scholarly journals pH-Based Control Strategies for the Nitrification of High-Ammonium Wastewaters

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 319
Author(s):  
Ignatius Leopoldus van Rooyen ◽  
Hendrik Gideon Brink ◽  
Willie Nicol
Keyword(s):  
Reaction Rate ◽  
Control Strategies ◽  
Environmental Issues ◽  
Control Algorithms ◽  
Maximum Reaction Rate ◽  
Tank Reactor ◽  
Industrial Sectors ◽  
Maximum Reaction ◽  
Control Schemes ◽  
Continuously Stirred Tank Reactor

Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove nitrogen or produce liquid fertilizers. Standard control methodologies for the efficient nitrification of high-ammonium wastewaters to produce liquid fertilizers have not yet been established and are still within their early stages of development. In this paper, novel pH-based control algorithms are presented that maintain operation at the microbial maximum reaction rate (υmax) in batch and continuous reactors. Complete conversion of ammonium to nitrate was achieved in a batch setup, and a conversion of 93% (±1%) was achieved in a continuously-stirred-tank-reactor. The unparalleled performance and affordability of the control schemes proposed offer a steppingstone to the future of sustainable fertilizer production.

scholarly journals Numerical Test of Several Controllers for Underactuated Underwater Vehicles

2020 ◽  
Vol 10 (22) ◽  
pp. 8292
Author(s):  
Przemyslaw Herman
Keyword(s):  
Control Algorithm ◽  
Control Strategies ◽  
Numerical Test ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Control Algorithms ◽  
Dynamics Model ◽  
Numerical Tests ◽  
Control Schemes ◽  
Testing Algorithm

This work is devoted to preliminary numerical tests of selected control strategies of underwater vehicles in the absence of a force applied to the side. The aim was to test the effectiveness of control algorithms for underwater vehicle models considered to be underactuated. Initially, the testing algorithm is used to obtain some information about the dynamics model. Several well-known control schemes for two underwater vehicles for two desired trajectories were selected and tested. The simulations made for the planar 3-DOF model of two underwater vehicles show the performance that can be achieved with each control algorithm according to the assumptions made.

Biodegradation of 2,4-dichlorophenol in a fluidized bed reactor with immobilized Phanerochaete chrysosporium

2010 ◽  
Vol 62 (4) ◽  
pp. 947-955 ◽  
Author(s):  
Xiao-ming Li ◽  
Qi Yang ◽  
Ying Zhang ◽  
Wei Zheng ◽  
Xiu Yue ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Phanerochaete Chrysosporium ◽  
Reaction Rate ◽  
Immobilized Cells ◽  
Fluidized Bed Reactor ◽  
Degradation Process ◽  
Maximum Reaction Rate ◽  
Monod Equation ◽  
Continuous Bioreactor ◽  
Maximum Reaction

The performance of a fluidized bed reactor using immobilized Phanerochaete chrysosporium to remove 2,4-dichlorophenol (2,4-DCP) from aqueous solution was investigated. The contribution of lignin peroxidase (LiP) and manganese peroxidase (MnP) secreted by Phanerochaete chrysosporium to the 2,4-DCP degradation was examined. Results showed that Lip and Mnp were not essential to 2,4-DCP degradation while their presence enhanced the degradation process and reaction rate. In sequential batch experiment, the bioactivity of immobilized cells was recovered and improved during the culture and the maximum degradation rate constant of 13.95 mg (Ld)−1 could be reached. In continuous bioreactor test, the kinetic behavior of the Phanerochaete chrysosporium immobilized on loofa sponge was found to follow the Monod equation. The maximum reaction rate was 7.002 mg (Lh)−1, and the saturation constant was 26.045 mg L−1.

Basic Studies on Anaerobic Degradation of Glucose in Continuous Stirred Tank Reactors

1991 ◽  
Vol 24 (5) ◽  
pp. 141-147
Author(s):  
Michimasa Nakamura ◽  
Atsushi Sakai ◽  
Jun'ichiro Matsumoto
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acid ◽  
Reaction Rate ◽  
Ph Value ◽  
Reaction Rate Constant ◽  
The Other ◽  
Total Volatile ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Total Volatile Fatty Acid

The two series of the characteristics of anaerobic degradation of low glucose concentrations were investigated. In the first series, the pH value in each reactor was not controlled. In the second series, the pH value in each reactor was controlled in the range of 6.9–7.2, by adding sodium bicarbonate into each influent. The ORP value was depressed by controlling the pH value of each reactor from acid range to approximately neutral range. In the pH uncontrolled series, the pH value in outflow decreased with increasing glucose concentration. In the pH uncontrolled series, produced total volatile fatty acid was about 70 to 550 mg/l; on the other hand, in pH controlled series, produced total volatile fatty acid was about 50 mg/l to 350 mg/l. The highest concentrations of acids formed were acetic acids, the second highest formed were propionic acids, the last formed were butyric acids. In the pH uncontrolled series, the maximum reaction rate constant Vm was 0.749 gCOD/gVS · day and the saturation constant Ks = 0.435 g/l. On the other hand, in the pH controlled series, the maximum reaction rate constant Vm was 1.441 gCOD/gVS · day and the saturation constant Ks = 0.739 g/l. Thus by controlling the pH value of the reactor, the activities of the anaerobic bacteria were much enhanced.

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