Coagulation Conditions Research Articles

Study of the variation in the ultrasonic attenuation of compression waves as a technique to monitor the enzymatic coagulation of milk

In this work, the variation in the ultrasonic attenuation of compression waves was studied as a technique to monitor the coagulation stage of milk in the cheese making process. The main difficulty found in applying this technique in the milk coagulation process was that, in the presence of gas bubbles in milk, the ultrasonic attenuation measures do not respond to the physicochemical changes generated in the process. Once the interference of gas bubbles in milk was overcome, the technique of measuring variation in the ultrasonic attenuation of compression waves showed potential to be applied in the coagulation process. With this technique, the gel cutting time can be objectively determined for different coagulation conditions.

The size of monomers of dust aggregates in planet-forming disks

Context. The size of the constituent particles (monomers) of dust aggregates is one of the most uncertain parameters directly affecting collisional growth of aggregates in planet-forming disks. Despite its importance, the monomer size has not yet been meaningfully constrained by disk observations. Aims. We attempt to derive the monomer size from optical and near-infrared (IR) polarimetric observations of planet-forming disks. Methods. We performed a comprehensive parameter survey on the degree of linear polarization of light scattered by dust aggregates, using an exact numerical method called the T-matrix method. We investigated the effect of the monomer size, aggregate size, porosity, and composition on the degree of polarization. The obtained results were then compared with observed polarization fractions of several planet-forming disks at optical and near-IR wavelengths. Results. We show that the degree of polarization of aggregates acutely depends on the monomer size unless the monomer size parameter is smaller than one or two. Comparing the simulation results with the disk observations, we find that the monomer radius is no greater than 0.4 μm. The inferred monomer size is therefore similar to subunit sizes of the solar system dust aggregates and the maximum size of interstellar grains. Conclusions. Optical and near-IR quantitative polarimetry will provide observational grounds on the initial conditions for dust coagulation and, thereby, planetesimal formation in planet-forming disks.

Application of Dragon Fruit Peel’s Mucilage in Coagulation – Flocculation Process to Remove Turbidity from Water

The study determined flocculation activity of mucilage extracted from dragon fruit peel (Hylocereus undatus) and its ability in reducing synthetic coagulant polyaluminium chloride (PAC) used in coagulation – flocculation process to remove turbidity of different types of water. Investigated waters were turbid waters made from kaolin suspension (KS), suspension of river water with hill soil (FW), and To Lich river water (TL). Turbidity removal was assessed in a sequent coagulation and flocculation model using PAC and mucilage extracted from dragon fruit peel in Jar-tests. Optimal coagulation conditions of PAC with PAC dosage of 20-50 mg/L and pH range of 6-8 regardless of water types and resulted in maximum turbidity removal of about 98%. In order to obtain a comparable turbidity removal, 50%-68% of the required PAC was reduced if mucilage was used. The presence of mucilage enhanced turbidity removal of PAC by 13-22% total efficiency. Mucilage extracted from dragon fruit peel has shown its flocculation ability and its potential as a green material in water treatment.
 
 

Optimizing coagulation–flocculation processes with aluminium coagulation using response surface methods

A data-based multivariate method such as response surface methods and desirability function is considered advantageous for analysing coagulation treatment optimization. Thus, this study investigated the optimization of coagulation–flocculation using response surface methodology. The parameters investigated were pH, alum dose and alkalinity. The optimum coagulation conditions for the individual responses: turbidity, colour, residual aluminium and phenanthrene were pH 7.0, alum dose 80.0 mg/L and alkalinity 80.0 mg/L; pH, 6.5, alum dose 70.0 mg/L and alkalinity 90.0 mg/L; pH, 7.0, alum dose 63.2 mg/L and alkalinity 80.0 mg/L and pH 6.2, alum dose 80.0 mg/L and alkalinity of 80.0 mg/L, respectively. The model equation derived from the optimization study was adequate for predicting the response values. The quadratic model was significant (p < 0.0001), and it had a high correlation (R2, 0.746–0.975) and an insignificant (LOF, p > 0.05) lack of fit.

