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The Lapindo mudflow disaster in East Java Province, or also known as LUSI (LUmpur “mud”-SIdoarjo) has become spectacular longest ongoing disaster in recent memory since 2006. The utilization of volcanic Lapindo mud could be the promising solution to prevent further environmental damage. The chemical composition of Lapindo mud contained of 44.1% SiO2, 23.7% Fe2O3, 13% Al2O3, 7.02% CaO, 5.35% MoO3, 2.53% K2O, 1.84% TiO2 and 0.7% Na2O. Aluminium sulfate (Al2(SO4)3) or “alum” have been widely used as coagulation compound in water treatment, paper and textiles industry. Aluminium sulfate can be synthesized from aluminium oxide (Al2O3) from Lapindo mud with acidic solutions (H2SO4). The aim of this work was to synthesize aluminum sulfate from Lapindo mud by using extraction process. The impact of H2SO4 concentration and heating time to the production of aluminium sulfate have been investigated. The results showed that the aluminium sulfate can be synthesized from Lapindo mud by using H2SO4. Based on XRF analysis, the variation of heating time and H2SO4 concentration affect the aluminium sulfate conversion. The increasing of heating time and H2SO4 concentration directly enhance the conversion until reach the optimum condition. The optimum condition for aluminium sulfate synthesis from Lapindo mud (75.78% conversion) was found to be 90 min for heating time with H2SO4 concentration of 80%

The adoption of aluminium sulfate and potassium sulfate as electrolyte additives were investigated to determine the possibility of enhancing the charge cycle of 2V/ 20AH lead acid battery with reference to the conventional dilute sulfuric acid electrolyte. The duration and efficiency of lead acid batteries have been a challenge for industries over time due to weak electrolyte and insufficient charge cycle leading to sulfation. This has affected the long-term production output in manufacturing companies that depend on lead acid batteries as alternative power source. Hence there is need to explore the use of specific sulfate additives that can possibly address this gap. The electrolyte solutions were in three separate charge and discharge cycles involving dilute sulfuric acid electrolyte, dilute sulfuric acid-aluminium sulfate mixed electrolyte and dilute sulfuric acid-potassium sulfate mixed electrolyte for one hour each. The total voltage after 30 minutes charge cycle was 2.3V, 2.35V and 5.10V for dilute sulfuric acid, aluminium sulfate additive and potassium sulfate additive respectively. The cell efficiency for dilute sulfuric acid, aluminium sulfate additive and potassium sulfate additive electrolytes are 77%, 77% and 33% respectively. The electrolyte sulfate additives were of no positive impact to the conventional dilute sulfuric acid electrolyte of a typical lead acid battery due to the low difference in potentials between the terminals.

Industri tahu merupakan usaha yang didirikan dalam rangka kegiatan industri makanan yang berdampak positif dan negatif terhadap lingkungan. Dampak negatif dari industri tahu berupa limbah yang menimbulkan pencemaran dan merusak lingkungan. Pencemaran lingkungan terjadi dalam bentuk pembuangan limbah padat (residu tahu) dan limbah cair. Sebagian besar limbah cair yang dihasilkan oleh industri pembuatan tahu merupakan cairan kental yang dipisahkan dari blok tahu yang disebut "whey".Limbah industri tahu tersebut mempunyai kandungan organik yang tinggi seperti COD dan TSS. Pada penelitian ini dilakukan beberapa metode untuk menurunkan kandungan organik tersebut. Koagulasi dengan alumunium sulfat (Al2(SO4)3. dapat menurunkan kandungan Chemical Oxygen Demand (COD) sebesar 50.3% dan Total Suspended Solid (TSS) sebesar 81% dengan dosis koagulan 1000 mg/l. Fotokatalis TiO2 dapat menurunkan Chemical Oxygen Demand (COD) sebesar 50 % dengan waktu pemaparan 150 menit.

