Papers by Keyword: Flocculation

Abstract: The article deals with the peculiarities of the process of clay particle aggregation when coagulant and flocculant are introduced, as well as the regularity of formation and deposition of the formed flocs. The studies were carried out on a model suspension of bentonite clay with a concentration of 1-10 g/l. In the course of the study, the regularities of aggregate formation in the process of coagulation; the combined action of coagulants and flocculants, as well as the destruction of flocs under the influence of mechanical action were determined, and theoretical ideas were formed regarding the models of the process and the structure of the formed aggregates. It was found that the aggregation of fine particles has optimal ratios of both the concentration of the solid phase and the ratio of flocculant to the solid phase, at which the maximum rate of particle settling is observed. The optimum concentration for this type of clay, at which the maximum flocculation rate is observed, was 4-6 g/l. At other optimum concentrations, a slowdown in floc settling is observed due to the lack of formation of a spherical structure at low concentrations and compressed settling at higher concentrations. To intensify the sedimentation of loose flocs, it was proposed to introduce additional mineral lime particles with a particle size of 20-40 μm, which increase the weight of flocs and accelerate their sedimentation.

Abstract: This research aims to investigate the potential effect on the performance of Al-Al electrodes in the electrocoagulation method. The influence of this potential can be observed through microplastic removal and turbidity levels. The research was conducted in situ using a chemical beaker, employing Al-Al electrodes at various different potentials (5, 10, 15, and 20 V) that were systematically investigated. The results of this research indicate that an increase in potential has a positive impact on the efficiency of microplastic removal and turbidity levels. Efficiency removal of microplastic and turbidity levels increase with an increase in potential until optimum condition. The microplastic removal efficiency was found to be 100% ± 0 at a potential of 10 V after 60 minutes of electrolysis, with a plate spacing of 2.5 cm and an electrolyte concentration of 0.01 mol/L. At a potential of 10 V, the value of NTU changed from >200 NTU to 30 NTU. This research showed that the effectiveness of the Al-Al electrodes performance is influenced by the potential.

Abstract: The granulometric composition of the metal/scale suspensions formed at electroerosive machining (EEM) of metal items made of the ST-10 steel has been determined to evaluate the need for a flocculant for the suspension particles extraction and decontamination of the machining working fluid. Even though most suspension particles are large enough and quickly self-precipitate, some particles are too small (sized 6 µm or less) and form quite stable suspensions, requiring additional flocculants to be extracted. Pure polyacrylamide with a molecular weight of 4-5*10⁶ atomic units and an anionic polymer flocculant BESFLOC-4041 were considered as decontamination agents for the metal/scale suspensions. It was found that the latter agent is more effective, and it ensures the effective decontamination of an EEM working fluid. An admixture of 0.05 g/L of BESFLOC-4041 ensures effective clarification (with the decontamination efficiency of 90-95 %) of the metal/scale suspension with a dispersed phase concentration of up to 1.0 g/L. The flocculation efficiency of polyacrylamimde is lower (67-85 %) and its best performance is achieved at the concentration of 0.08 g/L.

Abstract: Enhanced treatment of river water was investigated by the modified coagulation-flocculation process for the application of self-cleaning filters (SCF’s) in the removal of turbidity using a combination of Alum and Sudfloc 3880. This study is aimed to improve the removal of iron and turbidity concentrations from river water and reduce water loss. This is achieved by piloting innovative water treatment technologies such as the SCF’s Plant. The new technology further assessed the effectiveness, efficiency, and operability of the SCF’s Plant by varying certain operational parameters such as water flow, differential pressures, coagulant, and flocculent dosages. The results established in this study critically analyze the feasibility of deploying water treatment technologies such as the SCF Plant in areas with similar environmental conditions and/or facing similar water treatment challenges. The removal efficiencies of turbidity were about 40 % and further optimization will be continued until 90 % to 100 % is achieved. The average removal efficiency of turbidity was 40 % and achieved at a 250 m³/h flow rate. The average removal across all flow rates was over 20 %. Further optimization of the RF14 will be carried out using other chemical combinations and formulations at various process settings while bypassing the PLF filters. The PLF elements will be brought into service to further reduce the turbidity after the optimization of the RF14. Keywords: Water, Treatment, Coagulation, Flocculation, Processes, Technologies, Filters ^*

Abstract: The primary activity of an enterprise, where the wastewater samples have been taken, is applying lacquer coatings to glass and the mirrors production. For washing glass before the application of coatings a suspension of powder based on ceric oxide is prepared, which is used as a polishing solution. The physical and chemical properties of industrial sewage waters, generated after glass polishing, and of the initial and spent polishing powder based on ceric oxide have been researched. The optimal doses of flocculating agents for purifying wastewaters in order to reduce turbidity, suspended solids concentration and dry residue have been determined. After the flocculation the advanced treatment of the water was done, by means of filtering elements with pore size 5 and 1 μm, produced by the Pentek Company. The process scheme of wastewater purification, including the physico-chemical method (flocculation) and mechanical purification method by using bag filters, has been developed.

