Slow Mixing Time Research Articles

Optimization of the use of Moringa oleifera in wastewater treatment by rotational central composite design

Textile effluents have a complex waste composition due to the various compounds present and their resistance to degradation. Given the harmful effects of these pollutants on aquatic ecosystems, adequate treatment before disposal is essential, usually involving chemical processes such as coagulation and flocculation. This study optimizes textile wastewater treatment using Moringa oleifera as a natural coagulant through Rotational Central Composite Design (RCCD), a type of Response Surface Methodology (RSM), aiming to improve color removal, a key factor for effluent quality. By exploring Moringa oleifera as a sustainable alternative, the research provides new insights into environmentally friendly coagulant use and treatment optimization. The treatment’s effectiveness depends on the coagulant dosage, the energy applied, and the pollutant concentration. Dye removal was evaluated using spectrophotometry, and the evaluated factors in the optimization process were slow and fast mixing times, coagulant dosage, and pollutant concentration. The study identified pollutant concentration and slow mixing time as the most influential factors in treatment effectiveness. The model achieved a coefficient of determination (R²) of 87.9 %, and maximum dye removal reached 80.2 % under optimal conditions: 30 mL of coagulant, 20 min of slow mixing, 2 min of fast mixing, and a pollutant concentration of 300 mg ∙ L−1. The average removal efficiency was 47.86 %, indicating that natural coagulants offer a viable alternative for textile effluent treatment.

Experimental investigation on sludge conditioning and dewatering using an agricultural biomass coupled with resource recovery

In this study, the effect of modified areca husk fibre biochar (MAFB-AlCl3) on dairy sludge conditioning and dewatering along with raw and modified coconut shell biochar (MCSB-FeCl3) was investigated. Further, MgO impregnated biochars of areca husk fibre and coconut shells was carried out to evaluate the performance on phosphate recovery from the diary sludge. The enhancement in sludge dewatering with MAFB-AlCl3 were evaluated experimentally and significant reduction of capillary suction time (CST) (51.6 %), moisture content (18%), zeta potential (1.3 mV) and increased settleability (32.7%) were observed. The sludge conditioning parameters namely dosage (% of dry solids (DS)), rapid mixing time (RMT), slow mixing time (SMT) were optimized by response surface methodology for the modified biochars. Optimum CST (31.51 s) was obtained at dosage (50 % of DS), RMT (9.89 min) and SMT (17.23 min). Results of batch study for phosphate recovery by MgO impregnated biochars (MgB) was found to be 96.6 % and 100 % by MgB of areca husk fibre (MgAFB) and coconut shells (MgCSB) respectively. The morphological characteristics and elemental distribution using field emission scanning electron microscopy (FE-SEM) & energy dispersive X-ray spectroscopy (EDS) reveals the structural change in the sludge particles for the modified biochars as well as for sludge. Hence MAFB-AlCl3, MgAFB and MgCSB is proved to be suitable and an effective candidate for sludge conditioning and dewatering coupled with phosphate recovery in handling the diary sludge.

Chlorella vulgaris Harvesting: Chemical Flocculation with Chitosan, Aluminum Sulfate, and Ferric Sulfate

Chlorella vulgaris, a widely cultivated microalgae with diverse commercial applications, faces challenges in economic viability and scalability during the crucial biomass harvesting step. This study explores chemical flocculation followed by sedimentation as a cost-effective solution. Optimization was performed for three flocculants (chitosan, aluminum sulfate, and ferric sulfate), with experiments determining optimal pH and dosage ranges (10–200 mg·L−1). A 24-full factorial design optimized flocculant dosage, settling time, rapid mixing time, and slow mixing time, analyzing their effects on harvesting efficiency through empirical models. The optimal dosage ranges were 50–200 mg·L−1 for aluminum sulfate and 150–200 mg·L−1 for ferric sulfate at pH 9, and 10–50 mg·L−1 for chitosan at pH 5. Empirical models exhibited high fitting performance (R2 > 95%) and predictive capability (predicted R2 > 96%). All flocculants demonstrated high efficiencies (98.4–99.5%), with inorganic types requiring fast and slow mixing phases, while chitosan achieved optimal results without the need for both mixing phases, suggesting potential industrial advantages in time and energy efficiency for microalgae harvesting.