Different liquid accelerators including sodium aluminate liquid accelerator (SAa), fluoaluminate liquid accelerator (Fa) and aluminium sulfate liquid accelerator (ASa) were selected to investigate their influences on the carbonation properties and morphology of tricalcium aluminate (C3A) and tricalcium silicate (C3S) hydration products. After an accelerated carbonation test, the relative contents of ettringite (AFt), calcium hydroxide (CH) and calcium carbonate (CaCO3) in the hydration products of C3A and C3S samples were analysed by thermogravimetric analysis. The results indicated that the hydration products of C3A and C3S with liquid accelerators were easier to carbonate, and the promotion effect of SAa was the most obvious. The morphology of hydrated products of C3A and C3S was observed by scanning electron microscopy analysis. It was observed that different liquid accelerators had a different influence on the morphology of C3A and C3S hydration products. Among them, ASa had the greatest influence on the morphology of C3A and C3S hydration products, and experiments proved that ASa could promote the transformation of AFt into AFm and make the CH crystal structure become thicker and larger.

O alumínio (Al) presente nos solos ácidos reduz o potencial fisiológico de sementes e limita o crescimento plântulas de diversas espécies de interesse agronômico. Entretanto, informações quanto à toxicidade do Al em Arctium lappa L. (bardana, Asteraceae) são escassos. Objetivou-se nesse estudo avaliar o efeito do estresse por alumínio na germinação e no vigor de plântulas de A. lappa. Foram testadas cinco concentrações de sulfato de alumínio hidratado Al2(SO4)3·16H2O: 0 (controle), 5, 10, 15 e 20 mmol L-1. O teste de germinação foi feito em caixas do tipo Gerbox (sobre papel – SP) e em rolo papel – RP, utilizando papel germitest® umedecidos 2,5 vezes seu peso seco. As sementes foram mantidas em câmaras de B.O.D, sob 20-30ºC e luz branca constante. O potencial fisiológico das sementes e vigor de plântulas foi avaliado por meio dos testes de primeira contagem de germinação (4 dias), germinação (7 dias) e comprimento de plântulas. Observamos redução da germinação conforme aumento das concentração de Al em substrato SP. Os menores comprimentos da parte aérea das plântulas ocorreram com 20 mmol L-1 de Al e no substrato SP. Ocorreu inibição radicular das plântulas conforme aumento das concentração de Al nos dois substratos, especialmente no SP. O estresse por alumínio e substrato SP afetou negativamente a germinação de sementes e vigor das plântulas de A. lappa.

The main purpose of this study was first to investigate the removal of Hg(II) ions from industrial wastewaters by coagulation-flocculation with aluminum sulfate, secondly to understand the contribution of some parameters including the coagulant dose, pH, and the addition of adjuvant (activated carbons and lime). Jar-test experiments were carried out on wastewater samples containing mercury from the industrial area of Biskra (BIWW: Biskra industrial wastewater, C0= 1.01 mg/L) and Tizi Ouzou (TOIWW: Tizi Ouzou industrial wastewater, C0= 1.81 mg/L).The maximum elimination of mercury at ambient temperature was 49% and 58% that were obtained with concentrations of 180 mg/L and 200 mg/L of aluminum sulfate at a pH close to 7 for both Tizi Ouzou and Biskra samples, respectively. The obtained results showed that the removal efficiency of mercury ions is improved by the addition of adjuvant (activated carbon and lime). The removal efficiency of Hg (II) ions increased with increasing lime and activated carbon masses, experiments results indicated that the yield increased with the increase in the dose of the adjuvant to reach a maximum of 82.89% (TOIWW) and 83.38% (BIWW).The experiments were conducted to test the ability of coupling coagulation-flocculation to adsorption. It was verified that coupling was more efficient in the removal of Hg(II) ions from industrial wastewater than coagulation-flocculation alone. Almost complete removal (99.42) of Hg was obtained by coupling coagulation-flocculation and adsorption on powdered activated carbon.Accordingly, it is believed that coupling coagulation-flocculation and adsorption are practical for utilization in industrial wastewater treatment for mercury removal.

