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

Abstract

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.

Enhanced Dewatering of Activated Sludge by Skeleton-Assisted Flocculation Process

“…The changing trends of the filter cake pH and sludge pH were consistent with the addition of PFS alone, but the pH of sludge and pH of filtrate after PFS conditioning in combination with fly ash were greater than those after PFS conditioning alone. This phenomenon shows that PFS adsorbs hydroxyl groups from the solution to make the sludge acidic, and the calcium silicate and anorthite in the fly ash can neutralize a certain acidity after dissolving in water, which will affect the sludge pH and pH of the sludge can increase filtrate [ 27 ]. After considering the three indicators of SRF, sludge cake moisture content, and filtrate COD, the optimal PFS dosage became 200 mg/g DS.…”

Synergetic Effect of Organic Flocculant and Montmorillonite Clay on the Removal of Nano-CuO by Coagulation-Flocculation-Sedimentation Process

“…The effect of nano-CuO destabilization was enhanced by increasing the solution pH following the addition of PAFC; however, the tiny flocs remained suspended in the solution [ 30 ]. The compounding process of PAFC/PAM was relatively more stable than PAFC and PAM alone due to the wider pH adaptation range of organic flocculant (PAM) [ 31 , 32 ]. Moreover, the complex structure of the PAFC/PAM polymer remarkably enhanced the flocculant-specific surface area and improved the bridging effect during adsorption [ 32 ].…”

“…The compounding process of PAFC/PAM was relatively more stable than PAFC and PAM alone due to the wider pH adaptation range of organic flocculant (PAM) [ 31 , 32 ]. Moreover, the complex structure of the PAFC/PAM polymer remarkably enhanced the flocculant-specific surface area and improved the bridging effect during adsorption [ 32 ]. Consequently, the combination of inorganic and organic flocculants had a synergistic effect on the C/F/S process and on the overall nano-CuO removal performance from the aquatic environment.…”

Occurrence and removal of engineered nanoparticles in drinking water treatment and wastewater treatment processes: A review

“…When the concentration exceeded the optimal critical point, the removal effect of PAFC considerably decreased, whereas that of PAFC/CPAM remained relatively stable. Generally, the removal effect of TiO 2 -NPs at a high initial mass concentration exceeded that of TiO 2 -NPs at a low initial mass concentration [82]. Under the same flocculation conditions, the addition of kaolin improved the removal rate of the two NP materials.…”