Low temperature microwave and conventional heating pre-treatments to improve sludge anaerobic biodegradability

2013 ◽  
Vol 69 (3) ◽  
pp. 518-524 ◽  
Author(s):  
P. Vergine ◽  
J. Zábranská ◽  
R. Canziani
Keyword(s):  
Low Temperature ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Cost Effective ◽  
Conventional Heating ◽  
Waste Activated Sludge ◽  
Experimental Conditions ◽  
Primary Sludge ◽  
Batch Tests ◽  
Pre Treatment

This paper presents the results of lab-scale experiments on low temperature thermal pre-treatment (less than 100 °C) prior to anaerobic digestion of sewage sludge. Two heating ways, microwave heating (MH) and conventional heating (CH), and two types of sludge, primary and waste activated sludge, were compared under the same experimental conditions. The degree of solubilisation produced by MH and CH up to 72, 82 and 93 °C was firstly estimated. For both types of heating, increase in soluble chemical oxygen demand (COD) caused by the pre-treatment was about 14% on waste activated sludge and only 3% on primary sludge. The final temperature of 72 °C resulted as the most cost-effective in terms of additional soluble COD per unit of energy required. Subsequently, five series of biochemical methane potential mesophilic assays were run in 120 mL serum bottles on sludge samples pre-treated at 72 °C. When compared with control reaction vessels, no significant differences were noticed in net methane production of pre-treated primary sludge, whereas a relevant increase occurred regarding the pre-treated waste activated sludge. It was also observed that the trend of methane content in biogas during the batch tests can be described by a second order polynomial.

scholarly journals Process Optimization of Waste Activated Sludge in Anaerobic Digestion and Biogas Production by Electrochemical Pre-Treatment Using Ruthenium Oxide Coated Titanium Electrodes

2021 ◽  
Vol 13 (9) ◽  
pp. 4874
Author(s):  
Gan Chin Heng ◽  
Mohamed Hasnain Isa ◽  
Serene Sow Mun Lock ◽  
Choon Aun Ng
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Chemical Oxygen Demand ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Ruthenium Oxide ◽  
Parameters Optimization ◽  
Waste Activated Sludge ◽  
Capillary Suction ◽  
Pre Treatment

Anaerobic digestion (AD) appears to be a popular unit operation in wastewater treatment plant to treat waste activated sludge (WAS) and the produced methane gas can be harvested as renewable energy. However, WAS could inhibit hydrolysis stage during AD and hence pre-treatment is required to overcome the issue. This paper aimed to study the effect of electrochemical pre-treatment (EP) towards efficiency of AD using titanium coated with ruthenium oxide (Ti/RuO2) electrodes. The investigation has been carried out using in-house laboratory batch-scale mesophilic anaerobic digester, mixed under manipulation of important operating parameters. Optimization was performed on EP using response surface methodology and central composite design to maximize sludge disintegration and dewaterability. By operating at optimal conditions (pH 11.65, total solids 22,000 mg/L, electrolysis time 35 min, current density 6 mA/cm2, and 1000 mg/L of sodium chloride), the pre-treated WAS in terms of mixed liquor volatile suspended solids (MLVSS) removal, soluble chemical oxygen demand (sCOD), capillary suction time (CST) reduction, and extracellular polymeric substance (EPS) were 38%, 4800 mg/L (increased from 935 mg/L), 33%, and 218 mg/L, respectively. Following AD, the volatile solids (VS) removal and chemical oxygen demand (COD) removal by EP were enhanced from 40.7% and 54.7% to 47.2% and 61.5%, respectively, at steady-state. The biogas produced from control and electrochemical pre-treated WAS were in the ranges of 0.12 to 0.17 and 0.2 to 0.24 m3/kg VSfed, respectively, and the volume of biogas produced was 44–67% over the control. Based on the results obtained, suitability of EP for WAS prior to AD was confirmed.

scholarly journals Effect of pH and hydraulic retention time on volatile fatty acids production from real waste in dark fermentation process

2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan
Keyword(s):  
Fatty Acids ◽  
Activated Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Carbon Substrate ◽  
Primary Sludge

Waste-derived volatile fatty acids (VFAs) is an important carbon substrate for microorganisms engaged in the production of bioenergy, biodegradable plastics, and biological nutrient removal process. In this project, the generation and applications of waste-derived VFA were examined. Three solid wastes were used Primary sludge (PS), thickened waste activated sludge (TWAS) which were collected from Ashbridges Bay and source separated organics (SSO) that was collected from Disco Road facility. All the water quality analyses such as pH, TCOD, SCOD, TVFA, TSS, VSS, NH3 and, alkalinity were monitored. The results of this study showed that with increasing the Hydraulic retention time (HRT), the percentage of acidification increased. Furthermore, the results showed that alkaline pH was better than the acid pHs. Keywords: Total Volatile Fatty Acids, Soluble Chemical Oxygen Demand, Primary Sludge, Thickened Waste Activated Sludge, Source Separated Organics.