Optimization of the use of natural coagulants in wastewater treatment using Rotational Central Composite Design

Contamination of water resources by industrial effluents represents a major environmental problem and, in Brazil, the dairy industry is one of the main causes of these problems. The composition of its effluent has a high amount of organic matter and nutrients and, therefore, it is necessary to treat them before disposal. This study aimed to optimize the treatment of synthetic dairy effluents, simulating the coagulation/flocculation process, through the application of a natural coagulant based on Moringa oleifera seed extract, using the Rotational Central Composite Design associated with the Surface Methodology response (MSR). The independent variables in the project were the fast and slow mixing times, the coagulant dosage and the concentration of pollutants. A mathematical model was established with an R² of 0.6, in which the significance of the pollutant concentration and coagulant dosage was proven. From the re-parameterization of the mathematical model, considering only these two variables, an adjustment of 74% was obtained. As a result, a removal efficiency of 94.9% of turbidity was obtained, demonstrating – in the first approximation analysis – a strong result for the use of a natural coagulant to remove turbidity from dairy effluents.

Coagulation–flocculation of aquaculture effluent using biobased flocculant: From artificial to real wastewater optimization by response surface methodology

Coagulation–flocculation is currently the best practice for aquaculture effluent treatment, and biobased compounds are emerging as coagulant/flocculants. This study aimed to characterize the bioflocculant produced from Serratia marcescens and applied it to treat artificial turbid water (kaolin substrate) and real aquaculture effluent using the combination of one variable at a time (OVAT) and response surface methodology (RSM) analyses. The bioflocculant produced by S. marcescens was characterized as anionic flocculant with isoelectric point at pH 1.7 and 13.3. At pH 7, its protein content was 1.3 μg/mL, and its total carbohydrate level was 0.53 mg/L. The bioflocculant consisted of various carboxylic acids and enzyme intermediates, indicating the presence of polysaccharides and protein. Comparison of optimized treatment conditions between OVAT and RSM showed that rapid mixing speed, slow mixing time, and sedimentation time were the most influential factors for coagulation–flocculation. The aquaculture effluent required lower rapid mixing speed (125 rpm) and shorter sedimentation time (39 min) than artificial wastewater (160 rpm and 67 min, respectively). The low performance of the bioflocculant in treating aquaculture effluent was due to the more complex characteristics of real aquaculture effluent compared with those of kaolin substrate. Environmental implicationsThe characterization of bioflocculant produced by Serratia marcescens in terms of its protein level, total carbohydrate content, and isoelectric point has never been reported. The obtained results may provide an insight into the potential of this compound to substitute widely used chemical flocculants with reliable performance. The findings may also be used as a basis to upscale coagulation–flocculation from being applied to artificial wastewater in the laboratory to treating real wastewater, especially with the use of biobased compounds.

Sequential treatment of surfactant-laden wastewater using low-cost rice husk ash coagulant and activated carbon: Modeling, optimization, characterization, and techno-economic analysis

Treating surfactant-laden wastewater by a sequential coagulation/flocculation (C/F) and adsorption process was investigated. The treatment process performance was modeled and optimized using response surface methodology (RSM) and artificial neural network (ANN). C/F using rice husk ash (RHA) coagulant provided 42.3 % surfactant removal at 3.79 g/L RHA dosage, pH 3.6, and 23 min slow-mixing time. For adsorption onto granular activated carbon (GAC), 96.5 % surfactant removal was maintained at 10 g/L GAC and pH = 4.5. The ANN model showed better predictive capabilities for C/F and adsorption than RSM. By applying real wastewater, the combined system effluent contained 367 ± 2.4, 18.4 ± 1.2, 4.2 ± 0.2, and 0.95 ± 0.06 mg/L for TDS, COD, oil-grease, and surfactants, respectively, with almost complete removals of turbidity and TSS. The integrated system exhibited a profitability scenario with 6.3 years payback period. The study output is beneficial for designing full-scale systems of surfactant-laden wastewater treatment and predicting the associated performance under various operating conditions.

