Intermittent air mixing system for anaerobic digestion of animal wastewater: Operating conditions and full-scale validation

2021 ◽  
pp. 125304
Author(s):  
Hongnan Yang ◽  
Liangwei Deng ◽  
Jianwang Wu ◽  
Wenguo Wang ◽  
Dan Zheng ◽  
...  
1989 ◽  
Vol 21 (4-5) ◽  
pp. 145-155 ◽  
Author(s):  
R. Méndez ◽  
J. M. Lema ◽  
R. Blázquez ◽  
M. Pan ◽  
C. Forjan

We have evaluated the utility of applying anaerobic digestion treatment to the leachates from two landfill sites receiving solid urban refuse from populations of similar standards of living. Both tips are located in the same area and have very similar climates, but they differ as regards the length of time they have been operated. The leachates from the older tip have much lower levels of organic load, 40% of which was refractory to the anaerobic digestion treatment applied. The digestibility of leachates was studied by using a semicontinuous suspended sludge system.It was possible to remove up to 65% of the soluble COD of leachates from the young tip by means of an anaerobic filter working at HRTs less than 2 days. This system proved to be highly stable when its operating conditions were subjected to perturbations similar to those likely to be suffered by a full-scale plant.


2021 ◽  
Author(s):  
S. Naik ◽  
B. Stephan ◽  
M. Henze

Abstract This paper describes the full-scale turbine section validation of the GT36 heavy duty gas turbine, which was conducted in a test Power Plant in Birr, Switzerland. The GT36 Test Power Plant is extensively instrumented with both standard and specialised instrumentation. In the turbine section, specialised instrumentation includes metal and gas thermocouples, thermal paint, pressure sensors, hot gas rakes, strain gauges, five-hole probes, pyrometers and tip timing sensors. Similar specialised instrumentation also exists for the compressor, combustor and the rotor sections. Three major test campaigns were conducted over an extended period, which consisted of both long and short duration tests, including a range of off-design tests. Within the turbine section, detailed transient and steady-state measurements were obtained of the stage inlet pressures and temperatures, airfoil surface pressures and metal temperatures. These measurements indicated that both the aerodynamic and cooling performances of the turbine blades and vanes are highly consistent and repeatable over a range of operating conditions. Detailed comparisons of the measured engine pressures and temperatures with predictions also indicated that there was generally a very good match in the Mach numbers and metal temperatures for all the turbine blades and vanes.


1989 ◽  
Vol 21 (10-11) ◽  
pp. 1389-1402 ◽  
Author(s):  
R. Zaloum

Deviations from design expectations appear to stem from views which assume that a unique response should result from a given set of operating conditions. The results of this study showed that two systems operating at equal organic loads or F/M ratios and at the same SRT do not necessarily give equal responses. This deviation was linked to the manner in which the HRT and influent COD are manipulated to obtain a constant or uniform load, and to subtle interactions between influent COD, HRT and SRT on the biomass and effluent responses. Increases of up to 200% in influent COD from one steady level to the next did not significantly influence the effluent VSS concentration while an effect on filtered COD was observed for increases as low as 20%. Effluent TKN and filtered COD correlated strongly with the operating MLVSS while phosphorus residual depended on the operating SRT and the organic load removed. These results point to the inadequacy of traditional models to predict effluent quality and point to the need to consider these effects when developing simulation techniques or computer assisted expert systems for the control of waste treatment plants.


2021 ◽  
Vol 96 ◽  
pp. 29-43
Author(s):  
Dingena Schott ◽  
Javad Mohajeri ◽  
Jovana Jovanova ◽  
Stef Lommen ◽  
Wilbert de Kluijver

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 502
Author(s):  
Andrea Visca ◽  
Anna Barra Caracciolo ◽  
Paola Grenni ◽  
Luisa Patrolecco ◽  
Jasmin Rauseo ◽  
...  

Anaerobic digestion is one of the best ways to re-use animal manure and agricultural residues, through the production of combustible biogas and digestate. However, the use of antibiotics for preventing and treating animal diseases and, consequently, their residual concentrations in manure, could introduce them into anaerobic digesters. If the digestate is applied as a soil fertilizer, antibiotic residues and/or their corresponding antibiotic resistance genes (ARGs) could reach soil ecosystems. This work investigated three common soil emerging contaminants, i.e., sulfamethoxazole (SMX), ciprofloxacin (CIP), enrofloxacin (ENR), their ARGs sul1, sul2, qnrS, qepA, aac-(6′)-Ib-cr and the mobile genetic element intI1, for one year in a full scale anaerobic plant. Six samplings were performed in line with the 45-day hydraulic retention time (HRT) of the anaerobic plant, by collecting input and output samples. The overall results show both antibiotics and ARGs decreased during the anaerobic digestion process. In particular, SMX was degraded by up to 100%, ENR up to 84% and CIP up to 92%, depending on the sampling time. In a similar way, all ARGs declined significantly (up to 80%) in the digestate samples. This work shows how anaerobic digestion can be a promising practice for lowering antibiotic residues and ARGs in soil.


