ADM1 performance using SS-OFMSW with non-acclimated inoculums

2012 ◽  
Vol 66 (9) ◽  
pp. 1885-1892 ◽  
Author(s):  
M. El-Fadel ◽  
R. Maroun ◽  
R. Bou Fakher Eldeen ◽  
S. Ghanimeh
Keyword(s):  
Feeding Rate ◽  
General Trend ◽  
Oxygen Demand ◽  
Gas Production ◽  
Organic Fraction ◽  
Anaerobic Digesters ◽  
Start Up ◽  
Acclimation Period ◽  
Soluble Chemical Oxygen Demand ◽  
The Mathematical Model

This paper assesses the anaerobic digestion (AD) of the source-sorted organic fraction of municipal solid waste (SS-OFMSW). For this purpose, an experimental programme was implemented involving the operation and monitoring of two bench-scale anaerobic digesters, continuously fed with SS-OFMSW. The mathematical model (ADM1) was then applied to simulate the process of AD of SS-OFMSW. While start-up of the digesters was relatively slow, re-inoculation with cattle manure with effluent dilution reduced the acclimation period and achieved better stability, accommodating a feeding rate at an OLR = 2.39 kg TVS m−3 day−1. The high recorded methane gas production rate, reaching (0.1–2.5 m3 CH4/m3 reactor day), confirms the excellent biodegradability of the type of waste used (SS-OFMSW) and its suitability for AD. Satisfactory simulations of soluble chemical oxygen demand (COD), pH, and methane composition of biogas were obtained, whereas volatile fatty acid (VFA) concentrations in both reactors were over-predicted albeit capturing its general trend.

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.

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.

Fast Digester Start-Up under Mesophilic Conditions Using Thermophilic Inoculum

1992 ◽  
Vol 25 (4-5) ◽  
pp. 391-398 ◽  
Author(s):  
F. Cecchi ◽  
P. Pavan ◽  
J. Mata-Alvarez
Keyword(s):  
Solid Wastes ◽  
Organic Fraction ◽  
Municipal Solid Wastes ◽  
Anaerobic Digesters ◽  
Steady State Condition ◽  
Start Up ◽  
Thermophilic Conditions ◽  
Fast Start ◽  
Biological Wastes ◽  
Mesophilic Conditions

The paper deals with fast procedures adopted for starting-up anaerobic digesters treating biological wastes. In particular, results related to the behaviour of a digester treating sewage sludge with a fast start-up (in 22 days) and using a thermophilic inoculum are presented and compared with those related to a passage from mesophilic to thermophilic temperatures (from 37 to 55°C, in 31 days) and to a direct re-start-up under thermophilic conditions (27 days). In the latter cases, the organic fraction of municipal solid wastes was digested. Main findings concern: the identification of two retention times as the necessary period for reaching the first steady-state condition; the usefulness of performing a real time process monitoring the observation that thermophilic inoculum allows better digester performances in the first start-up period, a finding however, that requires more experimental work.

scholarly journals Energetic Valorization of Cereal and Exhausted Coffee Wastes Through Anaerobic Co-digestion With Pig Slurry

2021 ◽  
Vol 5 ◽  
Author(s):  
Sílvia Sousa ◽  
Elizabeth Duarte ◽  
Marta Mesquita ◽  
Sandra Saraiva
Keyword(s):  
Chemical Oxygen Demand ◽  
Feeding Rate ◽  
Synergetic Effect ◽  
Oxygen Demand ◽  
Microbial Consortia ◽  
Reference Scenario ◽  
Pig Slurry ◽  
Significant Difference ◽  
Soluble Chemical Oxygen Demand ◽  
Continuously Stirred Tank Reactor

In the past years, there has been steady growth in work relating to improve resource efficiency through waste minimization and bioenergy recovery to mitigate climate change. Agro-food industries produce large amounts of bio-waste, challenging innovative energetic valorization strategies in the framework of circular economy principles. Anaerobic digestion (AD) technology is an interesting route to stabilize organic matter and produce biogas as a renewable energy source. This study involves continuous co-digestion of pig slurry (PS), cereal and exhausted coffee wastes (CECW) performed in a continuously stirred tank reactor, with a hydraulic retention time (HRT) of 16 days under at mesophilic conditions (36.9 ± 0.3°C). The experimental trials, were designed to include different cereal and exhausted coffee liquor (CECL) shares in the feeding mixture, corresponding to different PS to CECL ratios (PS:CECL), respectively: 100:0 (T0), 90:10 (T1), 80:20 (T2), and 70:30 (T3), in terms of percentage of inlet feeding rate (v:v). The results obtained for the feeding rate (70:30) yield to the highest specific methane production (SMP = 341 ml.gVS−1) led to a 3.5-fold improvement in comparison with the reference scenario. The synergetic effect between the microbial consortia of PS and the high carbon to nitrogen ratio (C/N) of CECL explain the improvements achieved. The maximum soluble chemical oxygen demand (SCOD) reduction (84.0%) due to the high content and soluble chemical oxygen demand to total chemical oxygen demand ratio (SCOD/TCOD) corroborate the results achieved. The digester stability, evaluated by specific energetic loading rate, was below the limit (0.4 d−1). Results from ANOVA showed a significant effect of CECL on the resulting GPR and SMP values. Additionally, Tukey's “Honest Significant Difference” method, confirmed statistically significant differences between the trials T3-T0, T3-T1, T3-T2, and T2-T0. Thus, co-digestion of PS and of CECL seems to be a promising approach for bioenergy recovery and promoting biowastes circularity.

