Effects of increased influent nitrogen load on a part-time aerated activated sludge system

2013 ◽  
Vol 8 (1) ◽  
pp. 18-26
Author(s):  
T. Weinpel ◽  
V. Bakos ◽  
A. Jobbágy
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Ammonia Concentration ◽  
Content Increase ◽  
The North ◽  
Mathematical Simulations ◽  
Part Time ◽  
Anoxic Zones ◽  
Activated Sludge Systems

Part-time aeration is frequently applied in activated sludge systems in order to decrease treatment costs by achieving nitrification and denitrification in the same basin. However, measurements and mathematical simulations carried out at the North-Budapest Wastewater Treatment Plant (Budapest, Hungary), clearly show that especially in the increasingly characteristic shortage of readily biodegradable carbon-source, this technique may lead to high effluent nitrate and/or ammonia concentrations at decreased temperatures. This situation may be worsened when co-digestion of external wastes with high N-content increase the ammonia concentration of sludge processing return flows. In these cases, denitrification should rather be enhanced in pre-anoxic zones. Pronounced pre-denitrification leads to better usage of the influent carbon-source and to considerably less methanol demand when dosing external carbon-source proves to be necessary.

Study of factors affecting simultaneous nitrification and denitrification (SND)

1999 ◽  
Vol 39 (6) ◽  
pp. 61-68 ◽  
Author(s):  
Klangduen Pochana ◽  
Jürg Keller
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Physical Phenomenon ◽  
Treatment Plant ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Factors Affecting ◽  
Floc Size ◽  
Sludge Flocs ◽  
Activated Sludge Systems

Experiments have been performed to gain an understanding of the conditions and processes governing the occurrence of SND in activated sludge systems. Sequencing batch reactors (SBRs) have been operated under controlled conditions using the wastewater from the first anaerobic pond in an abattoir wastewater treatment plant. Under specific circumstances, up to 95% of total nitrogen removal through SND has been found in the system. Carbon source and oxygen concentrations were found to be important process parameters. The addition of acetate as an external carbon source resulted in a significant increase of SND activity in the system. Stepwise change of DO concentration has also been observed in this study. Experiments to determine the effect of the floc size on SND have been performed in order to test the hypothesis that SND is a physical phenomenon, governed by the diffusion of oxygen into the activated sludge flocs. Initial results support this hypothesis but further experimental confirmation is still required.

Small Activated Sludge Performance and Viability Characteristics under Intermittent and Reduced Flows

1993 ◽  
Vol 28 (10) ◽  
pp. 309-316
Author(s):  
Bilsen Beler Baykal
Keyword(s):  
Activated Sludge ◽  
System Performance ◽  
Treatment Plant ◽  
Generation Model ◽  
Transient States ◽  
Stepwise Manner ◽  
Seasonal Basis ◽  
Soluble Substrate ◽  
House Site ◽  
Activated Sludge Systems

Small activated sludge systems operate in transient states under intermittent and variable flows. Simulations for such a treatment plant in a summer house site operating on a seasonal basis is investigated for system performance and viability using the five component inert soluble substrate generation model. The results have revealed that the viability drops to zero within the first month after the cessation of the feed for intermittently loaded systems that are fed during the summer months, while it never reaches that value for systems operating all year round with reduced flows off season. Restartup is compulsory for the intermittent loadings while the system adapts itself in a stepwise manner for the year round operation. Other factors being comparable, conventional operation with shorter sludge ages may be preferable since viability of the sludge is higher and the effluent COD is comparable.

Treatment of organic chlorine in pulping effluents by activated sludge

1999 ◽  
Vol 40 (1) ◽  
pp. 275-279 ◽  
Author(s):  
G. (Goktayoglu) Demirbas ◽  
C. F. Gokcay ◽  
F. B. Dilek
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Organic Content ◽  
Domestic Sewage ◽  
Municipal Sewage ◽  
Removal Mechanism ◽  
Start Up ◽  
Organic Chlorine ◽  
Aox Removal

A model activated sludge (AS) plant was fed by pulping effluents from a straw and reed processing paper works. The model was initially operated to simulate a dedicated treatment plant by continuously receiving chlorinated effluents from the pulp bleachery. In this simulation cycle the model activated sludge was seeded only once during start-up and did not receive any domestic sewage after that. A carbon source was added in some of the experiments to bring up the organic content. In the second simulation cycle the pulping effluent was co-treated with municipal sewage. In this case the activated sludge unit was being continuously dosed by microorganisms and the organics present in the sewage. A higher organic chlorine (AOX) removal was obtained at shorter SRTs in the co-treatment AS. High AOX removal was achieved at longer SRTs in the dedicated, once-seeded AS. The AOX removal mechanism was mineralization in both cycles.

