Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

Chen, Zhan; Zhang, Weijun; Wang, Dongsheng; Ma, Teng; Bai, Runying; Yu, Dawei

doi:10.1016/j.watres.2016.07.018

Cited by 188 publications

(39 citation statements)

References 56 publications

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“…CPAM and the Fenton reaction were combined to condition the sludge to increase the sludge dewatering property. First, the sludge must be oxidized by Fenton's reagent for 60 min prior to adding CPAM . Then, the sludge was flocculated by CPAM at different flocculant dosages and pH values.…”

Section: Methodsmentioning

confidence: 99%

Effective sludge dewatering technique using the combination of Fenton's reagent and CPAM

et al. 2017

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In this study, the combination of Fenton's reagent and cationic polyacrylamide (CPAM) was used in sludge conditioning for the enhancement of sludge dewatering performance. The effects of CPAM, H2O2, and Fe2+ dosages and pH on the moisture content (MC) of the filter cake, the specific resistance of filtration (SRF), and the residual turbidity of the supernatant (RT) were investigated. To observe influencing mechanisms of sludge dewatering further, optical microscopy and scanning electron microscopy (SEM) were employed. Results demonstrated that the sludge dewatering performance obtained by the combination of Fenton's reagent and CPAM was significantly better than that obtained using Fenton's reagent or CPAM alone. The optimum conditions of sludge conditioning were as follows: 400 mg · L−1 Fe2+, 4 g · L−1 H2O2, 40 mg · L−1 CPAM, and pH 4. The SRF, MC, and RT at optimum conditions were reduced to minimum values of 1.06 × 1012 m/kg, 58.9 %, and 3.7, respectively. The optical microscopy and SEM analyses of sludge flocs confirmed that they were more conducive to sludge dewatering after the combination of Fenton oxidation and flocculation. The sludge dewatering results demonstrated that the combination of Fenton and flocculation process exhibited excellent performance in enhancing sludge dewatering and is a promising pretreatment approach to sludge disposal.

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Section: Methodsmentioning

confidence: 99%

Effective sludge dewatering technique using the combination of Fenton's reagent and CPAM

et al. 2017

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“…The management of the waste sludge is confronted with a crucial challenge due to high water content [2]. Therefore, sludge dewatering is regarded as an effective method before handling and disposal.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Sludge Dewaterability by Ultrasound-Initiated Cationic Polyacrylamide with Microblock Structure: The Role of Surface-Active Monomers

et al. 2017

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Cationic polyacrylamides have been employed widely to improve sludge dewatering performance, but the cationic units are randomly distributed in the molecular chain, which restricts the further enhancement of dewaterability. Common template technology to prepare block copolymers requiring a huge number of templates reduces the polymer purity and molecular weight. Here, we adopted the surface-active monomer benzyl dimethyl 2-(methacryloyloxy)ethyl ammonium chloride (BDMDAC) to synthesize cationic microblocky polyacrylamide initiated by ultrasound. The reactivity ratio of monomers suggested that novel cationic monomer BDMDAC had higher homopolymerization ability, and was thus more prone to forming a microblock structure. The statistical analysis of sequence-length distribution indicated that the number and length of cationic segments increased in the PAB molecules. In addition, the characteristic results of Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), and thermogravimetric analysis (TGA) provided evidence for the synthesis of copolymer with cationic microblocks. Finally, the results of dewatering tests demonstrated that sludge dewaterability was greatly improved by adding the synthesized novel flocculants, and the sludge-specific resistance to filtration, filter cake moisture content and residual turbidity all reached a minimum (68.7%, 5.4 × 1012 m·kg−1, and 2.6 NTU, respectively) at 40 mg·L−1. The PAB flocs were large, compact, difficult to break, and easy to regrow. Furthermore, PAB was more effective in the removal of protein from soluble extracellular polymeric substances (SEPSs). In summary, this study provides a novel solution to synthesize cationic microblock polyacrylamide for improving sludge dewatering.

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“…The problem of dehydration difficulties has become the bottleneck of sludge treatment. [5][6][7][8] Hence, it is essential to pretreat the sludge with chemicals prior to mechanical dewatering.…”

Section: Introductionmentioning

confidence: 99%

Formation of cationic hydrophobic micro-blocks in P(AM-DMC) by template assembly: characterization and application in sludge dewatering

et al. 2017

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Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

Cited by 188 publications

References 56 publications

Effective sludge dewatering technique using the combination of Fenton's reagent and CPAM

Effective sludge dewatering technique using the combination of Fenton's reagent and CPAM

Improvement of Sludge Dewaterability by Ultrasound-Initiated Cationic Polyacrylamide with Microblock Structure: The Role of Surface-Active Monomers

Formation of cationic hydrophobic micro-blocks in P(AM-DMC) by template assembly: characterization and application in sludge dewatering

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