Anaerobic digestion of high-sulphate-content wastewater from the industrial production of citric acid

1994 ◽  
Vol 30 (12) ◽  
pp. 263-273 ◽  
Author(s):  
E. Colleran ◽  
S. Finnegan ◽  
R. B. O'Keeffe
Keyword(s):  
Steady State ◽  
Citric Acid ◽  
Fixed Bed ◽  
Full Scale ◽  
Sulphate Content ◽  
Methanogenic Activity ◽  
Term Operation ◽  
Steady State Operation ◽  
Start Up

The start-up and steady-state operation of a full-scale fixed bed digester treating citric acid production wastewater with an estimated COD/sulphate ratio of approximately 4 are described. Parallel studies at laboratory-scale with two reactors, one of which received the same high influent sulphate concentration as the full-scale plant, confirmed the finding that methanogenesis was not inhibited by the level of sulphate reduction shown to occur. After long-term operation on a high sulphate influent, the retained biomass in the laboratory and full-scale reactors displayed a very low specific methanogenic activity against propionate and butyrate. Since propionate and butyrate were barely detectable in the effluents at steady-state, their oxidation under high influent sulphate conditions may be completely or incompletely mediated by fatty-acid-utilising SRB.

Start-up and long-term operation of the Anammox process in a fixed bed reactor (FBR) filled with novel non-woven ring carriers

Chemosphere ◽  
2013 ◽  
Vol 91 (5) ◽  
pp. 669-675 ◽  
Author(s):  
Tao Wang ◽  
Hanmin Zhang ◽  
Fenglin Yang ◽  
Yifei Li ◽  
Guangyi Zhang
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Term Operation ◽  
Start Up ◽  
Anammox Process

scholarly journals Co-digestion of Oil Palm Trunk Hydrolysate and Slaughterhouse Wastewater for Biohydrogen Production in a Fixed Bed Reactor by Immobilized Thermoanaerobacterium thermosaccharolyticum KKU19 on Expanded Clay

2021 ◽  
Vol 9 ◽  
Author(s):  
Sontaya Khamtib ◽  
Sureewan Sittijunda ◽  
Tsuyoshi Imai ◽  
Alissara Reungsang
Keyword(s):  
Oil Palm ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Hydrogen Yield ◽  
Support Material ◽  
Slaughterhouse Wastewater ◽  
Term Operation ◽  
Oil Palm Trunk ◽  
Thermoanaerobacterium Thermosaccharolyticum

The goal of this study was to evaluate the use of expanded clay as a support material for Thermoanaerobacterium thermosaccharolyticum KKU19 to produce hydrogen from oil palm trunk hydrolysate (OPT) and slaughterhouse wastewater (SHW) in a fixed-bed reactor (FBR) under non-sterile conditions. The effects of hydraulic retention time (HRT) on the performance of the FBR were also investigated. The FBR was operated at an OPT hydrolysate to SHW ratio of 2.55:1 (v:v), 60°C, initial pH 6.5, and 1.2 mg (as total volatile solids/g expanded clay) of T. thermosaccharolyticum KKU19 immobilized on expanded clay. A maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 7.15 ± 0.22 L/L day and 234.45 ± 5.14 mL H2/g-COD, respectively, were obtained at an HRT of 6 h. Long-term operation of FBR at 6 h HRT indicated that expanded clay efficiently immobilizes T. thermosaccharolyticum KKU19, for which an HPR of 6.82 ± 0.56 L H2/L day, and an HY of 231.99 ± 19.59 mL H2/g-COD were obtained. Furthermore, the COD removal efficiency of 30% obtained under long-term operation was comparable to that under short-term operation at an HRT of 6 days. Butyric and acetic acids were the main soluble metabolite products, thereby indicating a butyrate–acetate type fermentation. Our findings indicate that expanded clay is an effective support material that contributes to the protection of microbial cells and can be used for long-term operation.

Influence of Creep on Low-Cycle Fatigue Life Assessment of Ultra-Supercritical Steam Turbine Rotor

2014 ◽  
Author(s):  
W. Z. Wang ◽  
J. H. Zhang ◽  
H. F. Liu ◽  
Y. Z. Liu
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Turbine Rotor ◽  
High Temperature Creep ◽  
Cycle Fatigue ◽  
Term Operation ◽  
Start Up

Linear damage method is widely used to calculate low-cycle fatigue damage of turbine rotor in the long-term operation without fully considering the interaction between creep and low cycle fatigue. However, with the increase of steam turbine pressure and temperature, the influence of high-temperature creep on the strain distribution of turbine rotor becomes significant. Accordingly, the strain for each start-up or shut-down process is different. In the present study, the stress and strain during 21 iterations of continuous start-up, running and shut-down processes was numerically investigated by using the finite element analysis. The influence of high-temperature creep on low cycle fatigue was analyzed in terms of equivalent strain, Mises stress and low cycle fatigue damage. The results demonstrated that the life consumption of turbine rotor due to low cycle fatigue in the long-term operation of startup, running and shutdown should be determined from the full-time coverage of the load of turbine rotor.

