Development of a methanogenic process to degrade exhaustively the organic fraction of municipal “grey waste” under thermophilic and hyperthermophilic conditions

2000 ◽  
Vol 41 (3) ◽  
pp. 83-91 ◽  
Author(s):  
P.A. Scherer ◽  
G.-R. Vollmer ◽  
T. Fakhouri ◽  
S. Martensen
Keyword(s):  
Loading Rate ◽  
Cellulose Degradation ◽  
Gas Production ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Organic Fraction ◽  
Biogas Yield ◽  
Conversion Rates ◽  
Vs Removal ◽  
Removal Efficiencies

Different laboratory-scale, continuously driven reactor concepts (up to 3 reactors in series, max. 70°C) for anaerobic digestion of the organic fraction of municipal grey waste were investigated. Over a period of 2½ years several setups of reactors being daily fed and held in steady state balance were investigated. The preferred variant was a 2-stage setup with a HRT of 4.3d for the 1st and 14.2d for the 2nd reactor. Removal efficiencies of VS obtained by comparing the organic loading rate (OLR, g VS/l/d) of the effluent with the OLR of the feed could reach 80%. Removal efficiencies determined indirectly by the combined biogas yield of the 1st and 2nd reactor stage revealed even up to 91.5% of the theoretical possible yield of 807 l/kgVS. The produced gas had a methane content of 60–65%. A completely distinct hydrolysis stage with a gas production of only 1.6–5.5% of the theoretical yield could be reached by hyperthermophilic conditions (60–70°C) or by a HRT of 1.25d. It also demonstrated that a stable methanogenesis was not possible at temperatures of 60–70°C. Kinetic analyses of the 2nd reactor stage revealed that the degradation of VS fell from 80 to 40% with raising organic loading rate (OLR) from 3 to 11 g VS/l/d. In contrast to this the VS-removal of the first hydrolysis reactor stage increased linearily from 5 to 20% at raising OLR's from 12 to 26 g VS/l/d. The same kinetics with linear increase exhibited the specific cellulose degradation with conversion rates of 0.1–3x109 g cellulose/single bacterium (10–12 g)/d. This was an indication for the cellulose degradation as a rate limiting step. Both reactor stages combined allowed an optimal VS removal efficiency at OLR of 10 g VS/l/d. Analysis of bacterial populations of 28 reactors were referred either to eubacteria utilizing different sugars or cellulose or acetate or H2–CO2 or archaea (plus antibiotics) with acetate or H2–CO2 as substrate. H2–CO2 utilizers with numbers of 108–1010/g TS dominated obviously the acetotrophic methanogens by the factor 10–10,000. This explained the observed short HRTs being possible.

Effect of Organic Loading Rate (OLR) on Biogas Yield Using a Single and Three-Stages Continuous Anaerobic Digestion Reactors

2018 ◽  
Vol 39 ◽  
pp. 147-155 ◽  
Author(s):  
Ejiroghene Kelly Orhorhoro ◽  
Patrick Okechukwu Ebunilo ◽  
Godwin Ejuvwedia Sadjere
Keyword(s):  
Waste Water ◽  
Loading Rate ◽  
Single Stage ◽  
Organic Loading Rate ◽  
Cow Dung ◽  
Organic Loading ◽  
Continuous Increase ◽  
Biogas Yield ◽  
Load Rate ◽  
Three Stages

