A study on combined effect of Fenton and Free Nitrous Acid treatment on sludge dewaterability with ultrasonic assistance: Preliminary investigation on improved calorific value

Menon, Unnikrishna; Suresh, Nanditha; George, Giphin; Ealias, Anu Mary; Saravanakumar, M.P.

doi:10.1016/j.cej.2019.123035

Cited by 42 publications

(8 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the AD process, part of the substrate organic matter content was biodegraded and converted into methane; thus, reducing the lower energy content of the sludge, here determined by the LCV [50]. The highest LCV decrease was observed in TPAD (around 19% with HRT of 19 days), which supported the highest rate of organics transformation into biogas.…”

Section: Elemental Analysis and Lower Calorific Valuementioning

confidence: 85%

Digested Sludge Quality in Mesophilic, Thermophilic and Temperature-Phased Anaerobic Digestion Systems

Lanko

Hejnic

Ambrožová

et al. 2021

Water

View full text Add to dashboard Cite

Anaerobic digestion (AD) technology is commonly used to treat sewage sludge from activated sludge systems, meanwhile alleviating the energy demand (and costs) for wastewater treatment. Most often, anaerobic digestion is run in single-stage systems under mesophilic conditions, as this temperature regime is considered to be more stable than the thermophilic one. However, it is known that thermophilic conditions are advantageous over mesophilic ones in terms of methane production and digestate hygienisation, while it is unclear which one is better concerning the digestate dewaterability. Temperature-phased anaerobic digestion (TPAD) is a double-stage AD process that combines the above-mentioned temperature regimes, by operating a thermophilic digester followed by a mesophilic one. The aim of this study is to compare the digestate quality of single-stage mesophilic and thermophilic AD and TPAD systems, in terms of the dewaterability, pathogenic safety and lower calorific value (LCV) and, based on the comparison, consider digested sludge final disposal alternatives. The research is conducted in lab-scale reactors treating waste-activated sludge. The dewaterability is tested by two methods, namely, centrifugation and mechanical pressing. The experimental results show that the TPAD system is the most beneficial in terms of organic matter degradation efficiency (32.4% against 27.2 for TAD and 26.0 for MAD), producing a digestate with a high dewaterability (8.1–9.8% worse than for TAD and 6.2–12.0% better than for MAD) and pathogenic safety (coliforms and Escherichia coli were not detected, and Clostridium perfringens were counted up to 4.8–4.9 × 103, when for TAD it was only 1.4–2.5 × 103, and for MAD it was 1.3–1.8 × 104), with the lowest LCV (19.2% against 15.4% and 15.8% under thermophilic and mesophilic conditions, respectively). Regarding the final disposal, the digested sludge after TAD can be applied directly in agriculture; after TPAD, it can be used as a fertilizer only in the case where the fermenter HRT assures the pathogenic safety. The MAD digestate is the best for being used as a fuel preserving a higher portion of organic matter, not transforming into biogas during AD.

show abstract

Section: Elemental Analysis and Lower Calorific Valuementioning

confidence: 85%

Digested Sludge Quality in Mesophilic, Thermophilic and Temperature-Phased Anaerobic Digestion Systems

Lanko

Hejnic

Ambrožová

et al. 2021

Water

View full text Add to dashboard Cite

show abstract

“…At present, the standard disposal methods of waste activated sludge (WAS) in wastewater treatment plants (WWTP) are landfilling or incineration after concentration, dewatering, and drying 1 . However, WAS contains plenty of organic matter and nutrients 2,3 . The standard disposal methods are a waste of the resources from WAS and cause high energy consumption and environmental pollution.…”

Section: Introductionmentioning

confidence: 99%

“…1 However, WAS contains plenty of organic matter and nutrients. 2,3 The standard disposal methods are a waste of the resources from WAS and cause high energy consumption and environmental pollution. Anaerobic digestion (AD) is recognized for improving the performance of sludge dewatering and sludge reduction.…”