Improving Transverse Compressive Modulus of Carbon Fibers during Wet Spinning of Polyacrylonitrile

The performance of carbon fibers depends on the properties of the precursor polyacrylonitrile (PAN) fibers. Stretching of PAN fibers results in improved tensile properties, while potentially reducing its compressive properties. To determine optimization trade-offs, the effect of coagulation conditions and the stretching process on the compressive modulus in the transverse direction (ET) was investigated. A method for accurately determining ET from polymer fibers with non-circular cross-sectional shapes is presented. X-ray diffraction was used to measure the crystallite size, crystallinity, and crystallite orientation of the fibers. ET was found to increase with decreasing crystallite orientation along the drawing direction, which decreases the tensile modulus in the longitudinal direction (EL) proportionally to crystallite orientation. Stretching resulted in greater crystallite orientation along the drawing direction for fibers formed under the same coagulation conditions. Increasing the solvent concentration in the coagulation bath resulted in a higher average orientation, but reduced the impact of stretching on the orientation. The relationship between ET and EL observed in the precursor PAN fiber is retained after carbonization, with a 20% increase in ET achieved for a 2% decrease in EL. This indicates that controlled stretching of PAN fiber allows for highly efficient trading off of EL for ET in carbon fiber.

Optimal conditions of paint wastewater coagulation with gastropod shell conchiolin using response surface design and artificial neural network-genetic algorithm

The potential of gastropod shell conchiolin (GSC) (a waste product of the deprotenization stage of chitosan production) as one of the alternatives to chemical coagulants has been explored for treatment of paint industrial wastewater (PW). The accuracy of response surface design (RSD) and the precision of artificial intelligence in predicting and optimizing the process conditions were harnessed in raising experimental design matrix and response optimization, respectively for the bench scale jar test coagulation experiment. PW was characterized using American Public Health Association standard methods. Extraction of conchiolin was done via alkaline extraction method. PW contains 2098 mg/l total suspended solid above discharge limit (1905 mg/l). Fourier transform infrared (FTIR) spectrum of GSC revealed a broad N–H wagging band at 750–650 cm−1 indicating the presence of secondary amine linked to the presence of protein. Turbidity removal from PW via one factor at a time was found to be a function of pH, GSC dosage, temperature and time. Artificial neural network response prediction shows 92% correlation with the RSD experimental result. The optimal conditions obtained via genetic algorithm for the response optimization at the best pH of 4 indicate optimal turbidity removal of 98% at GSC dosage, time and temperature of 4 g, 20 min and 45 °C, respectively.

AWWA Water Science Author Spotlight

Having published an article in AWWA Water Science, Amir Alansari answered questions from the publication's editor-in-chief, Kenneth L. Mercer, about the research. Critical Elements of Flocculation in Drinking Water Treatment Amir Alansari and James Amburgey I'm a water treatment specialist at Stantec at their office in Winston-Salem, N.C. My research focus is primarily on coagulation chemistry and process optimization. Lately I've been working on developing new digital tools for predicting optimal coagulation conditions using artificial intelligence. It was a $5,000 stipend to participate in the Research Experiences for Undergraduates (REU) program over the summer at the University of North Carolina at Charlotte. I was in the civil and environmental engineering program and stumbled into the world of water treatment by chance. Amir won first place in the ACE19 student poster contest. Dr. Amburgey had the biggest influence on my career and on everything I have accomplished so far. I completed all three civil engineering degrees (bachelor's, master's, doctorate) working with him at the same university. In total, I spent 12 years under his mentorship, during which time I was able to freely follow my curiosity and work on whatever I wanted. The best advice I got from him was to use the time I had in graduate school to grow my skill sets as a researcher and an engineer as much as possible. My coauthor and I read a paper that was published in 1992 in Journal AWWA by Han and Lawler, where they mathematically showed that mechanical mixing played an insignificant role in the flocculation process. We recognized the implications of their work on the recommended design guidelines for flocculation; however, an extensive literature review did not yield any conclusive evidence that supported or challenged their theory. Our article presents results from a series of experiments we performed to measure the effects of various flocculation parameters (e.g., mixing duration) on settled and filtered water-turbidity removal efficiency and determine whether Han and Lawler were correct. I try my best to have a positive impact on the lives of people around me. I'd like to think that my work is contributing to the body of knowledge, even if it is a tiny contribution. Many of our current design guidelines are based on work done about four to six decades ago. There have been a lot of scientific and technological advancements since then. I believe water treatment design could benefit from a 21st-century overhaul, which would require a renewed research interest and collective effort from the research community, regulators, consulting engineers, and industry. The current funding model does not favor this type of research. It considers topics such as coagulation as matured topics, with nothing left to discover. Our research highlighted the benefits of optimizing coagulation conditions (via jar tests) using filtered turbidity as the performance metric instead of settled water turbidity. We found that jar-test mixing conditions had a significant effect on settled turbidity removals. This means that operators no longer have to “calibrate” their jar test procedures to get their results to match the full-scale process. It simplifies the optimization process by reducing the number of variables to just two—coagulant dose and coagulation pH—which ultimately means they can achieve better treatment performance while minimizing chemical usage. To learn more about Amir's research, visit his AWWA Water Science article, available online at https://doi.org/10.1002/aws2.1213.