Feasibility Study on Application of Natural Coagulants

Creating nations are confronting consumable water gracefully issues because of lacking money-related assets. The expense of water treatment is expanding, and the nature of waterway water isn’t steady because of a suspended and colloidal molecule load brought about via land advancement and high tempest overflow during the stormy season. Because of numerous issues made by utilizing engineered coagulants a popularity to locate an elective characteristic coagulant emerges. In this exertion, an endeavor is made to examine the likelihood of normal coagulants like Cassia Alata, Calotropis Procera, Hyacinth bean, Banana leaves, Carcia Papaya, Acacia Mearnsii, Jatropha Curcas, Cactus, and Tamarind seeds on the reduction of turbidity of water. The clump coagulation test was done to decide the ideal coagulant amount required for the evacuation of turbidity of 100 NTU and to recognize the successful coagulant out of the nine chose normal coagulants. From this study, it may be accomplished that banana leaf can be used as an effectual coagulant for low and medium turbid water, whereas for high turbid water cactus can be used as an effective coagulant. Further examinations were completed utilizing the recognized coagulant to streamline the parameters like coagulant measurements, pH, introductory turbid focus, blending time, blending rate, and settling time. The higher percentage removal of turbidity was observed when pH was maintained at 6.5, initial turbid concentration was 500NTU, rapid mixing time given was 1 minute, slow mixing time with 25 minutes, and settling time of 25 minutes.

Utilization of citrus microcarpa peels and papaya seeds as a natural coagulant for turbidity removal

Coagulation and flocculation are an essential component of both the treatment of drinking water and the treatment of wastewater. The coagulant is one of the materials or substances that is added to the water to remove, stabilizes and causes colloidal particles to settle. Chemical coagulants such as aluminum sulphate (alum), ferric chloride, and synthetic polymers are the most commonly used coagulants in the industry due to their efficacy in turbidity removal. However, the use of chemical-based coagulants has had some negative impacts on human health and the environment, such as Alzheimer’s disease, and has produced a high volume of toxic sludge. In order to reduce negative impacts, this led to the discovery of an alternative to the natural coagulant (plant-based) for drinking water treatment. The coagulant used in this study is a combination of fruit waste containing citrus microcarpa peels and papaya seed with a ratio of 80:20 and 40:60. In addition to determining the potential of the composite natural coagulant, the optimal dosage and the effect of the mixing duration are also studied in order to determine the best mixing duration for each stage of the coagulation-flocculation process. Laboratory-scale studies using jar test experiments were conducted on surface water to determine the percentage of turbidity removal. Fruit waste was collected from the UiTM Pulau Pinang cafeteria, dried in the oven for 24 hours at a temperature of 105°C. The optimum dosage of composite natural coagulant is 90 mg/L using an 80:20 ratio of citrus microcarpa peels and papaya seeds with 97% of turbidity removal. The optimum mixing time is determined where the fast mixing time is 180 rpm for 3 minutes, the slow mixing time is 20 minutes with 10 rpm and the settling time is 30 minutes. The study shows that citrus microcarpa peels and papaya seeds have the potential to become effective natural coagulants in the future.

Evaluation of extract of Ipomoea batatas leaves as a green coagulant–flocculant for turbid water treatment: Parametric modelling and optimization using response surface methodology and artificial neural networks

Wastewater produced from many industrial processes is characterized by high levels of turbidity which is usually an indication of the level of pollution. Coagulation coupled with flocculation has been reported to be one of the efficient ways of treating turbid wastewater. Thus, this work evaluated the potential use of Ipomoea batatas leaves extract as a green and novel coagulating and flocculating agent for treating turbid water. The process was modelled and optimized using response surface methodology (RSM) and artificial neural networks coupled with genetic algorithm (ANN-GA). The FTIR results showed that the coagulant–flocculant contained beneficial functional groups which facilitated turbidity removal. The FESEM results indicated a porous matrix while the EDS results showed that carbon (61.2%) and oxygen (29.7%) were the main components with some lesser amounts of potassium (4.7%), phosphorus (2%) and aluminium (1.4%) which had a synergistic effect on the process. Although RSM and ANN modelled the treatment process with relatively high accuracy, the ANN model was however found to perform better than RSM as seen in the better statistical metrics. The ANN model predicted a maximum turbidity removal of 96% with a corresponding initial turbidity, coagulant dosage, rapid mixing time, rapid mixing speed, slow mixing time and slow mixing speed values of 250 NTU, 10 g/L, 2 min, 150 rpm, 10 min and 70 rpm, respectively. Thus, based on these findings, Ipomoea batatas leaves extract could serve as a replacement for the conventional chemical coagulants currently in the market. • Ipomoea batatas L. leaves extract has the potential to be used as a novel and green coagulant for turbid water. • Ipomoea batatas L. leaves extract was able to remove over 90% turbidity from the synthetic wastewater. • ANN model is better than RSM for modelling and optimizing turbidity removal from wastewater. • Ipomoea batatas leaves extract could serve as a replacement for the conventional chemical coagulants. • The findings in this study could form the basis for future upscaling for industrial treatment of turbid wastewater.

Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate.

The removal of concentrated colour (around 5039 Pt-Co) and chemical oxygen demand (COD; around 4142 mg L-1) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L-1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient (R2 = 0.98 and 0.96) and predicted R2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.

Treatment of highly turbid water in disaster conditions using coagulation-flocculation process: modeling and optimization

Abstract In the present research, the coagulation-flocculation (CF) process was used to eliminate highly turbid water in disaster conditions. To better understand the efficiency of the system, the impact of various numerical factors namely; initial turbidity (10–350 NTU), pH (5–9), coagulant dosage (50–250 mg/L), rapid mixing (120–280 rpm), slow mixing (30–50 rpm), and sedimentation time (10–50 min) were optimized through the central composite design (CCD) under response surface methodology (RSM). Based on analysis of variance (ANOVA), the quadratic model was more suitable for the dataset with R2 = 0.85 for removing turbidity. Moreover, the results of the present study revealed that the highest turbidity removal (99.14%) was observed at pH (9), alum dosage (50 mg/L), initial turbidity (350 NTU), rapid mixing (280 rpm), slow mixing (50 rpm), and sedimentation time (50 min). Furthermore, the residual turbidity at the maximum efficiency of the system was 3 NTU.

Degradation of Cd, Cu, Fe, Mn, Pb and Zn by Moringa-oleifera, zeolite, ferric-chloride, chitosan and alum in an industrial effluent

Coagulation-flocculation constitute the backbone process in most water and wastewater treatment plants. This study focused on determining the optimum coagulant dose for moringa oleifera seed extract, zeolite, ferric chloride, chitosan and aluminium sulphate coagulants through the coagulation, flocculation and sedimentation process. It also ascertain which coagulant has the potential for higher removal of Cd, Cu, Fe, Mn, Pb and Zn. The test was conducted with initial pH, settling time, coagulant aid dose, rapid mixing speed & time, slow mixing speed & time as constant parameters. The determination of heavy metals concentration in POME was carried out using an Inductively Coupled Plasma (ICP) and an Atomic Absorption Spectrometer (AAS). The process efficiency was assessed in terms of percentage removals for the heavy metals examined. The results proved that chitosan, FeCl3, alum, zeolite and moringa oleifera had the concentrations of 400, 2000, 1000, 1000, and 4000 mg/L as the optimum dosage respectively.

Improvement of Drinking Water Properties Using a Novel Biosorbent Material . (Dept.C)

In the present study, a new material has been discovered in the world of natural coagulants and adsorbents to improve drinking water properties. Flaxseed husk was used as a natural coagulant and adsorbent to remove turbidity, natural organic matter and iron from underground water for several wells in Al-Jouf region in the north of the Kingdom of Saudi Arabia. To remove turbidity and natural organic matter, modified flaxseed husk (MFH) was prepared by addition of aluminum sulfate (AS) to flaxseed husk (FH) after removing mucilage and oil. The characterization of FH shows high specific surface area (125.18 m2/g) with average pore diameter of 26.28 μm. Moreover, FTIR spectra analysis indicated existence of large number of amino groups and another functional group indicated that FH efficiency about removal of turbidity and natural organic matter. The optimum ratio MFH:AS for removal was (80%:40%). Batch experiments were performed as function of process parameters such as slow mixing time, FH dosage and Initial NOM. The removal of turbidity and natural organic matter (NOM) by modified flaxseed husk (MFH) were investigated using a FH dosage of 40 mg.l-1 and 10 mg.l-1 AS which attained a removal efficiency of 98.0 % for turbidity and 99.3 % for NOM at the highest NOM concentration. Also, reduce the iron concentration in drinking water by flaxseed husk ash (FHA) which prepared by burning flaxseed husk at certain temperature was investigated. Batch experiments were performed as function of process parameters such as FHA type, contact time (CT), FHA dosage and initial Fe concentration. The FHA showed a high removal of Fe3+ from aqueous solution. The maximum Fe removal was 90% at FHA200, FHA dose 0.75 g/l and contact time 45 min, The pH value from 7 to 7.8 and the temperature value from 20 to 24 0C. The adsorption equilibrium has been studied by the pseudo first order kinetics model, the pseudo second order kinetics model, Langmuir and Freundlich isotherm, all these models demonstrated the adsorption efficiency of the adsorbent surface behaved in a favorable manner for Fe adsorption