Abstract: Excess deposits of phosphorus into surface waters have caused a lot of devastating effects on both human and aquatic lives and, of course, ecosystem disruption. Ox-eye seed (OES), an agricultural biomass, has been explored as a coagulant to remove phosphorus from aqueous solution through coag-flocculation process. The seeds were prepared into a coagulant and a proximate analysis was carried out on the prepared OES. Nephelometric analysis was employed to investigate the effects of settling time, coagulant dosage and pH on phosphate removal efficiency of OES. The process parameters were optimized using Response Surface Methodology. OES’s performance was compared with Alum’s, a conventional coagulant, and the results obtained reveal Alum as having a global minimum of zero turbidity, global optimum values for pH (7.4103) and dosage (301.6501mg/l) but a local optimum of 80min for settling time, while the optimum operating parameters for OES are 7.3740 (global), 500mg/l (local), 80min (local) and 11.2266mg/l (local) for pH, dosage, settling time and turbidity respectively. It is evident that, by increasing settling time and dosage , OES can effectively compete with Alum. The main attribute to effective performance of both OES and Alum is pH. The interactions pH-dosage and pH-settling time are significant. The model accuracy is confirmed by the values of R² >0.99 and is validated by the closeness of the experimental data to the predictions. Keywords: Phosphorus, wastewater, turbidity, Coagulant, ox-eye, flocculation

Abstract: Microalgae biomass has been established as a sustainable bio-product such as fish feed and supplement. However, the major challenge for recovering the biomass yield lies in the harvesting process. The recent direction is to use the natural coagulation as alternative techniques for the conventional methods. Therefore, the present study aimed to investigate the efficiency of Moringa oleifera in recovering Scenedesmus sp. biomass from wet market wastewater medium in comparison to Aluminium Sulphate (alum). The efficiency of alum and M.oleifera was tested with 10, 20, 30, 40 and 50 mg/L of the dosage. The results revealed that M.oleifera exhibited high percentage recovery of Scenedesmus sp. than alum (97.5 vs. 95.4 %respectively). Moreover, the final pH of microalgae cultured wastewater after the harvesting with M.oleifera was 6.4, while decreased to 4.37 with alum. These findings indicated that the using M.oleifera the using natural coagulants are better than the chemical coagulants in terms of recovery efficiency and the characteristics of wastewater. Therefore, M.oleifera has the potential to be used as a natural coagulants alternative for alum.

Abstract: In this paper, the separation of sulphuric acid from a suspension of cellulose nanocrystal by manual shaking is described. Cellulose nanocrystals are prepared from acid hydrolysis of cotton using 64 wt% sulphuric acid at ca. 45 °C for 45 minutes. After the hydrolysis was complete, water was added to dilute the mixture to a resulting concentration of 30 wt% of the acid. This mixture was shaken rigorously in a closed container and after 48 hours, separation occurs such that cellulose nanocrystals float, with the bubbles introduced by the shaking, to give clear acid solution at the bottom. This shaking-floating process is repeatable for several cycles after the acid was removed from the bottom and more water was added. Using this simple process, the total acid recovery of > 90% has been achieved, and the concentration of all the acid recovered combined was 17.5 wt%. This work demonstrates a method that allows energy efficient and up-scalable separation of cellulose nanocrystals from the acidic suspension from which it was extracted.

Abstract: A novel hybrid flocculant of acrylamide and cellulose was synthesized by using microwave irradiation method. Cellulose was extracted from kenaf by using TAPPI method. 57.4% of percentage grafting and efficiency has been obtained from the grafting process. There are additional peaks that appeared in FTIR spectroscopy analysis that show PAM was grafted into cellulose backbone. The flocculation behavior was studied by using ethyl orange wastewater. The result shows that hybrid flocculant (cellulose-g-PAM) has potential to be used as flocculant in treating dyes waste water.

Abstract: This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.