Poly aluminum chloride (PAC) enhanced formation of aerobic granules: Coupling process between physicochemical–biochemical effects

Liu, Zhe; Liu, Yongjun; Kuschk, Peter; Wang, Jiaxuan; Chen, Yi; Wang, Xiaochang C.

doi:10.1016/j.cej.2015.09.061

Cited by 52 publications

(9 citation statements)

References 41 publications

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“…Aluminum coagulants, a kind of widely used inorganic coagulants in water and wastewater treatment, can be divided into single-molecule aluminum like AlCl 3 ·6H 2 O, Al 2 (SO 4 ) 3 ·18H 2 O, and AlK(SO 4 ) 2 ·12H 2 O and polymer aluminum like polymeric aluminum chloride (PAC), polymeric aluminum ferric sulfate (PAFS), and polymeric aluminum chloride sulfate (PACS) et al − The polymeric aluminum is usually obtained by forced prehydrolysis of single-molecule aluminum, and the main difference between single-molecule aluminum and polymeric aluminum is their different dominant hydrolyzed species in water solution. − There are many hydrolyzed species in aluminum solution that have been identified by scientists, such as Al(OH) 2 + , Al(OH) 2+ , [A1 6 (OH) 15 ] 3+ , [A1 7 (OH) 17 ] 4+ , [AlO 4 Al 12 (OH) 24 (H 2 O) 12 ] 7+ , [Al 16 (OH) 38 ] 10+ , [A1 30 O 8 (OH) 56 (H 2 O) 24 ] 18+ , and [A1 9 (OH) n ] (27– n )+ . − It is usually believed that the single-molecule aluminum solution possesses a large amount of mononuclear and oligomer polymer species Al a , while the medium polymeric species Al b and high polymeric species Al c are the main ingredients in polymeric aluminum solution. In addition, it is generally considered that the coagulation mechanism of single-molecule aluminum and polymeric aluminum has a fundamental difference; otherwise, it is difficult to explain the fact that the coagulation effect of polymeric aluminum doubled that of single-molecule aluminum.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Neutralization Model and Floc Growth Kinetics Properties of Aluminum Coagulants Based on Sips and Boltzmann Equations

Wu¹,

Zhang²,

Zhou

et al. 2017

ACS Appl. Mater. Interfaces

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Single-molecule aluminum salt AlCl, medium polymerized polyaluminum chloride (PAC), and high polymerized polyaluminum chloride (HPAC) were prepared in a laboratory. The characteristics and coagulation properties of these prepared aluminum salts were investigated. The Langmuir, Freundlich, and Sips adsorption isotherms were first used to describe the adsorption neutralization process in coagulation, and the Boltzmann equation was used to fit the reaction kinetics of floc growth in flocculation. It was novel to find that the experimental data fitted well with the Sips and Boltzmann equation, and the significance of parameters in the equations was discussed simultaneously. Through the Sips equation, the adsorption neutralization reaction was proved to be spontaneous and the adsorption neutralization capacity was HPAC > PAC > AlCl. Sips equation also indicated that the zeta potential of water samples would reach a limit with the increase of coagulant dosage, and the equilibrium zeta potential values were 30.25, 30.23, and 27.25 mV for AlCl, PAC, and HPAC, respectively. The lower equilibrium zeta potential value of HPAC might be the reason why the water sample was not easy to achieve restabilization at a high coagulant dosage. Through the Boltzmann equation modeling, the maximum average floc size formed by AlCl, PAC, and HPAC were 196.0, 188.0, and 203.6 μm, respectively, and the halfway time of reactions were 31.23, 17.08, and 9.55 min, respectively. The HPAC showed the strongest floc formation ability and the fastest floc growth rate in the flocculation process, which might be caused by the stronger adsorption and bridging functions of Al and Al contained in HPAC.

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Section: Introductionmentioning

confidence: 99%

Adsorption Neutralization Model and Floc Growth Kinetics Properties of Aluminum Coagulants Based on Sips and Boltzmann Equations

Wu¹,

Zhang²,

Zhou

et al. 2017

ACS Appl. Mater. Interfaces

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“…The reactor was operated at 12 h HRT for acclimatization during this phase. Poly aluminium chloride (PAC) of 50 mL at a concentration of 20 g/L was fed to the AGR only during the start-up phase to enhance the formation of granulation from sludge (Liu et al 2016). The synthetic leachate with a COD of 244±21 mg/L was supplied to the microorganisms during this phase.…”

Section: Operating Methodologymentioning

confidence: 99%

Simultaneous removal of carbon, nitrogen, and phosphorus from landfill leachate using an aerobic granular reactor