Beyond Classic Anastomoses Training Models: Overview of Aneurysm Creation in Rodent Vessel Model.

Nowadays, due to the decline in the number of microsurgical clippings for cerebral aneurysms and revascularization procedures, young neurosurgeons have fewer opportunities to participate and train on this type of surgery. Vascular neurosurgery is a demanding subspecialty that requires skills that can only be acquired with technical experience. This background pushes the new generations to be ready for such challenging cases by training hard on different available models, such as synthetic tubes, chicken wings, or placenta vessels. Although many training models for vascular neurosurgery have been described worldwide, one of the best is the rodent vessels model. It offers pulsation, coagulation, and real blood flow conditions in a physiologic atmosphere that mimics perfectly the intracranial human vessels environment, especially in terms of size. However, the current differences in governmental different regulations about the use of living animals in medical experimentation and the social awareness, as well as the lack of financial support, cause more difficulties for neurosurgeons to start with that kind of training. In this review, we describe the tools and techniques as basic steps for vascular microsurgery training by using rodent models, that provide an accurate copy of brain vessels environment under stable conditions. The initial three classical known microanastomoses for neurosurgeons are end-to-end, end-to-side, and side-to-side, but in literature, there have been described other more complex exercises for training and investigation, such as aneurysm models. Although there is still little data available, we aim to summarize and discuss aneurysm's training models and reviewed the current literature on the subject and its applications, including a detailed description of the techniques.

Dependency of polyacrylonitrile membrane structures on Hansen solubility parameters during non‐solvent induced phase separation

AbstractIn this study, non‐solvent induced phase separation (NIPS) is used to prepare polyacrylonitrile (PAN) based membranes. A thorough analysis on the correlations between coagulation conditions and membrane structures was carried out according to Hansen solubility parameters of coagulants and solvents. When coagulant is various, a larger Hansen solubility distance (Ra) between PAN and coagulant leads to a quicker phase separation and faster growth of finger‐like pores. By comparison, when PAN solvent is tuned by adding small amount of water, the Ra plays totally different roles for the formation of dense layer and the growth of finger‐like pores. The structural variations of PAN membranes have been mapped in Hansen space according to the Ra. Additionally, the low temperature induced sol–gel transition of PAN solution also affects the pore structures of the resultant membranes. These results would be helpful for better understanding the NIPS and fabricating PAN and other types of polymer membranes with desired structures and performances.

Multistage treatment for olive mill wastewater: Assessing legal compliance and operational costs

A treatment train for the remediation of a raw olive mill wastewater (OMW) was investigated, aiming to comply with the emission limit values (ELVs) for direct discharge into water bodies. The following stages were proposed: (i) pre-treatment (filtration and sedimentation), (ii) coagulation, (iii) biological oxidation, and (iv) advanced oxidation process (AOP). Under the best-operating conditions for coagulation (0.8 g L−1 of Al2(SO4)3, pH = 4.5), high removal of total suspended solids (TSS) (97%), turbidity (98%), and phenols (57%) was achieved, along with a decrease in the inhibition of the biological activity. A subsequent biological oxidation stage provided a high removal of organic matter (chemical oxygen demand (COD) removal of 73%). For the third stage, three AOPs were applied and compared – photo-Fenton with UVA radiation (PF-UVA), anodic oxidation (AO), and ozonation (O3). After 3 h of treatment, the PF-UVA process (pH = 2.8, [H2O2] = 400–500 mg L−1, [Total dissolved iron]0 = 100 mg L−1) allowed to meet the ELV for COD, but the other parameters exceeded the threshold, while O3 process (inlet concentration = 100 mg O3 Ndm−3, gas flow = 0.2 Ndm3 min−1) allowed to comply with phenols, TSS, and sulfate limits. The AO process (current density up to 200 mA cm−2) was the least efficient AOP for all studied parameters. The operational costs for the coagulation and biological oxidation stages were estimated at 1.20 € m−3. Regarding the most effective AOPs, ozonation presented an estimated cost 2.3-fold higher than PF-UVA (11.9 € m−3vs. 5.2 € m−3).