A microwave liquid-phase desorption technique for enhancing mass transfer with chemical dissociation has been proposed for the first time. In this paper, the static desorption system of basic aluminium sulfate (aluminium base) desulfurization rich liquid was investigated through an experiment and numerical simulation. By establishing a desorption mass transfer rate equation and the internal heat source and concentration source of microwave desorption, the mechanism of microwave desorption thermal and non-thermal effect was revealed. Results showed that desorption mass transfer rate (NSO2) is related to temperature, pressure, film thickness and liquid SO2 concentration (CSO2). Desorption temperature and gas film thickness have limited influence on desorption performance, while CSO2 and liquid film thickness have significant influence. The increase in NSO2 per unit reduction of liquid film thickness increased five times when liquid film thickness decreased from 50 to 30 and then to 10 μm. At the same film thickness, microwave thermal desorption was controlled on the basis of desorption temperature and time, and microwave power only changed the heating rate. The important value of microwave non-thermal effect was that CSO2 was greatly increased by enhancing the chemical dissociation ability of SO2. At 800 W, the NSO2, mass transfer rate chemical influence factor (Φ) and physical influence factor (ψ) of thermal desorption end point were 0.98, 0.92 and 1.07 times those at 480 W, respectively, at the same film thickness, whereas microwave desorption end point were 3.28, 3.18 and 1.03 times, respectively, those at 480 W. Furthermore, the impact ratio (X) between non-thermal and thermal effects on NSO2 of microwave desorption was between 6.3 and 15.5 at 800 W and between 2.8 and 10.6 at 480 W. High microwave power showed stronger non-thermal effect capability.

Paper degradation on a macroscopic scale is characterised primarily by yellowing, an increase in brittleness, and other destructive changes caused by the hydrolysis of glycoside bonds and oxidation reactions. Until now, lignin has been believed to cause these changes. However, contemporary analysis has not confirmed this assumption and has attributed low paper resistance to ageing with acidification owing to the production in acid environments that involve aluminium sulfate. In view of the common belief this manuscript presents studies on the accelerated ageing of papers with different lignin contents that are produced in neutral environments. To achieve the objective, artificially aged papers under conditions of increased humidity and temperature were investigated using chromatographic (SEC) and spectroscopic (FTIR and UV–Vis spectroscopy) techniques. Mechanical tests were used to determine the decrease in tensile properties of the samples. We observed no effects of the lignin content on the ageing rate of paper produced at neutral pH. This work also reveals the extent to which spectroscopic methods are useful for studying the papers containing lignin.

Rose (Rosa spp.) production for cut flowers is an integral part of the horticultural industry. However, because roses are exotic plants they exhibit serious problems related to poor climatic adaptation. A study was conducted at the School of Agricultural Sciences, University of Zambia to evaluate chemicals to extend flower shelf life. The cultivar ‘Akito’ was used as the test variety. Benzyl amino purine ([6- (benzylamino) purine]) (BAP), a growth regulator and aluminium sulphate (an acidifying reagent) were applied to cut flowers at 0, 5, 10, 15, and 20 mg L-l and 0, 400, 800 and 1200 mg L-l, concentration, respectively. BAP was applied to the plants in the greenhouse 2 days before harvest. A randomised complete block design arranged as a two- factor- factorial arrangement with three replications was used. Harvesting was done at the loose open calyx stage. Aluminium sulphate was applied to the holding solution where flowers were kept after harvest. The pH of the holding solution, blossoming (flower opening), leaf color of subtending leaves and bacterial population were monitored. The 400 mg L-l aluminium sulphate treatment caused an increase in acidity. There was concurrent decline in bacterial count in the first three days of application at less than 1 x 106 which was five times lower than the water control treatment. Bacterial population followed the trend of water acidity. The 20 mg L-l BAP application increased shelf life by 35 %. The results showed that BAP and aluminum sulphate treatment could enhance shelf life. Int. J. Agril. Res. Innov. Tech. 10(1): 6-12, June 2020

Sulphur trioxides are common toxic gaseous pollutants which can be produced from alternative routes via calcination of aluminum sulfate derived from kaolin clay. Its demand increases geometrically, thus the need to optimize the yield of SO 3 from the calcination of alum is essential. The rate of alum decomposition was monitored by the formation of SO 3 via thermogravimetric analysis and X-ray fluorescence analysis. This study aimed to evaluate the effect of calcination temperature and curing time on the SO 3 conversion and yields using Face Central Composite Design and optimize the process conditions to evaluate the maximum yield of SO 3 using response surface methodology and its effects and interactions were investigated between 800–900 °C at 60-180 minutes. Results indicated that experimental data satisfied second order polynomial regression model for SO 3 conversion and SO 3 yield from TG analysis while XRF analysis satisfied first order model respectively. An increase in SO 3 conversion and yields was observed as the calcination temperature and time were increased both independently and simultaneously. The calcination temperature was found to have a stronger influence compared to the calcination time. Validation indicated agreement between experimental and predicted values with a regression value of 97.8 %, 97.77 % and 97.67 % for SO 3 conversion, SO 3 yield via TG and XRF analyses respectively. Based on the ANOVA, the SO 3 yield via XRF produced the best model with R 2 pred of 91.98% while SO 3 yield via TG analysis and SO 3 conversion had R 2 pred of 79.99% and 78.01% respectively. Optimization of the production of SO 3 was carried out and the optimal condition for SO 3 conversion, SO 3 yield via TG and XRF analyes were 90.11 %, 91.67 % and 75.81 % respectively at an optimal calcination temperature of 877.43 o C and time of 155.04 minutes respectively.

