The stability of nitrite nitrification with strong nitrogenous wastewater: effects of organic concentration and microbial diversity

2004 ◽  
Vol 49 (5-6) ◽  
pp. 89-96 ◽  
Author(s):  
Z. Yun ◽  
Y.-H. Jung ◽  
B.-R. Lim ◽  
E. Choi ◽  
K.S. Min
Keyword(s):  
Experimental Study ◽  
Microbial Community ◽  
Profile Analysis ◽  
Control Unit ◽  
Operating Period ◽  
Ammonia Inhibition ◽  
Start Up ◽  
Quinone Profile ◽  
Competition Hypothesis ◽  
The Stability

A stable achievement of nitritation with strong nitrogenous wastewaters is considered as a difficult task in practice, probably due to the fate of interaction between dominating heterotrophs and nitrifier species. An experimental study was carried out to examine the organic effects in lab-scale biofilm nitritation reactors. The control unit without organic addition showed a stable nitritation performance for more than 220 days of operating period. The nitritation activity gradually failed at the reactors with an organic addition, but the nitritation activity eventually recovered with a prolonged aeration. It was not possible to explain the nitritation recovery with neither free ammonia inhibition concept nor DO competition hypothesis in these cases. The results suggest that the nitritation with organic requires a long start-up period for acclimation. In addition, the results of quinone profile analysis were in agreement with nitritation activity in reactors. The diversity of microbial community in the nitritation reactors could be described by the quinone profiles.

EXPERIMENTAL STUDY OF START-UP FLOWS OF GELLED WAXY OILS IN PIPELINES – A REVIEW

2018 ◽  
Author(s):  
Roque Martins Duarte Junior ◽  
Andrade Diogo ◽  
Tainan Gabardo ◽  
Cezar Otaviano Ribeiro Negrao
Keyword(s):  
Experimental Study ◽  
Start Up

A simulation apparatus for the experimental study of batch reactor control methods

1986 ◽  
Vol 51 (6) ◽  
pp. 1259-1267
Author(s):  
Josef Horák ◽  
Petr Beránek
Keyword(s):  
Experimental Study ◽  
Closed Loop ◽  
Dynamic Properties ◽  
Batch Reactor ◽  
Exothermic Reaction ◽  
Electric Heating ◽  
Batch Reactors ◽  
Exchange Area ◽  
The Stability ◽  
Methods Of Control

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.

scholarly journals Environmental parameters and microbial community profiles as indication towards microbial activities and diversity in aquaponic system compartments

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zala Schmautz ◽  
Carlos A. Espinal ◽  
Andrea M. Bohny ◽  
Fabio Rezzonico ◽  
Ranka Junge ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Profile Analysis ◽  
Operation Mode ◽  
Environmental Parameters ◽  
Plant Production ◽  
Microbial Activities ◽  
Anaerobic Processes ◽  
Abiotic Parameters ◽  
Aerobic And Anaerobic

Abstract Background An aquaponic system couples cultivation of plants and fish in the same aqueous medium. The system consists of interconnected compartments for fish rearing and plant production, as well as for water filtration, with all compartments hosting diverse microbial communities, which interact within the system. Due to the design, function and operation mode of the individual compartments, each of them exhibits unique biotic and abiotic conditions. Elucidating how these conditions shape microbial communities is useful in understanding how these compartments may affect the quality of the water, in which plants and fish are cultured. Results We investigated the possible relationships between microbial communities from biofilms and water quality parameters in different compartments of the aquaponic system. Biofilm samples were analyzed by total community profiling for bacterial and archaeal communities. The results implied that the oxygen levels could largely explain the main differences in abiotic parameters and microbial communities in each compartment of the system. Aerobic system compartments are highly biodiverse and work mostly as a nitrifying biofilter, whereas biofilms in the anaerobic compartments contain a less diverse community. Finally, the part of the system connecting the aerobic and anaerobic processes showed common conditions where both aerobic and anaerobic processes were observed. Conclusion Different predicted microbial activities for each compartment were found to be supported by the abiotic parameters, of which the oxygen saturation, total organic carbon and total nitrogen differentiated clearly between samples from the main aerobic loop and the anaerobic compartments. The latter was also confirmed using microbial community profile analysis.

Experimental Study of a 200 kW Partial Oxidation Gas Turbine (POGT) for Co-Production of Power and Hydrogen-Enriched Fuel Gas

2009 ◽  
Author(s):  
Joseph Rabovitser ◽  
Stan Wohadlo ◽  
John M. Pratapas ◽  
Serguei Nester ◽  
Mehmet Tartan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Gas Turbine ◽  
Partial Oxidation ◽  
Synthesis Gas ◽  
Combustion Products ◽  
Working Fluid ◽  
Fuel Gas ◽  
Lean Combustion ◽  
Start Up ◽  
Oxidation Reactor

Paper presents the results from development and successful testing of a 200 kW POGT prototype. There are two major design features that distinguish POGT from a conventional gas turbine: a POGT utilizes a partial oxidation reactor (POR) in place of a conventional combustor which leads to a much smaller compressor requirement versus comparably rated conventional gas turbine. From a thermodynamic perspective, the working fluid provided by the POR has higher specific heat than lean combustion products enabling the POGT expander to extract more energy per unit mass of fluid. The POGT exhaust is actually a secondary fuel gas that can be combusted in different bottoming cycles or used as synthesis gas for hydrogen or other chemicals production. Conversion steps for modifying a 200 kW radial turbine to POGT duty are described including: utilization of the existing (unmodified) expander; replacement of the combustor with a POR unit; introduction of steam for cooling of the internal turbine structure; and installation of a bypass air port for bleeding excess air from the compressor discharge because of 45% reduction in combustion air requirements. The engine controls that were re-configured for start-up and operation are reviewed including automation of POGT start-up and loading during light-off at lean condition, transition from lean to rich combustion during acceleration, speed control and stabilization under rich operation. Changes were implemented in microprocessor-based controllers. The fully-integrated POGT unit was installed and operated in a dedicated test cell at GTI equipped with extensive process instrumentation and data acquisition systems. Results from a parametric experimental study of POGT operation for co-production of power and H2-enriched synthesis gas are provided.

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