Experimental Study on the Rapid Start-Up of Two-Phase Anaerobic Reactor Treating Domestic Sewage

2013 ◽  
Vol 448-453 ◽  
pp. 589-595
Author(s):  
Zhi Li Chen ◽  
Zhen Jie Ren ◽  
Yang Yao ◽  
Yi Yang ◽  
Wan Tu Zhang
Keyword(s):  
Loading Rate ◽  
Kinetic Method ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Gas Production ◽  
Two Phase ◽  
Anaerobic Reactor ◽  
Start Up ◽  
Volumetric Loading ◽  
Chemical Oxygen Demand Concentration

An integrated two-phase anaerobic reactor was designed to treat domestic sewage, and the corresponding start-up process was investigated.In this investigation, the volumetric loading rate ( VLR) of the system was raised by basically maintaining the influent COD ( Chemical Oxygen Demand) concentration and gradually decreasing the hydraulic retention time (HRT) at 35°C，and the start-up process was completed only in the 36 days. When the Influent pH was kept in the range of 7.39 ~ 7.67，the acidogenic phase and the methanogenic phaseof integrated two-phase anaerobic reactor were separated only by using the kinetic method. After completing this process, the reactor operated well with VLR at 1.31 kg / ( m3·d) and HRT at about 7h, and a COD removal of more than 80%,a SS removal of about 90% and a gas production rate of about 0.31L/h were respectively achieved.

Use of Combined NaOH-Microwave Pretreatment for Enhancing Mesophilic Anaerobic Digestibility of Thickened Waste Activated Sludge

2010 ◽  
Vol 113-116 ◽  
pp. 459-468 ◽  
Author(s):  
Yong Zhi Chi ◽  
Yu You Li ◽  
Min Ji ◽  
Hong Qiang ◽  
Heng Wei Deng ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Uniform Design ◽  
Oxygen Demand ◽  
Holding Time ◽  
Waste Activated Sludge ◽  
Methane Potential ◽  
Soluble Chemical Oxygen Demand ◽  
Anaerobic Digestibility ◽  
Relationship Of ◽  
The Mathematical Model

A combined NaOH-microwave (MW) pretreatment process was studied in order to investigate the effects of NaOH-MW pretreated thickened waste activated sludge (TWAS) on anaerobic digestion. In the NaOH-MW pretreatment studies, Uniform design was successfully applied to determine the relationship of TWAS solubilization to environmental conditions (NaOH dose, target temperature, and MW holding time) and to establish the mathematical model describing the solubilization degree to changes in these variables. The maximum solubilization ratio (85.1%) of volatile suspended solids (VSS) could be achieved at 210°C with 0.2 g-NaOH/g-SS and 35 min holding time. The biochemical methane potential (BMP) tests showed that all digesters fed with pretreated TWAS improved the methane production compared to control system, and the optimal conditions, at 170°C with 0.05 g-NaOH/g-SS and 1 min holding time, were suggested for NaOH-MW pretreatment of TWAS. In spite of the increase in the soluble chemical oxygen demand concentration and decrease in the dewaterability of digested sludge, the semi-continuous reacter fed with the pretreated TWAS without neutralization was stable and gave higher organics reductions and methane yields compared to the control.

scholarly journals The Start-Up of Continuous Biohydrogen Production from Cheese Whey: Comparison of Inoculum Pretreatment Methods and Reactors with Moving and Fixed Polyurethane Carriers

2021 ◽  
Vol 11 (2) ◽  
pp. 510
Author(s):  
Elza R. Mikheeva ◽  
Inna V. Katraeva ◽  
Andrey A. Kovalev ◽  
Dmitriy A. Kovalev ◽  
Alla N. Nozhevnikova ◽  
...  
Keyword(s):  
Cheese Whey ◽  
Hydraulic Retention Time ◽  
Continuous Production ◽  
Oxygen Demand ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Acid Pretreatment ◽  
Methanogenic Activity ◽  
Start Up ◽  
Load Rate

