Synthesis of denitrification enzymes in activated sludge: modelling with structured biomass

1994 ◽  
Vol 30 (6) ◽  
pp. 113-122 ◽  
Author(s):  
D. Wild ◽  
R. von Schulthess ◽  
W. Gujer
Keyword(s):  
Enzyme Activity ◽  
Activated Sludge ◽  
Selection Process ◽  
Waste Water Treatment ◽  
Enzyme Synthesis ◽  
Plant Design ◽  
Unknown Parameters ◽  
Ecological Selection ◽  
Water Treatment Process ◽  
A Cell

Three mechanisms are responsible for microbiological elimination processes in activated sludge: the survival of qualified organisms in the ecological selection process, the expression of specific enzymes and the absence of inhibitors limiting enzyme activity. A mathematical model with structured biomass has been formulated to improve the description of data from denitrification experiments. The model includes synthesis and decay of denitrification enzymes and is able to predict nitrate, nitrite and N2O concentrations. Kinetic parameters have been estimated and used to simulate the effect of cell saturation with enzymes in a waste water treatment process. Low dissolved oxygen concentrations in the anoxic reactor reduce the denitrification efficiency equally by inhibiting enzyme activity and enzyme synthesis: at 0.5 gm−3 O2 enzyme decay causes a cell saturation of below 40 %. Enzyme synthesis can take place in the sludge blanket of a secondary sedimentation tank and improve denitrification efficiency. The benefit of modelling with structured biomass is shown. The comprehension of experimental observations has been improved, and plant design and operation can be optimized. However, the multitude of unknown parameters still may restrict the validity of complex models.

Structured modelling of denitrification intermediates

1995 ◽  
Vol 31 (2) ◽  
pp. 45-54 ◽  
Author(s):  
D. Wild ◽  
R. von Schulthess ◽  
W. Gujer
Keyword(s):  
Competitive Inhibition ◽  
Enzyme Synthesis ◽  
Plant Design ◽  
Low Oxygen ◽  
Unknown Parameters ◽  
Wastewater Treatment Process ◽  
Oxygen Inhibition ◽  
Complex Models ◽  
A Cell ◽  
Oxygen Concentrations

Two mathematical models have been formulated to describe the turnover of denitrification intermediates. Batch experiments with different nitrite concentrations have been performed to calibrate the models. In these experiments the concentration of oxygen in the reactor has been varied from 4 g O2m−3 to 0 g O2m−3. Model I includes the reduction of nitrate, nitrite, and nitrous oxide. Non-competitive inhibition of these processes by oxygen and nitrite has been included in the kinetics. The estimated parameters indicate that the net production of N2O at low oxygen concentrations can be explained by different oxygen inhibition of the three reduction steps. Model II works with structured biomass to improve the description of the data from the experiments. In addition to Model I, the synthesis and decay of denitrification enzymes are described to allow correct predictions of nitrate, nitrite and N2O concentrations. Model II has been used to simulate the effect of cell saturation with enzymes in a wastewater treatment process. Low dissolved oxygen concentrations in the anoxic reactor reduce the denitrification efficiency equally by inhibiting enzyme activity and enzyme synthesis: at 0.5 gm−3 O2 enzyme decay causes a cell saturation of below 40%. The benefits of modelling with structured biomass are shown: The comprehension of experimental observations is improved, and plant design and operation can be optimized. However, the multitude of unknown parameters still may restrict the application of complex models.

Commercialization of Pressurized Electroosmotic Dehydrator (PED)

1990 ◽  
Vol 22 (12) ◽  
pp. 259-268 ◽  
Author(s):  
S. Kondoh ◽  
M. Hiraoka
Keyword(s):  
Activated Sludge ◽  
Water Content ◽  
Treatment Process ◽  
Waste Water Treatment ◽  
Filter Press ◽  
Carbon Electrodes ◽  
Water Treatment Process ◽  
The World ◽  
First Time ◽  
Scanning Electron

Application of electroosmosis to conventional filter press dehydrators has been studied to decrease water content in the sludge generated from waste water treatment process. Experiments realized the reduction of water content in the biological excess activated sludge down to 50-60%, which had never been achieved by the conventional dewatering method. The new method has been commercialized by pre-concentration of the excess activated sludge, addition of electrolyte, and development of special carbon electrodes. Moreover, observation using a scanning electron microscope enabled us to demonstrate the suitability of the PED process to the excess activated sludge. The newly-developed dehydrators and processes have been operating successfully at three commercial plants for the first time in the world.

