Predicting the formation of trihalomethanes and haloacetic acids in water treated with chlorine dioxide

2009 ◽  
Vol 9 (4) ◽  
pp. 449-458 ◽  
Author(s):  
Reham Mahmoud Abu Shmeis ◽  
Manar Fayyad ◽  
Mahmoud Alawi
Keyword(s):  
Mathematical Models ◽  
Chlorine Dioxide ◽  
Disinfection Byproducts ◽  
Organic Content ◽  
Haloacetic Acids ◽  
Ion Concentration ◽  
Haloacetic Acid ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Bromide Ion

Factors affecting formation of disinfection byproducts (DBPs) such as trihalomethane THM and haloacetic acid HAA in drinking water treated with chlorine dioxide ClO2 as disinfectant were investigated. The collected data were used to develop mathematical models that predict the formation of THM and HAA in terms of each of the studied factor: ClO2 dose, total organic content TOC, bromide ion concentration, pH, temperature and contact time. Mathematical models were developed for four trihalomethane species, as well as total trihalomethanes TTHM, in addition to six haloacetic acid species and total haloacetic acids THAA. Predicted THM and HAA concentrations using developed models were compared to actual concentrations measured in real samples. Results showed good correlation between measured and calculated values. This means that the method presented could be used to obtain good estimates of THM and HAA concentrations formed when the water is treated with ClO2 under different experimental conditions.

Correlations between surrogate nitrogenous organic precursors and C-, N-DBP formation

2011 ◽  
Vol 64 (12) ◽  
pp. 2395-2403 ◽  
Author(s):  
H. H. Chang ◽  
G. S. Wang
Keyword(s):  
Organic Compounds ◽  
Chlorine Dioxide ◽  
Benzalkonium Chloride ◽  
Product Formation ◽  
Disinfection Byproducts ◽  
Free Chlorine ◽  
Haloacetic Acids ◽  
Source Water ◽  
Organic Precursors ◽  
Different Characteristics

Nitrosamines have been emerging as disinfection byproducts in drinking water using source water impacted with domestic wastewaters. Nitrogenous organic compounds are suggested as precursors of nitrosamines, but many of them have not been identified. This study investigated the correlations between nine selected nitrogenous organic compounds with different characteristics and corresponding disinfection by-product formation potentials (nitrosamines, trihalomethanes (THMs), and haloacetic acids (HAAs)) from their reactions with free chlorine, chlorine dioxide and monochloramine. Besides dimethylamine, the well-known precursor of nitrosamines, 3-(N,N-dimethyloctylammonio)propanesulfonate (3-N,N-DAPSIS) inner salt and benzyldimethyltetradecylamine (benzalkonium chloride, BKC) were suggested as important nitrosamine precursors. 3-N,N-DAPSIS could form about 1,000 ng/L of N-nitrosodimethylamine (NDMA) and more than 1,000 μg/L of THMs. More than 150,000 ng/L of NDMA were observed when BKC was treated with monochloramine, and high levels of THMs (up to 2,700 μg/L) were also yielded. As expected, free chlorine produced higher levels of THMs and HAAs, and chlorine dioxide generated minor levels of traditional DBPs. Nitrosamines were mainly formed when the precursors were treated with monochloramine.

Development of Predictive Models for the Formation of Trihalomethanes and Haloacetic Acids during Chlorination of Bromide-Rich Water

2004 ◽  
Vol 39 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Themistokles D. Lekkas ◽  
Anastasia D. Nikolaou
Keyword(s):  
Human Health ◽  
Dichloroacetic Acid ◽  
Haloacetic Acids ◽  
Individual Species ◽  
Formation Mechanisms ◽  
Factors Affecting ◽  
Major Species ◽  
Bromide Ion ◽  
Major Factors ◽  
Scientific Attention

Abstract The formation of disinfection by-products (DBPs) during chlorination of drinking water is an issue which has drawn significant scientific attention over the last few years, due to the adverse effects of these compounds on human health. The complicated mechanisms of the formation of DBPs are still under investigation, and modelling attempts are being made. One of the major factors affecting the yields of DBPs is the concentration of bromide ion. In bromide-rich waters, the brominated species—bromoform, dibromoacetic acid—which are considered more toxic than their chlorinated analogues, may be the major species formed and therefore the consumption of these waters may be more harmful to human health than the consumption of water containing chlorinated species (chloroform, dichloroacetic acid). During this study, the effect of bromide ion on DBP formation was investigated by bench-scale chlorination experiments and statistically evaluated for individual species of DBPs. The importance of interactions between pairs of chlorination factors, pH, bromide concentration, chlorine dose and time for DBP formation was highlighted by statistical analysis results. Moreover, multiple regression models were developed for the concentrations of total trihalomethanes and total haloacetic acids, the two major DBP groups formed. The models developed provide satisfactory estimations of, but also indicate different formation mechanisms for, these two groups of DBPs.

