Enhanced nitrogen removal in SBRs bypassing nitrate generation accomplished by multiple aerobic/anoxic phase pairs

2003 ◽  
Vol 47 (11) ◽  
pp. 53-59 ◽  
Author(s):  
A.N. Katsogiannis ◽  
M. Kornaros ◽  
G. Lyberatos

A lab-scale SBR was used for the study of nitrogen removal from a synthetic wastewater with an ammonium-nitrogen concentration of 50 mg/L. The react phase of the reactor operation was divided into three sets of consecutive aerobic and anoxic periods with a duration ratio of 1:3 (20 min aerobic and 1 h anoxic phase). Under these operating conditions, nitrogen removal was achieved via nitrite i.e. no nitratification (oxidation of nitrite to nitrate) and hence no denitratification (reduction of nitrate to nitrite) was taking place in the aerobic and anoxic phase, respectively. This was attributed to the suppression of the nitrite-oxidizers activity due to the short aerobic phase duration. This presumption was supported by the ever decreasing amount of nitrate-nitrogen generated in the react phase during the transient, even when the activated sludge of the reactor was supplemented with additional nitrite-oxidizers. On the other hand, denitrification was mainly based on stored carbon sources, as long as the organic carbon (provided in the form of acetate) was never accumulated during the anoxic/anaerobic fill phase of the reactor operation.

2020 ◽  
Vol 81 (1) ◽  
pp. 62-70
Author(s):  
Roumi Bhattacharya ◽  
Debabrata Mazumder

Abstract Nitrification of ammonium nitrogen (NH4+-N)-bearing synthetic wastewater was performed in a batch-activated sludge reactor by varying the initial ammonium nitrogen concentration up to 400 mg/L at a pH of 8.1 ± 0.2 and temperature of 36 ± 2 °C for developing the process kinetics using acclimatised biomass. Maximum ammonium nitrogen removal efficiency of 98.3% was achieved with initial ammonium nitrogen and mixed liquor suspended solids concentration of 235 mg/L and 2,180 mg/L, respectively, at 48 h batch period. Based on the experimental results, kinetic constants for ammonia nitrogen removal following Monod's approach were obtained as maximum substrate removal rate coefficient = 0.057 per day, yield coefficient = 0.336 mg volatile suspended solids/mg ammonium nitrogen, half velocity constant = 12.95 mg NH4+-N/L and endogenous decay constant = 0.02 per day. Nitrification is a consecutive reaction with ammonium oxidation as the first step followed by nitrite oxidation. The overall rate of nitrite and nitrate formation was observed to be 1.44 per day and 0.34 per day, respectively.


2003 ◽  
Vol 48 (10) ◽  
pp. 209-216 ◽  
Author(s):  
H. Nakasone ◽  
H. Kuroda ◽  
T. Kato ◽  
T. Tabuchi

Nowadays, it has become very common to find in Japan that nitrate nitrogen concentrations are very high in spring water and in well water where the land use of a watershed is agricultural. We have often observed around 50 mg/L of nitrate nitrogen in the spring water where we live. Crops produced in those fields are mainly vegetables such as celery, cabbage, lettuce, carrots, and so on. Green tea is also popular in Japan. In order to produce good quality green tea, farmers apply a great amount of nitrogen fertilizer. This amount can reach up to 1,000 kg/ha in some areas, although the average application amounts to 628 kg/ha in Japan. As a result, ground water that is rich in nitrate flows into the river, which results in a high nitrogen concentration in river water and ground water. Further, this causes a low pH in river water in some tributary rivers in Japan, though this kind of case is very rare. We knew from field tests that if water contained a high nitrogen concentration and was introduced into paddy fields, high nitrogen removal would be performed. This paper presents the outline and results of a system on how to remove nitrogen using paddy fields (wetlands). Further, this paper presents the evaluated results of the removal quantity at the watershed level.


