Flocculation Effect Research Articles

Investigating the Effect of Coagulation and Flocculation - Adsorption Process on Boron Removal from Industrial Wastewater (Case Study: Ceramic Tile Industry)

Investigating the Effect of Coagulation and Flocculation - Adsorption Process on Boron Removal from Industrial Wastewater (Case Study: Ceramic Tile Industry)

Glycine betaine grafted nanocellulose as an effective and bio-based cationic nanocellulose flocculant for wastewater treatment and microalgal harvesting.

Flocculation is a widely used technology in industry including for wastewater treatment and microalgae harvesting. To increase the sustainability of wastewater treatment, and to avoid contamination of the harvested microalgal biomass, there is a need for bio-based flocculants to replace synthetic polymer flocculants or metal salt coagulants. We developed the first cellulose nanocrystalline flocculant with a grafted cationic point charge, i.e. glycine betaine (i.e. N,N,N-trimethylglycine) grafted cellulose nanocrystals (CNCs) effective for the flocculation of kaolin (a model system for wastewater treatment), the freshwater microalgae Chlorella vulgaris, and the marine microalgae Nannochloropsis oculata. We successfully grafted glycine betaine onto CNCs using a one-pot reaction using a tosyl chloride activated esterification reaction with a degree of substitution ranging from 0.078 ± 0.003 to 0.152 ± 0.002. The degree of substitution is controlled by the reaction conditions. Flocculation of kaolin (0.5 g L−1) required a dose of 2 mg L−1, a comparable dose to commercial polyacrylamide-based flocculants. Flocculation was also successful for freshwater as well as marine microalgae (biomass concentration about 300 mg L−1 dry matter), although the flocculation efficiency of the latter remained below 80%. The dose to induce flocculation (DS = 0.152 ± 0.002) was 20 mg L−1 for the freshwater Chlorella vulgaris and 46 mg L−1 for the marine Nannochloropsis oculata, comparable to other bio-based flocculants such as chitosan or TanFloc.

Poređenje uticaja poliakrilamida i natrijum-oleata na selektivnu flokulaciju getita iz taloga

The paper represents a part of research conducted with the aim of examining the possibility of applying selective flocculation of goethite from sludge that occurs in the process of iron ore production. The aim of this study was to compare the influence of polyacrylamide and sodium oleate as a flocculant on the settling behavior of goethite under different conditions. The paper presents the results of the research on the influence of the flocculants based on polyacrylamide and sodium oleate, as well as pH values on the settling rate of a natural goethite sample. The results showed that the settling rate of goethite was influenced by pH value and the type of flocculant, while the concentration of flocculant did not significantly affect the settling rate. Measurements of zeta potential showed the effect of flocculants on the surface of the goethite.

Screening and Identification of Flocculant Producing Bacteria and Its Application in Wastewater

Background: with the increasingly serious global water pollution, industrial and agricultural wastewater treatment is becoming more and more important. Flocculant precipitation is the first process in wastewater treatment. One of the keys to achieve efficient water purification is to add microbial flocculant with excellent performance. Objective: the research of high-efficiency and non-toxic microbial flocculant for wastewater treatment has increasingly become important in environmental protection. Method: CMC-Na medium and dilute iodine staining was used to separate and screen flocculant producing bacteria. The distribution of flocculant activity and the effect of different types of wastewater treatment were studied. Results: the flocculant producing strain 71-1 separate from ruminant feces was identified as <i>Cellulosimicrobiums sp</i>. The flocculating rate of MBF-P71 was 97.83%, which had obvious degradation effect on COD value of pig farm manure water and ship port sewage. The removal rates of cod were 66.95% and 46.68% respectively. Conclusion: MBF-P71 has the advantages of good flocculation effect, low production cost, high efficiency and low dosage. It has a good development and application prospect for wastewater treatment.