Use of aluminum-based water treatment sludge as coagulant for animal farm wastewater treatment

Unlike other studies of artificial wastewater treatment, this study aims to use the aluminum-based water treatment sludge (Al-WTS) as a substitute for traditional chemicals as coagulant in the coagulation-flocculation process for a real animal farm wastewater treatment. The study was designed for a lab-scale trial to explore the optimum conditions of coagulation and flocculation process so that the removal efficiencies of the total suspended solids (TSS), total organic carbon (TOC) and PO43− concentration of the wastewater can be maximized. The experiments were conducted in a series jar-test apparatus to simulate the coagulation-flocculation process. The effects of initial pH and the dosage of liquid Al-WTS on the removal efficiencies of the animal farm wastewater were examined and discussed. Moreover, a Box-Behnken statistical experimental design (BBD) by Design expert 8.0 was used to optimize the experimental conditions. At the optimum initial pH value of 7.0 and Al-WTS dosage of 1588 mg/L, the removal efficiencies of TSS, PO43−, and TOC were 87.8 ± 2.2%, 96.9 ± 2.9%, and 62.1 ± 1.8%, respectively. It is concluded that the Al-WTS could be used for the treatment of animal farm wastewater with considerable removal efficiencies, thus opening a cost-effective way for using a “waste” for wastewater treatment.

Simultaneous reduction and coagulation removal of perrhenate with titanium (III) trichloride: Performance and mechanism

Abstract 99 Tc is a common radioactive element in nuclear waste. Due to its long half-life and high mobility, it easily leads to environmental pollution. This study firstly reported the use of titanium trichloride (TiCl 3 ) as reductant and coagulant to remove perrhenate (ReO 4 − ), which is a non-radioactive chemical substitute for 99 TcO 4 − . The results showed that ReO 4 − could be completely removed (removal efficiency of Re reach 99.6%) under the optimal coagulation conditions and achieved rapid separation of pollutants from water. When competing ions (such as ClO 4 − ) coexist at a concentration of 1850 times, the removal efficiency of Re can still reach 93.9%. The standing experiment of flocs in aerobic condition exhibited the existence of high affinity between flocs and Re oxides, guaranteeing the fixation of Re. Based on the experimental results and various characterizations of the flocs, it is proposed that the mechanism is the reduction-electrostatic interaction-coagulation process. Firstly, the added Ti(III) hydrolyzed to generate the Ti(III) hydrates and reacted with ReO 4 − . And then, the titanium hydrates and ReO 2 aggregated with each other through electrostatic interaction to form flocs, which settled down quickly to achieve the removal of Re. The results indicated TiCl 3 may be used as a candidate reagent to eliminate 99 Tc pollution in water efficiently. • TiCl 3 was firstly applied as reducing agent and coagulant for perrhenate treatment. • The in-situ formed Ti(OH) 3 were essential for the perrhenate reduction. • The high affinity between flocs and Re oxides guaranteed the fixation of Re.

Responses of Coagulant Type, Dosage and Process Conditions to Phosphate Removal Efficiency from Anaerobic Sludge.

Phosphorus, a crucial component of life, may cause eutrophication if it is discharged untreated into the aquatic ecosystem. Phosphate (PO43-) may exist at an elevated level in anaerobic digestion (AD) effluents and can lead to the clogging of pipes by forming struvite crystals. This study was conducted to assess the responses of coagulant type, dosage and process conditions to phosphate removal efficiency from anaerobic sludge. The experiments were performed in two steps. First, a sensitivity test was conducted to compare five coagulant types (alum, poly-aluminum chloride (PAC), FeCl2, FeCl3 and PAC + FeCl3) at standard coagulation conditions. The results showed that PAC would be the best coagulant among the tested, while a combination of PAC and FeCl3 may be beneficial under circumstances. Second, an optimization study was performed for PAC using response surface methodology employing central composite design. Among the three independent variables (coagulant dosage, slow mixing duration and agitation speed), the dosage was the sole significant variable for phosphate removal efficiency, while the other two had limited effects. A future study to optimize the rapid mixing conditions would give additional insights into the process. The results of this study may be useful to design a process to counteract phosphate discharges from AD plants, as well as to reduce the risks of pipe clogging and maintenance problems due to crystalline struvite formation in the later stage of AD.