scholarly journals Enzymatic Process for Cystoseira barbata Valorization: Ethanol Production and Additional By-Products

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 741
Author(s):  
Doinita-Roxana Cioroiu Tirpan ◽  
Ancaelena Eliza Sterpu ◽  
Claudia Irina Koncsag ◽  
Alina Georgiana Ciufu ◽  
Tănase Dobre
Keyword(s):  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Product Yield ◽  
Liquid Ratio ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cystoseira Barbata ◽  
Main Factors ◽  
Process Factors

The aim of this study is to evaluate the potential of dried Cystoseira barbata alga for ethanol production through alcoholic fermentation. The influence of the main factors affecting the fermentation are studied in the frame of a 23 factorial experimental plan. The main factors influencing the process are the fermentation temperature (t from 25 °C to 35 °C), the solid to liquid ratio (S/L from 0.040 g/g to 0.080 g/g), and the cellulase ratio (R from 8 U/g d.m to 16 U/g d.m.). The maximum volatile compounds yield of 0.2808 g/g d.m and ethanol yield of 0.0158 g/g d.m were favored by the following experimental conditions: process temperature of 35 °C, solid to liquid ratio of 0.0415, and enzyme ratio of 16 U/g d.m. A statistical model was used to correlate the product yield with the process factors. Additionally, 19 interesting bioactive compounds were found in the enzymatic hydrolysis and alcoholic fermentation broths which seem likely to maintain natural defence mechanisms against diseases and physical disorders.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

scholarly journals New extraction techniques on bioseparations: 2. Pertraction, direct extraction

2004 ◽  
Vol 58 (12) ◽  
pp. 535-547
Author(s):  
Anca-Irina Galaction ◽  
Dan Cascaval
Keyword(s):  
Mathematical Models ◽  
Carboxylic Acids ◽  
Separation Efficiency ◽  
Extraction Techniques ◽  
Direct Extraction ◽  
Experimental Conditions ◽  
Maximum Separation

The second part of this review presents our original results on the separation of some biosynthetic products (antibiotics, carboxylic acids, alcohols) by pertraction and direct extraction from broths without biomass filtration. For the analyzed systems, the experimental conditions required for reaching maximum separation efficiency and the mathematical models describing the process have been established. For all the studied cases, these extraction techniques simplify the technologies and reduce the overall cost of the product.

scholarly journals Analysis on Present Mathematical Model for Predicting the Crop Production

2020 ◽  
Vol 9 (12) ◽  
pp. 168-170
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Real World ◽  
Crop Production ◽  
Ghg Emissions ◽  
Data Set ◽  
Factors Affecting ◽  
The Government ◽  
The Mathematical Model ◽  
Government Website

India is a worldwide agriculture business powerhouse. Future of agriculture-based products depends on the crop production. A mathematical model might be characterized as a lot of equations that speak to the conduct of a framework. By using mathematical model in agriculture field, we can predict the production of crop in particular area. There are various factors affecting crops such as Rainfall, GHG Emissions, Temperature, Urbanization, climate, humidity etc. A mathematical model is a simplified representation of a real-world system. It forms the system using mathematical principles in the form of a condition or a set of conditions. Suppose we need to increase the crop production, at that time the mathematical model plays a major role and our work can be easier, more significant by using the mathematical model. Through the mathematical model we predict the crop production in upcoming years. .AI, ML, IOT play a major role to predict the future of agriculture, but without mathematical models it is not possible to predict crop production accurately. To solve the real-world agriculture problem, mathematical models play a major role for accurate results. Correlation Analysis, Multiple Regression analysis and fuzzy logic simulation standards have been utilized for building a grain production benefit depending model from crop production. Prediction of crop is beneficiary to the farmer to analyze the crop management. By using the present agriculture data set which is available on the government website, we can build a mathematical model.

Control of disinfection and halogenated disinfection byproducts by the electrochemical process

2007 ◽  
Vol 55 (12) ◽  
pp. 213-219 ◽  
Author(s):  
Y.J. Jung ◽  
B.S. Oh ◽  
J.W. Kang ◽  
M.A. Page ◽  
M.J. Phillips ◽  
...  
Keyword(s):  
Kinetic Studies ◽  
Disinfection Byproducts ◽  
Electrochemical Process ◽  
Free Chlorine ◽  
Haloacetic Acids ◽  
Oh Radicals ◽  
Inactivation Kinetic ◽  
E Coli ◽  
Electrochemical Processes

The aim of this study was to investigate some aspects of the performance of electrochemical process as an alternative disinfection strategy, while minimising DBPs, for water purification. The study of electrochemical processes has shown free chlorine to be produced, but smaller amounts of stronger oxidants, such as ozone, hydrogen peroxide and OH radicals (•OH), were also generated. The formation of mixed oxidants increased with increasing electric conductivity, but was limited at conductivities greater than 0.6 mS/cm. Using several microorganisms, such as E. coli and MS2 bacteriophage, inactivation kinetic studies were performed. With the exception of free chlorine, the role of mixed oxidants, especially OH radicals, was investigated for enhancement of the inactivation rate. Additionally, the formation and reduction of DBPs was studied by monitoring the concentration of haloacetic acids (HAAs) during the process.