scholarly journals The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 482
Author(s):  
Anna Remiszewska-Skwarek ◽  
Ryszard Wierzchnicki ◽  
Otton K. Roubinek ◽  
Archana Kasinath ◽  
Alicja Jeżewska ◽  
...  
Keyword(s):  
Low Temperature ◽  
Activated Sludge ◽  
Fermentation Process ◽  
Biogas Production ◽  
Correlation Coefficients ◽  
Gompertz Model ◽  
Waste Activated Sludge ◽  
Distillation Residue ◽  
Accumulation Curves ◽  
Pre Treatment

Innovative low-temperature disintegration (process temperature 55 °C and oxygen concentration 0.2 mg/dm3) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation residue and waste-activated sludge before the co-fermentation process increased biogas production by 30% and methane production by 65% (over a 26 d duration). The obtained results confirm that the low-temperature disintegration method can be effectively used to pre-prepare this type of feed. At the same time, it was discovered that the Gompertz model can be used to mathematically describe the biogas accumulation curves in the methane co-fermentation processes of the tested feeds (the correlation coefficients were higher than 0.98).

scholarly journals Effect of Thermal Hydrolysis Pretreatment on Solubilization of Primary Sludge and Thickened Waste Activated Sludge (TWAS) During Dark Fermentation Process

2021 ◽  
Author(s):  
Alborz Mahmoudi
Keyword(s):  
Activated Sludge ◽  
Fermentation Process ◽  
Continuous Fermentation ◽  
Reduction Rate ◽  
Treatment Temperature ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Primary Sludge ◽  
Treated Sample ◽  
Pre Treatment

The objective of this research was to evaluate the effect of thermal hydrolysis pre-treatment on the solubilization of primary sludge (PS) and thickened waste activated sludge (TWAS) through the semi-continuous fermentation process under the mesophilic conditions. For this measure, the inoculum (anaerobic digestate), Primary Sludge (PS) and Thickened waste activated Sludge (TWAS) was subjected to the pre-treatment condition. The pre-treatment temperature ranged from 20°C to170°C. Then both raw and pre-treated sample was introduced the semi-continuous reactors for the fermentation process. The degree of solubilization was achieved 18% for raw (unpretreated sample) and 38% for the pre-treated sample. Moreover, the volatile suspended solids (VSS) reduction rate for the raw and pre-treated sample was 24% and 50% respectively. Additionally, the soluble COD production yield for the raw and pre-treated sample was obtained 247 mg COD/g VSS and 544 mg COD/g VSS correspondingly. Keywords: Fermentation process, Anaerobic digestion, Thermal hydrolysis pretreatment.

scholarly journals Effect of pH and hydraulic retention time on volatile fatty acids production from real waste in dark fermentation process

2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan
Keyword(s):  
Fatty Acids ◽  
Activated Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Carbon Substrate ◽  
Primary Sludge

Waste-derived volatile fatty acids (VFAs) is an important carbon substrate for microorganisms engaged in the production of bioenergy, biodegradable plastics, and biological nutrient removal process. In this project, the generation and applications of waste-derived VFA were examined. Three solid wastes were used Primary sludge (PS), thickened waste activated sludge (TWAS) which were collected from Ashbridges Bay and source separated organics (SSO) that was collected from Disco Road facility. All the water quality analyses such as pH, TCOD, SCOD, TVFA, TSS, VSS, NH3 and, alkalinity were monitored. The results of this study showed that with increasing the Hydraulic retention time (HRT), the percentage of acidification increased. Furthermore, the results showed that alkaline pH was better than the acid pHs. Keywords: Total Volatile Fatty Acids, Soluble Chemical Oxygen Demand, Primary Sludge, Thickened Waste Activated Sludge, Source Separated Organics.

scholarly journals Pre-treatment of thickened waste activated sludge (TWAS) for enhanced biogas production via the application of a novel radial horn sonication technology

2017 ◽  
Vol 75 (9) ◽  
pp. 2179-2193 ◽  
Author(s):  
Sri Suhartini ◽  
Lynsey Melville ◽  
Tony Amato
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Applied Pressure ◽  
Low Frequency ◽  
Waste Activated Sludge ◽  
Biochemical Methane Potential ◽  
Experimental Conditions ◽  
Working Volume ◽  
Methane Potential ◽  
Pre Treatment