In this paper we studied the intensification of the water clarification process on contact clarifiers with quartz sand filtering bed, which was modified with a solution of aluminum sulphate coagulant. The modification of the quartz sand filtering bed was carried out by applying to the surface of grains of quartz sand solution of coagulant aluminum sulphate with different doses. Investigation of the electrokinetic potential of the filtering material (quartz sand) was carried out by the percolation potential method. The influence of electrical properties (size and sign of the charge) of the filtering bed itself and suspended solids in the water on the filtration process was studied. The filter material – quartz sand used in contact clarifiers has a negative electric charge. When the electric charge of the particles decreases, that is, as the ζ-potential decreases, the repulsive forces decrease and it the adhesion of particles becomes possible. This is the process of coagulation of the colloid. The forces of mutual gravity between the colloidal particles begin to predominate over the electric repulsive forces at the ζ-potential of the system less than 0.03 V. Modification of quarts filtering bed with a solution of coagulant aluminum sulphate recommended for the purification of surface water allows: to intensify the process of water clarification, to reduce the consumption of reagents by 25–30%, with the obtaining purified water of the required quality, to reduce the production areas necessary for reagent management of treatment facilities, and to reduce the cost of water treatment by 20–25%.

Dosing alum to remove phosphorus (P) from wastewater is a common practice. However, the dosing-location and quantity of alum required to meet P discharge limits are vaguely defined. As such, utilities overdose alum to avoid noncompliance, but this leads to wastage and costs. This study aimed to address this issue through a long-term evaluation of an alum-assisted full-scale intermittently decanted extended aeration (IDEA) plant. Specifically, the effects of relocating alum dosing from a low P containing IDEA-tank to a bioselector containing elevated P concentrations were examined. The plant is fitted with two IDEA-tanks, each retrofitted with a bioselector at the inlet end. Over 359 d, key parameters (dissolved oxygen (DO), NH4+-N, NO2−-N, NO3−-N, PO43–-P) were quantified to account for the effects of switching alum-dosing into the bioselector and varying dosages (429, 643, 1072 and 1286 g-Al3+ per treatment cycle). Results indicated a 52% reduction of alum usage with no impact on discharge limit (≤0.85 mg-P/L). As expected, a failure to maintain DO setpoint (1.6 mg/L) reduced both NH4+-N and PO43–-P removal. Increasing alum dosage simply could not alleviate this problem, but maintenance of DO at least 85% of setpoint enabled effective rectification. This 15% DO buffer zone offers operators an opportunity to rectify imminent operational failures related to DO, prior to escalating alum dosage. An operational framework to manage DO related failures is proposed. Overall, this study offers insights on how to cost effectively apply alum and manage DO failures to achieve P discharge limits in IDEA plants.

Accelerating admixtures for shotcreting in general commercial use today are mixtures of sodium carbonate and sodium aluminate. While they produce acceptable early strengths relative to plain concrete, they typically reduce the ultimate strength by more than half, requiring the use of thicker layers than would be necessary in the absence of the accelerator to achieve the same structural strength. Additionally, these admixtures are highly caustic and great care must be taken in handling them. The new generation of accelerators that are free of alkali metal ions and chlorides contain at least one water-soluble sulfate and further constituents. The sulfate is mostly aluminium sulfate. The sulfate ions react with calcium hydroxide and with the surface of the tricalcium aluminate particles, producing a compound called ettringite. The mode of action of aluminium sulfate on the hydration of different cements from the time of mixing up to 7 days was investigated using X-ray diffraction.