2021 ◽  

<p>Conversion of ammonia to nitrate is sensitive to a number of inhibitors. There is limited information on the nitrification inhibition coefficient and kinetic model in the current literature. Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) inhibition constants were found in nitrogen removal using an activated sludge system. Firstly, OPE and BPA free wastewater was used to determine the optimum operating conditions. The effect of OPE and BPA concentration on system performance was investigated. The ammonium removal rate was less affected by lower OPE and BPA concentrations. When the BPA and OPE concentrations were increased from 0 mg/L to 30 mg/L, the outlet ammonium nitrogen concentrations were increased respectively from 2.8 mg/L to 49.8 mg/L and from 2.6 mg/L to 20.40 mg/L. Due to the inhibition created by these compounds on Nitrobacter, nitrite nitrogen increased in the medium. As the OPE and BPA concentrations increased, the conversion rate of the ammonium nitrogen into nitrate decreased. Based on the experimental results, a kinetic model was developed, and the OPE and BPA inhibition constants (KOPE and KBPA) were found to be 40.7 mg/L and 11.76 mg/L, respectively. In nitrogen removal, BPA created a higher inhibition effect in comparison to OPE.</p>


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3240
Author(s):  
Jinfeng Jiang ◽  
Liang Ma ◽  
Lianjie Hao ◽  
Daoji Wu ◽  
Kai Wang

In order to achieve advanced nitrogen removal from landfill leachate without the addition of external carbon sources, a Sequencing Batch Reactor (SBR) and a Sequencing Biofilm Batch Reactor (SBBR) were proposed for the treatment of actual landfill leachate with ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) concentrations of 1000 ± 100 mg/L and 4000 ± 100 mg/L, respectively. The operating modes of both systems are anaerobic–aerobic–anoxic. After 110 days of start-up and biomass acclimation, the effluent COD and the total nitrogen (TN) of the two systems were 650 ± 50 mg/L and 20 ± 10 mg/L, respectively. The removal rates of COD and total nitrogen could reach around 85% and above 95%, respectively. Therefore, advanced nitrogen removal was implemented in landfill leachate without adding any carbon sources. After the two systems were acclimated, nitrogen removing cycles of SBR and SBBR were 24 h and 20 h, respectively. The nitrogen removing efficiency of SBBR was improved by 16.7% in comparison to SBR. In the typical cycle of the two groups of reactors, the nitrification time of the system was the same, which was 5.5 h, indicating that although the fiber filler occupied part of the reactor space, it had no significant impact on the nitrification performance of the system. At the end of aeration, the internal carbon source content of sludge of SBBR was equivalent to that of the SBR system. However, the total nitrogen concentration of SBBR was only 129 mg/L, which is 33.8% lower than that of SBR at 195 mg/L. The main reason was that biofilm enhanced the simultaneous nitrification and denitrification (SND) effect of the system.


1985 ◽  
Vol 63 (12) ◽  
pp. 2283-2287
Author(s):  
Olubukanla T. Okusanya ◽  
Olusola O. Lakanmi

The growth responses of Luffa aegyptiaca to various nitrogen sources and concentrations were investigated. In sand culture at high concentrations of nitrogen, the species showed equally favourable responses to nitrate nitrogen (KNO3 or Ca(NO3)2), ammonium nitrogen ((NH4)2SO4), and the combination of nitrate and ammonium nitrogen (NH4NO3). There was poor growth in response to NaNO3, CO(NH2)2, and a solution lacking nitrogen. In lateritic soil, the species responded better to ammonium nitrogen and the combination of nitrate and ammonium nitrogen than to nitrate nitrogen. Growth was generally poorer in lateritic soil than in sand. Neither the nitrogen sources nor their concentrations had any significant effect on root weight or the leaf weight ratio. There was a significant decrease in growth as nitrogen concentration decreased in KNO3 and Ca(NO3)2 treatments but it was only at the low concentrations of (NH4)2SO4 and NH4NO3 that growth was significantly reduced. The shoot: root mass ratio decreased as nitrogen concentration decreased. The nature of the growth media and the ecological habit of the species are used to partly explain its responses to different nitrogen sources and concentrations. The possible application of these results to increasing the production of L. aegyptiaca is also discussed.


