Enhanced Silica Removal by Polyamine‐ and Polyacrylamide‐Polyaluminum Hybrid Coagulants

Miranda, Rubén; Latour, Isabel; Hörsken, Arne; Jarabo, Rocío; Blanco, Ángeles

doi:10.1002/ceat.201400604

Cited by 16 publications

(5 citation statements)

References 24 publications

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“…The sporadic rise in EC observed in all the samples tested could be due to the presence of the dissolved ions of the wastewater coupled with the dissolved ions of the coagulants and the pH regulator (NaOH). Similar observations have been made by other researchers [49,50].…”

Section: Effect Of the Coagulants On Electric Conductivitysupporting

confidence: 92%

Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation

Mwewa

Stopić

Ndlovu

et al. 2019

Metals

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The wastes generated from both operational and abandoned coal and metal mining are an environmental concern. These wastes, including acid mine drainage (AMD), are treated to abate the devastating effects they have on the environment before disposal. However, AMD contains valuable resources that can be recovered to subsidize treatment costs. Two of the major constituents of coal AMD are iron and aluminium, which can be recovered and engineered to function as coagulants. This work examines the potential of producing a poly-alumino-ferric sulphate (AMD-PAFS) coagulant from coal acidic drainage solutions. The co-precipitation of iron and aluminium is conducted at pH values of 5.0, 6.0 and 7.0 using sodium hydroxide in order to evaluate the recovery of iron and aluminium as hydroxide precipitates while minimizing the co-precipitation of the other heavy metals. The precipitation at pH 5.0 yields iron and aluminium recovery of 99.9 and 94.7%, respectively. An increase in the pH from 5.0 to 7.0 increases the recovery of aluminium to 99.1%, while the recovery of iron remains the same. The precipitate formed at pH 5.0 is used to produce a coagulant consisting of 89.5% and 10.0% iron and aluminium, respectively. The production of the coagulant is carried out by dissolving the precipitate in 5.0% (w/w) sulphuric acid. Subsequently, the treatment of the brewery wastewater shows that the AMD-PAFS coagulant is as efficient as the conventional poly ferric sulphate (PFS) coagulant. The turbidity removal is 91.9 and 87.8%, while the chemical oxygen demand (COD) removal is 56.0 and 64.0% for AMD-PAFS and PFS coagulants, respectively. The developed process, which can easily be incorporated into existing AMD treatment plants, not only reduces the sludge disposal problems but also creates revenue from waste.

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Section: Effect Of the Coagulants On Electric Conductivitysupporting

confidence: 92%

Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation

Mwewa

Stopić

Ndlovu

et al. 2019

Metals

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“…Polyaluminum chlorides (PACs), as well as polyaluminum nitrate sulfate (PANS), have been extensively used in the last decades for wastewater treatment in the paper industry (Pernitsky and Edzwald 2006;Miranda et al 2009bMiranda et al , 2015. These products can be modified with organic polymers to create inorganic-organic hybrids or composite coagulants, which improve the coagulation performance of the inorganic salts alone due to the synergy between the individual components (Lee et al 2012;Latour et al 2015).…”