Application of the concomitant flocculation effect in wastewater treatment in respect of fine suspended particles

Application of the concomitant flocculation effect in wastewater treatment in respect of fine suspended particles

The Effect of Complexing Reagents on Flotation of Sulfide Minerals and Cassiterite from Tin-Sulfide Tailings

ABSTRACT Using a combination of UV-spectrophotometry, IR-Furie spectroscopy, analytical scanning electron (LEO 1420VP INCA OXFORD ENERGY 350) and laser (KEYENCE VK-9700) microscopy the effect of complexing reagents DBDTC, TMPPh, TOFA, and IM-50 on adsorption layer on the surface of chalcopyrite, galena, arsenopyrite, and cassiterite was studied. The individual formation character of the adsorption layer on each of the listed minerals was identified and the sizes of thin discrete films of the newly formed reagent phase, the strength of their fixation, and the coverage area of the mineral surface were determined. Kinetic photometry established the effective flocculation of cassiterite slimes by a thermomorphic polymer with a phosphine group TMPPh, which helps to reduce the loss of tin with fine fractions. TOFA is a selective tin collector and has advantages over IM-50 in terms of the fixation contrast on cassiterite and quartz. Tests of the developed reagent modes using a composition of complexing reagents have shown the possibility of obtaining sulfide and tin concentrates that met the requirements of metallurgical processing.

Research on flocculation effect of fly ash composite on high turbidity and high salinity mine water

Research on flocculation effect of fly ash composite on high turbidity and high salinity mine water

Comparison of two starch-based flocculants with polyacrylamide for the simultaneous removal of phosphorus and turbidity from simulated and actual wastewater samples in combination with FeCl3

Two laboratory-made cationic starch-based flocculants (St-CTA and St-AD) with different chain architectures were used to simultaneously remove phosphorus and turbidity from two simulated wastewaters and one actual wastewater with laboratory and pilot scales, respectively, in conjunction with FeCl3. A commercial polyacrylamide (PAM) has been also tried and compared with aforementioned starch-based flocculants. The removal extents of phosphorus and turbidity increased, the required dosages of FeCl3 decreased, and floc properties improved after dosing each polymeric flocculant after FeCl3 in all tested wastewaters due to their synergistic effects. However, the three flocculants exhibited different improvement efficiencies on the treated wastewaters containing different forms of phosphorus and showed various synergistic mechanisms owing to their distinct structural features. In inorganic–phosphorus-simulated wastewater, the linear nonionic PAM with a high molecular weight had a more notable contribution than the two starch-based flocculants due to its efficient bridging flocculation effect. Given the branched-chain structure and high positive charge density of St-AD, it had a higher efficiency in treating real wastewater and organic–phosphorus-simulated wastewater than PAM and linear cationic St-CTA. These results may serve as references for the design and selection of a suitable flocculant in treating target wastewaters.

Removal of micropollutants from municipal wastewater using different types of activated carbons

The water reservoirs are getting polluted due to increasing amounts of micropollutants such as pharmaceuticals, organic polymers and suspended solids. Powdered activated carbon (PAC) has been proved to be a promising solution for the purification of water without having harmful impacts on the environment. Parameters such as PAC dosing, wastewater hardness, the effect of coagulant and flocculant were evaluated in a batch scale study. These parameters were further applied on a pilot plant scale for the performance evaluation of PAC based removal of micropollutants concerning the contact time and PAC dosing with main focus on recirculation of PAC sludge. The obtained optimum dose was 10–20 mg/L providing 84.40–91.30% removal efficiency of suspended solid micropollutants (MPs) and this efficiency increased to 88.90–93.00% along with coagulant which further raised by the addition of polymer and recirculation process at batch scale. On pilot plant scale, the concentration in contact reactor and PAC removal effectiveness of dissolved air flotation, lamella separator and sedimentation tank were compared. Constant optimisation resulted in a concentration ranging from 2.70 to 3.40 g/L at dosing of PAC 10 mg/L, coagulant 2.00 mg/L and polymer 0.50 mg/L. PAC doses of 10–20 mg/L with 15–30 min contact time proved best for above 70–80% elimination. The recirculation system has also proved an efficient technique because the PAC's adsorption capacity was practically completely used. Small PAC dosages yielded high micropollutants elimination.

The analysis of flotation whey treatment

The empirical analysis of the scheme of whey treatment was carried out. Controlled parameters for the further investigations and assessment criteria of effectiveness of whey treatment have been singled out: the best conditions for protein coagulation, intensity of flocculation, the choice of the facility capable of effective working with high temperature of waste water and flocculant application contributing to formation of the larger flakes and process intensity. Real-time experiment on dairy enterprise LLC “SCHUCHINSKY CHEESE MANUFACTURE” was carried out. The following equipment was applied in the experiment: electroflotator, screw dehydrator, pump assemblies, containers for preparation of reagents and whey heating, measuring equipment: pH-meter, flowmeter, thermometer, photometric analyzer of chemical oxygen consumption (COC), scales. In the process of the experiment on the plants we determined the data of COC, pH and mass of emitting protein depending on the type of the flocculants used: superfloc A-130 and praestol 2530. The results of the experiment with whey treatment with COC equal to more than 10000 mg/l revealed high effectiveness of high charge anionic flocculants. New innovative technology of separate whey treatment in the technological process of dairy factories without its discharge to waste water is presented.