Optimizing of Coagulation and Solid-Liquid Separation Conditions Using Aluminum Sulfate and Poly-Aluminum Chloride Coagulants from Brine Wastewater Discharged by the Epoxy-resin Process

Optimizing of Coagulation and Solid-Liquid Separation Conditions Using Aluminum Sulfate and Poly-Aluminum Chloride Coagulants from Brine Wastewater Discharged by the Epoxy-resin Process

AN EXTRACORPOREAL MEMBRANE OXYGENATION TREATMENT IN COVID-19 PATIENT – A CASE REPORT FROM SOETOMO HOSPITAL SURABAYA

COVID-19 patients can experience severe or critical symptoms, which develop into an acute respiratory distress syndrome (ARDS) necessitating an intensive care, of which 80% demanding the mechanical ventilation therapy. Patients with severe and critical infection from COVID-19 can receive Extracorporeal membrane oxygenation (ECMO) therapy. This study reported a successful ECMO therapy at Soetomo Hospital in Surabaya, Indonesia, despite all the problems which occurred during ECMO support especially with coagulation conditions. Thus, an anticoagulant therapy contributed significantly in the success of ECMO therapy.

Synthesis and Performance of PAFS Coagulant Derived from Aluminium Dross

Polymerised aluminium ferric sulphate (PAFS) was prepared from aluminium dross as a coagulant in wastewater treatment. The effects of leaching time, leaching temperature, and sulfuric acid concentrations on the turbidity removal of the wastewater were investigated, and the optimum conditions were determined using response surface methodology. The results showed that the optimum PAFS preparation conditions were at a leaching time of 60 minutes, a leaching temperature of 65°C, and a sulfuric acid concentration of 1 mol/L. Furthermore, experiments were performed to investigate the effect of coagulant dosages using the PAFS prepared under the optimum leaching conditions, settling time and initial pH of the wastewater on the turbidity removal efficiency. As a result, it was found that the optimum coagulation conditions for PAFS coagulants were at a settling time of 15 minutes, coagulant dosage of 0.5g, and raw water pH 8. Under these optimum conditions, the turbidity removal efficiency of the wastewater was 91.45%. The purpose of this study was to investigate the possibility of aluminium dross utilisation as a coagulant agent for wastewater treatment. Therefore, it can be concluded that PAFS prepared by leaching metal oxides from aluminium dross is an effective wastewater coagulant.

Response surface optimisation of a magnetic coagulation process for wastewater treatment via Box-Behnken

In the wastewater treatment settings, conventional coagulants for wastewater treatment are becoming very complex with environmental concern. This necessitates the investigation for the use of magnetized rice starch as alternate coagulants. Herein, its application in the coagulation operational mechanism for decontamination of wastewater was investigated. The coagulation conditions were optimised via response surface methodology (RSM) based on a Box–Behnken design (BBD). Three operational parameters viz. coagulant dosage (2–4 g), settling time (15–30 min) and mixing rate (50–150 rpm) were investigated with their effects on turbidity and phosphate removal (at a wavelength of 880 nm) with 17 experimental runs by the BBD. Using the analysis of variance (ANOVA), the results obtained were analysed and quadratically modelled as a function of the input parameters with a significant regression coefficient (R2 > 0.96) at a 95% confidence level. At numerical optimum conditions of coagulant dosage (3.4 g), settling time (17.3 min) and mixing rate (103 rpm), 100% desirability treatability efficiency was attained with 100 distinctive conditional solutions. Interestingly, validation of the optimal condition revealed proper adjustment of the coagulant dosage and settling time can maximise the coagulation efficiency. Also, the findings demonstrated that the applicability of the magnetised rice starch in the wastewater settings can be used as a viable coagulant alternative.

