A benchmark simulation to verify an inhibition model on decay stage for nitrification

2013 ◽  
Vol 68 (6) ◽  
pp. 1242-1250 ◽  
Author(s):  
Bing Liu ◽  
Ian Jarvis ◽  
Daisuke Naka ◽  
Rajeev Goel ◽  
Hidenari Yasui
Keyword(s):  
Water Environment ◽  
Treatment Plant ◽  
Nitrifying Bacteria ◽  
Plant Design ◽  
Inhibition Model ◽  
Nitrification Process ◽  
Bulk Oxygen ◽  
Benchmark Datasets ◽  
One Step ◽  
Chemostat Reactor

Activated Sludge Models (ASMs) are widely used for biological wastewater treatment plant design, optimisation and operation. In commonly used ASMs, the nitrification process is modelled as a one-step process. However, in some process configurations, it is desirable to model the concentration of nitrite nitrogen through a two-step nitrification process. In this study, the benchmark datasets published by the Water Environment Research Foundation (WERF) were used to develop a two-step nitrification model considering the kinetics of Ammonium Oxidising Bacteria (AOB) and Nitrite Oxidising Bacteria (NOB). The WERF datasets were collected from a chemostat reactor fed about 1,000 mg-NH3-N/L synthetic influent with at different sludge retention times of 20, 10 and 5-d, whereas the pH in the reactor varied in the range of 5.8 and 8.8. Supplemental laboratory batch experiments were conducted to assess the toxicity of nitrite-N on nitrifying bacteria. These tests suggested that 500 mg-N/L of nitrite at pH 7.3 was toxic to NOB and resulted in continuous decrease in bulk oxygen uptake rate. To model this phenomenon, a poisoning model was used instead of the traditional Haldane-type inhibition model. The poisoning model for NOB and AOB with different threshold poisonings for unionised NO2-N and NH3-N concentrations could successfully reproduce the three WERF datasets.

Impact of seeding with nitrifying bacteria on nitrification process efficiency

2001 ◽  
Vol 43 (1) ◽  
pp. 155-164 ◽  
Author(s):  
E. Plaza ◽  
J. Trela ◽  
B. Hultman
Keyword(s):  
Simple Model ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Process Efficiency ◽  
Nitrifying Bacteria ◽  
Activated Sludge Process ◽  
Municipal Wastewater Treatment ◽  
Nitrification Process ◽  
High Fraction

Seeding of nitrifying bacteria into the activated sludge process was studied both theoretically and experimentally. A simple model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. The purpose of seeding is to improve the treatment results and the process stability as well as to decrease the volume requirements of the process. Pilot plant studies were carried out at the Uppsala municipal wastewater treatment plant in order to evaluate the effects of seeding. One line was supplied with supernatant from dewatering of digested sludge and the nitrification process gave an activated sludge with a high fraction of nitrifying bacteria, suitable for seeding. The other line was supplied with pre-precipitated wastewater and with the excess sludge from the line treating the supernatant. The experimental results showed that nitrification could be obtained at sludge ages that would otherwise preclude nitrification. Performance relationships for the system developed, based on laboratory and on-line measurements were studied and are presented. The studies show that seeding may decrease the necessary volume needs for a stable nitrification process and that the effects could be predicted by use of a simple model.

Wheal Jane mine water active treatment plant - design, construction and operation

2003 ◽  
Vol 11 (2) ◽  
pp. 245-252 ◽  
Author(s):  
Richard Coulton ◽  
Chris Bullen ◽  
John Dolan ◽  
Clive Hallett ◽  
Jim Wright ◽  
...  
Keyword(s):  
Active Treatment ◽  
Mine Water ◽  
Treatment Plant ◽  
Plant Design ◽  
Design Construction

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

Optimal Water Treatment Plant Design

1987 ◽  
Vol 113 (3) ◽  
pp. 567-584 ◽  
Author(s):  
Mark R. Wiesner ◽  
Charles R. O'Melia ◽  
Jared L. Cohon
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Plant Design

Flow and Load Variations in Treatment Plant Design

1978 ◽  
Vol 104 (2) ◽  
pp. 289-303
Author(s):  
James C. Young ◽  
John L. Cleasby ◽  
E. Robert Baumann
Keyword(s):  
Treatment Plant ◽  
Plant Design ◽  
Load Variations

Simultaneous immobilization of ammonium and phosphate from aqueous solution using zeolites synthesized from fly ashes