Sorption post-treatment of accumulator waste

Annotation. The main goal when creating typical waste water of JSC “Tyumen Battery Plant” is to bring the composition as close as possible to real waste water. The aim of the work is to study the process of sorption post-treatment when working with different types and concentrations of coagulants and flocculants, to select the most effective coagulants and flocculants and their doses, which give maximum effect of sorption post-treatment from colloidal-dispersed impurities and lead ions. For work the following coagulants were selected: FeSO4·7H2O; FeCl3 and Al2(SO4)3 in various relations (1:1), (2:1), (1:2); Flocculants: Flopam FO 4125 SH, Flopam FO 4440 SH, Flopam FO 4115 SSH; Praestol 2531 TR, Praestol 650 TR, Na2O · mSiO2 · nH2O sodium metasilicate (Liquid glass). In process of operation method of dynamic sorption on sorbent of KΦГM-7 is used for additional purification of waste water from lead ions. Based on the data obtained, recommendations can be made to intensify the subsequent treatment of waste water from battery production using the following reagents: FeCl3 (83mg/l) + Al2 (SO4)3 (42mg/l) and Liquid glass (1mg/l); FeSO4 7H2O (150g/L) и Flopam FO 4115 SSH (1mg/L); FeSO4 · 7H2O (150 mg/L) and liquid glass (1 ml).

Research on the Influence of Different Flocculants on Concrete Performance

By adding different types and amounts of flocculants into concrete, the effects of different types and amounts of flocculants on the initial flow performance, slump retention performance and compressive strength of concrete at different ages were studied. The test results show that PAM-3 has the greatest influence on the performance of concrete. When the content of PAM-3 exceeds 0.48g/15L, the compressive strength of concrete will be reduced. When the content of PAM-1 and PAM-2 is less than 0.24g/15L, it has no obvious influence on concrete performance. When PAC content is less than 1.8g/15L, it has no obvious influence on concrete performance. Increasing the amount of concrete admixture can alleviate the adverse effect of flocculant on concrete to a certain extent.

Dewaterability of sewage sludge conditioned with a graft cationic starch-based flocculant: Role of structural characteristics of flocculant

Coagulation/flocculation is one of the most extensive and cost-effective pretreatments to improve the dewaterability of sludge in water treatment plants. In this study, three series of graft cationic starch (St)-based flocculants with distinct structural characteristics including charge density (CD), graft-chain length (L), and graft-chain distribution (N) were synthesized by graft copolymerization of [(2-methacryloyloxy-ethyl) trimethyl ammonium chloride] and acrylamide onto St backbone. The structural effects of these St-based flocculants on the sludge dewaterability have been quantitatively analyzed by using a second-order polynomial model according to phenomenological theory. The predicted dewatering performance and optimal dose were fully consistent with the experimental results. On the basis of this established model, the dewatering mechanisms were discussed in detail by combination of the analysis of the changes in filter cake moisture content, specific resistance of filtration, bound water content, compression coefficient, extracellular polymeric substances fractions and components, spatial distributions of proteins and polysaccharides, microstructures of sludge cake, and flocs properties in the dewatering process. This graft St-based flocculant, with the structural characteristics of high CD, long L, and low N, exhibited superior sludge dewaterability because of the enhanced charge neutralization and bridging flocculation effects. Among these three structural factors, CD played a more important role in improvement of sludge dewaterability than L and N due to the dominant effect of charge neutralization. This study provided a better understanding of structure-activity relationship of these grafting modified flocculants, which was of significant guidance for the exploit and design of novel and efficient flocculants for improvement of sludge dewaterability.

