Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge

2004 ◽  
Vol 50 (9) ◽  
pp. 17-23 ◽  
Author(s):  
B. Park ◽  
J.-H. Ahn ◽  
J. Kim ◽  
S. Hwang
Keyword(s):  
Control System ◽  
Microwave Irradiation ◽  
Biogas Production ◽  
Irradiation Time ◽  
Oxygen Demand ◽  
Volatile Solid ◽  
Anaerobic Digesters ◽  
Secondary Sludge ◽  
Working Volume ◽  
Soluble Chemical Oxygen Demand

This work elucidates the effects of pretreatment of secondary sludge by microwave irradiation on anaerobic digestion. The soluble chemical oxygen demand (COD) concentration increased up to 22% as microwave irradiation time increased, which indicated the sludge particles disintegrated. Three identical automated bioreactors with working volume of 5 l were used as anaerobic digesters at mesophilic temperature (35°C). The reactors were separately fed with sludge with microwave pretreated- and controlsludge at different hydraulic retention times (HRT). The volatile solid (VS) reduction in the control operation was approximately 23.2 ± 1.3%, while it was 25.7 ± 0.8% for the reactors with the pretreated sludge. The average biogas production rate with the pretreated sludge at 8, 10, 12, and 15 days HRTs was 240 ± 11, 183 ± 9, 147 ± 8, and 117 ± 7 ml/l/d respectively, while those with the control sludge were134 ± 12 and 94 ± 7 ml/l/d at 10 and 15 days HRTs. Maximum rates of COD removal and methane production with the pretreated sludge were 64% and 79% higher than those of the control system, respectively.

Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility

2013 ◽  
Vol 69 (2) ◽  
pp. 269-277 ◽  
Author(s):  
C. Da Ros ◽  
C. Cavinato ◽  
F. Cecchi ◽  
D. Bolzonella
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Waste Activated Sludge ◽  
Organic Loading ◽  
Operational Conditions ◽  
Loading Rates ◽  
Thermophilic Conditions ◽  
Soluble Chemical Oxygen Demand

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

scholarly journals Effect of digester F/M ratio on gas production and sludge minimization of ultrasonically treated sludge

2010 ◽  
Vol 62 (7) ◽  
pp. 1510-1517 ◽  
Author(s):  
Gözde T. Köksoy ◽  
F. Dilek Sanin
Keyword(s):  
Oxygen Demand ◽  
Gas Production ◽  
Batch Reactors ◽  
Thermal Methods ◽  
Anaerobic Digesters ◽  
Sludge Pretreatment ◽  
Sludge Minimization ◽  
Effect Of Food ◽  
Soluble Chemical Oxygen Demand ◽  
Sonication Parameters

Sludge pretreatment by mechanical, chemical or thermal methods before anaerobic digestion has been applied to increase the digestability of excess sludge. Pretreatment processes rely on their ability to disrupt cell membranes and to release organic materials from the cells into the aqueous phase. Pretreatment by mechanical disintegration has grown rapidly in recent years in parallel with the advances in technology. Ultrasonic sludge disintegration –one of the most commonly used mechanical pretreatment methods- enables the occurrence of cavitation bubbles for the break-up of microorganism cells to extract intracellular materials. The purpose of this study was to conduct disintegration experiments to optimize sonication parameters and to operate subsequent batch anaerobic digesters to examine the effect of food to microorganism ratio (F/M) in sonicated and unsonicated samples. Results showed that high sonication powers and longer treatment times were effective in sludge disintegration in terms of soluble chemical oxygen demand release. Sonicated sludge digested in batch reactors with higher initial F/M ratio caused higher methane generations, higher sludge reductions and had better dewatering characteristics.