Mixed culture microalgae removal for water quality improvement using chitosan

The presence of microalgae affects water quality and beneficial uses of surface freshwaters. Chitosan with proven potential for harvesting specific microalgae species from their culture medium to produce biofuels and bioproducts also appears promising for efficient removal of mixed microalgae species from surface freshwaters. The main focus of the present study was on removal of mixed microalgae species using chitosan as a coagulant to help improve water quality. Important operational parameters were optimized for economical microalgae removal. The microalgae cells, chlorophyll-a, total nitrogen, and total phosphorous removal efficiency were 82.06%, 89.90%, 69.32%, and 44.01%, respectively, at an optimum chitosan dose of 10 mg/L, pH 8, slow mixing time 7 min, slow mixing rate 30 rpm, and settling time of 15 min. The results show that chitosan coagulation efficiently removed mixed microalgae species from surface freshwater with significant improvement in water quality and recovery of algal biomass for other beneficial applications.

Sustainable use of natural and chemical coagulants for contaminants removal from palm oil mill effluent: A comparative analysis

• Raw Palm Oil Mill Effluent characterized; sample treated and 4000 mg/L Alum dose was obtained as the optimum. • 1000 mg/L of Ferric chloride significantly increased the removal efficiency in the experimental sample. • Chitosan as a biopolymer showed continuous removal efficiency until the optimum dose was reached at 400 mg/L. • Moringa Oleifera dose of 2000 mg/L as a natural coagulant was very efficient in heavy metals removal from the sample. • Zeolite dose of 1000 mg/L showed significant increase in removal efficiency as it provides the highest removal percentages for Cadmium, Zinc and Iron. This article aimed at determining the optimum coagulant dose for various coagulants. This is to ascertain coagulant with the potential for higher removal of contaminants. By fixing the initial pH, settling time, coagulant aid dose, rapid mixing speed & time, slow mixing speed & time as constant parameters, the study assessed the process efficiency in terms of percentage removals for TSS, oil & grease, COD, NH 3 -N, turbidity and colour. The results indicated that the optimum dosage for FeCl 3 , moringa oleifera , aluminum sulphate, chitosan and zeolite was found to be 1000, 2000, 4000, 400 and 1000 mg/L, respectively. Results were analysed using the one-way analysis of variance (One-Way ANOVA) of Statistical Package for Social Sciences (SPSS) Version 17 where P-values for all contaminants tested across various coagulants and their dosages found to be <0.05. Thus, the null hypothesis is discredited which indicate there is significant improvement in the removal efficiencies.

Application of Chitosan as Cyanide Adsorbance on Gold Ore Processing

&lt;p&gt;Gold ore processing method have an impact on water pollution if the waste produced is not managed properly. Chitosan have the ability as an adsorbent, but its effectiveness to absorb cyanide content in gold processing wastewater is unknown. This study aimed to examine the ability of chitosan adsorption on cyanide in the processing of gold ore. The statistic design used was a factorial in-time Completely Randomized Design (CRD) with two repetitions. The analysis carried out consisted of the effect of chitosan concentration on absorbance, pH, TDS, turbidity, cyanide, and the modification effect of chitosan production on absorbance power. The method used in this research was flocculation coagulation method by the jar test.The method was carried out by rapid and slow mixing process with a flocullator. The method was used to determine the best of chitosan type and the best contact time to decrease the concentration of cyanide waste from the processing of gold ore. The results showed that the best concentration of chitosan modified was chitosan modification with swelling crosslink glutaraldehid (GA) in 1000 ppm concentration and using slow mixing contact time for 120 minutes. That chitosan modified significantly adsorp cyanide waste in 90.38%.&lt;/p&gt;

Minimizing residual black particles in sand filtrate when applying super-fine powdered activated carbon: Coagulants and coagulation conditions