Flocculation-to-adsorption transition of novel salt-responsive polyelectrolyte for recycling of highly polluted saline textile effluents

Herein, a new salt responsive starch flocculant (SSF) via starch etherification with butyl glycidyl ether (BGE) and 2-chloro-4,6-diethylamino-[1,3,5]-triazine (CDAT) was reported as highly salt-responsive polymer. The resulting polymer exhibits a reversible switch from dissolution to precipitation in response to slight external salt stimuli due to the integration of highly charged CDAT moiety. The extent of phase separation, relative solubility and residual polymer in water solution could be precisely modulated by changing the salt concentration and the type of counter ions. The results demonstrated that dyes removal is salt dependent, and that the addition of inorganic salt leads to a pronounced broadening of flocculation window. The as-prepared polymers experience an obvious transition from flocculation to adsorption processes with an increasing salt concentration from 0 to 100 g/L due to the salt-triggered switchable solubility of SSF. Two different mechanisms combined the coagulation and adsorption may be involved in dye decolourization from saline reactive dyeing effluents. The beneficial effect of salt-sensitive flocculant was found to be more significant in reuse of saline wastewater for fabric dyeing, in which the flocculant residuals are significantly low (less than 10.9%). After flocculation and sedimentation, the clarified saline wastewater can be readily recovered and reused three times while retaining high-quality colour reproduction. The salt-driven switchable solubility of polymer from water-soluble flocculants to solid-state adsorbents offers a possibility to overcome the limitations of industrial flocculation processes, such as a narrow flocculation window and high polymer residuals at flocculant overdose.

Solidification effect of river bottom sediments after flocculation via different composite flocculants.

The main problem in the reduction of river bottom sediments is to solve the dewatering of the rive sediments. The reduction of river bottom sediments is usually dehydrated by natural air drying and requires more time and economic costs. Different proportions of composite flocculants and curing agents have been developed to the reduction of river bottom sediments according to the requirements of the project. Two or more flocculants were mixed with the rive sediments. Therefore, anionic polyacrylamide (PAM), polyaluminum chloride (PAC), polysilicate aluminum ferric (PSAF), and iron perchloride (IC) were selected for flocculation of river sediments. Through the sedimentation column test, the relationship between sedimentation amount and time was plotted, the turbidity value and pH value of the supernatant filtration supernatant were detected, and the flocculation effect of different flocculants was evaluated to obtain suitable groups of composite flocculants. The optimum ratio of two types of polyacrylamide with a molecular weight of 18 million and 23 million was 3:7. The turbidity of the supernatant of water could well be reduced by adding polysilicate aluminum ferric. Finally, the 6 groups of composite flocculants were determined according to the sedimentation and the turbidity value of the supernatant. The relative water content was maintained at about 60% before and after flocculation. At the same curing age, the compressive strength increased as the amount of curing agent increased after flocculation. At the same curing agent dosage, the overall solidification effect was reduced with increase of curing time after flocculation.

Polyhydroxamic acid as an efficient metal chelator and flocculant for wastewater treatment

Hydroxamic acid containing organic polymeric flocculants were synthesized from three different commercially available polymeric flocculants, such as WAS590, Zetag 4100, and Zetag 4110. These three polymers are acrylamide and acrylic acid‐based copolymers with different molecular weights and anionic charge density. The conversion of the amide groups to hydroxamic acid groups in the polymers was carried out by the reaction with hydroxylamine at pH 14. The modified polymers were characterized for structure and composition by elemental analysis, FTIR, and NMR. The chelation activity of the modified polymers was determined toward iron (Fe3+) and copper (Cu2+). The flocculation activity of the non‐modified and modified polymers was evaluated toward produced water and scrubber water. The results showed that all the modified flocculants exhibit better chelation with Fe3+ and Cu2+. In addition, the modified polymers display improved flocculation effect on tested wastewater.

Improved production of an acidic exopolysaccharide, the efficient flocculant, by Lipomyces starkeyi U9 overexpressing UDP-glucose dehydrogenase gene

In order to increase content of glucuronic acid in the exopolysaccharide (EPS) and its flocculating activity, an UDP-glucose dehydrogenase gene was overexpressed in Lipomyces starkeyi V19. The obtained U9 strain could produce 62.1 ± 1.2 g/l EPS while the V19 strain only produced 53.5 ± 1.3 g/l EPS. The compositions of monosaccharides (mannose, glucuronic acid and galactose) in the purified EPS (U9-EPS) from the U9 strain contained 3.79:1:5.52 while those in the purified EPS (V19-EPS) were 3.94:1:6.29. The flocculation rate of the U9-EPS on kaolin clay reached 87.9%, which was significantly higher than that (74.7%) of the V19-EPS while the decolorization rate of Congo Red (CR) by the U9-EPS reached 94.3%, which was significantly higher than that of CR by the V19-EPS (86.23%). The results showed that the purified bioflocculant U9-EPS had effective flocculation of kaolin clay. The U9-EPS also had high ability to flocculate the polluted river water and decolorize Congo red.