Effect of Ultrasonic Pretreatment for the Anaerobic Digestion of Sewage Sludge

2012 ◽  
Vol 531 ◽  
pp. 528-531 ◽  
Author(s):  
Na Wei
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
High Concentration ◽  
Ultrasonic Pretreatment ◽  
Soluble Chemical Oxygen Demand ◽  
Pre Treatment ◽  
Settling Characteristics

Anaerobic digestion is an economic and environmentally friendly technology for treating the biomass material-sewage sludge, but has some limitations, such as the low efficient biogass production. In this paper ultrasound was proposed as pre-treatment for effective sludge anaerobic digestion. Sludge anaerobic digestion experiments with ultrasonic pretreatment was investigated. It can be seen that this treatment effectively leaded to the increase of soluble chemical oxygen demand(SCOD) and volatile fatty acids(VFA)concentration. High concentration of VFA leaded to a increase in biogas production. Besides, the SV of sludge was reduced and the settling characteristics of sludge was improved after ultrasonic pretreatment. It can be concluded that sludge anaerobic digestion with ultrasonic pretreatment is an effective method for biomass material transformation.

scholarly journals Enhancement anaerobic digestion and methane production from kitchen waste by thermal and thermo-chemical pretreatments in batch  leach bed reactor with down flow

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 128-135 ◽  
Author(s):  
Radmard Seyed Abbas ◽  
Alizadeh Hossein Haji Agha ◽  
Seifi Rahman
Keyword(s):  
Anaerobic Digestion ◽  
Microwave Irradiation ◽  
Methane Production ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Lag Phase ◽  
Kitchen Waste ◽  
Gompertz Equation ◽  
Chemical Pretreatments ◽  
Pretreatment Conditions

The effects of thermal (autoclave and microwave irradiation (MW)) and thermo-chemical (autoclave and microwave irradiation – assisted NaOH 5N) pretreatments on the chemical oxygen demand (COD) solubilisation, biogas and methane production of anaerobic digestion kitchen waste (KW) were investigated in this study. The modified Gompertz equation was fitted to accurately assess and compare the biogas and methane production from KW under the different pretreatment conditions and to attain representative simulations and predictions. In present study, COD solubilisation was demonstrated as an effective effect of pretreatment. Thermo-chemical pretreatments could improve biogas and methane production yields from KW. A comprehensive evaluation indicated that the thermo-chemical pretreatments (microwave irradiation and autoclave- assisted NaOH 5N, respectively) provided the best conditions to increase biogas and methane production from KW. The most effective enhancement of biogas and methane production (68.37 and 36.92 l, respectively) was observed from MW pretreated KW along with NaOH 5N, with the shortest lag phase of 1.79  day, the max. rate of 2.38 l·day<sup>–1</sup> and ultimate biogas production of 69.8 l as the modified Gompertz equation predicted.

Synergistic effect of co-digestion to enhance anaerobic degradation of catering waste and orange peel for biogas production

2017 ◽  
Vol 35 (9) ◽  
pp. 967-977 ◽  
Author(s):  
Muzammil Anjum ◽  
Azeem Khalid ◽  
Samia Qadeer ◽  
Rashid Miandad
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Antimicrobial Agents ◽  
Biogas Production ◽  
Nutrient Balance ◽  
Oxygen Demand ◽  
Orange Peel ◽  
Soluble Form ◽  
Orange Peel Waste ◽  
Soluble Chemical Oxygen Demand

Catering waste and orange peel were co-digested using an anaerobic digestion process. Orange peel is difficult to degrade anaerobically due to the presence of antimicrobial agents such as limonene. The present study aimed to examine the feasibility of anaerobic co-digestion of catering waste with orange peel to provide the optimum nutrient balance with reduced inhibitory effects of orange peel. Batch experiments were conducted using catering waste as a potential substrate mixed in varying ratios (20–50%) with orange peel. Similar ratios were followed using green vegetable waste as co-substrate. The results showed that the highest organic matter degradation (49%) was achieved with co-digestion of catering waste and orange peel at a 50% mixing ratio (CF4). Similarly, the soluble chemical oxygen demand (sCOD) was increased by 51% and reached its maximum value (9040 mg l-1) due to conversion of organic matter from insoluble to soluble form. Biogas production was increased by 1.5 times in CF4 where accumulative biogas was 89.61 m3 t-1substrate compared with 57.35 m3 t-1substrate in the control after 80 days. The main reason behind the improved biogas production and degradation is the dilution of inhibitory factors (limonene), with subsequent provision of balanced nutrients in the co-digestion system. The tCOD of the final digestate was decreased by 79.9% in CF4, which was quite high as compared with 68.3% for the control. Overall, this study revealed that orange peel waste is a highly feasible co-substrate for anaerobic digestion with catering waste for enhanced biogas production.