Stečena hemofilija kod bolesnika na oralnoj antikoagulantnoj terapiji - prikaz slučaja

Introduction: Acquired hemophilia is a severe, sometimes even fatal condition of impaired coagulation. It most often leads to severe mucocutaneous, gastrointestinal, urinary, and, rarely, intracranial bleeding. This disorder occurs due to the production of antibodies against clotting factor VIII (F VIII), which interfere with its normal function. In laboratory analyses, prolonged activated partial thromboplastin time (aPTT), which cannot be normalized after being mixed with pooled normal plasma, is noticeable. Case report: In this article, the clinical course of the disease is described in a patient with acquired hemophilia, who was treated with oral anticoagulant therapy, and who initially also had prolonged prothrombin time, measured in international normalized ratio (INR) units, which measure how long it takes for a clot to form in a blood sample. Hemorrhagic syndrome was explained by iatrogenic effect. However, since bleeding continued after INR normalization, it was suspected that there was a different cause of hemorrhagic syndrome. The aPTT mixing test was performed (mixing an equal volume of the patient's plasma and normal pooled plasma (NPP) and repeating the aPTT test immediately and after one-hour incubation), after which the aPTT remained prolonged. This proved the presence of coagulation inhibitors, which is why acquired hemophilia was suspected. The patient was referred to a tertiary medical institution for further diagnostics and treatment. Conclusion: The objective of this case report is to show that patients with hemorrhagic syndrome, who are on anticoagulant therapy, may develop hemorrhagic syndrome for a different, non-iatrogenic reason. The purpose of the study is to draw the attention of medical doctors to various causes of hemorrhagic syndrome in patients receiving anticoagulant therapy.

Copper oxide nanoparticles removal by coagulation and optimization by matter–element analysis model

Nanoparticles have been inspected in water environment and sewage treatment plants, but how to achieve efficient removal of them through existing treatment processes is a potential issue. In this study, the organic–inorganic composite coagulant (PAC-CA) was applied to remove copper oxide nanoparticles (CuO-NPs) and study their coagulation behavior and the characteristics of flocs produced by coagulation. Under the optimal coagulation conditions with a dosage of 25 mg/L, pH of 7, stirring intensity of 200 s−1, and settling time of 15 min, the removal rates of CuO-NPs and turbidity were 89.83% and 93.51%, respectively. Zeta potential studies show that the main action mechanism of PAC-CA under low dosage or alkaline conditions is charge neutralization, and under high dosage or acidic conditions, the main action mechanism is adsorption bridging. A matter–element analysis model was established based on the evaluation index of stirring intensity, kaolin concentration, humic acid concentration, initial CuO-NPs concentration, pH, PAC-CA dosage, turbidity removal rate, and CuO-NPs removal rate. Kaolin can promote the removal of CuO-NPs and turbidity by PAC-CA. The main action mechanisms of PAC-CA are charge neutralization and adsorption bridging. PAC-CA has good coagulation performance for CuO-NPs wastewater, and provides a theoretical basis for the practical engineering application of coagulation for removing nanoparticles in wastewater.

The Relationship between Crystal Structure and Mechanical Performance for Fabrication of Regenerated Cellulose Film through Coagulation Conditions.

Cellulose films regenerated from aqueous alkali–urea solution possess different properties depending on coagulation conditions. However, the correlation between coagulant species and properties of regenerated cellulose (RC) films has not been clarified yet. In this study, RC films were prepared from cellulose nanofiber (CNF) and microcrystalline cellulose (MCC) under several coagulation conditions. Cellulose dissolved in aqueous LiOH–urea solution was regenerated using various solvents at ambient temperature to investigate the effects of their dielectric constant on the properties of RC film. The crystal structure, mechanical properties, and surface morphology of prepared RC films were analyzed using X-ray diffraction (XRD), tensile tester, and atomic probe microscopy (AFM), respectively. It is revealed that the preferential orientation of (110) and (020) crystal planes, which are formed by inter- and intramolecular hydrogen bonding in cellulose crystal regions, changed depending on coagulant species. Furthermore, we found out that tensile strength, elongation at break, and crystal structure properties of RC films strongly correlate to the dielectric constant of solvents used for the coagulation process. This work, therefore, would be able to provide an indicator to control the mechanical performance of RC film depending on its application and to develop detailed researches on controlling the crystal structure of cellulose.