Polyelectrolyte Flocculation Research Articles

Effects of polyacrylamide on microbial density levels and biodegradability in waste‐activated sludge

AbstractThis study addressed the possible role of polyelectrolyte flocculation on microbial density levels in a waste‐activated sludge. Such an effect is commonly ignored. Applying polyelectrolyte reduced the density level of coliform bacteria in the flocculated sludge. Polyelectrolyte also reduced the 5‐day biochemical oxygen demand of sludge, possibly retarding the subsequent biodegradation processes.© 2001 Society of Chemical Industry

Novel cake characteristics of waste-activated sludge

Breaking down the time limit constraints for conventional compression–permeation (C–P) cell test, this work has, for the first time, experimentally evaluated the cake characteristics of viable waste-activated sludge subject to polyelectrolyte flocculation and to freeze/thaw treatment under a pressure range of 25–200 kPa. There exists a threshold pressure exceeding which the cake structure would significantly deteriorate. Also, the present biological sludge is a “super-compactible” sludge, whose compactibility is greater than most data ever reported in open literature. The information presented herein has implications to filter design/operation and can be used as a reference data set for examining the existing filtration theories.

Treatment of the Wastewater of Finishing-and-Dyeing Production Using Polyelectrolyte Flocculants Based on Nitron Fiber Scrap

The performance of FK-1 and FK-3 cationic polyelectrolytes and of new AMF-2 amphoteric polyelectrolyte in treatment of the wastewater of finishing-and-dyeing production was studied as influenced by the concentrations of flocculant and coagulant.

Thermogravimetric Analysis of Activated Sludge Flocculated with Polyelectrolyte

This work examines the thermal pyrolysis characteristics of polyelectrolyte-flocculated activated sludge at a heating rate up to 873 K by means of thermogravimetric analysis (TGA). Although the polyelectrolyte does not affect the pyrolysis rate of the sludge at a temperature of 8 or 14 K/min, using polyelectrolyte flocculation to charge neutralization appears to accelerate the pyrolysis process at 20 K/min. TGA mass spectrometer tests were performed to identify the species released during pyrolysis of the sludges. A parallel-reaction kinetic model (Reactions 1 and 2) was applied to interpret the experimental data, with Reaction 1 corresponding to the release of C\d7H\D14\N equivalents or lighter and Reaction 2 corresponding to the heavier compounds. Using polyelectrolyte flocculation to change the neutralization point enhances Reaction 1 by transforming the heavier organics that are originally released at elevated temperature (Reaction 2) to the lighter compounds in the low-temperature regime (Reaction 1).

Thermal pyrolysis characteristics of polymer flocculated waste activated sludge

Polyelectrolyte conditioning is a common practice in wastewater management. This paper experimentally elucidated the thermal pyrolysis characteristics of waste activated sludge at a temperature range of 300–900 K (27–627°C) using thermogravimetric analysis (TGA) in inert atmosphere, with especial attention on the effect of polyelectrolyte flocculation (using cationic polyacrylamide). On the pyrolysis rate vs temperature plot two maxima were noted. At the heating rate of 8°C/min, polyelectrolyte does not influence the pyrolysis process. As higher heating rates (14 and 20°C/min), on the other hand, flocculation to charge neutralization point would enhance the rate of thermal pyrolysis. A simple two parallel-reaction kinetic model is applied to interpret the experimental data. Possible roles of flocculant on sludge pyrolysis are discussed on the basis of change in sludge structures and the hindrance of surface reactions of sludge particles.

A case study of microwave processing of metal hydroxide sediment sludge from printed circuit board manufacturing wash water

The large quantity of wash water used in the electroplating and etching process in the manufacturing of printed circuit boards (PCBs) contains a high level of heavy metal ions (Cu ++, Zn ++, Ni ++, Cr +++, Pb ++). These potentially toxic ions are removed from the wash water effluent through a polyelectrolyte flocculation and hydroxide precipitation process during which a hydroxide sediment sludge rich in metal ions and polymers is generated. This sediment sludge possesses some unique characteristics and properties in terms of composition, fine particle size distribution, high specific surface area, and a tendency to agglomerate after drying. Direct disposal of this classified “special waste” (Department of Environment of Northern Ireland, The Special Waste Regulations, Northern Ireland, 1998) at landfill sites may cause serious soil and underground water pollution through a gradual ionic leaching process. This paper describes an experimental investigation, exploratory in nature, which employs microwave radiation for detoxification of the sediment sludge through microwave heating, drying and metal ion immobilization within the sediment solids. The effectiveness of microwave assisted binding and immobilization of the metal ions within the sediment solids was studied in conjunction with an evaluation of microwave energy efficiency in comparison to the more conventional convective heating and drying processes. Given a sufficient amount of microwave radiation, leaching of Cu 2+ and Pb 2+ was reduced by 2700% and 1080%, respectively, over a period of 12 weeks, and further leaching was not detectable within six months at simulated local landfill aqueous conditions. This paper also attempts, through experimental observation, to add to the very limited understanding of the complex interactions and binding of free metal ions with the polymeric materials and metal hydroxides under the influence of an electromagnetic field. The high specific surface of the sediment solids and their adsorption properties were further explored and characterized in a study of adsorption of reactive dyes by the microwave processed solids.