scholarly journals Comparison between biodegradable polymers from cassava starch and glycerol as additives to biogas production

2016 ◽  
Vol 37 (4) ◽  
pp. 1827 ◽  
Author(s):  
Paulo André Cremonez ◽  
Armin Feiden ◽  
Joel Gustavo Teleken ◽  
Samuel Nelson Melegari de Souza ◽  
Michael Feroldi ◽  
...  
Keyword(s):  
Biodegradable Polymers ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Cassava Starch ◽  
Swine Wastewater ◽  
Batch Reactors ◽  
Total Volatile ◽  
Swine Waste ◽  
Volatile Solids ◽  
Working Volume

In this study, we compared cassava starch-based biodegradable polymers (PBMs) and glycerol (G) as additives used to increase biogas production from the co-digestion of swine wastewater (ARS). We chose to work with an inoculum comprising 40% (v/v) of the total volume of the reactor; this inoculum was obtained from a Canadian model digester for treating swine waste. In the anaerobic digestion process, batch reactors were used on a laboratory scale with a total volume of approximately 4 L and a working volume of 3.2 L. Three treatments were conducted to compare the efficiency of solid removal, the chemical oxygen demand (COD), and the production of biogas. The first treatment contained only swine waste; the second included the addition of glycerol at 1, 3, and 5% (w/v); and the third treatment included the addition of 1, 3, and 5% (w/v) of PBM residue in relation to the swine wastewater. From the results, it can be concluded that higher yields were obtained for the treatment with 3% PBM and 1% glycerol. Most treatments showed high removal rates of total solids and total volatile solids. Reductions lower than 70% were obtained only for treatments with PBM and glycerol at a ratio of 5%.

scholarly journals In Situ Sonification of Anaerobic Digestion: Extended Evaluation of Performance in a Temperate Climate

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5349
Author(s):  
John Loughrin ◽  
Stacy Antle ◽  
Jason Simmons ◽  
Karamat Sistani ◽  
Nanh Lovanh
Keyword(s):  
Control System ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Low Frequency ◽  
Sine Wave ◽  
Temperate Climate ◽  
Anaerobic Digesters ◽  
Environmental Consequences ◽  
The Cost ◽  
Wave Induced

Increasing the efficiency of anaerobic digesters and improving sludge breakdown is vital to reducing the cost of biogas production and reducing the environmental consequences of sludge disposal. The performance of two unheated anaerobic digestion systems, one exposed to sound at <20 kHz by waterproofed speakers and one acting as a control, were compared for over a year. The digester systems were both composed of primary (11.4 m3) and secondary (3.8 m3) anaerobic tanks, facultative tertiary (3.0 m3) tanks and an aerobic holding tank from which effluent was mixed with feed and recirculated back to the system. Exposure of the gas saturated digestate to a low frequency sine wave induced numerous bubble harmonics up to, and presumably beyond, ultrasonic range, showing that sonification of a highly gaseous liquid might be used to accomplish low power ultrasonication of digestate at greater distances than is possible with conventional ultrasonic technology. Through the summer of 2019, the sound-treated system produced 27% more biogas than the control system, and 74 times more during the winter when biogas production by the control systems essentially ceased. Afterwards, the control system produced more biogas due to depletion of volatile solids in the sound-treated digester. Results show that sound can be used for faster digester startup and substitute for a share of heating requirements during cool months.

scholarly journals FOG Waste receiving and processing facility design considerations

2018 ◽  
Vol 13 (1) ◽  
pp. 164-171
Author(s):  
Todd O. Williams ◽  
Dale Gabel ◽  
Dan Robillard
Keyword(s):  
Biogas Production ◽  
Oxygen Demand ◽  
High Strength ◽  
Primary Treatment ◽  
Maximum Energy ◽  
Anaerobic Digesters ◽  
The North ◽  
Chp System ◽  
Processing And Storage ◽  
Number Of Treatment