DESIGN PLANNING WASTEWATER TREATMENT PLANT OF NATA DE COCO INDUSTRY WITH THE ACTIVATED SLUDGE PROCESS

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Dinda Rita K. Hartaja ◽  
Imam Setiadi
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Appropriate Technology ◽  
Waste Water Treatment Plant ◽  
Activated Sludge Process ◽  
High Level

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL

Anaerobic-Aerobic Combined Process for the Treatment of Sewage with Nutrient Removal: The Ananox® Process

1992 ◽  
Vol 25 (7) ◽  
pp. 383-394 ◽  
Author(s):  
G. Garuti ◽  
M. Dohanyos ◽  
A. Tilche
Keyword(s):  
Organic Matter ◽  
Nutrient Removal ◽  
Treatment Process ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Warm Season ◽  
Combined Process ◽  
Water Treatment Process ◽  
A Value ◽  
N Removal

Results of a three year experience on a combined anaerobic-anoxic-oxic municipal waste water treatment process - named ANANOX® - are presented. This process demonstrated to be highly efficient, with 89.6% CODt, 89.2% TSS and 81.2% N removal, and a sludge production of only 0.2 kg TSS.kg COD removed−1, a value which is roughly 50% less if compared with traditional nitrification/denitrification processes. Sulphates play a very significant role in the process because, after being reduced in the anaerobic step, where they give a contribution to the organic matter degradation, they are reoxidized in the anoxic step by nitrates, reducing the organic matter need for denitrification. Due to the high dependence of efficiency on temperature, the system proposed has advantageous uses for sewage treatment, particularly in warm climates and in tourist and recreational areas where the population increases during the warm season.

scholarly journals Microgrids: The agria test location

2010 ◽  
Vol 14 (3) ◽  
pp. 747-758 ◽  
Author(s):  
Aleksandra Krkoleva ◽  
Verica Taseska ◽  
Natasa Markovska ◽  
Rubin Taleski ◽  
Vesna Borozan
Keyword(s):  
Treatment Process ◽  
Low Voltage ◽  
Waste Water Treatment ◽  
Test Results ◽  
Design Development ◽  
Water Treatment Process ◽  
Western Balkan Region ◽  
Pig Farm ◽  
Balkan Region ◽  
Test Scenarios

The paper presents the pilot Microgrid in Macedonia, developed within the framework of the MOREMICROGRIDS (EU EP6 projecet, contract No. SES6-019864) project. This Microgrid is the first of its kind being developed in the Western Balkan region and serves as pilot site for introduction and examination of the Microgrids concept in non European Union conditions. The test network consists of a part of the low voltage grid, located on a pig farm. The main electricity source for the Microgrid is a small biogas plant, which uses the biogas produced by a waste water treatment process. The paper addresses the Microgrid design, development of test scenarios and test results from the pilot location.

scholarly journals Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

2013 ◽  
pp. 31-42
Author(s):  
Olivera Babic ◽  
Jelica Simeunovic ◽  
Natasa Skrbic ◽  
Dajana Kovac ◽  
Zorica Svircev
Keyword(s):  
Enzyme Activity ◽  
Specific Property ◽  
Enzyme Synthesis ◽  
Ecological Group ◽  
Extreme Conditions ◽  
Survival Strategy ◽  
Acid Phosphatases ◽  
Nitrogen Fixing ◽  
Cyanobacterial Strain ◽  
Alkaline Phosphatases

Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 ?molpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 ?molpNP/s/dm3). The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 ?molpNP/s/dm3) compared to the activity of alkaline phosphatases (1.11-5.96 ?molpNP/s/dm3). Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions.

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