Polymer flocculation and coagulation for sedimentation of copper flotation tailings

Employing a combination of two types of polyelectrolyte might become necessary to enhance both the settling rate of the flocs and the water clarity of a fine-particle suspension in a high-capacity thickening process. The sequence of addition, mixing, type and dosage of polymer all affect the overall performance and capacity of a thickening process. For the sedimentation of copper flotation tailings, the cylinder test results showed that two different techniques may be used to achieve the required performance, i.e., a high settling rate of the flocs and the deisired underflow density and overflow water clarity. The required performance can be acheived by either adjusting the pH prior to anionic polyelectrolyte flocculation or using a combination of polymer flocculant and coagulant (dual-polymer system). The dynamic thickening test results showed that only the approach using a dual-polymer system is capable of meeting the required performance. The effects of polyelectrolyte dosage, the sequence and numbers of polyelectrolyte addition, the feed concentration, the bed level and the rake speed on the settling rate, underflow percent solids and water clarity were studied in cylinder tests and in a laboratory dynamic thickening unit. The dynamic test is especially valuable in evaluating the addition and mixing of polymers. The results were evaluated quantitatively using total suspended solids in supernatant, underflow density and capacity per unit of settling area per unit of time. The objective of this study was to quantify and explain some of the parameters involved in the sedimentation of copper flotation tailings.

Flocculation in presence of organic macromolecules of natural water and secondary effluents

Flocculation processes were studied in three types of water representing turbid natural surface water, controlled synthetic systems of reference clay minerals suspensions in the presence of humates and fulvates at various degrees of interactions, and municipal wastewater treatment plant effluents. These systems contain suspended and colloidal dispersed solids accompanied by organic substances in dissolved or colloidal form. The presence of organic anionic macromolecules and soluble organics in water affects flocculation processes by raising the flocculant demand appreciably and hence affects the final water quality. Extraction and elimination of the organics from natural suspended solids, and removal of soluble organics from effluents reduced the organic content, thus decreasing considerably the flocculant demand. The addition of the extracted and separated organics to pure clay dispersions increased accordingly the cationic polyelectrolyte flocculant demand.

Flocculation in presence of organic macromolecules of natural water and secondary effluents

Flocculation processes were studied in three types of water representing turbid natural surface water, controlled synthetic systems of reference clay minerals suspensions in the presence of humates and fulvates at various degrees of interactions, and municipal wastewater treatment plant effluents. These systems contain suspended and colloidal dispersed solids accompanied by organic substances in dissolved or colloidal form. The presence of organic anionic macromolecules and soluble organics in water affects flocculation processes by raising the flocculant demand appreciably and hence affects the final water quality. Extraction and elimination of the organics from natural suspended solids, and removal of soluble organics from effluents reduced the organic content, thus decreasing considerably the flocculant demand. The addition of the extracted and separated organics to pure clay dispersions increased accordingly the cationic polyelectrolyte flocculant demand.

Dynamics of initial stage flocculation of polystyrene latex spheres with polyelectrolytes

Abstract An end-over-end rotation apparatus was created in order to obtain reproducible mixing suitable for the study of the kinetics of flocculation. The validity was verified by measuring the rate of coagulation of monodispersed polystyrene latex particles with simple electrolytes by means of a Coulter Counter. The method was applied to the analysis of the initial behavior of flocculation induced by the addition of excess polyelectrolyte flocculant with a nominal molecular weight of 4.5 million. In contrast to coagulation with a simple electrolyte, the rate of flocculation in the initial stage was remarkably enhanced and then decreased abruptly after certain mixing steps. The degree of the initial stage of enhancement and the duration of this stage were found to be dependent on the concentration of the polyelectrolyte. Ascribing the enhancement to the increase in the effective collision radius of the colloidal particles due to the attached polymer layer, the thickness of this layer, δHe, was calculated. Analyses showed that δHe increases as polymer concentration increases up to a layer thickness of 500 nm, which correlates with the size of the polymer in the solution. However, an analysis of the collision process between particles and polyelectrolytes implied that the kinetics of polymer adsorption in the initial stage are limited by transportation until near saturation. Taking into account the data on electrophoretic mobility, we concluded that our results are consistent with the picture of kinetically-controlled polymer adsorption proposed by De Witt and van de Ven [J.A. De Witt and T.G.M. van de Ven, Langmuir, 8 (1992) 788].

Effects of polyelectrolyte characteristics and flocculation conditions on fine particle floc properties

Polystyrene latex was flocculated with cationic polyelectrolytes of different charge densities at low ionic strength and the effects of different flocculation conditions were studied. The flocs wer ...

Improved separation of bacteria with a dual flocculant hydrocol? system

Polyelectrolyte flocculants are inefficient at flocculating Z. mobilis and B. subtilis in a complex medium, when administered singly or when combined with an oppositely charged polymer. However, when polymer dosing is followed by bentonite addition, particularly when chitosan constitutes the soluble polymer, effective flocculation occurs. High broth clarities can be attributed to chitosan interaction with cells, extracellular polymer and bentonite.