The rate at which feedstock is added to the anaerobic digester (AD) reactor has to be adjusted for the growth rate of methanogens bacteria. Increase in biogas yield is as a result of improved mathanogens forming bacteria. Under loading and over loading of feedstock in the AD reactor has effect on methanogens forming bacteria. If more feedstock is added than the bacteria are able to degrade, the process will become acidic. Feedstock has to been fed to the reactor at a uniform rate and volume. If feeding pattern has to change, this must be done gradually so that bacteria can adapt to the new conditions. For optimum biogas yield, required amount of feedstock must be added to the AD reactor. The aim of this research work is to determine the effect of organic loading rate (OLR) on biogas yield from food waste, water hyacinth, cow dung, waste water from abattoir, poultry dropping and pig dung. The experimental set up comprises of single stage and three-stage continuous AD reactors. The same quantity and composition of feedstock were used and this was subjected to a variation of OLR 0.5 kg/m3(1.5 kg/m3, 2 kg/m3, 2.5 kg/m3, and 3 kg/m3). The experiment was conducted within a mesophilic temperature range of 36°C-37°C, percentage total solid (%TS) of 9.98% and percentage volatile solid (%VS) of 78%. pH meter was used to monitored the daily pH reading of the slurry. It was observed that the quantity of biogas yield from the feedstock increases with increasing organic load rate to the optimum value of 1.5 kg/m3and started decreasing above the optimum value for a single stage AD reactor but this was not the case for the three-stages continuous AD reactors that experienced continuous increase in biogas yield with a successive increase in OLR from 1-5 kg/m3-3.0 kg/m3.

Kinetics of an anaerobic fluidized bed reactor using biolite carrier

1996 ◽  
Vol 23 (6) ◽  
pp. 1305-1315 ◽  
Author(s):  
R. Prakash ◽  
K. J. Kennedy
Keyword(s):  
Steady State ◽  
Fluidized Bed ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Loading Rates ◽  
Start Up ◽  
Removal Efficiencies ◽  
Biofilm Development ◽  
Kinetics Of

Start-up and steady state operation of anaerobic fluidized bed reactors (AFBRs) with biolite as the inert carrier material was studied. Start-up and concomitant biofilm development of AFBRs was performed using two common start-up techniques, the maximum efficiency profile (MEP) technique and the maximum load profile (MLP) technique. The MEP start-up technique increases the volumetric organic loading rates to the reactor gradually and is tied to the removal efficiency of the process. The MLP start-up technique maintains a moderately high but constant volumetric organic loading rate irrespective of reactor performance. Using sucrose-based wastewater as feed, both start-up techniques led to equally fast biofilm development and start-up times of approximately 5 weeks. However, the MEP technique resulted in more stable controlled reactor operation during the start-up period. The quick start-up confirms the high compatibility of biolite for bio-adhesion and the development of a healthy active biofilm.High concentrations of biofilm biomass achieved in AFBRs (69 g volatile biofilm solids (VBS)/L of expanded bed volume at an organic loading rate of 25 g COD/(Lùd)) allowed the successful treatment of wastewaters at high organic loading rates and organic removal efficiencies. During steady state experiments, organic removal efficiencies over 80% were obtained for organic loading rates as high as 20 g COD/(L∙d). It was found that the dependence of removal efficiency on hydraulic retention time is influenced by substrate concentration. Total biofilm yield was determined to be 0.08 g VBS/g COD removed, demonstrating the low net synthesis of solids in the AFBR. AFBRs had an average solids retention time of 150 days, corresponding to a washout factor of 0.01. Extrinsic kinetics of the AFBRs was determined to be zero order with a maximum specific utilization rate of 0.48 g COD/(g VBS∙d).AFBRs used to treat municipal landfill leachate with a BOD5:COD ratio of 0.86 achieved steady state COD removal efficiencies that ranged from 70% to 87%, depending on the reactor organic loading rate and the concentration of the leachate being treated. During leachate treatment, biofilm biomass gradually became "mineralized" as a result of precipitation of metal sulfides and carbonates. This eventually resulted in a decrease in biofilm microbial activity and the need for higher pumping rates to maintain the same degree of bed expansion. Key words: anaerobic, biological fluidized bed reactor, biolite, landfill leachate, sucrose, modeling, start-up, steady state kinetics.

scholarly journals Performance of AnMBR in Treatment of Post-consumer Food Waste: Effect of Hydraulic Retention Time and Organic Loading Rate on Biogas Production and Membrane Fouling

2021 ◽  
Vol 8 ◽  
Author(s):  
Javkhlan Ariunbaatar ◽  
Robert Bair ◽  
Onur Ozcan ◽  
Harish Ravishankar ◽  
Giovanni Esposito ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Food Waste ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Biogas Production ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Side Stream ◽  
Removal Efficiencies