2020 ◽  
Author(s):  
Γεώργιος Πατεράκης

The current work describes an experimental investigation of isothermal and turbulent reacting flow field characteristics downstream of axisymmetric bluff body stabilizers under a variety of inlet mixture conditions. Fully premixed and stratified flames established downstream of this double cavity premixer/burner configuration were measured and assessed under lean and ultra-lean operating conditions. The aim of this thesis was to further comprehend the impact of stratifying the inlet fuelair mixture on the reacting wake characteristics for a range of practical stabilizers under a variety of inlet fuel-air settings. In the first part of this thesis, the isothermal mean and turbulent flow features downstream of a variety of axisymmetric baffles was initially examined. The effect of different shapes, (cone or disk), blockage ratios, (0.23 and 0.48), and rim thicknesses of these baffles was assessed. The variations of the recirculation zones, back flow velocity magnitude, annular jet ejection angles, wake development, entrainment efficiency, as well as several turbulent flow features were obtained, evaluated and appraised. Next, a comparative examination of the counterpart turbulent cold fuel-air mixing performance and characteristics of stratified against fully-premixed operation was performed for a wide range of baffle geometries and inlet mixture conditions. Scalar mixing and entrainment properties were investigated at the exit plane, at the bluff body annular shear layer, at the reattachment region and along the developing wake were investigated. These isothermal studies provided the necessary background information for clarifying the combustion properties and interpreting the trends in the counterpart turbulent reacting fields. Subsequently, for selected bluff bodies, flame structures and behavior for operation with a variety of reacting conditions were demonstrated. The effect of inlet fuel-air mixture settings, fuel type and bluff body geometry on wake development, flame shape, anchoring and structure, temperatures and combustion efficiencies, over lean and close to blow-off conditions, was presented and analyzed. For the obtained measurements infrared radiation, particle image velocimetry, laser doppler velocimetry, chemiluminescence imaging set-ups, together with Fouriertransform infrared spectroscopy, thermocouples and global emission analyzer instrumentation was employed. This helped to delineate a number of factors that affectcold flow fuel-air mixing, flame anchoring topologies, wake structure development and overall burner performance. The presented data will also significantly assist the validation of computational methodologies for combusting flows and the development of turbulence-chemistry interaction models.


Author(s):  
Brian Hollon ◽  
Erlendur Steinthorsson ◽  
Adel Mansour ◽  
Vincent McDonell ◽  
Howard Lee

This paper discusses the development and testing of a full-scale micro-mixing lean-premix injector for hydrogen and syngas fuels that demonstrated ultra-low emissions and stable operation without flashback for high-hydrogen fuels at representative full-scale operating conditions. The injector was fabricated using Macrolamination technology, which is a process by which injectors are manufactured from bonded layers. The injector utilizes sixteen micro-mixing cups for effective and rapid mixing of fuel and air in a compact package. The full scale injector is rated at 1.3 MWth when operating on natural gas at 12.4 bar (180 psi) combustor pressure. The injector operated without flash back on fuel mixtures ranging from 100% natural gas to 100% hydrogen and emissions were shown to be insensitive to operating pressure. Ultra-low NOx emissions of 3 ppm were achieved at a flame temperature of 1750 K (2690 °F) using a fuel mixture containing 50% hydrogen and 50% natural gas by volume with 40% nitrogen dilution added to the fuel stream. NOx emissions of 1.5 ppm were demonstrated at a flame temperature over 1680 K (2564 °F) using the same fuel mixture with only 10% nitrogen dilution, and NOx emissions of 3.5 ppm were demonstrated at a flame temperature of 1730 K (2650 °F) with only 10% carbon dioxide dilution. Finally, using 100% hydrogen with 30% carbon dioxide dilution, 3.6 ppm NOx emissions were demonstrated at a flame temperature over 1600 K (2420 °F). Superior operability was achieved with the injector operating at temperatures below 1470 K (2186 °F) on a fuel mixture containing 87% hydrogen and 13% natural gas. The tests validated the micro-mixing fuel injector technology and the injectors show great promise for use in future gas turbine engines operating on hydrogen, syngas or other fuel mixtures of various compositions.


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