The efficacy of sonication as a pre-treatment to anaerobic digestion (AD) was assessed using thickened waste activated sludge (TWAS). Efficiency was measured in relation to solubilisation, dewaterability, and AD performance. Eighteen experimental conditions were evaluated at low frequency (20 kHz), duration (2–10 s), amplitude (∼8–12 μm) and applied pressure (0.5–3.0 barg), using a sonix™ patented titanium sonoprobe capable of delivering an instantaneous power of ∼6 kW provided by Doosan Enpure Ltd (DEL). An optimised experimental protocol was used as a pre-treatment for biochemical methane potential (BMP) testing and semi-continuous trials. Four digesters, with a 2-L working volume were operated mesophilically (37 ± 0.5 °C) over 22 days. The results showed that the sonix™ technology delivers effective sonication at very short retention times compared to conventional system. Results demonstrate that the technology effectively disrupts the floc structures and filaments within the TWAS, causing an increase in solubilisation and fine readily digestible material. Both BMP tests and semi-continuous trials demonstrated that sonicated TWAS gave higher biodegradability and methane potential compared to untreated TWAS. Partial-stream sonication (30:70 sonicated to untreated TWAS) resulted in a proportionate increase in biogas production illustrating the benefits of full-stream sonication.

scholarly journals Effect of Thermal Hydrolysis Pretreatment on Solubilization of Primary Sludge and Thickened Waste Activated Sludge (TWAS) During Dark Fermentation Process

2021 ◽  
Author(s):  
Alborz Mahmoudi
Keyword(s):  
Activated Sludge ◽  
Fermentation Process ◽  
Continuous Fermentation ◽  
Reduction Rate ◽  
Treatment Temperature ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Primary Sludge ◽  
Treated Sample ◽  
Pre Treatment

The objective of this research was to evaluate the effect of thermal hydrolysis pre-treatment on the solubilization of primary sludge (PS) and thickened waste activated sludge (TWAS) through the semi-continuous fermentation process under the mesophilic conditions. For this measure, the inoculum (anaerobic digestate), Primary Sludge (PS) and Thickened waste activated Sludge (TWAS) was subjected to the pre-treatment condition. The pre-treatment temperature ranged from 20°C to170°C. Then both raw and pre-treated sample was introduced the semi-continuous reactors for the fermentation process. The degree of solubilization was achieved 18% for raw (unpretreated sample) and 38% for the pre-treated sample. Moreover, the volatile suspended solids (VSS) reduction rate for the raw and pre-treated sample was 24% and 50% respectively. Additionally, the soluble COD production yield for the raw and pre-treated sample was obtained 247 mg COD/g VSS and 544 mg COD/g VSS correspondingly. Keywords: Fermentation process, Anaerobic digestion, Thermal hydrolysis pretreatment.

Evaluation of non-thermal effects by microwave irradiation in hydrolysis of waste-activated sludge

2014 ◽  
Vol 70 (4) ◽  
pp. 742-749 ◽  
Author(s):  
I. G. Byun ◽  
J. H. Lee ◽  
J. M. Lee ◽  
J. S. Lim ◽  
T. J. Park
Keyword(s):  
Microwave Irradiation ◽  
Activated Sludge ◽  
Thermal Effect ◽  
Oxygen Demand ◽  
Conventional Heating ◽  
Waste Activated Sludge ◽  
Molecular Formula ◽  
First Order Kinetics ◽  
Soluble Chemical Oxygen Demand ◽  
Hydrolysis Of

The activation energy (Ea) for waste-activated sludge (WAS) hydrolysis was compared between microwave irradiation (MW) and conventional heating (CH) methods to evaluate the non-thermal effect of MW. The microwave-assisted hydrolysis of WAS was assumed to follow the first-order kinetics on the basis of volatile suspended solids (VSS) conversion to soluble chemical oxygen demand (SCOD) for different initial VSS concentrations. By comparing the VSS decrement and the SCOD increment between MW and CH at different absolute temperatures of 323, 348 and 373 K, the average ratio of VSS conversion to SCOD was determined to range from 1.42 to 1.64 g SCOD/g VSS. These results corresponded to the theoretical value of 1.69 g SCOD/g VSS based on the assumption that the molecular formula of sludge was C10H19O3N. Consequently, the Ea of the MW-assisted WAS hydrolysis was much lower than that of CH for the same temperature conditions. The non-thermal effect of MW in the hydrolysis of WAS could be identified with the lower Ea than that of CH.

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