The mobility of intramembrane particles in non-haemolysed human erythrocytes. Factors affecting acridine-orange-induced particle aggregation

1986 ◽  
Vol 86 (1) ◽  
pp. 57-67
Author(s):  
G. Lelkes ◽  
I. Fodor ◽  
G. Lelkes ◽  
S.R. Hollan
Keyword(s):  
Acridine Orange ◽  
Intracellular Ph ◽  
Lateral Diffusion ◽  
Inhibitory Effect ◽  
Human Erythrocytes ◽  
Particle Aggregation ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cross Links ◽  
Phosphate Buffered Saline

It has previously been shown that reversible intramembrane particle aggregation can be induced in non-haemolysed human erythrocytes. This phenomenon, which can be induced by the cationic dye Acridine Orange, has been further investigated using different experimental conditions that are expected to influence the rate of aggregation of the particles. In addition to the concentration of the dye, the rate of aggregation was also found to be dependent on the extracellular and intracellular pH, as well as on the type of buffer used. While lowering the pH of the Acridine Orange solutions resulted in decreased particle clustering, low intracellular pH increased and elevated intracellular pH decreased particle aggregation. Furthermore, at a given dye concentration and a given pH, Acridine Orange caused more intense aggregation in Tris-buffered saline than in isotonic phosphate buffer or phosphate-buffered saline. Under appropriate conditions Acridine Orange caused significant particle aggregation at concentrations as low as 0.25 mM within 30 s. During this period only discocyte-stomatocyte transformation occurred; neither agglutination nor vesiculation of the erythrocytes could be detected. Treatment of the erythrocytes with Diamide (Serva), which cross-links spectrin via disulphide bridges and thereby reduces lateral diffusion of integral membrane proteins over large distances, had no inhibitory effect on Acridine-Orange-induced particle aggregation. Heating the erythrocytes to 50 degrees C, at which temperature denaturation of spectrin and fragmentation of the erythrocytes occur, and subsequently incubating them in Acridine Orange at room temperature, caused an almost maximal rate of particle aggregation within 10–30 s, without haemolysis. The possible mechanism and significance of the particle aggregation phenomenon are discussed.

Analysis of Bromide Ion in Wine by Ion Selective Electrode

1976 ◽  
Vol 59 (1) ◽  
pp. 53-55
Author(s):  
James E Graf ◽  
Troy E Vaughn ◽  
William H Kipp
Keyword(s):  
Country Of Origin ◽  
Ion Selective Electrode ◽  
Ion Concentration ◽  
Selective Electrode ◽  
Bromide Ion

Abstract The use of the bromide ion selective electrode for the determination of bromide ion in wine has been found to be rapid and reliable. The method has been used for still wines and carbonated wines and is applicable to all wines regardless of their country of origin. The method consists of treating a 50 ml aliquot of wine with 2 ml each of 3.75M H3PO4, saturated KNO3, and 1M CuSO4. After 10 min the electrodes are immersed in the samples and a millivolt reading is obtained. One hundred μl 500 ppm bromide ion standard is added and the millivolt reading is taken. Bromide ion concentration in the wine = (CΔ × 1)/((antilog ΔE/S) − 1) where CΔ = 1, ΔE = the change in potential expressed in millivolts, and S = the electrode slope.

Factors affecting constancy of acetate concentration and correct determination of methanogenic activity in pH-stat experiments

2003 ◽  
Vol 48 (6) ◽  
pp. 111-118
Author(s):  
M. Mösche ◽  
U. Meyer
Keyword(s):  
Accurate Determination ◽  
Original Method ◽  
Experimental Conditions ◽  
Methanogenic Activity ◽  
Factors Affecting ◽  
Acetate Concentration ◽  
Correct Determination ◽  
Ph Stat ◽  
The Stability

The determination of methanogenic activity with a pH-stat titration bioassay is evaluated utilising a mathematical model of this system. For given kinetic parameters and experimental conditions the model calculates the development of titrant flow and acetate concentration during experiments. Simulations of experiments under various conditions are compared. They show that the original method inherently causes a strong drift of acetate concentration during the experiments and a misestimation of methanogenic activity. As a solution to these disadvantages the addition of sodium hydroxide to the titrant and a careful control of pH during flushing the reactor with gas prior to the experiment are recommended. In this way a better constancy of acetate concentration and a more accurate determination of methanogenic activity should be achievable. The accuracy of this method is limited by the stability of pH-electrode calibration parameters.

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