CFD Analysis on Biogas Bubble Creation Within a Stirred Tank of a Wastewater Treatment Plant

Treatment Plant ◽

Fluid Flows ◽

Stirred Tank ◽

Dead Volume ◽

Homogeneous Fluid ◽

Multiphase Fluid ◽

Mixer Rotation

Abstract A mixing strategy for assuring a homogeneous fluid flow inside wastewater treatment plants (WWTPs) is a necessity, in order to keep continuous contacts of substrates and degraders. On the other hand, mixing is an energy-demanding process. Therefore, the power consumption for mixing the fluid flow within bioreactors affects the overall efficiency of WWTPs. The current study aims at evaluating the incorporation of biogas bubble creation on the mixing of WWTP tanks. Computational fluid dynamics (CFD) enables simulating hydrodynamics of multiphase fluid flows injected with bubble parcels. The case is a cylindrical stirred tank, in which the fluid flow is agitated via a rotating mixer. Mixer rotates at various speeds; and for each case, the ultimate fluid flow is captured both with and without bubble creation. Non-Newtonian characteristics of the fluid flow within the tank are considered and k–ε turbulence closure is selected for the model. By a two-way coupling of an Eulerian-Lagrangian platform, velocity fields and the amount of dead volume are analyzed and discussed. Our key finding is that the biogas bubble creation contributes to the reduction of dead volume inside the WWTP tank, when there is no external rotating mixing, or once the amount of mixer rotation speed is low.

Analysis and balance of phosphorous removal from wastewater at urban wastewater treatment plant

Pollack Periodica ◽

10.1556/606.2020.15.2.13 ◽

2020 ◽

Vol 15 (2) ◽

pp. 142-151

Author(s):

Peter Lukac ◽

Lubos Jurik

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Phosphorus Recovery ◽

Anaerobic Sludge ◽

Biological Phosphorus Removal ◽

The Mean

Abstract:Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.

Sludge minimization by disintegration at different wastewater treatment plants

Water Practice & Technology ◽

10.2166/wpt.2008.010 ◽

2008 ◽

Vol 3 (1) ◽

Author(s):

Luchien Luning ◽

Paul Roeleveld ◽

Victor W.M. Claessen

Keyword(s):

Organic Matter ◽

Wastewater Treatment ◽

Anaerobic Digestion ◽

Sewage Sludge ◽

New Technologies ◽

Treatment Plant ◽

Biological Degradation ◽

Ongoing Research ◽

Sludge Minimization

In recent years new technologies have been developed to improve the biological degradation of sewage sludge by anaerobic digestion. The paper describes the results of a demonstration of ultrasonic disintegration on the Dutch Wastewater Treatment Plant (WWTP) Land van Cuijk. The effect on the degradation of organic matter is presented, together with the effect on the dewatering characteristics. Recommendations are presented for establishing research conditions in which the effect of sludge disintegration can be determined in a more direct way that is less sensitive to changing conditions in the operation of the WWTP. These recommendations have been implemented in the ongoing research in the Netherlands supported by the National Institute for wastewater research (STOWA).

Planning Replicable Small Flow Wastewater Treatment Facilities in Developing Nations

10.2166/wst.1993.0196 ◽

1993 ◽

Vol 28 (10) ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

A. Gaber ◽

M. Antill ◽

W. Kimball ◽

R. Abdel Wahab

Keyword(s):

Wastewater Treatment ◽

Local Development ◽

Treatment Plant ◽

Development Program ◽

The United States ◽

Appropriate Technology ◽

Funding Agency ◽

Small Scale ◽

Technology Choice

The implementation of urban village wastewater treatment plants in developing countries has historically been primarily a function of appropriate technology choice and deciding which of the many needy communities should receive the available funding and priority attention. Usually this process is driven by an outside funding agency who views the planning, design, and construction steps as relatively insignificant milestones in the overall effort required to quickly better a community's sanitary drainage problems. With the exception of very small scale type sanitation projects which have relatively simple replication steps, the development emphasis tends to be on the final treatment plant product with little or no attention specifically focused on community participation and institutionalizing national and local policies and procedures needed for future locally sponsored facilities replication. In contrast to this, the Government of Egypt (GOE) enacted a fresh approach through a Local Development Program with the United States AID program. An overview is presented of the guiding principals of the program which produced the first 24 working wastewater systems including gravity sewers, sewage pumping stations and wastewater treatment plants which were designed and constructed by local entities in Egypt. The wastewater projects cover five different treatment technologies implemented in both delta and desert regions.

