is suggested that the differences may be a result of either lower enzyme activity in the Hb-SS erythrocytes or of differences in the uptake and possibly binding of sex steroids by intact Hb-SS and Hb-AA erythrocytes.

On the Problem of “Two-Phase” Activated Sludge

1991 ◽  
Vol 24 (7) ◽  
pp. 59-64 ◽  
Author(s):  
R. W. Szetela
Keyword(s):  
Activated Sludge ◽  
Single Phase ◽  
Phase System ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Sludge Stabilization ◽  
Technological Advantage ◽  
In Series ◽  
State Models ◽  
Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

scholarly journals Do Animals Play a Role in the Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2)? A Commentary

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Anna Costagliola ◽  
Giovanna Liguori ◽  
Danila d’Angelo ◽  
Caterina Costa ◽  
Francesca Ciani ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Experimental Studies ◽  
Infectious Agent ◽  
Human Infection ◽  
Farm Animals ◽  
Partial Protection ◽  
Management Measures ◽  
First Case ◽  
And Behavior

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) belongs to the Beta-coronavirus genus. It is 96.2% homologous to bat CoV RaTG13 and 88% homologous to two bat SARS-like coronaviruses. SARS-CoV-2 is the infectious agent responsible for the coronavirus disease (COVID-19), which was first reported in the Hubei province of Wuhan, China, at the beginning of December 2019. Human transmission from COVID-19 patients or incubation carriers occurs via coughing, sneezing, speaking, discharge from the nose, or fecal contamination. Various strains of the virus have been reported around the world, with different virulence and behavior. In addition, SARS-CoV-2 shares certain epitopes with some taxonomically related viruses, with tropism for the most common synanthropic animals. By elucidating the immunological properties of the circulating SARS-CoV-2, a partial protection due to human–animal interactions could be supposed in some situations. In addition, differential epitopes could be used for the differential diagnosis of SARS-CoV-2 infection. There have been cases of transmission from people with COVID-19 to pets such as cats and dogs. In addition, wild felines were infected. All These animals were either asymptomatic or mildly symptomatic and recovered spontaneously. Experimental studies showed cats and ferrets to be more susceptible to COVID-19. COVID-19 positive dogs and felines do not transmit the infection to humans. In contrast, minks at farms were severely infected from people with COVID-19. A SARS-Cov-2 variant in the Danish farmed mink that had been previously infected by COVID-19 positive workers, spread to mink workers causing the first case of animal-to-human infection transmission that causes a moderate decreased sensitivity to neutralizing antibodies. Thus, more investigations are necessary. It remains important to understand the risk that people with COVID-19 pose to their pets, as well as wild or farm animals so effective recommendations and risk management measures against COVID-19 can be made. A One Health unit that facilitates collaboration between public health and veterinary services is recommended.

scholarly journals Influent with Particulate Substrate, Clean, Innocuous and Sustainable Solution for Bulking Control and Mitigation in Activated Sludge Process

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 984
Author(s):  
Pedro Cisterna-Osorio ◽  
Claudia Calabran-Caceres ◽  
Giannina Tiznado-Bustamante ◽  
Nataly Bastias-Toro
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Nutrient Deficiency ◽  
Microscopic Analysis ◽  
Volume Index ◽  
Favorable Effect ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Active Sludge ◽  
Chemical Reagents

This research studies the incidence of the type of substrate, soluble or particulate, in the emergence, development, and inhibition of bulking in activated sludge systems. It was evaluated using the sludge volume index (SVI), mixing liquor-suspended solids (MLSS), microscopic analysis of biomass, and effluent suspended solids (ESS). In the first experiment, four sequencing batch reactors (SBRs) were fed with soluble substrate at a fixed mass, while the mass of the particulate substrate varied, as those (saccharose mass/flour mass) ratios were 3:1, 3:2, 3:3 and 3:4., with a deficit ranging from 20 to 30% compared to the ratio recommended. The four SBRs have similar MLSS, IVL, and ESS. From day 30, with a deficit from 80 to 90%, the influents have ratios 1/1 and 1/2 until 48 days. The SBRs present IVL between 600 and 730 mL/g and ESS from 370 to 440 mg/L; unlike influents with ratios 1/3 and 1/4, they present IVL between 170 and 185 mL/g, and ESS from 260 to 270 mg/L. The favorable effect of particulate matter is categorical. In the second set of experiments, two SBRs were studied: SBR 1 fed with saccharose, and SBR 2 with flour; there is a lack of nutrients causing bulking in SBRs. Once the nutrient deficiency condition is changed in day 11 to excess, after 22 days, the SVI was 190 mL/g, ESS was 360 mg/L, and MLSS was 2000 mg/L for influents with saccharose; the influent with flour, with an SVI of 80 mL/g, ESS of 100 mg/L, and MLSS of 4000 mg/L, shows faster and more consistent recovery with the particulate substrate. Therefore, the proposal is to add particulate substrate-like flour to active sludge plants facing bulking. It is a clean, innocuous and sustainable alternative to processes that use chemical reagents.