Because of the eminent adsorptive capacity and rate for dissolved organic molecules compared to conventionally-sized powdered activated carbon (PAC), super-fine powdered activated carbon (SPAC) is gathering momentum for use in not only the pretreatment for membrane filtration for drinking water purification but also the conventional water purification process consisting of coagulation-flocculation, sedimentation, and rapid sand-filtration (CSF). However, the probability of SPAC particles to leak through a sand bed is higher than that of PAC, and their strict leakage control is an issue to be challenged when applying SPAC to CSF. However, study focusing on very high particle removal, which yield residual concentrations down to around 100 particles/mL, has been very limited. A previous study mentioned that the tendency of SPAC leakage is related to its low destabilization. In response to this, the present study focused on the two key components of coagulation (mixing intensity and coagulants) and investigated how to effectively reduce the residual SPAC after CSF.Astonishingly, the flash mixing (the first process of CSF), especially its G (velocity gradient) value, played the most important role in determining the residual SPAC in the filtrate of sand filter (the fourth process). Even if the slow mixing time was short, a sufficiently large G value but short T (mixing time) value in flash mixing effectively reduced the residual SPAC. When the total GT value of flash and slow mixing was fixed at a constant, priority should be given to flash mixing to reduce the residual SPAC.Among 23 PACl (poly-aluminum chloride) coagulants, PACl with a high-basicity (basicity 70%) and with sulfate ion (0.14 of sulfate/aluminum in molar ratio), produced by Al(OH)3-dissolution, were the most effective to reduce the residual SPAC after CSF. PACls produced by base-titration, which have been intensively investigated in previous researches, were not effective due to lack of floc-formation ability. However, their Al species composition determined by the ferron method were almost the same as those of PACl by Al(OH)3-dissolution, and their charge-neutralization capacities were higher. PACls produced by Al(OH)3-dissolution possessed both charge-neutralization and floc-formation abilities, but the former ability was more important to minimize the residual of SPAC.

Using vegetable tannin and polyaluminium chloride as coagulants for dairy wastewater treatment: A comparative study

The aim of this work was to compare the performance of tannin and polyaluminium chloride (PAC) in the coagulation process for dairy industry wastewater. The conditions of coagulation/flocculation with regards to the dosage, pH, velocity gradient and slow-mixing time were optimized and some parameters such as floc aggregation (KA) and breakage (KB) coefficients were computed. Additionally, it was carried out a thermogravimetric analysis of the obtained sludge for both coagulants. The results showed no statistical differences between the performance of the two coagulants based on chemical oxygen demand, colour, turbidity and total solids removal. Particularly, the PAC showed higher alkalinity consumption and increased the electrical conductivity of the clarified wastewater, while tannin showed good performance within a wider pH, ranging from 5.0 to 10.0. Moreover, although the greatest KA values were observed for PAC usage, the tannin use presented higher resistance to floc breakage during the slow-mixing time. The obtained sludge from the experiments using tannin accounted for higher volatile solids and fixed carbon, and lower ash content when compared to PAC. In conclusion, tannin is a promising alternative for dairy wastewater treatment regarding its process performance and wastewater treatment residuals management.

Moringa oleiferaLam. and Its Potential Association with Aluminium Sulphate in the Process of Coagulation/Flocculation and Sedimentation of Surface Water

The present study aims to optimize the operational conditions in surface water coagulation/flocculation and sedimentation step, besides evaluating the association between seeds ofMoringa oleiferaLam. (M. oleifera) and the synthetic coagulant aluminium sulphate for surface water treatment. The assays were performed in Jar Test using surface water from Pirapó River basin, Maringá, PR. It was observed that the operational conditions affect the coagulation/flocculation and sedimentation process efficiency. Optimal operational conditions for coagulants association are as follows: rapid mixing velocity (RMV) of 105 rpm, rapid mixing times (RMT) of 1 min, slow mixing velocity (SMV) of 30 rpm, slow mixing times (SMT) of 15 min, and sedimentation time (ST) of 15 min; this enables an improvement in the process, contributing to a reduction in synthetic coagulant aluminium sulphate demand of up to 30%, combined with an increase inM. oleiferadosage, not affecting the coagulation/flocculation and sedimentation process efficiency, considering the water pH range between 7 and 9.

Accelerated Monte Carlo simulations with restricted Boltzmann machines

Despite their exceptional flexibility and popularity, the Monte Carlo methods often suffer from slow mixing times for challenging statistical physics problems. We present a general strategy to overcome this difficulty by adopting ideas and techniques from the machine learning community. We fit the unnormalized probability of the physical model to a feedforward neural network and reinterpret the architecture as a restricted Boltzmann machine. Then, exploiting its feature detection ability, we utilize the restricted Boltzmann machine for efficient Monte Carlo updates and to speed up the simulation of the original physical system. We implement these ideas for the Falicov-Kimball model and demonstrate improved acceptance ratio and autocorrelation time near the phase transition point.