Modelling and simulation revealing mechanisms likely responsible for achieving the nitrite pathway through aeration control

2010 ◽  
Vol 61 (6) ◽  
pp. 1459-1465 ◽  
Author(s):  
A. Guisasola ◽  
M. Marcelino ◽  
R. Lemaire ◽  
J. A. Baeza ◽  
Z. Yuan

Nitrogen removal via nitrite has recently gained a lot of interest because it results in significant savings in both aeration costs and COD (chemical oxygen demand) requirements for denitrification, when compared to the conventional biological nitrogen removal via nitrate. The effectiveness of two different control strategies to achieve the nitrite pathway in systems with sludge retention has been experimentally demonstrated: (i) control of aerobic phase length, with which aeration is terminated as soon as ammonia is completely oxidised; (ii) operation at low DO setpoints in the aerobic phase. These strategies have been extensively studied in nitrifying reactors and are currently applied in real systems achieving biological carbon, nitrogen and phosphorus removal. In this work, we aim to demonstrate, through modelling and simulation, that the competition between nitrite reducers and nitrite oxidisers for nitrite, rather than kinetic selection plays a major role in NOB washout. Moreover, the results show that the occurrence of simultaneous nitrification and denitrification under “aerobic” conditions is very helpful for the nitrite pathway obtainment and for a more efficient COD utilisation.

1993 ◽  
Vol 28 (11-12) ◽  
pp. 549-560 ◽  
Author(s):  
Dines E. Thornberg ◽  
Marinus K. Nielsen ◽  
Klaus L. Andersen

New control strategy principles with respect to nitrogen and phosphorus removal in activated sludge plants are described. The principles include control of phase length and oxygen set point based on criteria functions and continuous on-line measurements of ammonium, nitrate, phosphate and pH. Five case studies are stated which describe improvements in biological nitrogen and phosphorus removal and in chemical phosphorus removal at activated sludge plants ranging from 5000 to 220000 population equivalents (0.25 to 11 MGD). The improvements due to the new strategies are basically a reduction of nutrients in the effluent and a reduction in the amount of chemicals and electricity consumed.


2010 ◽  
Vol 62 (8) ◽  
pp. 1745-1754 ◽  
Author(s):  
X. Chen ◽  
T. Fujiwara ◽  
K. Ohtoshi ◽  
S. Inamori ◽  
K. Nakamachi ◽  
...  

A novel oxidation ditch system using anaerobic tanks and innovative dual dissolved oxygen (DO) control technology is proposed for biological nitrogen and phosphorus removal from domestic sewage. A continuous bench-scale experiment running for more than 300 days was performed to evaluate the system. Monitoring and controlling the airflow and recirculation flow rate independently using DO values at two points along the ditch permitted maintenance of aerobic and anoxic zone ratios of around 0.30 and 0.50, respectively. The ability to optimize aerobic and anoxic zone ratios using the dual DO control technology meant that a total nitrogen removal efficiency of 83.2–92.9% could be maintained. This remarkable nitrogen removal performance minimized the nitrate recycle to anaerobic tanks inhibiting the phosphorus release. Hence, the total phosphorus removal efficiency was also improved and ranged within 72.6–88.0%. These results demonstrated that stabilization of the aerobic and anoxic zone ratio by dual DO control technology not only resulted in a marked improvement of nitrogen removal, but it also enhanced phosphorus removal.


2004 ◽  
Vol 50 (6) ◽  
pp. 87-94 ◽  
Author(s):  
J. Ferrer ◽  
J.J. Morenilla ◽  
A. Bouzas ◽  
F. Garcia-Usach

Control and optimisation of plant processes has become a priority for WWTP managers. The calibration and verification of a mathematical model provides an important tool for the investigation of advanced control strategies that may assist in the design or optimization of WWTPs. This paper describes the calibration of the ASM2d model for two full scale biological nitrogen and phosphorus removal plants in order to characterize the biological process and to upgrade the plants' performance. Results from simulation showed a good correspondence with experimental data demonstrating that the model and the calibrated parameters were able to predict the behaviour of both WWTPs. Once the calibration and simulation process was finished, a study for each WWTP was done with the aim of improving its performance. Modifications focused on reactor configuration and operation strategies were proposed.


2013 ◽  
Vol 67 (7) ◽  
pp. 1425-1433 ◽  
Author(s):  
E. Desmidt ◽  
A. Monballiu ◽  
H. De Clippeleir ◽  
W. Verstraete ◽  
B. D. Meesschaert

Anaerobic digestion yields effluents rich in ammonium and phosphate and poor in biodegradable organic carbon, thereby making them less suitable for conventional biological nitrogen and phosphorus removal. In addition, the demand for fertilizers is increasing, energy prices are rising and global phosphate reserves are declining. This requires both changes in wastewater treatment technologies and implementation of new processes. In this contribution a description is given of the combination of a ureolytic phosphate precipitation (UPP) and an autotrophic nitrogen removal (ANR) process on the anaerobic effluent of a potato processing company. The results obtained show that it is possible to recover phosphate as struvite and to remove the nitrogen with the ANR process. The ANR process was performed in either one or two reactors (partial nitritation + Anammox). The one-reactor configuration operated stably when the dissolved oxygen was kept between 0.1 and 0.35 mg L−1. The best results for the two-reactor system were obtained when part of the effluent of the UPP was fully nitrified in a nitritation reactor and mixed in a 3:5 volumetric ratio with untreated ammonium-containing effluent. A phosphate and nitrogen removal efficiency of respectively 83 ± 1% and of 86 ± 7% was observed during this experiment.