1998 ◽  
Vol 38 (6) ◽  
pp. 237-243 ◽  
Author(s):  
A. Mohseni-Bandpi ◽  
D. J. Elliott

A pilot scale rotating biological contactor (RBC) was used to investigate the removal of nitrate-nitrogen from groundwater using three different carbon sources, i.e., methanol, ethanol and acetic acid. Optimum carbon sources to influent nitrate-nitrogen ratio were established by varying the influent concentration of carbon sources. The optimum ratio of methanol, ethanol and acetic acid to nitrate-nitrogen ratios were found to be 2.9, 2.35 and 4.3 respectively. The nitrate-nitrogen removal efficiency averaged 93, 91 and 98 for methanol, ethanol and acetic acid respectively at a loading rate of 76 mg/m2.h. The results of this study show that the acetic acid is the most efficient carbon source for removal of nitrate-nitrogen. Effluent nitrite-nitrogen concentration was minimum for acetic acid as compared with ethanol and methanol. The effluent contained minimum suspended solids and turbidity for methanol as a carbon source. The results of this study indicate that biological nitrate removal using a RBC is a reliable and stable system under all the three carbon sources. The denitrified water in all cases requires some post treatment to oxidise the residual carbon source and remove biomass before distribution.


2004 ◽  
Vol 49 (5-6) ◽  
pp. 373-386 ◽  
Author(s):  
S.-M. Park ◽  
H.-B. Jun ◽  
Y.-J. Chung ◽  
S.-H. Lee

Nitrogen removal from a piggery wastewater was investigated in a post-denitrification modified Lüdzack Ettinger (PDMLE) process. Overall hydraulic retention time (HRT) of the PDMLE, consisting of contact/separator (C/S), nitrification, denitrification and re-aerobic bioreactor was 10 days. 60% of the influent SCOD was separated in the C/S by contacting the return sludge with the synthetic wastewater, however, only 10% of the influent SCOD was separated from the piggery wastewater. Biosorption capacities of the synthetic wastewater and piggery wastewater were 800 and 150 mg/g-MLSS, respectively. In spite of the high organic and nitrogen load, nitrification efficiency was above 95%, and nitrification rate was about 180 mg-NH4+-N/L·day. The removed ΔCOD/Δnitrate ratios in the denitrification tank were 4.0 and 11.5 g-SCOD/g-nitrate, while denitrification rates were 8.4 and 2.6 mg-nitrate/day for synthetic and piggery wastewater, respectively. In the proposed PDMLE process, both bio-sorbed and bypassed organic matter could be successfully used for nitrate reduction as carbon sources and the final TN removal efficiency was as high as 95%.


