Improved sludge dewaterability and hydrolysis performance after pretreatment with Fenton's reagent

Abstract

The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe and 5.0 g/L of HO were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 10 m/kg to 6.49 × 10 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: HO > pH > Fe > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH-N) and phosphate (PO-P) released from the sludge showed different trends: NH-N increased by 200%, while PO-P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.

Research on the Promotion of Sludge Anaerobic Fermentation with Sodium Citrate under Low Concentrations of Polyaluminum Chloride

“…The sludge dewatering performance also determines the sludge anaerobic fermentation performance [27]. Generally, the specific resistance (SRF) of sludge is used as a key indicator for studying dewatering performance [28]. The effect of different concentrations of SC on the dewatering performance of sludge is shown in Figure 8.…”

Excess secondary sludge reuse by H2O2 thermal dehydration

“…Substances like persulfate (Chen et al 2021 ; Ruan et al 2021 ), peroxymonosulfate (Li et al 2018 ), hydrogen peroxide (Abelleira et al 2012b ), CaCl 2 (Guan et al 2012 ; Yu et al 2014 ), cations, acids, and alkalis (Neyens and Baeyens 2003 ) have been used in the past. In the particular case of hydrogen peroxide, this oxidant has preferentially been used in Fenton like systems at ambient temperature (Ferrentino et al 2020 ; Liu et al 2022b ; Yu et al 2019 ; Yuan et al 2018 ). Surprisingly, the number of studies using the thermal decomposition of H 2 O 2 in sewage sludge dewatering is rather low (Abelleira et al 2012b ; Cacho Rivero and Suidan 2006 ; Genç et al 2002b ; Takashima and Tanaka 2008 ; Zhang et al 2020 ).…”