Author(s):  
Giedre Vaboliene ◽  
Algirdas Bronislovas Matuzevičius

Nitrogen and phosphorus removal is necessary to avoid eutrophication of water bodies when treated wastewater is outlet to slowly flowing water bodies or recycled as technological water. The “BioBalance” technology as the latest way of nitrogen and phosphorus removal was applied at Utena Wastewater Treatment Plant. Composition of wastewater has an impact on biological phosphorus removal, particularly the ratio of biochemical oxygen demand and total phosphorus (BOD7/Total-P) in wastewater after mechanical treatment. Nitrates in the anaerobic zone can have a negative effect on biological phosphorus removal. Consequently, it is necessary to evaluate the impact of the mentioned factors on biological nitrogen and phosphorus removal. Biological nitrogen and phosphorus removal was evaluated and compared by using the “BioBalance” technology for biological nitrogen and phosphorus removal and technology before reconstruction during this investigation. The correlation regressive analysis of the biochemical oxygen demand and total phosphorus (BOD7/Total‐P) after mechanical treatment and the total phosphorus concentration in the effluent was evaluated. The correlation regressive analysis of nitrates in an anaerobic zone on the aeration tank and the efficiency of phosphorus removal was also evaluated.


2001 ◽  
Vol 43 (6) ◽  
pp. 185-192 ◽  
Author(s):  
E. Choi ◽  
Z. Yun ◽  
Y. Park ◽  
H. Lee ◽  
H. Jeong ◽  
...  

Experimental investigations were performed to determine the possibility of simultaneous biological nitrogen and phosphorus removal during various biofilm processes in conjunction with biofilm characterisation, especially extracellular polymeric substance (EPS). Since biological nitrogen removal requires an alternating exposure of anaerobic-anoxic-oxic conditions in the bulk liquid that surrounds the biofilm growth media, a sequencing batch reactor (SBR)-type operation was used. Various materials including expanded clay, polystyrene, polyurethane, and acrylic materials were used as the biofilm growth support medium. Simultaneous nitrogen and phosphorus removal was possible with SBR, but it was postulated that nutrient removal efficiencies varied with film thickness. Thinner biofilm promoted nitrification and phosphorus removal, but thicker biofilm enhanced denitrification and reduced phosphorus removal. EPS contents were similar regardless of support media types or biofilm configuration, but EPS contents gradually increased as the film growth continued after backwashing. EPS contents were increased with increased nitrogen removal, but it was difficult to define its relation with phosphorus removal. In addition, suspended solids removal was correlated well with the EPS content in the biofilms.


2016 ◽  
Vol 74 (6) ◽  
pp. 1457-1468 ◽  
Author(s):  
J. Podedworna ◽  
M. Zubrowska-Sudol ◽  
K. Sytek-Szmeichel ◽  
A. Gnida ◽  
J. Surmacz-Górska ◽  
...  

This article presents the results of research into the influence of one, two and three wastewater feedings in a cycle on efficiency and performance of combined biological nitrogen and phosphorus removal in an integrated fixed-film activated sludge and moving-bed sequencing batch biofilm reactor (IFAS-MBSBBR). The experiment lasted 158 days and was conducted in two laboratory models of the IFAS-MBSBBR with an active volume of 28 L. It was found that along with an increase in the number of wastewater feedings, an increase in nitrogen removal efficiency was observed (from 56.9 ± 2.30% for a single feeding to 91.4 ± 1.77% for three feedings). Moreover, the contribution of simultaneous nitrification/denitrification in nitrogen removal increased (from 2.58% for a single feeding to 69.5% for three feedings). Systems with a greater number of feedings stimulated the process of denitrifying phosphorus removal. Regardless of the way in which wastewater feeding was applied to the IFAS-MBSBBR, highly efficient chemical oxygen demand (COD) removal (94.8 ± 1.80%) and biological phosphorus removal (98.9 ± 0.87%) were achieved.


RSC Advances ◽  
2015 ◽  
Vol 5 (73) ◽  
pp. 59326-59334 ◽  
Author(s):  
A. Chen ◽  
Y. Chen ◽  
C. Ding ◽  
H. Liang ◽  
B. Yang

The presence of 2 and 5 mg L−1of tetracycline decreased total nitrogen removal. Tetracycline induced EPS release and decreased its protective role on cells. Denitrifiers instead of nitrifiers were negatively affected by tetracycline.


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