Anaerobic digestion of food waste (FW) is typically limited to large reactors due to high hydraulic retention times (HRTs). Technologies such as anaerobic membrane reactors (AnMBRs) can perform anaerobic digestion at lower HRTs while maintaining high chemical oxygen demand (COD) removal efficiencies. This study evaluated the effect of HRT and organic loading rate (OLR) on the stability and performance of a side-stream AnMBR in treating diluted fresh food waste (FW). The reactor was fed with synthetic FW at an influent concentration of 8.24 (± 0.12) g COD/L. The OLR was increased by reducing the HRT from 20 to 1 d. The AnMBR obtained an overall removal efficiency of >97 and >98% of the influent COD and total suspended solids (TSS), respectively, throughout the course of operation. The biological process was able to convert 76% of the influent COD into biogas with 70% methane content, while the cake layer formed on the membrane gave an additional COD removal of 7%. Total ammoniacal nitrogen (TAN) and total nitrogen (TN) concentrations were found to be higher in the bioreactor than in the influent, and average overall removal efficiencies of 17.3 (± 5) and 61.5 (± 3)% of TAN and TN, respectively, were observed with respect to the bioreactor concentrations after 2 weeks. Total phosphorus (TP) had an average removal efficiency of 40.39 (± 5)% with respect to the influent. Membrane fouling was observed when the HRT was decreased from 7 to 5 d and was alleviated through backwashing. This study suggests that the side-stream AnMBR can be used to successfully reduce the typical HRT of wet anaerobic food waste (solids content 7%) digesters from 20 days to 1 day, while maintaining a high COD removal efficiency and biogas production.

STUDY ON CAPACITY OF A TRICKLING FILTER USING BIOCHAR MEDIUM FOR TREATING WASTEWATER FROM AN CUU MARKET IN HUE CITY, VIETNAM

2020 ◽  
Vol 129 (3C) ◽  
Author(s):  
Nguyễn Thị Cẩm Yến
Keyword(s):  
Wastewater Treatment ◽  
Organic Pollutants ◽  
Suspended Solids ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Trickling Filter ◽  
Untreated Wastewater ◽  
Investment Capital ◽  
Removal Efficiencies

Abstract: Pollution caused by market wastewater has occurred for many years in Vietnam. In particular, untreated wastewater from a riverside market is often directly discharged into a river, increasing loads of pollutants for the river. Every day, An Cuu market wastewater is averagely discharged about 19 cubic metres into An Cuu river. However, a wastewater treatment system has not been yet built at the market due to many reasons including the lack of investment capital. A Trickling filter (TF) consisting of a fix bed of biochar is a cost acceptable technology, effectively treating parameters like organic pollutants, nutrients and suspended solids. In this study, a model of TF using biochar medium for An Cuu market wastewater treatment were effectively operated with the organic loading rate (OLR) varying from 188 to 550 gBOD5.m-3.day-1 and the hydraulic loading rate (HLR) from 532 to 1899 L.m-2.day-1. The biochar trickling filter showed high removal efficiencies: 97%  BOD5, 92% COD, 97% TSS, 66% PTot and 62% NTot.Key words: An Cuu market, wastewater treatment,  biochar trickling filter, Vietnam

Anaerobic monodigestion of poultry manure: determination of operational parameters for CSTR

2012 ◽  
Vol 65 (1) ◽  
pp. 53-59 ◽  
Author(s):  
R. Chamy ◽  
C. León ◽  
E. Vivanco ◽  
P. Poirrier ◽  
C. Ramos
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Poultry Manure ◽  
Organic Loading Rate ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Operational Parameters ◽  
Volatile Solids ◽  
High Alkalinity ◽  
Vs Removal