Water is a fundamental substance for the existence of life on earth. However, globally there is a freshwater crisis. Hospitals generate exorbitant volumes of effluents (5 to 15 times more toxic than urban ones). Hospital laundry is known for demanding the highest volumes of water, generating a proportional amount of complex effluents with high toxicity and recalcitrance. Adequate treatment for hospital wastewater is always an essential solution. Among all treatment methods, coagulation/flocculation emerges as one of the best alternatives. However, the use of traditional compounds such as aluminium sulfate has caused secondary pollution; its residues are harmful to public and environmental health. In this sense, the present study used natural compounds that do not cause adverse effects, such as chitosan/hydroxyapatite, to clarify the laundry effluents of the largest hospital from the Tocantins. The results showed that the hydroxyapatite associated with chitosan, at pH 6 and dosage of 50 mg/L, reduced the turbidity and apparent colour of these wastewaters by up to 67 and 55%, respectively. With lower performance and higher dosage (60 mg/L), the chitosan gel used (pH 6) promoted a maximum reduction of 35% of the apparent colour and 40% of turbidity.

Coagulant dosing has played an essential role in urban water management for centuries. In fact, the first documented use of coagulant dosing for the production of drinking water dates back as far as 77 AD, where the Romans used aluminium sulfate to remove solids and colour from river water. The widespread use of coagulants for drinking water production started in the early 1900’s. Rather surprisingly, not much has changed ever since. The majority of drinking water treatment plants (DWTPs) still heavily rely on coagulation and flocculation for the removal of turbidity, colour, natural organic matter (NOM) and pathogens. Amongst the various coagulants used at DWTPs, the most commonly used are aluminium sulfate (also known as alum) and iron salts (i.e. either in the form of ferrous/ferric chloride and/or sulfate).Iron salts also play an important role in other segments of our urban water infrastructure. First, they are the most commonly used chemicals to combat sulfide induced concrete corrosion and odour problems in sewer networks, a notorious and multibillion dollar problem for wastewater utilities worldwide. Second, the addition of iron salts is a prevalent approach for chemical phosphate precipitation in downstream wastewater treatment plants (WWTPs). Lastly, they are also dosed as a means to control hydrogen sulfide generation during anaerobic digestion.A universal aspect of coagulation-flocculation processes is the generation of large amounts of an unavoidable by-product, namely drinking water sludge (DWS). To give an idea of the size of the problem, the generation of DWS for the United Kingdom and Netherlands alone exceeds 130,000 and 29,700 wet tons per year, respectively. Management of DWS incurs large costs and often comprises a substantial fraction of the operational expenditure of DWTPs, with landfilling often used as the ultimate disposal route. As we are entering the era of a circular economy, such a linear use of large amounts of chemicals will not suffice in the 21st century.Hence, to find a long-term sustainable solution to coagulant usage in our urban water infrastructure, there is an urgent need to develop a more circular management approach to coagulant usage. Therefore, this PhD thesis aimed to demonstrate the practical feasibility and economic potential of an ‘urban water infrastructure-wide’ iron salt dosing management approach achieving multiple reuse and ultimate recovery and direct reuse of iron in our urban water infrastructure.First, the practical feasibility and effectiveness of multiple beneficial reuse of iron salts were investigated by replacing in-WWTP alum dosing with upstream in-sewer FeCl2 dosing through a year-long comprehensive testing at full-scale WWTP. The results showed that FeCl2 dosed (at 160 kg Fe/day) in sewer network effectively controlled sulfide concentrations (up to 93%) and was successfully reused for efficient phosphate removal in the activated sludge tanks of down-stream WWTPs. Moreover, the iron-phosphate rich sludge, when fed to the anaerobic digesters, was again re-used for sulfide control, thereby releasing part of the iron-bound phosphate. Importantly, in-sewer FeCl2 dosing did not negatively affect the biological nitrogen removal and UV effluent disinfection process. Finally, the above described benefits were accompanied by a reduction in overall chemical demand of ~6%. The results clearly demonstrated that significant benefits in terms of wastewater treatment operation as well as chemical savings can be achieved by utilities by adopting such integrated iron salts dosing approach.While in-sewer iron salt dosing practically eliminates the need for additional iron dosing in WWTP and brings economic benefits to utilities, it is still based upon a linear management approach, with ultimately the iron ending up in the excess sludge. Therefore, in the second part of the thesis, a thorough investigation was conducted aiming to demonstrate the feasibility of a combined ‘iron recovery and reuse’ approach through long-term comprehensive laboratory testing over a period of 3 years. The results showed that both FeCl3 and ferric iron-rich DWS (a waste by-product at DWTPs resulting from coagulation with FeCl3) dosing in sewer network results in similar performance in terms of sulfide control in sewers followed by successful reuse for phosphate removal and sulfide control in downstream wastewater treatment. More importantly, both type of iron forms a paramagnetic iron phosphate mineral called vivianite in the digested sludge and hence has the potentials for magnetic recovery. The results showed that about 92±2% of the in-sewer dosed Fe was bound in vivianite in digested sludge. A simple insertion of neodymium magnet allowed to recover 11±0.2% and 15.3±0.08% of the vivianite formed in the digested sludge of the in-sewer dosed iron in the form of FeCl3 and Fe-DWS, respectively. More importantly, almost complete (i.e. 98±0.3%) separation of Fe in the form of ferrihydrite (an amorphous ferric oxyhydroxide) was achieved from vivianite after alkaline washing. Subsequent batch experiments demonstrated that recovered ferrihydrite can be directly reused back to sewers for efficient sulfide control (achieving sulfide concentration of