Changes in 3β-hydroxy-Δ5-steroid dehydrogenase activity in granulosa tissue during the ovulatory cycle of the laying hen (Gallus domesticus)

1985 ◽  
Vol 106 (3) ◽  
pp. 269-273 ◽  
Author(s):  
D. G. Armstrong
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Domestic Fowl ◽  
Ovarian Follicle ◽  
Laying Hen ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Lh Surge ◽  
Maximal Plasma ◽  
Steroid Dehydrogenase

ABSTRACT The object of this study was to examine changes in the activity of granulosa 3β-hydroxy-Δ5-steroid dehydrogenase during the ovulatory cycle of the domestic fowl. The enzyme activity in granulosa tissue from the largest follicle increased significantly during the period 8–14 h before an expected ovulation. The increase in activity occurs before the preovulatory surge of LH and near the time of lights off. During the 4–8 h period before an ovulation, i.e. the time of maximal plasma LH concentrations, 3β-hydroxy-Δ5-steroid dehydrogenase activity decreased in granulosa tissue from the largest follicle. This observation is explained by proposing that the enzyme is inhibited by the large amounts of progesterone found in the tissue at this time. The results indicate that important biochemical changes are taking place within granulosa tissue of the largest ovarian follicle before the preovulatory LH surge. J. Endocr. (1985) 106, 269–273

VITAMIN A POISONING

PEDIATRICS ◽  
1951 ◽  
Vol 7 (3) ◽  
pp. 372-385
Author(s):  
DONALD GRIBETZ ◽  
SAMUEL H. SILVERMAN ◽  
ALBERT E. SOBEL
Keyword(s):  
Vitamin A ◽  
Experimental Studies ◽  
Plasma Vitamin ◽  
Hypervitaminosis A ◽  
Total Vitamin ◽  
Toxic Factor ◽  
Vitamin Intake ◽  
First Case ◽  
Alcohol Fraction ◽  
Clinical Literature

Two cases of hypervitaminosis A have been presented together with a review of experimental and clinical literature. The first case presented the highest reported fasting plasma vitamin A level, the increase being chiefly due to a high vitamin A alcohol fraction. This elevated level of alcoholic vitamin A probably denotes large stores of vitamin A in the liver and data have been given to show that it is a better index of hypervitaminosis A than is the total vitamin A level. In addition, evidence has been presented that the toxic factor in hypervitaminosis A is the permanent elevated plasma vitamin A level. The similarity between the experimental studies in animals and the observations in the authors' first case has been shown. The important points necessary for making a diagnosis of hypervitaminosis A have been discussed and several similar conditions have been differentiated. It cannot be emphasized too strongly that excess vitamin intake may be as dangerous as a deficient intake.

An investigation into studying of the activated sludge foaming potential by using physicochemical parameters

2002 ◽  
Vol 46 (1-2) ◽  
pp. 525-528 ◽  
Author(s):  
K. Hladikova ◽  
I. Ruzickova ◽  
P. Klucova ◽  
J. Wanner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Physicochemical Parameters ◽  
Wastewater Treatment Plants ◽  
Physicochemical Characteristics ◽  
Full Scale ◽  
Aeration Tank ◽  
Foam Formation ◽  
Individual Parameter

This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full-scale plants can be assessed. The relations among activated sludge and biological foam hydrophobicity, scum index, aeration tank cover and filamentous population are evaluated. Individual parameter comparison reveals the scumming intensity can be estimated only on the assumption that foams is already established. None of the above mentioned characteristics can be reliably used to predict the foaming episodes at wastewater treatment plants.

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