Virus elimination in activated sludge systems: from batch tests to mathematical modeling

2014 ◽  
Vol 70 (6) ◽  
pp. 1115-1121 ◽  
Author(s):  
Emma Haun ◽  
Katharina Ulbricht ◽  
Regina Nogueira ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Virus Concentration ◽  
Extended Model ◽  
Municipal Wastewater Treatment ◽  
Virus Elimination ◽  
Somatic Coliphages ◽  
Batch Tests ◽  
Activated Sludge Systems

A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents.

scholarly journals Biological Treatment Of Simulated Humic Acid Wasre Water In A Laboratory Scale Aerobic Reactor

REAKTOR ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Yunardi Yunardi
Keyword(s):  
Humic Acid ◽  
Carbon Source ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Ammonium Nitrogen ◽  
Synthetic Wastewater ◽  
Waste Water Treatment Plant ◽  
Organic Carbon Concentration

A laboratory study was  conducted to determine the feasibility of activated sludge reactor for treating humic acid waste waterand examine the effect of the presence of glucose as the second carbon source on treatment performance. Activated sludge obtained from a waste water treatment plant treating domestic wastewater was used as a seed for reactors. Synthetic wastewater containing humid acid as the sole carbon source and glucose as the second carbon source were used as feeds for the reactors operated in a fill-and-draw mode. The result showed  tht the presence of glucose in the wastewater enhanced the production of higher MLSS (mixed liquor suspended solids) than that without of glucose. The TOC (Total Organic Carbon) concentration in both reactors fluctuated greatly until the end of the experiment due to inability of keeping the input TOC at desired level. However the decrease in TOC suggested that there are some microorganisms capable of degrading the humic acid. Addition of glucose to the simulated humic acid wastewater improved the capability of microbes in degrading the acids. Most ammonium nitrogen in the wastewater was converted to nitrate nitrogen. Although the performance was lower compared to that of conventional system, activated sludge process was capable of degrading wastewater containing humic acids.Keywords : activated sludge, ammonium nitrogen, fill and draw, glucose, humic acid, wastewater

Microbial population dynamics in laboratory-scale activated sludge reactors

2002 ◽  
Vol 46 (1-2) ◽  
pp. 19-27 ◽  
Author(s):  
K. Kaewpipat ◽  
C.P.L. Grady
Keyword(s):  
Activated Sludge ◽  
Microbial Communities ◽  
System Performance ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Treatment Plant ◽  
Laboratory Scale ◽  
Rrna Gene ◽  
Significant Finding ◽  
Prokaryotic Community ◽  
Activated Sludge Systems

As a first step in understanding nonlinear dynamics in activated sludge systems, two laboratory-scale sequencing batch reactors were operated under identical conditions and changes in their microbial communities were followed through microscopic examination, macroscopic observation, and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene segments from the prokaryotic community. Two experiments were performed. The first used activated sludge from a local wastewater treatment plant to start the replicate reactors. The second used the biomass from the first experiment as a source by intermixing the two and equally redistributing the biomass into the two replicate reactors. For both experiments, the two reactors behaved fairly similarly and had similar microbial communities for a period of 60 days following start-up. Beyond that, the microbial communities in the two reactors in the first experiment diverged in composition, while those in the second experiment remained fairly similar. This suggests that the degree of change occurring in replicate reactors depends upon the severity of perturbation to which they are exposed. The DGGE data showed that the bacterial communities in both experiments were highly dynamic, even though the system performance of the replicate reactors were very similar, suggesting that dynamics within the prokaryotic community is not necessarily reflected in system performance. Moreover, a significant finding from this study is that replicate activated sludge systems are not identical, although they can be very similar if started appropriately.

scholarly journals Coke oven wastewater treatment by two activated sludge systems

