scholarly journals The Ability of Froth Formed without Chemicals to Hold Bacteria

2019 ◽  
Author(s):  
Ghanim Hassan ◽  
Robert G. J. Edyvean
Keyword(s):  
Drinking Water ◽  
Froth Flotation ◽  
Operating Conditions ◽  
Optimum Conditions ◽  
Bacterial Concentration ◽  
Taste And Odor ◽  
Water Taste ◽  
The University ◽  
Solid Liquid ◽  
Solid Liquid Separation

Abstract. Froth flotation is a solid-liquid separation technique that uses hydrophobicity as a driving force. Bacteria and other drinking water microorganisms tend to be hydrophobic and can be removed from water using this application. The biggest limitation against using froth flotation in the drinking water industry is the difficulty of producing froth without chemical frothers and holding bacteria in this froth without chemical collectors which deteriorate water taste and odor. Recently, researchers at the University of Sheffield described a method for producing froth using only water and compressed air. This has enabled froth flotation to be studied as an alternative to biocides for the removal of bacteria from drinking water. This work examines the ability of froth, produced by controlling air pumping through a water column, to hold bacteria. Bacteria are moved to the top of the column and collected in the froth. The operating conditions determine the percentage of bacteria removed. At optimum conditions, froth can hold up to 2×108 cfu/ml of bacteria. It has been found that air pumping at 130 l/min in a 20 cm diameter column will give the highest froth bacterial content. Time to reach stable froth bacterial concentration is decreased by increasing other variables.

scholarly journals Froth Production in Potable Water without Chemicals

2019 ◽  
Author(s):  
Ghanim Hassan ◽  
Robert G. J. Edyvean
Keyword(s):  
Drinking Water ◽  
Driving Force ◽  
Potable Water ◽  
Froth Flotation ◽  
Operating Parameters ◽  
Air Bubbles ◽  
Air Flow Rate ◽  
Pharmaceutical Industries ◽  
Solid Liquid ◽  
Solid Liquid Separation

Abstract. Froth flotation is a well-known solid-liquid separation technique. Hydrophobicity is the main driving force for such processes. Hydrophobic solids attach to air bubbles and rise up while hydrophilic or less hydrophobic species settle down. Froth can be produced with chemical frothers such as alcohols and polyglycols. However, the use of chemicals limits the use of this separation method in applications such as drinking water, food, and pharmaceutical industries. Therefore, developing a technique that produces froth without adding any chemicals would be useful to such industries. This work demonstrates that with suitable operating parameters a 27 cm froth height can be obtained in a 20 cm diameter column by using an air flow rate of 130 l/min.

The Environmental Fate and Mechanism of Formation of 2-Ethyl-5,5′-Dimethyl-1,3-Dioxane (2EDD) – a Malodorous Contaminant in Drinking Water

1999 ◽  
Vol 40 (6) ◽  
pp. 217-224 ◽  
Author(s):  
L. Schweitzer ◽  
J. Noblet ◽  
Q. Ye ◽  
E. Ruth ◽  
I. H. Suffet
Keyword(s):  
Waste Water ◽  
Drinking Water ◽  
Environmental Fate ◽  
Profile Analysis ◽  
Threshold Concentration ◽  
Odor Threshold ◽  
Taste And Odor ◽  
The Stability ◽  
Water Taste ◽  
Flavor Profile Analysis

A malodorous chemical, 2-ethyl-5,5′-dimethyl-1,3-dioxane (2EDD) created a drinking water taste and odor episode in Pennsylvania (USA) during 1992. The odor episode occurred as the result of a reaction between propionaldehyde and neopentyl glycol in the waste tank of a resin manufacturer. Samples of this waste water were extracted and analyzed. An in situ aqueous preparation of 2EDD was completed to demonstrate that 2EDD could have formed under the conditions found in the waste water. The stability (fate) of 2EDD was studied at different aqueous pHs (pH3, 5, 7, and 9). Some hydrolysis of 2EDD was found at pHs<7 after one week, but 2EDD appeared to be stable at pH 9. The odor characteristics and odor threshold of 2EDD were determined by the method of flavor profile analysis. The odor threshold concentration of 2EDD was found to be between 5 and 10 ng/l and was described as having a sweet, tutti fruitti odor (near the odor threshold concentration) and a burnt, sickening sweet odor at higher concentrations. This study also discovered that slight antagonism in chloraminated drinking water may occur at or near the threshold odor level of 2EDD.

scholarly journals On the Use of Iron Chloride and Starch for Clarification in Drinking Water Treatment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Gomes CEP ◽  
Oliveira HA ◽  
Azevedo AC ◽  
Rubio J
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Iron Chloride ◽  
Raw Water ◽  
Polyaluminum Chloride ◽  
Gelatinized Starch ◽  
Slow Mixing ◽  
Solid Liquid ◽  
Solid Liquid Separation

In drinking water treatment plants, chemical reagents are employed to aggregate and remove suspended particles. However, not all reagents are eco-friendly and exists concerns over environmental, economic, and health issues. This study shows features of the sustainability of commercial coagulants/flocculants and presents experimental research on floc characterization and settling of dispersed solids with a combination of Ferric Chloride (FeCl3 ) and gelatinized starch. Bench studies were conducted using kaolin suspensions and results were validated with raw water collected from a river (Rio dos Sinos, Brazil). Flocculation indexes, floc structure, and residual turbidities were compared with Polyaluminum Chloride (PAC), as a reference. All techniques showed that the combination of FeCl3 and starch formed well-structured, larger, and more settleable flocs than those produced with PAC. Superficial loadings, in a continuous separation tank (2 to 4 m.h-1) were studied with and without lamellae. Best results were obtained with 15 mg.L-1 Fe3+ and 10 mg.L-1 starch, with a velocity gradient, G, of 60 s-1 in the slow mixing and with 60° inclined lamellae spaced 1.3 cm apart. Best conditions were applied to the clarification of the raw water and again, due to the rapid settling of flocs with FeCl3 and starch, better results were obtained compared to PAC. A turbidity reduction of 94% and a residual value of 2.5 NTU with superficial loadings of 3 m.h-1 were obtained. Results were discussed in terms of interfacial and operating parameters and a promising potential for the combination of FeCl3 with starch for solid/liquid separation was envisaged.