2013 ◽  
Vol 67 (6) ◽  
pp. 1324-1331 ◽  
Author(s):  
X. D. Ji ◽  
M. L. Zhang ◽  
Y. Y. Ke ◽  
Y. C. Song
Keyword(s):  
Sewage Treatment ◽  
Water Environment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Quality Standard ◽  
Exchange Capacity ◽  
Fly Ashes ◽  
Adsorption Processes ◽  
Equilibrium Data ◽  
Intra Particle Diffusion

Zeolites were synthesized from silica-rich (SF-Z) and calcium-rich (CF-Z) fly ashes, respectively, and their performance in immobilizing ammonium and phosphate was investigated through batch experiments. The cation exchange capacity and phosphate immobilization capacity of SF-Z were identified as 2.79 meq/g and 12.97 mg/g while those of CF-Z were 0.69 meq/g and 87.41 mg/g, respectively. The mixture of SF-Z and CF-Z (MSC-Z) immobilized simultaneously ammonium and phosphate, and the ratio of SF-Z to CF-Z depended on the ammonium and phosphate concentrations in wastewater and the discharge standard. The adsorption processes of ammonium and phosphate on MSC-Z followed Ho's pseudo-second-order model and the intra-particle diffusion was a rate-controlling step. The Langmuir model produced better suitability to the equilibrium data. The thermodynamic study revealed that the adsorption of both ammonium and phosphate on MSC-Z was an endothermic reaction. After treatment by MSC-Z, the ammonium and phosphate concentrations in wastewater from a sewage treatment plant decreased from 7.45 and 1.42 mg/L to 2.06 and 0.51 mg/L, respectively, and met Surface Water Environment Quality Standard in China δ. These results show that the immobilization of ammonium and phosphate in wastewater can be achieved by the combination of zeolites synthesized from silica-rich and calcium-rich fly ashes.

scholarly journals Efficiency of Biological Phosphorus Removal by Filamentous Bacteria

2016 ◽  
Vol 21 (1-2) ◽  
pp. 117-123 ◽  
Author(s):  
Alicja Machnicka ◽  
Klaudiusz Grübel
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Water Environment ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Heterogeneous Structure ◽  
Filamentous Bacteria ◽  
Biological Phosphorus Removal ◽  
High Concentration ◽  
Sludge Flocs

AbstractPhosphorus removal in wastewater treatment plant is carried out by chemical precipitation, advanced biological treatment or a combination of both. One of the biggest problems with high concentration of phosphorus in water environment is eutrophication. Activated sludge flocs have a heterogeneous structure, which consist of a variety of microorganisms. Filamentous bacteria are normally present in the activated sludge and have ability to assimilation of phosphorus. In this study phosphorus accumulation by isolated filamentous bacteria from activated sludge foam was present.

scholarly journals An Overview on Major Design Constraints, Impact and Challenges for a Conventional Wastewater Treatment Design

2020 ◽  
Vol 9 (1) ◽  
pp. 7-16
Keyword(s):  
Wastewater Treatment ◽  
Analytical Calculation ◽  
Treatment Plant ◽  
Field Application ◽  
Design Parameters ◽  
Plant Design ◽  
Political Commitment ◽  
Design Constraints ◽  
Technical Requirements ◽  
Set Up

The conventional wastewater (WW) treatment plant includes physical, chemical, and biological treatment processes that can protect the receiving water bodies from water pollution. The common design constraints, challenges as well as environmental impact would make the wastewater treatment plant’s (WWTP) construction and operation more complex and demanding tasks. Major project constraints for WW plant design are economic, accessibility, fulfilling technical requirements, institutional set-up, health and environment, personnel capacity, and political commitment etc. Design methodology adopted in the current study included project location, unit selections, the design capacity, design period as well as proximity to the population and layout plan. The present manuscript discussed briefly about effluent quality requirements, design issues, environmental impacts, details, and safety concerns. It also highlighted the necessary flexibility to carry out satisfactorily within the desired range of influent WW characteristics and flows. In the present study, every step of the design was verified with Environmental Regulations and suggested to overcome all constraints while designing WWTPs so that standard operational code for the specific region could be implemented to achieve the best treatment performance. The results obtained from analytical calculation were optimized to achieve the best design parameters for field application. The optimized values also reduce the construction and operation cost during the field application.

Oxygen Theory in Biological Treatment Plant Design

1972 ◽  
Vol 98 (3) ◽  
pp. 471-489
Author(s):  
Dilip S. Mehta ◽  
Harry H. Davis ◽  
Robert P. Kingsbury
Keyword(s):  
Biological Treatment ◽  
Treatment Plant ◽  
Plant Design
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