Phase diagrams and liquid ? liquid equilibrium (LLE) data for aqueous two-phase systems (ATPSs) containing zinc sulfate, magnesium sulfate or aluminium sulfate and polyethylene glycols PEG 300, 400 and 600 have been determined at 298.15 K. It was attempted to show how the PEG molecular weight and the type of cation influence the binodal curve, tie line length (TLL) and slope of the tie line (STL). The results have shown that as the PEG molecular weight increases, the two-phase region becomes extended and the binodal curve shifts to the origin. The refractive index and density of ternary (PEG 300,400 and 600 + zinc sulfate/magnesium sulfate/aluminium sulfate + water) systems have been measured to achieve the phase composition and the tie lines. Finally, the effective excluded volume (EEV) model was applied to describe the salting-out ability of the systems. The LLE data from this research may be potentially used for recovering biological molecules like proteins.

Background & objectives: Avian influenza (AI) viruses have been a major cause of public health concern. Wild migratory birds and contaminated environmental sources such as waterbodies soiled with bird droppings play a significant role in the transmission of AI viruses. The objective of the present study was to develop a sensitive and user-friendly method for the concentration and detection of AI viruses from environmental water sources. Methods: Municipal potable water, surface water from reservoirs and sea were spiked with low pathogenic AI viruses. To concentrate the viruses by precipitation, a combination of potassium aluminium sulphate with milk powder was used. Real-time reverse transcription-polymerase chain reaction was performed for virus detection, and the results were compared with a virus concentration method using erythrocytes. Drinking water specimens from poultry markets were also tested for the presence of AI viruses. Results: A minimum of 101.0 EID50 (50% egg infectious dose)/ml spiked H5N1 and 101.7 EID50/ml spiked H9N2 viruses were detected from spiked potable water; 101.0 and 102.0 EID50/ml spiked H5N1 virus was detected from surface water and seawater samples, respectively. The present method was more sensitive than the erythrocyte-binding method as approximately 10-fold higher infectious virus titres were obtained. AI H9N2 viruses were detected and isolated from water from local poultry markets, using this method. Interpretation & conclusions: Viability and recovery of the spiked viruses were not affected by precipitation. The present method may be suitable for the detection of AI viruses from different environmental water sources and can also be applied during outbreak investigations.