This article presents the results of the start-up of continuous production of biohydrogen from cheese whey (CW) in an anaerobic filter (AF) and anaerobic fluidized bed (AFB) with a polyurethane carrier. Heat and acid pretreatments were used for the inactivation of hydrogen-scavengers in the inoculum (mesophilic and thermophilic anaerobic sludge). Acid pretreatment was effective for thermophilic anaerobic sludge to suppress methanogenic activity, and heat treatment was effective for mesophilic anaerobic sludge. Maximum specific yields of hydrogen, namely 178 mL/g chemical oxygen demand (COD) and 149 mL/g COD for AFB and AF, respectively, were obtained at the hydraulic retention time (HRT) of 4.5 days and organic load rate (OLR) of 6.61 kg COD/(m3 day). At the same time, the maximum hydrogen production rates of 1.28 and 1.9 NL/(L day) for AF and AFB, respectively, were obtained at the HRT of 2.02 days and OLR of 14.88 kg COD/(m3 day). At the phylum level, the dominant taxa were Firmicutes (65% in AF and 60% in AFB), and at the genus level, Lactobacillus (40% in AF and 43% in AFB) and Bifidobacterium (24% in AF and 30% in AFB).

scholarly journals Application of Ozone and Oxygen to Reduce Chemical Oxygen Demand and Hydrogen Sulfide from a Recovered Paper Processing Plant

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Patricia A. Terry
Keyword(s):  
Hydrogen Sulfide ◽  
Chemical Oxygen Demand ◽  
Contact Time ◽  
Oxygen Demand ◽  
Gas Production ◽  
Injection System ◽  
Processing Plant ◽  
Short Contact Time ◽  
Production Of Hydrogen ◽  
Fox River

A pilot study was performed at the Fox River Fiber recovered paper processing company in DePere, Wisconsin, to determine the extent to which injection of oxygen and ozone could reduce the high chemical oxygen demand, COD, in the effluent and the effectiveness of the ozone/oxygen stream in suppressing production of hydrogen sulfide gas in downstream sewage lines. Adaptive Ozone Solutions, LLC, supplied the oxygen/ozone generation and injection system. Samples were analyzed both before and after oxygen/ozone injection. Hydrogen sulfide gas was continuously monitored at sewer stations downstream of Fox River Fiber. Results showed that with a very short contact time, effluent COD was reduced by over 15%. A simple kinetic model predicts that a contact time of fewer than 30 minutes could reduce COD by as much as 60%. In addition, downstream hydrogen sulfide gas production in the sewage mains was also better controlled, such that costly Bioxide applications could be reduced.

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.

Two-stage entrapped mixed microbial cell process for simultaneous removal of organics and nitrogen for rural domestic sewage application

2004 ◽  
Vol 49 (5-6) ◽  
pp. 281-288 ◽  
Author(s):  
S.J. Kim ◽  
P.Y. Yang
Keyword(s):  
Removal Efficiency ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Microbial Cell ◽  
Two Stage ◽  
Rate Limiting Step ◽  
Soluble Chemical Oxygen Demand ◽  
Removal Efficiencies ◽  
Entrapped Mixed Microbial Cell

A two-stage entrapped mixed microbial cell (2SEMMC) process which separates nitrification and denitrification phases by the installation of the anoxic and oxic EMMC reactors packed with EMMC carriers was operated with 6, 4, 3, and 2 hours of hydraulic retention time (HRT) using simulated domestic wastewater. The activated sludge was immobilized using cellulose acetate for the EMMC carriers. Similar soluble chemical oxygen demand (SCOD) removal efficiencies of 90-97% were observed for all HRTs (SCOD loading rate of 0.84-2.30 g/L/d) applied. In order to achieve more than 80 % of TN removal efficiency, the HRT should be maintained higher than 4 hours (less than 0.24 g/L/d of TN loading rate). Denitrification was a rate-limiting step which controlled overall TN removal efficiency at TN loading rate of 0.15-0.31 g/L/d although nitrification efficiencies achieved 97-99 %. The effluent TSS of less than 25 mg/L in the 2SEMMC process was maintained at the SCOD loading rate of less than 1.23 g/L/d with back-washing intervals of 5 and 10 days in the anoxic and oxic EMMC reactors, respectively. The minimum HRT of 4 hours is required for high removal efficiencies of organics (average 95.6 %) and nitrogen (average 80.5 %) in the 2SEMMC process with 3 times of recirculation ratio.

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