Abstract Fats, Oils, and Grease (FOG) wastes and high-strength wastes (HSW) are frequently received at municipal water resource recovery facilities (WRRFs) as trucked-in wastes. These wastes offer significant benefits in terms of revenue from tipping fees and feedstock for co-digestion in anaerobic digesters that produce biogas, which can be beneficially used as fuel. The number of treatment plants receiving and beneficially using trucked-in wastes currently in operation or under investigation is increasing rapidly across the North America as utilities strive to remove this material from normal wastewater to avoid sewer system clogging, maintenance and backups, avoid the oxygen demand of these wastes in secondary treatment systems, and to capture and beneficially reuse the energy that is contained within the material. Historically, trucked-in wastes have been discharged to the head end of treatment plants or to an upstream manhole in the incoming interceptor sewer to enable the material to be mixed with raw wastewater prior to treatment through the liquid stream of the WRRF. However, this approach results in loss of material and degradation of the energy value of the FOG wastes and HSW and also creates collection and maintenance issues in the preliminary and primary treatment systems. To prevent degradation of the material and retain maximum energy for the CHP system, receiving stations are being constructed for direct off-loading of the wastes to processing and storage facilities prior to their transfer to anaerobic digesters at a relatively uniform rate to minimize the potential for digester upsets while at the same time to increase biogas production. This paper presents the key components and considerations in the design and operation of modern FOG waste receiving and processing facilities.

scholarly journals Inter-stage thermophilic aerobic digestion may increase organic matter removal from wastewater sludge without decreasing biogas production

2017 ◽  
Vol 77 (3) ◽  
pp. 721-726
Author(s):  
Sasha D. Hafner ◽  
Johan T. Madsen ◽  
Johanna M. Pedersen ◽  
Charlotte Rennuit
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Aerobic Digestion ◽  
Anaerobic Digesters ◽  
Stage System ◽  
Thermophilic Aerobic Digestion ◽  
Pre Treatment

Abstract Combining aerobic and anaerobic digestion in a two-stage system can improve the degradation of wastewater sludge over the use of either technology alone. But use of aerobic digestion as a pre-treatment before anaerobic digestion generally reduces methane production due to loss of substrate through oxidation. An inter-stage configuration may avoid this reduction in methane production. Here, we evaluated the use of thermophilic aerobic digestion (TAD) as an inter-stage treatment for wastewater sludge using laboratory-scale semi-continuous reactors. A single anaerobic digester was compared to an inter-stage system, where a thermophilic aerobic digester (55 °C) was used between two mesophilic anaerobic digesters (37 °C). Both systems had retention times of approximately 30 days, and the comparison was based on measurements made over 97 days. Results showed that the inter-stage system provided better sludge destruction (52% volatile solids (VS) removal vs. 40% for the single-stage system, 44% chemical oxygen demand (COD) removal vs. 34%) without a decrease in total biogas production (methane yield per g VS added was 0.22–0.24 L g−1 for both systems).

Anaerobic waste activated sludge co-digestion with olive mill wastewater

2012 ◽  
Vol 65 (12) ◽  
pp. 2251-2257 ◽  
Author(s):  
E. Athanasoulia ◽  
P. Melidis ◽  
A. Aivasidis
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Olive Mill Wastewater ◽  
System Stability ◽  
Waste Activated Sludge ◽  
Loading Rates ◽  
Soluble Chemical Oxygen Demand ◽  
Continuous Stirred Tank ◽  
Olive Mill

Co-digestion of waste activated sludge (WAS) with agro-industrial organic wastewaters is a technology that is increasingly being applied in order to produce increased gas yield from the biomass. In this study, the effect of olive mill wastewater (OMW) on the performance of a cascade of two anaerobic continuous stirred tank (CSTR) reactors treating thickened WAS at mesophilic conditions was investigated. The objectives of this work were (a) to evaluate the use of OMW as a co-substrate to improve biogas production, (b) to determine the optimum hydraulic retention time that provides an optimised biodegradation rate or methane production, and (c) to study the system stability after OMW addition in sewage sludge. The biogas production rate at steady state conditions reached 0.73, 0.63, 0.56 and 0.46 lbiogas/lreactor/d for hydraulic retention times (HRTs) of 12.3, 14, 16.4 and 19.7 d. The average removal of soluble chemical oxygen demand (sCOD) ranged between 64 and 72% for organic loading rates between 0.49 and 0.75 g sCOD/l/d. Reduction in the volatile suspended solids ranged between 27 and 30%. In terms of biogas selectivity, values of 0.6 lbiogas/g tCOD removed and 1.1 lbiogas/g TVS removed were measured.

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