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited disposal capacity, and more stringent regulations. Meanwhile, large volumes of freshwater are used for hydraulic fracturing. The goal of this study is to develop cost-effective technologies, and optimize system design and operation to treat highly saline produced water (120&ndash, 140 g/L total dissolved solids) for hydraulic fracturing. Produced water was collected from a salt water disposal facility in the Permian Basin, New Mexico. Chemical coagulation (CC) using ferric chloride and aluminum sulfate as coagulants was compared with electrocoagulation (EC) with aluminum electrodes for removal of suspended contaminants. The effects of coagulant dose, current density, and hydraulic retention time during EC on turbidity removal were investigated. Experimental results showed that aluminum sulfate was more efficient and cost-effective than ferric chloride for removing turbidity from produced water. The optimal aluminum dose was achieved at operating current density of 6.60 mA/cm2 and 12 min contact time during EC treatment, which resulted in 74% removal of suspended solids and 53%&ndash, 78% removal of total organic carbon (TOC). The energy requirement of EC was calculated 0.36 kWh/m3 of water treated. The total operating cost of EC was estimated $0.44/m3 of treated water, which is 1.7 or 1.2 times higher than CC using alum or ferric chloride as the coagulant, respectively. The EC operating cost was primarily associated with the consumption of aluminum electrode materials due to faradaic reactions and electrodes corrosions. EC has the advantage of shorter retention time, in situ production of coagulants, less sludge generation, and high mobility for onsite produced water treatment. The fine particles and other contaminants after coagulation were further treated in continuous-flow columns packed with different filter media, including agricultural waste products (pecan shell, walnut shell, and biochar), and new and spent granular activated carbon (GAC). Turbidity, TOC, metals, and electrical conductivity were monitored to evaluate the performance of the treatment system and the adsorption capacities of different media. Biochar and GAC showed the greatest removal of turbidity and TOC in produced water. These treatment technologies were demonstrated to be effective for the removal of suspended constituents and iron, and to produce a clean brine for onsite reuse, such as hydraulic fracturing.

Treatment of real (RVORW) and synthetic (SVORW) vegetable oil refinery wastewaters using membrane filtration system was experimentally studied. Experimental runs with SVORW were used to identify the best conditions to perform with RVORW treatment. The bench-scale experiment was carried out using a commercial ceramic 0.245 m2 ultrafiltration (UF) membrane (150 kDa) in cross-flow filtration (CFF) mode at a flow rate of 3000 L⋅ h−1 and a trans-membrane pressure (TMP) of 1.2 bars. However, such membrane is vulnerable to fouling and it is insufficient to give water of good quality suitable for reuse. This investigation, aims to improve the purification performances of UF by exploring its combination with other treatment options, i.e. optimized coagulation/flocculation (CF) as pre-treatment and dead-end filtration (DEF) as post-treatment for better treated-water quality. According to the results, when using CF as pre-treatment under optimal conditions (2.4 g⋅L-1of aluminium sulfate, 60.05 mg⋅L-1 of CHT flocculant, under initial pH of 9.23), the hybrid CF/UF process allows to achieve the best treated RVORW water quality with turbidity, COD and TOC removals reaching 100 %, 98 % and 97 % respectively compared to those of CF and UF used separately, with membrane permeability of 135 L⋅ h−1⋅ m-2⋅ bar−1 which is in agreement with an industrial application.

Most of the water supplied in Brazil comes from water streams that may have higher values for apparent color than turbidity. Treatability trials were performed for color and turbidity removal to evaluate the advantages of coagulation during the charge neutralization mechanism when compared to sweep flocculation for water with those characteristics. There were three types of trials: conventional Jar Test with raw water, with and without filtration, and in a pilot Water Treatment Plant, direct downward filtration, with synthetic water. Auxiliary equipment such as Continuous Flocculation Monitoring Equipment (CFME) and image analysis were used to evaluate the growth of flocs. In the Jar Tests experiments, similar levels of color (61.49%) and turbidity (61.30%) removal were observed, with a lower dosage of coagulant (46 mg/L) in the charge neutralization mechanism compared to the ones with sweep flocculation (58.22% for color and 54.73% for turbidity removal with 52 mg/L of aluminium sulfate). Similar results were found on pilot plant. At filtration rates of 180 and 300 m3 m&minus, 2 day&minus, 1, sweep flocculation mechanism had shorter filtration cycle (&lt, 5 m&sup3, ) compared to other mechanisms. Therefore, a change in the operation of Water Treatment plants that use a coagulant dosage associated with sweep flocculation can bring advantages such as the reduction of coagulant consumption and sludge productions, as well as the increase of chlorine disinfection and filtration cycles.