Aerial Mapping of Odorous Gases in a Wastewater Treatment Plant Using a Small Drone

Remote Sensing ◽

10.3390/rs13091757 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1757

Author(s):

Javier Burgués ◽

María Deseada Esclapez ◽

Silvia Doñate ◽

Laura Pastor ◽

Santiago Marco

Keyword(s):

Wastewater Treatment ◽

Treatment Plant ◽

Principal Component ◽

Hazardous Air Pollutants ◽

Sampling System ◽

Aerial Mapping ◽

Sensor Signals ◽

Current Monitoring ◽

Flexible Tubes

Wastewater treatment plants (WWTPs) are sources of greenhouse gases, hazardous air pollutants and offensive odors. These emissions can have negative repercussions in and around the plant, degrading the quality of life of surrounding neighborhoods, damaging the environment, and reducing employee’s overall job satisfaction. Current monitoring methodologies based on fixed gas detectors and sporadic olfactometric measurements (human panels) do not allow for an accurate spatial representation of such emissions. In this paper we use a small drone equipped with an array of electrochemical and metal oxide (MOX) sensors for mapping odorous gases in a mid-sized WWTP. An innovative sampling system based on two (10 m long) flexible tubes hanging from the drone allowed near-source sampling from a safe distance with negligible influence from the downwash of the drone’s propellers. The proposed platform is very convenient for monitoring hard-to-reach emission sources, such as the plant’s deodorization chimney, which turned out to be responsible for the strongest odor emissions. The geo-localized measurements visualized in the form of a two-dimensional (2D) gas concentration map revealed the main emission hotspots where abatement solutions were needed. A principal component analysis (PCA) of the multivariate sensor signals suggests that the proposed system can also be used to trace which emission source is responsible for a certain measurement.

Broad diversity of bacteria degrading 17ß-estradiol-3-sulfate isolated from river sediment and biofilm at a wastewater treatment plant discharge

Archives of Microbiology ◽

10.1007/s00203-021-02409-0 ◽

2021 ◽

Author(s):

Tamara Mainetti ◽

Marilena Palmisano ◽

Fabio Rezzonico ◽

Blaž Stres ◽

Susanne Kern ◽

...

Keyword(s):

Wastewater Treatment ◽

River Sediment ◽

Treatment Plant ◽

Aquatic Environments ◽

Bacterial Isolates ◽

Degrading Bacteria ◽

17Β Estradiol ◽

Aquatic Wildlife ◽

Harmful Effects

AbstractConjugated estrogens, such as 17β-estradiol-3-sulfate (E2-3S), can be released into aquatic environments through wastewater treatment plants (WWTP). There, they are microbiologically degraded into free estrogens, which can have harmful effects on aquatic wildlife. Here, the degradation of E2-3S in environmental samples taken upstream, downstream and at the effluent of a WWTP was assessed. Sediment and biofilm samples were enriched for E2-3S-degrading microorganisms, yielding a broad diversity of bacterial isolates, including known and novel degraders of estrogens. Since E2-3S-degrading bacteria were also isolated in the sample upstream of the WWTP, the WWTP does not influence the ability of the microbial community to degrade E2-3S.

Removal improvement of bacteria (Escherichia coli and enterococci) in maturation ponds using baffles

10.2166/wst.2012.896 ◽

2012 ◽

Vol 65 (4) ◽

pp. 589-595 ◽

Cited By ~ 5

Author(s):

A. Ouali ◽

H. Jupsin ◽

J. L. Vasel ◽

L. Marouani ◽

A. Ghrabi

Keyword(s):

Escherichia Coli ◽

Wastewater Treatment ◽

Treatment Plant ◽

E Coli ◽

Conventional Activated Sludge ◽

In Series ◽

Hydrodynamic Study ◽

Rhodamine Wt ◽

Engineering Intervention

Korba wastewater treatment plant is a conventional activated sludge followed by three maturation ponds (MP1, MP2, MP3) in series acting as a tertiary treatment. The first study of wastewater treatment plants showed that the effluent concentration of Escherichia coli and enterococci at the outlet of the (MP3) varies between 103 and 104CFU/100 ml. After the hydrodynamic study conducted by Rhodamine WT which showed short-circuiting in the MP1, two baffles were introduced in the first maturation pond (MP1) to improve the hydrodynamic and the sanitary performances. The second hydraulic study showed that the dispersion number ‘d’ was reduced from 1.45 to 0.43 by this engineering intervention and the Peclet number was raised from 0.69 to 2.32. The hydraulic retention time was increased by 14 h. Because of well-designed baffles, the removal efficiency of E. coli and enterococci was raised between 0.2 and 0.7 log units for the first maturation pond.

Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants

10.2166/wst.2013.004 ◽

2013 ◽

Vol 67 (7) ◽

pp. 1481-1489 ◽

Cited By ~ 36

Author(s):

R. Barat ◽

J. Serralta ◽

M. V. Ruano ◽

E. Jiménez ◽

J. Ribes ◽

...

