| 1. |
- Gut, Luiza, 1979-
(författare)
-
Assessment of a partial nitritation/Anammox system for nitrogen removal
- 2006
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis evaluates the performance of a deammonification system designed as a two-step tech-nology consisting of an initial partial nitritation followed by an Anammox process. Operation of a technical-scale pilot plant at the Himmerfjärden Wastewater Treatment Plant (Grödinge, Swe-den) has been assessed. Oxygen Uptake Rate (OUR) to evaluate the respiration activity of nitrifi-ers in the system and batch tests to assess reaction rates have also been applied in the study. It was found that the total inorganic nitrogen elimination strongly depended on the nitrite-to-ammonium ratio in the influent to the Anammox reactor, which was correlated with the per-formance of the partial nitritation phase. Therefore, a control strategy for oxidation of ammo-nium to nitrite has been proposed. Controlled oxygen supply to the partial nitritation reactor is obligatory to obtain a proper pH drop indicating oxidation of ammonia to nitrite at the adequate ratio. A very high nitrogen removal efficiency (an average of 84%) and stable operation of the system have been reached. Conductivity measurements were also used to monitor the system influent nitrogen load and the nitrogen removal in the Anammox reactor. The data gathered from the operation of the pilot plant enabled the use of multivariate data analysis to model the process behaviour and the assessment of the covariances between the process parameters. The options for full-scale implementation of the Anammox systems have been proposed as a result of the study.
|
|
| 2. |
- Gut, Luiza, et al.
(författare)
-
Assessment of a two-step partial nitritation/Anammox system with implementation of multivariate data analysis
- 2007
-
Ingår i: Chemometrics and Intelligent Laboratory Systems. - : Elsevier BV. - 0169-7439 .- 1873-3239. ; 86:1, s. 26-34
-
Tidskriftsartikel (refereegranskat)abstract
- Complexity of biological wastewater treatment, in which a variety of physical and (bio)chemical processes concurrently take place, demands appropriate approach in the data analysis. In this study, the data set collected during a 20 month operation of a two-step partial nitritation/Anammox system for nitrogen removal from wastewater (semi-industrial pilot plant scale) are subjected to Principal Component Analysis (PCA) and Partial Least Squares projections to latent structures (PLS) analysis. Interpretation of PCA- and PLS models enable to discern relationships between different factors for the start-up period and stable operation of the pilot plant. Variables like conductivity, pH value, dissolved oxygen concentration and nitrite-to-ammonium ratio (NAR) appear to be the key factors in the process control and monitoring. Extension of the Anammox reactor capacity demands accurate monitoring, principally by scrutinizing nitrite nitrogen concentration in the reactor. These findings suggest that the two methods complement each other in assessing the partial nitritation/Anammox system. This study demonstrated that multivariate data analysis provides the powerful implement in the field of wastewater treatment, especially in investigating novel systems.
|
|
| 3. |
|
|
| 4. |
- Gut, Luiza, et al.
(författare)
-
Combined partial nitritation/Anammox system for treatment of digester supernatant
- 2006
-
Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 53:12, s. 149-159
-
Tidskriftsartikel (refereegranskat)abstract
- One-year (2004) comprehensive investigations in a semi-industrial pilot plant (5 m(3)) were carried out with the aim of assessing the influence of operational parameters on the partial nitritation/Anammox system performance. In the system designed as a moving-bed biofilm reactor, the influent nitrogen load to the Anammox reactor was progressively increased and a stable Anammox bacterial culture was obtained. Interaction between subsequent, aerobic and anaerobic conditions in the partial nitritation and Anammox reactors, respectively, granted conditions to remove nitrogen through the nitrite route. It implies that the oxygen supply can be limited to a high extent. A control strategy for the partial nitritation step relied on concomitant adjustment of the air supply with a variable influent nitrogen load, which can be monitored by both pH and conductivity measurements. In the Anammox reactor, an influent nitrite-to-ammonium ratio plays a vital role in obtaining efficient nitrogen removal. During the 1-year experimental period, the Anammox reactor was operated steadily and average nitrogen removal efficiency was 84% with 97% as the maximum value.
|
|
| 5. |
|
|
| 6. |
- Gut, Luiza, et al.
(författare)
-
Oxygen Uptake Rate (OUR) tests for assessment of nitrifying activities in the deammonification system
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The two-step deammonification system for nitrogen removal was established in a technical-scale pilot plant with moving-bed reactors with Kaldnes rings as biofilm carriers. The study consisted in observing the presence of nitrifiers in both activated sludge and biofilm in the partial nitritation reactor and in the Anammox reactor. Oxygen Uptake Rate (OUR) tests were used as a tool to assess qualitatively and quantitatively ammonia- and nitrite-oxidizing bacteria as well as heterotrophic activity. Thirteen series of OUR tests focussed on monitoring the activity of nitrifying microorganisms in the deammonification system. It was demonstrated that the nitrifying culture mostly forms biofilm in the partial nitritation reactor. The results confirmed that there is only insignificant nitrifying activity present in the Anammox reactor and it is mainly concentrated in the activated sludge. It is most likely that nitrifiers sustain oxygen-limited conditions for the Anammox bacteria. The moving-bed system is therefore appropriate to obtain efficient removal of nitrogen with taking advantage of the cooperation of many bacterial cultures.
|
|
| 7. |
- Gut, Luiza, et al.
(författare)
-
Partial nitritation process assessment
- 2005
-
Ingår i: Vatten: tidskrift för vattenvård. - 0042-2886. ; 61:3, s. 175-182
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, partial nitritation has the aim to oxidise a fraction of ammonium (about 50–60 %) into nitrite without following oxidation to nitrate. Experiments performed during eight months describe partial nitritation of supernatant from dewatering of digested sludge at Himmerfjärden wastewater treatment plant in the south Stockholm region. The process was the first step (reactor R1) and was followed by a second step (reactor R2) for oxidation of ammonium with nitrite to nitrogen gas. The evaluation was based on time series analysis and results from 15 profiles of inorganic nitrogen compounds and different operational parameters. The effluent Nitrite-to-Ammonium Ratio (NAR) depends on the influent supernatant composition (mainly ammonium concentration and alkalinity) and conditions in R1 (mainly dissolved oxygen concentration and drop in pH value). Modified methodology for biofilm was developed to measure Oxygen Uptake Rate (OUR) of ammonium and nitrite oxidisers.
|
|
| 8. |
|
|
| 9. |
- Trela, Jozef, et al.
(författare)
-
Deammonifikation, en ny process för behandling av avloppsströmmar med hög kvävehalt – fortsatta pilot-plant experiment
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Experimental studies have been performed at the Himmerfjärden WWTP with partial nitritation (oxidation of about half of ammonium to nitrite) followed by Anammox with oxidation of ammonium with nitrite to nitrogengas. Stable operational conditions could be obtained during the year 2004 with an average nitrogen removal of 84 %. With the help of conductivity, pH and oxygen measurements the process reactions could be predicted and controlled.
|
|
| 10. |
|
|