The removal of oil from water is of increasing importance in many industries, such as oil and gas, petrochemical and food industries, because of the large volumes of oily wastewater they produce. The aim of this work is to evaluate and compare the performance of ferrous and aluminium sulfate coagulations and to compare between sand filter, coagulation and a hybrid coagulation/sand filter process when used as pre-treatment options. When the concentration of oil was low in the oil-water emulsion, the treatment by sand filter alone was adequate (oil ≤50 mg/L). On the other hand, when the oil concentration was greater than 50 mg/L, advanced treatments such as coagulation are required as post-processes to reach good water quality. Aluminium sulfate was observed to be more efficient (about 5% to 7% higher than the use of ferrous sulfate) and less costly than ferrous sulfate to remove oil from oil-water emulsion using coagulation. The optimal technology for pre-treatment to remove oil from oil-water emulsion was found to be a coagulant dosage of aluminium sulfate combined with sand filter at pH 8 during various concentrations as hybrid. Optimal conditions were found to occur at mixing duration and speed of 120 s and 250 rpm respectively.

Aluminium salts are widely investigated for the coagulation process for removal of fluoride, but the residual Al above the acceptable limit is the main concern which is mainly due to the formation of soluble and colloidal Al-F complexes of aluminium and fluoride. Hence, it is necessary to investigate the nature and mechanism of formation of colloidal, dissolved and precipitated Al-F complexes and other Al associated species, that govern the concentration of residual Al in the defluoridated water. In the present study, experiments were performed to find the optimized dosage of aluminium sulfate (alum) and polyaluminium (PACl) for removal of fluoride from drinking water. Residual fluoride, turbidity and TDS were found to be 1.3 ppm, 7 NTU & 280 ppm respectively, for alum and 0.48 ppm, 4 NTU & 200 ppm respectively for PACl for initial fluoride concentration of 4 ppm. Residual Al was found to be above the acceptable limit (0.2 ppm), but it was less for PACl as compared to alum, however, after the subsequent microfiltration, residual Al was 0.268 & 0.13 for alum & PACl respectively that almost met the acceptable limit. Characterization of the treated water before and after filtration by using microfiltration membrane was done through electrospray ionization mass spectroscopy (ESI-MS) to identify the colloidal, dissolved Al-F species. Aluminium species in the form AlF52−,AlF2+, AlF4−, Al2(OH)22+, Al(OH)2+, Al(OH)2F2−, AlOHF+ etc. as Al-F were recognised. From the ESI-MS results, it was observed that only a few Al-F complexes with lesser concentrations were formed in case of PACl, which confirmed the fact that PACl worked better for the fluoride removal with low residual Al. The settling of the Al-F complexes for PACl was better than alum due to the difference in flocculation mechanism bridging in case of PACl and sweep flocculation for alum. XRD, SEM & FT-IR analysis of alum and PACl sludge was done to identify the precipitated species.

Results of test coagulation of highly colored Dnieper water by a composite coagulant (CC) obtained by acidizing red mud are presented. It is shown that CC ensures a decrease of basic quality indexes of Dnieper water by 10–20% more effectively than aluminum sulfate (AS). In this case water is contaminated with iron compounds. To lower its concentration it is proposed additionally treat water with ozone, chlorine dioxide or sodium hypochlorite being fed to mixers or flocculation chambers. An alternative way is the use of composition mixture in the form of addition CC to AS in the ratio 1/2–1/1 (in terms of Fe2O3/Al2O3).

In this paper, home-made mullite and mullite–alumina microfiltration membranes fabricated by extrusion and sintering procedures employed in novel microfiltration-powdered activated carbon–coagulation hybrid process for oily wastewater (or oil-in-water emulsion) treatment. Powdered activated carbon and four types of coagulants: aluminum chloride, aluminum sulfate, ferrous chloride and ferrous sulfate plus equal concentration of calcium hydroxide Ca(OH)2 was added to the oily wastewater in the hybrid process. Powdered activated carbon was used as adsorbent agent in all tests. All experiments were performed under the best operating condition of cross-flow velocity = 1.5 m s−1, transmembrane pressure = 3 bar and temperature = 35 °C. Total organic hydrocarbon rejection and permeate flux of membranes for each test were reported and discussed. Hermia’s models for cross-flow microfiltration were used for prediction of permeate flux reduction with time for both membranes in hybrid process. Average errors between experimental and modeling permeate flux were calculated for each model and compared with the other models. Results showed that by using iron salts, total organic hydrocarbon rejection and permeate flux are higher than aluminum salts for both mullite and mullite–alumina membranes. Cake layer formation is dominant fouling mechanism under all coagulant agents and is in good agreement with experimental permeate flux for mullite and mullite–alumina membranes.