Keyword(s):

Wastewater Treatment ◽

Nitrogen Removal ◽

Nutrient Removal ◽

Treatment Plant ◽

Operating Conditions ◽

Plant Performance ◽

Biological Nutrient Removal ◽

Nitrite Oxidizing Bacteria ◽

Removal Model

This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via nitrite, apart from nitrite oxidizing bacteria two groups of ammonium oxidizing organisms (AOO) have been considered since different sets of kinetic parameters have been reported for the AOO present in activated sludge systems and SHARON (Single reactor system for High activity Ammonium Removal Over Nitrite) reactors. Due to the new processes considered, BNRM2 allows an accurate prediction of wastewater treatment plant performance in wider environmental and operating conditions.

Use of modelling for optimization and upgrade of a tropical wastewater treatment plant in a developing country

10.2166/wst.2007.675 ◽

2007 ◽

Vol 56 (7) ◽

pp. 21-31 ◽

Cited By ~ 6

Author(s):

D. Brdjanovic ◽

M. Mithaiwala ◽

M.S. Moussa ◽

G. Amy ◽

M.C.M. van Loosdrecht

Keyword(s):

Wastewater Treatment ◽

Developing Country ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Coupled Model ◽

Reject Water ◽

Complex Interactions ◽

N Removal ◽

Discharge Criteria

This paper presents results of a novel application of coupling the Activated Sludge Model No. 3 (ASM3) and the Anaerobic Digestion Model No.1 (ADM1) to assess a tropical wastewater treatment plant in a developing country (Surat, India). In general, the coupled model was very capable of predicting current plant operation. The model proved to be a useful tool in investigating various scenarios for optimising treatment performance under present conditions and examination of upgrade options to meet stricter and upcoming effluent discharge criteria regarding N removal. It appears that use of plant-wide modelling of wastewater treatment plants is a promising approach towards addressing often complex interactions within the plant itself. It can also create an enabling environment for the implementations of the novel side processes for treatment of nutrient-rich, side-streams (reject water) from sludge treatment.

OPTIMIZING OPERATION OF WASTEWATER TREATMENT PLANTS BY OFFLINE AND ONLINE COMPUTER SIMULATION

10.2166/wst.1994.0040 ◽

1994 ◽

Vol 30 (2) ◽

pp. 165-174 ◽

Cited By ~ 4

Author(s):

Ralf Otterpohl ◽

Thomas Rolfs ◽

Jörg Londong

Keyword(s):

Computer Simulation ◽

Wastewater Treatment ◽

Activated Sludge ◽

Nitrogen Removal ◽

Treatment Plant ◽

Historical Analysis ◽

Computer Work ◽

Biological Phosphorus Removal ◽

Wide Range

Computer simulation of activated sludge plant for nitrogen removal has become a reliable tool to predict the behaviour of the plant Models including biological phosphorus removal still require some practical experience but they should be available soon. This will offer an even wider range than today's work with nitrogen removal. One major benefit of computer simulation of wastewater treatment plants (WTP) is the optimization of operation. This can be done offline if hydrographs of a plant are collected and computer work is done with “historical” analysis. With online simulation the system is fed with hydrographs up to the actual time. Prognosis can be done from the moment of the computer work based on usual hydrographs. The work of the authors shows how accuratly a treatment plant can be described, when many parameters are measured and available as hydrographs. A very careful description of all details of the special plant is essential, requiring a flexible simulation tool. Based on the accurate simulation a wide range of operational decisions can be evaluated. It was possible to demonstrate that the overall efficiency in nitrogen removal and energy consumption of ml activated sludge plant can be improved.

Integrated Wastewater Treatment Plant Performance Evaluation Using Artificial Neural Networks

10.2166/wst.1999.0327 ◽

1999 ◽

Vol 40 (7) ◽

pp. 55-65 ◽

Cited By ~ 12

Author(s):

Mohamed F. Hamoda ◽

Ibrahim A. Al-Ghusain ◽

Ahmed H. Hassan

Keyword(s):

Neural Networks ◽

Wastewater Treatment ◽

Artificial Neural Networks ◽

Wastewater Treatment Plant ◽

Municipal Wastewater ◽

Treatment Plant ◽

Plant Performance ◽

Municipal Wastewater Treatment ◽

Artificial Neural

Proper operation of municipal wastewater treatment plants is important in producing an effluent which meets quality requirements of regulatory agencies and in minimizing detrimental effects on the environment. This paper examined plant dynamics and modeling techniques with emphasis placed on the digital computing technology of Artificial Neural Networks (ANN). A backpropagation model was developed to model the municipal wastewater treatment plant at Ardiya, Kuwait City, Kuwait. Results obtained prove that Neural Networks present a versatile tool in modeling full-scale operational wastewater treatment plants and provide an alternative methodology for predicting the performance of treatment plants. The overall suspended solids (TSS) and organic pollutants (BOD) removal efficiencies achieved at Ardiya plant over a period of 16 months were 94.6 and 97.3 percent, respectively. Plant performance was adequately predicted using the backpropagation ANN model. The correlation coefficients between the predicted and actual effluent data using the best model was 0.72 for TSS compared to 0.74 for BOD. The best ANN structure does not necessarily mean the most number of hidden layers.