Section: Introductionmentioning

confidence: 99%

Anaerobic digestion of waste activated sludge to produce volatile fatty acids and release nutrients using sodium citrate with sodium hydroxide pretreatment

Zhou

Fang

Ding

et al. 2022

Env Prog and Sustain Energy

View full text Add to dashboard Cite

This study investigated the synergistic effect of sodium citrate (SC) and sodium hydroxide (NaOH) on the anaerobic digestion (AD) efficiency of waste activated sludge (WAS). Using the amount of SC as the control variable, changes in sludge cell cracking and AD performance under different pretreatment conditions was investigated. The optimum treatment conditions were a NaOH input of initial pH 10 and an SC concentration of 0.20 g/g total suspended solids. The pretreatment was monitored in 150 min. And the changes in soluble chemical oxygen demand (SCOD), soluble polysaccharide, soluble protein, volatile fatty acids (VFAs), PO 4 3À -P and NH 4 + -N during the pretreatment stage and fermentation process were studied. Results show a significant disintegration effect on WAS under optimal pretreatment conditions, with the peak concentration of SCOD, soluble protein, and soluble polysaccharide being 2059.5, 114.86, and 190.97 mg/L, respectively, which means that large amounts of intracellular carbon sources were released. The production of VFAs included acetic acid, propionic acid, isobutyric acid, n-butyric acid, isovaleric acid, and n-valeric acid,

show abstract

“…Advanced oxidation processes (Miklos et al, 2018) like ozone (Quan et al, 2020), Fenton (Gautam et al, 2019;Zhao et al, 2020), and persulfates (Poblete et al, 2019) have been proposed as a solution for the elimination of complex e uents (Joshi and Gogate, 2019;Menon et al, 2020). A successful practice in the use of advanced oxidation technology (AOT S ) is the use and enhancement of the process by the use of oxidants and their activation processes.…”

Section: Introductionmentioning

confidence: 99%

Activation of periodate using ultrasonic waves and UV radiation for landfill leachate treatment

Moradian

Ramavandi

Jaafarzadeh

et al. 2022

Environ Sci Pollut Res

View full text Add to dashboard Cite

Waste leachate contains heavy metals, toxic compounds, and resistant substances such as humic acids, which make its biological decomposition di cult. In the present work, the saline leachate of the coastal city (Bushehr, Iran) was puri ed using the ultraviolet/ultrasonication wave/periodate process. The initial TDS and TOC values of the leachate studied were 7390 mg/L and 975 mg/L, respectively. The effect of various parameters on leachate puri cation was tested and the experiments were optimized at pH 3, oxidizer concentration of 4 mM, and treatment time of 120 min. The initial BOD/COD ratio of 0.66 was reached 0.42 at the end of the reaction. After leachate treatment under optimal conditions, the amount of BOD 5 , COD, and UV 254 were 451.5 mg/L, 1072 mg/L, and 12.69 cm − 1 , respectively. Concentrations of heavy metals in crude leachate by ICP-OES were checked. Also, using GC-Mass, the concentration of organic compounds before and after puri cation was determined. According to the COD factor, the energy consumption of the system designed for leachate treatment was 11.4 kWh/m 3 . The observed results indicate the effectiveness of the UV/US/IO 4 − process for leachate with high salinity.

show abstract

A study on combined effect of Fenton and Free Nitrous Acid treatment on sludge dewaterability with ultrasonic assistance: Preliminary investigation on improved calorific value

Cited by 42 publications

References 95 publications

Digested Sludge Quality in Mesophilic, Thermophilic and Temperature-Phased Anaerobic Digestion Systems

Digested Sludge Quality in Mesophilic, Thermophilic and Temperature-Phased Anaerobic Digestion Systems

Anaerobic digestion of waste activated sludge to produce volatile fatty acids and release nutrients using sodium citrate with sodium hydroxide pretreatment

Activation of periodate using ultrasonic waves and UV radiation for landfill leachate treatment

Contact Info

Product

Resources

About