Saxena

Padhi

Bhatt

et al. 2021

Preprint

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In this study, aerobic granular reactor (AGR) was used to treat landfill leachate by changing the concentrations of chemical oxygen demand (COD) (668 ± 110–1149 ± 93 mg/L), ammonia (NH3-N) (30 ± 3.3–48 ± 1.3 mg/L), and phosphorus (PO4-P) (147 ± 18–221 ± 17 mg/L). The average COD removal was gradually reduced from 81 to 75%, increasing COD concentrations from 668 ± 110 to 1149 ± 93 mg/L. In phase I, the maximum removal of COD (94%) and NH3-N (85%) were observed at influent concentrations of 668 ± 110 mg/L and 30 ± 3.3 mg/L, respectively. Significant removal of PO4-P was observed, resulting in a maximum of up to 87%, further reducing up to 34% due to an increase in influent PO4-P concentration. The SVI30 reduced from 77 mL/g to 24.15 mL/g towards the end of phase III indicates the formation of granular biomass. The stability of AGR was also investigated in extreme conditions like shut-down and shock-loading phases. The treatment of real leachate diluted with wastewater (~ 20:80% v/v) using AGR showed a significant COD, NH3-N, and PO4-P removal of 62–65%, 61–93%, and 56–64%, respectively. Proteobacteria and Planctomycetes were identified as the predominant (80%) bacterial community in aerobic granules responsible for removing COD, NH3-N, and PO4-P from leachate using AGR. The maximum biodegradation rate (rmax) and half-saturation constant (Ks) in AGR were determined as 123.5 mg/L h and 309 mg/L, respectively.

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“…It is important to emphasize that the coal ash application was performed only once, at the beginning of the operation. This decision was made in the light of the experiment conducted by Liu et al (2016), which demonstrated that the long-term application of PAC in a conventional SBR did not produce significant differences in relation to the short-term application, although both accelerated the granulation in comparison with the control reactor.…”

Section: Inoculum and Feeding Solutionmentioning

confidence: 99%

“…In order to solve these issues, studies have demonstrated that the addition of calcium (JIANG et al, 2003), magnesium (LI et al, 2009, and polyaluminum chloride (PAC) (LIU et al, 2016) can lead to a faster granulation, thus improving sludge settleability. Supplementation with dried sludge micropowder also proved beneficial to granule stability, having eliminated extended filaments through several mechanisms, such as collision and friction against granules, which stimulate extracellular polymeric substances (EPS) secretion (LIU et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Effects of coal ash supplementation on aerobic granular sludge cultivated in a simultaneous fill/draw sequencing batch reactor

Barros

Carvalho

Rollemberg

et al. 2020

Eng. Sanit. Ambient.

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This study aimed to verify if coal ash, a residue from thermal power plants, could act as a granulation nucleus, cations source, and abrasive element to favor granules formation and stability in aerobic granular sludge (AGS) systems. Two simultaneous fill/draw sequencing batch reactors (SBRs) (R1 and R2) were operated with 6-h cycles, i.e., the filling and drawing phases occurred simultaneously, followed by the reaction and settling phases. R1 was maintained as control, while R2 was supplemented with coal ash (1 g·L-1) on the first day of operation. Granulation was achieved in both reactors, and no significant differences were observed in terms of settleability, biomass retention, morphology, resistance to shear, and composition of the EPS matrix. However, the ash addition did not change the settleability, biomass retention, granule morphology, shear resistance, and extracellular polymeric substances (EPS) content significantly. COD removal was high (≥ 90%), while nitrogen (~50%) and phosphorus (~40%) removals were low, possibly due to the presence of nitrate during the anaerobic phase. With granulation, microbial population profile was altered, mainly at the genus level. In general, the operational conditions had a more considerable influence over granulation than the ash addition. The possible reasons are because the ash supplementation was performed in a single step, the low sedimentation rate of this particular residue, and the weak interaction between the ash and the EPS formed in the granular sludge. These factors appear to have decreased or prevented the action of the ash as granulation nucleus, source of cations, and abrasive element.

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Poly aluminum chloride (PAC) enhanced formation of aerobic granules: Coupling process between physicochemical–biochemical effects

Cited by 52 publications

References 41 publications

Adsorption Neutralization Model and Floc Growth Kinetics Properties of Aluminum Coagulants Based on Sips and Boltzmann Equations

Adsorption Neutralization Model and Floc Growth Kinetics Properties of Aluminum Coagulants Based on Sips and Boltzmann Equations

Simultaneous removal of carbon, nitrogen, and phosphorus from landfill leachate using an aerobic granular reactor

Effects of coal ash supplementation on aerobic granular sludge cultivated in a simultaneous fill/draw sequencing batch reactor

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