Section: Hybrid Coagulantsmentioning

confidence: 99%

Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities

Hubbe

Metts

Hermosilla

et al. 2016

BioRes

183

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The pulp and paper (P&P) industry worldwide has achieved substantial progress in treating both process water and wastewater, thus limiting the discharge of pollutants to receiving waters. This review covers a variety of wastewater treatment methods, which provide P&P companies with costeffective ways to limit the release of biological or chemical oxygen demand, toxicity, solids, color, and other indicators of pollutant load. Conventional wastewater treatment systems, often comprising primary clarification followed by activated sludge processes, have been widely implemented in the P&P industry. Higher levels of pollutant removal can be achieved by supplementary treatments, which can include anaerobic biological stages, advanced oxidation processes, bioreactors, and membrane filtration technologies. Improvements in the performance of wastewater treatment operations often can be achieved by effective measurement technologies and by strategic addition of agents including coagulants, flocculants, filter aids, and optimized fungal or bacterial cultures. In addition, P&P mills can implement upstream process changes, including dissolved-air-flotation (DAF) systems, filtration save-alls, and kidney-like operations to purify process waters, thus reducing the load of pollutants and the volume of effluent being discharged to end-of-pipe wastewater treatment plants. Keywords: Wastewater treatment; Pulp and paper manufacturing; Advanced oxidation; Membrane technologies; Clarification; Activated sludgeContact information: a: North Carolina State University, Dept. of Forest Biomaterials, Campus Box 8005, Raleigh, NC 29695-8005; b: WestRock Company, Water and Waste Treatment, 600 S 8th St, Fernandina Beach, FL 32034; c: Department of Agricultural and Forestry Engineering, University of Valladolid, Campus Duques de Soria, E-42004 Soria, Spain; d: Complutense University of Madrid, Department of Chemical Engineering, Ingn. Quim, Facultad de Ciencias Químicas, Ciudad Universitaria s/n,S-N, E-28040 Madrid, Spain; e: Concordia University, Dept. Bldg. Civil & Environm. Engn., 1455 Maisonneuve Blvd, West Montreal, PQ H3G 1M8, Canada; f: University of Jyväskylä, Dept. Chem., Box 35, FI-40014 Jyväskylä, Finland; g: Department of Biology, Center for Environmental and Marine Studies, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; h: Department of Environment and Planning, Center for Environmental and Marine Studies, CESAM, Aveiro & Department of Materials and Ceramics, Institute of Materials, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal; i: FPInnovations, 570 St. Jean Blvd., Pointe Claire, PQ H9R 3J9, Canada; * Corresponding author: hubbe@ncsu.edu Contents of the Article INTRODUCTIONThe pulp and paper (P&P) industry occupies a challenging position with respect to the natural environment. On the positive side, the industry is based on the usage of renewable, photosynthetic resources. On the other hand, the industry discharges huge quantities of aqueous effluents. Large volumes (up to 70 m 3 ) of wastewater ...

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“…Previous studies have demonstrated that the coagulants with the highest efficiency in removing COD were usually those with the lowest efficiency in silica removal, and vice versa (Hermosilla et al, 2012;Latour et al, 2013;Miranda et al, 2015b). However, the reason for this was not established.…”

Section: Soluble Silicamentioning

confidence: 94%

Understanding the Efficiency of Aluminum Coagulants Used in Dissolved Air Flotation (DAF)

2020

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This paper reports on the efficiency of five aluminum coagulants for the treatment of a paper mill wastewater by dissolved air flotation (DAF). The coagulants studied were: alum, a polyaluminum chloride coagulant of high aluminum content and intermediate basicity (PAC-MB), another with intermediate aluminum content and high basicity (PAC-HB), a polyaluminum nitrate sulfate of intermediate aluminum content and basicity (PANS) and one hybrid coagulant formed by the combination of PANS and a mixture of polyamines (PANS-PA). The influence of Al speciation on contaminants removal and the main flocculation mechanisms involved have been analyzed. High removal of suspended solids together with significant removal of dissolved and colloidal material (COD and silica) were obtained, which is required for extended reuse of this process water. PAC-HB was the best product for removing suspended solids (85%) and soluble silica (50%) with a rather limited COD removal (5%), while PANS-PA obtained high turbidity (90%) and silica removal (45%) together with a significant soluble COD removal (15%). Monomeric Al (Al a , Al m) was more efficient in removing suspended solids and soluble COD than polymeric or colloidal Al (Al c , Al u), but the latter was more efficient in removing soluble silica. Results demonstrated that the main flocculation mechanism varies with the aluminum dosage, being predominantly charge neutralization at low dosages and sweep flocculation at high dosages. The floc strength factor however, was very high and similar for all the coagulants and dosages tested (85-90%), as it was mainly determined by the behavior of the pre-flocculated suspended solids present in wastewater. The reflocculation factor varied from 45 to 75% at the lowest dosages to almost zero at the highest dosages, confirming the transition from charge neutralization to sweep flocculation. The flocs formed by PANS-PA had lower strength than the others and it decreased with the dosage while its reflocculation factor was almost zero, even at low dosages. Due to the polyamines present in this coagulant, its flocculation mechanism is through both charge neutralization and patch formation, especially at low dosages, and sweep flocculation and interparticle bridge formation at high dosages.

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Enhanced Silica Removal by Polyamine‐ and Polyacrylamide‐Polyaluminum Hybrid Coagulants

Cited by 16 publications

References 24 publications

Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation

Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation

Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities

Understanding the Efficiency of Aluminum Coagulants Used in Dissolved Air Flotation (DAF)

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