Factors Affecting the Separation of Ti-Al Alloy in the TiPro Process

2013 ◽  
Vol 551 ◽  
pp. 44-54
Author(s):  
Kenneth Sichone ◽  
De Liang Zhang ◽  
Stella Raynova
Keyword(s):  
Powder Particle ◽  
Composite Powder ◽  
Al Alloy ◽  
Composite Powders ◽  
Factors Affecting ◽  
Al Composite ◽  
Al2o3 Phase ◽  
The University ◽  
Solid Liquid ◽  
Solid Liquid Separation

Abstract This paper presents and discusses the factors influencing the yield of Ti-Al alloy in the TiPro process which is a process developed at the University of Waikato for producing titanium alloy powders by mechanically activating Al/TiO2 powder mixtures and subsequently preheating the resultant composite powder in order to ignite a combustion synthesis reaction and separate the liquid Ti-Al alloy by extrusion. In this study, TiO2/Al composite powders with different powder particle microstructures have been produced and used to study the effects of starting composite powder particle microstructure on the solid/liquid separation of TiAl from solid Al2O3 by extrusion. Results obtained so far indicate that maximizing the time the Ti-Al alloy phase is maintained in the liquid state after the reaction between TiO2 and Al is one of the critical factors to increase the yield of Ti-Al alloy produced through the separation of liquid Ti-Al from the solid Al2O3 phase by extruding the mixture of liquid Ti-Al and Al2O3 formed through reactions and heating.

scholarly journals Treatment of Manure and Digestate Liquid Fractions Using Membranes: Opportunities and Challenges

2021 ◽  
Vol 18 (6) ◽  
pp. 3107
Author(s):  
Maria Salud Camilleri-Rumbau ◽  
Kelly Briceño ◽  
Lene Fjerbæk Søtoft ◽  
Knud Villy Christensen ◽  
Maria Cinta Roda-Serrat ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Review Paper ◽  
Inorganic Compounds ◽  
Cross Flow ◽  
Ammonia Nitrogen ◽  
Operating Conditions ◽  
Physico Chemical ◽  
Removal Of Heavy Metals ◽  
Solid Liquid ◽  
Solid Liquid Separation

Manure and digestate liquid fractions are nutrient-rich effluents that can be fractionated and concentrated using membranes. However, these membranes tend to foul due to organic matter, solids, colloids, and inorganic compounds including calcium, ammonium, sodium, sulfur, potassium, phosphorus, and magnesium contained in the feed. This review paper is intended as a theoretical and practical tool for the decision-making process during design of membrane-based systems aiming at processing manure liquid fractions. Firstly, this review paper gives an overview of the main physico-chemical characteristics of manure and digestates. Furthermore, solid-liquid separation technologies are described and the complexity of the physico-chemical variables affecting the separation process is discussed. The main factors influencing membrane fouling mechanisms, morphology and characteristics are described, as well as techniques covering membrane inspection and foulant analysis. Secondly, the effects of the feed characteristics, membrane operating conditions (pressure, cross-flow velocity, temperature), pH, flocculation-coagulation and membrane cleaning on fouling and membrane performance are presented. Finally, a summary of techniques for specific recovery of ammonia-nitrogen, phosphorus and removal of heavy metals for farm effluents is also presented.

scholarly journals Bio-purification of drinking water by froth flotation

2019 ◽  
Author(s):  
Ghanim Hassan ◽  
Robert Edyvean
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Froth Flotation ◽  
Raw Water ◽  
Bacterial Concentration ◽  
Experimental Conditions ◽  
Biofilm Growth ◽  
Main Technique ◽  
Flotation Columns ◽  
By Products

Abstract. The main technique for removing bacteria from water for various applications is chemical disinfection. However, this method has many disadvantages such as producing disinfectant by-products (DBPs), biofilm formation and either rendering the water unpotable (at high residual disinfection) or leaving a potential for lethal diseases such as Cholera (if the residual disinfection is too low). Recently, a process was developed for continuous removal of bacteria from water using the principle of froth flotation through compressed air only without any chemicals (Hassan, 2015). This work examines the extent to which chemical free froth flotation can purify drinking water. The experiments were carried out using two flotation columns with different column lengths, each equipped with ceramic air sparger. Raw water containing bacteria was fed into the column from the top. Air was pumped through the water enough to produce a froth which separated the bacteria and, when removed, the bacterial content measured. The results show that the bacterial concentration can be reduced by 55% of its original concentration under the optimal experimental conditions so far found. This suggests that the technique can be used as a pre-purification step to minimize the use of disinfectants; hence their byproducts, and to control biofilm growth.

Implementing the Drinking Water Taste-and-Odor Wheel to Improve the Consumer Lexicon

Opflow ◽  
2017 ◽  
Vol 109 ◽  
pp. E453-E463 ◽  
Author(s):  
Katherine Phetxumphou ◽  
Aarathi Raghuraman ◽  
Andrea M. Dietrich
Keyword(s):  
Drinking Water ◽  
Taste And Odor ◽  
Water Taste
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