Anaerobic treatment of rapeseed meal

2013 ◽  
Vol 67 (12) ◽  
Author(s):  
Nina Kolesárová ◽  
Miroslav Hutňan ◽  
Viera Špalková ◽  
Michal Lazor
Keyword(s):  
Biogas Production ◽  
Rapeseed Meal ◽  
Anaerobic Treatment ◽  
Biodiesel Production ◽  
Organic Loading Rate ◽  
Laboratory Model ◽  
Continuous Stirred Tank Reactor ◽  
Methanogenic Activity ◽  
Term Operation

AbstractRapeseed meal is a solid by-product obtained from rapeseed after oil extraction. This contribution summarises experiences from batch experiments as well as the long-term processing of this substrate in a laboratory stirred anaerobic reactor (continuous stirred-tank reactor). On the basis of the batch tests of hydrolysis, acidogenesis, and methanogenic activity, it was concluded that the anaerobic degradation of rapeseed meal can be performed using a one-step system and it is not necessary to include a hydrolytic-acidogenic step prior to the methanogenic step. Although the methanogenic potential of rapeseed meal appears to be very promising, the long-term processing as a single substrate led to serious problems arising from the inhibitory effects. It was, therefore, co-fermented with crude glycerol from biodiesel production. From the long-term operation of the laboratory model, it may be stated that, due to the co-fermentation of by-products from biodiesel production, the individual inhibition effects can be suppressed to a large extent and biogas production can be stabilised. The maximum organic loading rate in the continuous stirred reactor achieved 2.42 kg m−3 d−1 of volatile solids (15 g of rapeseed meal and 20 mL of gas-phase), which was 3.13 kg m−3 d−1 of chemical oxygen demand.

scholarly journals Performance Analysis of a Full-Scale Desalination Plant with Reverse Osmosis Membranes for Irrigation

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 774
Author(s):  
Federico Leon ◽  
Alejandro Ramos
Keyword(s):  
Reverse Osmosis ◽  
Specific Energy Consumption ◽  
Production Capacity ◽  
Pressure Vessels ◽  
Full Scale ◽  
Operating Data ◽  
Term Operation ◽  
Desalination Plant ◽  
Pre Treatment

Reverse osmosis (RO) is the most widely used technology for seawater desalination purposes. The long-term operating data of full-scale plants is key to analyse their performance under real conditions. The studied seawater reverse osmosis (SWRO) desalination plant had a production capacity of 5000 m3/d for irrigation purposes. The operating data such as conductivities flows, and pressures were collected for around 27,000 h for 4 years. The plant had sand and cartridge filters without chemical dosing in the pre-treatment stage, a RO system with one stage, 56 pressure vessels, seven RO membrane elements per pressure vessel and a Pelton turbine as energy recovery device. The operating data allowed to calculate the average water and salt permeability coefficients (A and B) of the membrane as well as the specific energy consumption (SEC) along the operating period. The calculation of the average A in long-term operation allowed to fit the parameters of three different models used to predict the mentioned parameter. The results showed a 30% decrease of A, parameter B increase around 70%. The SEC was between 3.75 and 4.25 kWh/m3. The three models fitted quite well to the experimental data with standard deviations between 0.0011 and 0.0015.

Nitritation of real sewage: start-up and maintenance by the side-stream heat-shock treatment

2019 ◽  
Vol 79 (4) ◽  
pp. 753-758 ◽  
Author(s):  
Jianfei Chen ◽  
Shujun Zhang ◽  
Xiaoyu Han ◽  
Liang Zhang ◽  
Yongzhen Peng
Keyword(s):  
Heat Shock ◽  
Accumulation Rate ◽  
Batch Reactor ◽  
Shock Treatment ◽  
Nitrite Accumulation ◽  
Heat Shock Treatment ◽  
Term Operation ◽  
Side Stream ◽  
Start Up

Abstract In this study, the side-stream heat-shock treatment was used to start up and maintain the nitritation of real sewage. Complete nitrification was obtained when the real sewage was treated in a sequencing batch reactor (SBR). Then, about 50% of the mixed sludge was collected from the SBR and treated with the heat-shock treatment at 60 °C for 40 min in another reactor every 2 weeks. After providing the heat-shock treatment for four times, the effluent nitrate in the SBR gradually decreased from 22.5 to 3.2 mg/L, while the nitrite accumulation rate increased from 4.4% to 81.8%, indicating a successful start-up of nitritation. Further, the sewage nitritation was stable with the regular side-steam heat-shock treatment for 91 days, and the ammonium removal efficiency of 80.6% and nitrite accumulation rate of 91.2% were achieved. This study suggests that the side-stream heat-shock treatment could be used to start up sewage nitritation and maintain stability for a long-term operation.

scholarly journals Concurrent operation of 10 gyrotrons at W7-X experience and improvement opportunities

2018 ◽  
Vol 187 ◽  
pp. 01003 ◽  
Author(s):  
H. Braune ◽  
K.J. Brunner ◽  
H.P. Laqua ◽  
S. Marsen ◽  
D. Moseev ◽  
...  
Keyword(s):  
Steady State ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Heating System ◽  
Current Drive ◽  
Electron Cyclotron Resonance Heating ◽  
Neutral Gas ◽  
Steady State Operation ◽  
Start Up ◽  
Operation Phase

At the stellarator Wendelstein 7-X (W7-X) Electron Cyclotron Resonance Heating (ECRH) is the main heating system for steady-state operation and was the only available heating system during the operation phase OP1.2a in 2017. The ECRH, equipped with 10 operational 140 GHz gyrotrons [1], was used for different tasks at W7-X such as wall conditioning, controlled plasma start-up from the neutral gas up to steady state plasma control and different heating scenarios such as X2-mode and O2-mode heating as well as current drive (ECCD). The operational experiences and improvement opportunities of the ECRH plant will be discussed.

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