In this work the anaerobic monodigestion for the treatment of turkey manure was evaluated, without its codigestion with another substrate. The effect of the organic loading rate (OLR) and the substrate concentration (high total solids (TS) concentration) or product concentration (high volatile fatty acids (VFA) and/or ammonia (NH3-N) concentrations) was studied. The results show that for a continuous stirred tank reactor (CSTR) operation, a maximum of 40 g/L of TS and 4.0 g/L of ammonium (NH4+) was required. In addition, the maximum organic loading rate (OLR) will not exceed 1.5 kg VS/m3d. Higher TS and NH4+ concentrations and OLR lead to a reduction on the methane productivity and volatile solids (VS) removal. During the CSTR operation, a high alkalinity concentration (above 10 g/L CaCO3) was found; this situation allowed maintaining a constant and appropriate pH (close to 7.8), despite the VFA accumulation. In this sense, the alkalinity ratio (α) is a more appropriate control and monitoring parameter of the reactor operation compared to pH. Additionally, with this parameter a VS removal of 80% with a methane productivity of 0.50 m3CH4/m3Rd is achieved.

Field Test of a Composite Methane Gas Production System Incorporating a Membrane Module for Municipal Sewage

1992 ◽  
Vol 25 (7) ◽  
pp. 135-141 ◽  
Author(s):  
K. Kiriyama ◽  
Y. Tanaka ◽  
I. Mori
Keyword(s):  
Field Test ◽  
Loading Rate ◽  
Membrane Module ◽  
Municipal Sewage ◽  
Organic Loading Rate ◽  
Test Plant ◽  
Organic Loading ◽  
Practical Test ◽  
Methane Gas ◽  
Conversion Rates

We examined a field test plant based on anaerobic sewage treatment to elucidate the process of methane fermentation with a UASB in municipal sewage and domestic waste water. The process consists of a pretreatment system for sparating suspended solids, a hydrolyzation reactor with a membrane module for organic solids, and a UASB reactor. The membrane module increases the sludge residence time in the hydrolyzation reactor. This field test plant is a commercial size system which combines these processes to verify the feasibility of the system. The aim of this practical test is to produce gas with a conversion rate of over 60% when the volumetric organic loading rate is more than 2 kg BOD/reactor m3.d, and to construct a methane gas generation system which generates the gas from raw sewage. This practical test demonstrated gas conversion rates from 57% to 60.0%. Volumetric organic loading rate was 1.4 - 2.0 kg BOD/m3.d; BOD removal was 70 - 80% at ambient temperature, and excess sludge did not exceed 0.04 kg per sewage.m3.

Anaerobic digestion of Jatropha curcas L. press cake and effects of an iron-additive

2011 ◽  
Vol 29 (11) ◽  
pp. 1171-1176 ◽  
Author(s):  
Thomas Schmidt
Keyword(s):  
Anaerobic Digestion ◽  
Jatropha Curcas ◽  
Loading Rate ◽  
Press Cake ◽  
Biogas Production ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Biogas Yield ◽  
Jatropha Curcas L ◽  
The Stability

Oil production from Jatropha curcas L. seeds generates large amounts of Jatropha press cake (JPC) which can be utilized as a substrate for biogas production. The objective of this work was to investigate anaerobic mono-digestion of JPC and the effects of an iron additive (IA) on gas quality and process stability during the increase of the organic loading rate (OLR). With the increase of the OLR from 1.3 to 3.2 gVS L−1 day−1, the biogas yield in the reference reactor (RR) without IA decreased from 512 to 194 LN kgVS−1 and the CH4 concentration decreased from 69.3 to 44.4%. In the iron additive reactor (IAR), the biogas yield decreased from 530 to 462 LN kgVS−1 and the CH4 concentration decreased from 69.4 to 61.1%. The H2S concentration in the biogas was reduced by addition of the IA to values below 258 ppm in the IAR while H2S concentration in the RR increased and exceeded the detection limit of 5000 ppm. The acid capacity (AC) in the RR increased to more than 20 g L−1, indicating an accumulation of organic acids caused by process instability. AC values in the IAR remained stable at values below 5 g L−1. The results demonstrate that JPC can be used as sole substrate for anaerobic digestion up to an OLR of 2.4 gVS l−1 day−1. The addition of IA has effectively decreased the H2S content in the biogas and has improved the stability of the anaerobic process and the biogas quality.

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