Temperature sensitive self-assembling hydroxybutyl chitosan nanoparticles with cationic enhancement effect for multi-functional applications

Hydroxybutyl chitosan (HBC) with different degree of substitution (DS) were prepared using a homogeneous reaction system (KOH/urea), which could achieve temperature-dependent reversible morphological transition in aqueous solution. During hydrophobic assembly, amino groups on HBC chains exposed on the surface of nanoparticles formed a poly-cationic structure. The structure of HBCs was characterized by FTIR, 13C NMR, XRD, TGA and rheology. The morphology and assembly mechanism of HBC nanoparticles were studied by TEM, AFM and DLS. Also, the results of coagulation, bacteriostatic, superoxide anion clearance and anionic contaminant removal tests suggested that HBC nanoparticles had excellent flocculation and removal effect of anionic composites. Moreover, the cytocompatibility test indicated that HBC could effectively promote proliferation and division of mouse fibroblast, mouse embryonic fibroblast and rat bone marrow mesenchymal stem cells. These cationic HBC nanoparticles exhibited great potential in multi-functional applications.

Effect of welan gum and nanoclay on thixotropy of UHPC

This study evaluates the effect of welan gum (WG) and nanoclay (NC) on thixotropy of ultra-high-performance concrete (UHPC) matrix made with 0.20 water-to-binder ratio. The mortar mixtures were proportioned with a fixed superplasticizer (SP) content and WG and NC contents varying between 0 and 0.09% and 0 and 0.4%, respectively. The dynamic yield stress of these mixtures varied from 40 to 170 Pa. Similarly, UHPC made with different WG and NC contents were prepared with variable SP dosages to maintain initial mini-slump flow of 200 ± 5 mm. Test results indicate that thixotropy can be enhanced by using WG or NC in UHPC with a fixed SP dosage. On the other hand, for UHPC made with variable SP, the incorporation of WG increased thixotropy, whereas the use of NC had limited contribution to thixotropy. Particle flocculation was correlated to the water film thickness (WFT) onto solid particles in UHPC. The rapid increase in static yield stress immediately after mixing (τfloc) showed a linear growth with the decrease of WFT due to enhancement of particle flocculation. A qualitative approach relating particle flocculation and bridging effect of nucleation of early-age hydration products was proposed to describe the rate of linear increase in static yield stress with rest time (Athix). The model yielded good prediction for UHPC prepared with NC, which was not the case for mixtures made with WG where other factors, such as polymer entanglement and association, can play a major role in controlling thixotropy.

Application of composite degradable modified starch-based flocculant on dewatering and recycling properties.

Sludge dewatering is an important step for wastewater treatment. Composite degradable flocculant (CDF) was prepared by cationic polyacrylamide (PAM) grafting onto modified starch with a novel initiator, and characterized by Fourier transform infrared spectroscopy. The microstructure of flocculated sludge was characterized by scanning electron microscopy. The study investigated the properties of CDF compared to PAM, which showed that the prepared CDF exhibited a highly effective flocculation on sludge dewatering, a higher transmittance and chemical oxygen demand removal rate, and a lower value of effluent ammonia nitrogen and total phosphorus. The fermentation process was also analyzed by testing the performance of dewatered sludge (temperature, pH, ammonia nitrogen, E4/E6 (humic acid absorbance at 465 nm (E4) and 665 nm (E6))). The dehydrated sludge with CDF could be easily compressed into cakes by belt-filter for easy transportation and storage. With the continuous addition of CDF and PAM, the corresponding index of capillary suction time (CST) increased. Moreover, the total value of CST with CDF was low, showing a good dewaterability. In addition, the sludge index of pumping time and moisture content with CDF were low in contrast with PAM. Fermentation experiments demonstrated that sludge with CDF had a comparatively high temperature and low value of E4/E6. Such novel CDF shows enormous potential in wastewater treatment and sludge fermentation.