Streaming Potential Studies on Anthracite in the Presence of Inorganic Ions and Polyelectrolytes

Zeta potentials on carefully prepared and characterized anthracite (also limited data on associated roof and floor samples) are determined by the streaming potential technique. Values are reported as functions of pH in distilled water. Three inorganic electrolytes were used, giving rise to mono-, di and trivalent counterions. Zeta potentials are reported over the range 10−6 to 10−3 Mdm−3 at the unbuffered pH's (5.8 ± 0,2), Four poly-electrolyte flocculants were used, ranging from anionic to cationic. Zeta potentials are reported as functions of concentration and age of polymer solution and also in the presence of inorganic electrolytes. The Gouy-Chapman-Stern-Grahame model of the electrical double layer is used primarily to explain the effects of the inorganic ions.

Cationic polyelectrolyte flocculation of oil-water emulsions. Effects of mixing intensity and oil concentration

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCationic polyelectrolyte flocculation of oil-water emulsions. Effects of mixing intensity and oil concentrationRichard J. Shaughnessy III, John J. Byeseda, and N. D. SylvesterCite this: Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 3, 473–478Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September 1983https://doi.org/10.1021/i300011a017RIGHTS & PERMISSIONSArticle Views186Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (649 KB) Get e-Alerts

Modified procedure for the recovery of naturally accumulated poliovirus from oysters

Methods were compared for their ability to recover poliovirus from oysters (Crassostrea gigas) which had been allowed to accumulate virus via normal filtration activities. Clarification procedures included glycine-NaCl and polyelectrolyte extraction methods followed by a variety of acid precipitation concentration methods. Polyelectrolyte flocculation followed by a beef extract-supplemented acid precipitation carried out at pH 3.5 yielded the most efficient recoveries. Direct assay of homogenates was found to be an unreliable method for determining the initial virus concentration in "naturally infected" oysters.

Polyelectrolyte Flocculation of Oil-Water Emulsions

Turbidimetric measurements of an emulsion stabilized with an oil-soluble ammonium petroleum sulfonate of a paraffinic oil in 1Vertical Bar3< aqueous sodium chloride with 1 of 12 high molecular weight polyelectrolytes showed that 4 of the polymers, including 3 cationic and 1 anionic one, reduced turbidity by 20-30Vertical Bar3< at their optimum dosages, 0.6-30 ppm. The flocculants were provided by the Calgon Corp., and Dearborn Chemical Co., and no data were available on molecular weights and chemical structures for most of them.

Effect of temperature on flocculation of aqueous dispersions

Only scant and conflicting information is available in the literature on the effect of temperature on flocculation. In the present work an attempt was made to determine the effect of temperature on zeta potential, the rate of flocculation, and the optimum pH and dosage of flocculant. Cell electrophoresis and light absorption techniques were used in flocculation experiments. Bentonite and kaolinite clays dispersed in distilled water were chosen as dispersion systems. Alum and three polyelectrolytes (cationic, anionic and non-ionic) were used as flocculants. The temperature range investigated was 1°–20°C. The results indicate that: 1. 1. Temperature has no significant effect on the zeta potential of a clay particle dispersed in water. This is in agreement with the theoretical prediction of the Poisson-Boltzman equation. 2. 2. Charge neutralization is an important factor in the flocculation of charged clay dispersion. However, the degree of charge neutralization necessary for effective flocculation depends strongly on the nature of the clay used. 3. 3. There is some correlation between zeta potential and flocculation. In the case of alum, for example, zeta potential may be used as a criterion of flocculation. 4. 4. The optimum pH for a given degree of flocculation varies with temperature when alum is used as flocculant. However, when flocculation is carried out at optimum pH conditions temperature has no effect. This supports the kinetic equations of Smoluchowski. 5. 5. When cationic polyelectrolytes are used for flocculation of aqueous dispersion, the rate of flocculation, the optimum pH, and the flocculant dosage required to achieve a given degree of flocculation are independent of temperature. This is interesting from a practical point of view, for example when the substitution of alum with a cationic polyelectrolyte flocculant is considered in a water treatment facility.

Polyelectrolyte Flocculation as an Aid to Recovery of Enteroviruses from Oysters

Polyelectrolyte Flocculation as an Aid to Recovery of Enteroviruses from Oysters

Polyelectrolyte flocculation as an aid to recovery of enteroviruses from oysters.

A simple and rapid method for recovering enteroviruses from oysters is described. A polycation sewage flocculant promoted cohesion of oyster solids and thereby aided separation of these from the viruses. Recovery of 80 to 100% of experimentally inoculated virus was achieved, and the suspension or extract obtained could be inoculated directly into tissue cultures or concentrated first for greater sensitivity.

The laboratory evaluation of polyelectrolyte flocculants

AbstractThe application of polyelectrolyte flocculants as primary coagulants, coagulant aids and sludge conditioners in the treatment of water for public supply is discussed. Laboratory techniques that have been used to evaluate commercial polyelectrolytes for these uses are described and exemplified with results. The difficulty of defining floc characteristics is emphasised.