2013 ◽  
Vol 8 (1) ◽  
pp. 16-22
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Coke Oven ◽  
Synthetic Wastewater ◽  
Removal Efficiencies ◽  
Activated Sludge Systems

In this study two bench scale activated sludge systems were used, a CSTR and an SBR for the treatment of coke – oven wastewater. Both reactors were inoculated with activated sludge from a municipal wastewater treatment plant. At the first stages of operation, reactors were feed by a mixture of municipal wastewater and synthetic wastewater. Full acclimatization of the microorganisms to synthetic wastewater was achieved in 60 days. The operation of the reactors was divided into three distinct periods. The first period was characterized by the treatment of high organic but non-toxic synthetic wastewater. During this period COD and BOD5 removal efficiencies reached 95 and 98% respectively, in both reactors. Nutrient removal was better in the SBR reactor rather than in the CSTR. In the second period phenol was added in concentrations up to 300 mg l-1. Degradation of phenol started about the 20th day after its introduction to the reactors. In this period no effects of phenol to nutrient removal were observed, whereas the removal efficiency of organic matter in both reactors was slightly decreased. During the third period phenol concentrations of the influent were gradually increased to 1000 mg l-1, while cyanide and thiocyanite were added to the influent composition to concentrations reaching concentrations of 20 and 250 mg l-1 respectively. The composition of the influent of this period was a full assimilation of coke oven wastewater. Introduction of increased phenol concentrations along with cyanide compounds initiated irreversible effects on the activated sludge microfauna of the CSTR causing inherent problems to the treatment process, while SBR showed greater capacity to withstand and degrade toxic compounds. The beginning of this period was characterized by decreased settleability of the suspended solids as well as decrease of organic matter and nutrient removal efficiencies. Monitoring of the effluent characteristics during this period reported over 90% for organic load, 85% of nutrient removal and over 90% of phenol and cyanide removal in SBR, while the removal efficiencies for the CSTR were 75, 65 and 80% respectively.

Model and Sensor Based Optimization of Nitrogen Removal at Klagshamn Wastewater Treatment Plant

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1315-1323 ◽  
Author(s):  
H. Aspegren ◽  
B. Andersson ◽  
U. Nyberg ◽  
J. la C. Jansen
Keyword(s):  
Wastewater Treatment ◽  
Carbon Source ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
On Line ◽  
Ammonia Sensors

Optimization of wastewater treatment plants with extensive phosphorus and nitrogen removal is complicated. The Klagshamn wastewater treatment plant in Sweden is operated with pre-precipitation of phosphorus with ferric chloride and denitrification with methanol as carbon source. An activated sludge process, operated with pre-precipitation and denitrification with external carbon source in a compartmentalized plant, requires only small tank volumes but increases the need for proper operation and optimization. On-line nitrogen, ammonia, and TOC sensors are used for a day-to-day control and optimization while mathematical modelling is used for long term strategic planning. The on-line measurements are further used as the basis for the modelling. TOC and ammonia sensors at the influent clearly identify typical and extreme loading variations and nitrate measurements in the activated sludge tanks and the effluent shows the dynamics of the processes. These measurements provide a basis for model calibration. In combination low residuals of nitrogen, phosphorus and organic matter can be achieved.

The implementation of biokinetics and conservation principles in ASIM

1995 ◽  
Vol 31 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Willi Gujer ◽  
Tove A. Larsen
Keyword(s):  
Activated Sludge ◽  
Dynamic Behaviour ◽  
Control Strategies ◽  
Treatment Plant ◽  
Practical Application ◽  
Biokinetic Model ◽  
Conservation Principles ◽  
Definition Of ◽  
Transformation Processes ◽  
Activated Sludge Systems

The Activated Sludge SIMulation program ASIM is introduced as a didactic tool to be used in design courses for the simulation of the dynamic behaviour of modern nutrient removal activated sludge systems. It allows for free definition of the biokinetic model, the flow scheme, process control strategies and load variation. Its user interface is simple enough to be used in the classroom but powerful enough to support even professional work. The most difficult aspect of ASIM is the preparation of the biokinetic model (transformation processes) to be used. A systematic use of stoichiometric conservation principles simplifies this task and at the same time reduces the number of empirical parameters. The practical application of conservation principles for charge, elements and theoretical COD is presented in detail. Composition equations are introduced as a link to the wastewater treatment plant reality.

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