Author(s):  
О.В. Харькина ◽  
К.Р. Искалиева ◽  
Е.В. Малич

Проведено сравнение результатов расчета аэротенков по модели ATV (Standard ATV-DVWK-A131 E «Dimension of Single-Stage Activated Sludge Plants 2000»), которая является стохастической «табличной» моделью, и по модели ASM2d, которая относится к теоретическим и описывает, в отличие от ATV, процессы биологической очистки сточных вод с помощью формул ферментативной кинетики. Расчеты выполнены для одних и тех же входных данных. Результаты расчетов показали существенную ограниченность использования модели ATV. Данная модель, как изначально указано авторами в ее описании, рассчитывает аэротенки только на единственное значение качества очищенной воды по аммонийному азоту 1 мг/л и не рассчитывает аэротенки на нитриты. Более того, сравнение ATVс ASM2d показало, что и достижение указанного качества очищенной воды по аммонийному азоту 1 мг/л возможно только при конкретных значениях кинетических констант, которые были определены авторами в данной статье, а изменение хотя бы одного из кинетических параметров сточных вод приводит к увеличению необходимого значения аэробного возраста активного ила и, как следствие, расчетного объема аэробной зоны на десятки процентов, что доказывает риск недостижения требуемого качества очищенной воды при использовании модели ATVдаже на концентрацию аммонийного азота 1 мг/л. С учетом того, что методика ATV не рассчитывает аэротенки на качество очищенных вод по нитритам, результаты проведенного нами расчета показывают, что предлагаемые в ATVзначения аэробного возраста активного ила 4,05 суток для температуры 17 ºС позволят достичь качество очищенной воды по азоту нитритов 0,35–0,52 мг/л N–NO2. Это доказывает невозможность использования ATV, если даны требования к качеству очищенной воды по нитритам. Авторами на основании проведенных расчетов сделаны выводы о риски недостижения качества очищенной воды по аммонийному азоту, как и 1 мг/л при использовании ATV, из-за того, что ATVявляется стохастической моделью, то есть все представленные в данной методике зависимости были определены для конкретных условий проведения работ. Более того, как и указано в описании ATV, данная методика применима, даже в ограниченных условиях, строго для городских сточных вод. Проведенные расчеты показали, что при наличии требований к качеству очищенной воды по нитритам, вне зависимости от значений требуемых концентраций нитритов, методика ATVне подходит вообще, при этом ASM2dс учетом того, что она основывается на формулах ферментативной кинетики, позволяет рассчитывать аэротенки на любое требуемое качество очищенной воды как по аммонийному азоту, так и по азоту нитритов и применима для любого типа сточных вод. A comparison is made of the results of calculating aeration tanks by ATV model (Standard ATV-DVWK-A131 E «Dimension of Single-Stage Activated Sludge Plants 2000»), that is a stochastic «table» model, and by ASM2d model, that is referred to as theoretical and describes, unlike ATV, biological wastewater treatment processes using enzymatic kinetics formulas. Calculations are performed for the same input data. The calculation results show essentially limited use of ATV model; this model, as originally given in the description of this model by the designers, provides for calculating aeration tanks only for a single value of the effluent quality in terms of ammonia nitrogen as 1 mg/l and does not provide for calculating aeration tanks in terms of nitrites. Moreover, the comparison of ATV and ASM2d show that achieving the specified quality of effluent in terms of ammonia nitrogen as 1 mg/l is possible only at specific values ​​of the kinetic constants determined by the authors in this article; whereas, any change in at least one kinetic parameter of the wastewater results in an increase in the required aerobic age of activated sludge and, as a consequence, in the calculated volume of the aerobic zone by tens of percent, which proves the risk of not achieving the required effluent quality while using ATV model even for ammonium nitrogen concentration of 1 mg/l. Taking into account the fact that ATV Method does not provide for calculating aeration tanks for the effluent quality in terms of nitrites, the results of our calculation show that the aerobic age of activated sludge of 4.05 days for a temperature of 17 ºС proposed in ATV will make it possible to achieve the effluent quality in terms of nitrite nitrogen, 0.35–0.52 mg/l N–NO2, proving the unavailability of ATV, if the requirements to the effluent quality in terms of nitrites are specified. The authors, on the basis of the calculations, make conclusions about the risk of failure to achieve the effluent quality in terms of ammonia nitrogen as well as 1 mg/l while using ATV, because ATV is a stochastic model, that is, all dependencies presented in this method have been determined for the specific operating conditions. Moreover, as specified in the ATV description, this method, even in limited conditions, is applicable strictly for urban wastewater. The calculations show that if there are requirements for the effluent quality in terms of nitrites, regardless of the required concentration value of nitrites, the ATV method is absolutely not suitable, while ASM2d, taking into account the fact that it is based on the formulas of enzymatic kinetics, provides for calculating aeration tanks for any required effluent quality in terms of both ammonium nitrogen and nitrite nitrogen and is applicable for any type of wastewater.


2007 ◽  
Vol 56 (3) ◽  
pp. 145-150 ◽  
Author(s):  
D. Paredes ◽  
P. Kuschk ◽  
F. Stange ◽  
R.A. Müller ◽  
H. Köser

Anaerobic ammonia oxidation (Anammox) has been identified as a new general process-strategy for nitrogen removal in wastewater treatment. In order to evaluate the role and effects of the Anammox process in wetlands, laboratory-scale model experiments were performed with planted fixed bed reactors. A reactor (planted with Juncus effusus) was fed with synthetic wastewater containing 150–200 mg L−1 NH+4 and 75–480 mg L−1 NO−2. Under these operating conditions, the plants were affected by the high ammonia and nitrite concentrations and the nitrogen removal rate fell within the same range of 45–49 mg N d−1 (equivalent to 0.64–0.70 g Nm−2d−1) as already reported by other authors. In order to stimulate the rate of nitrogen conversion, the planted reactor was inoculated with Anammox biomass. As a result, the rate of nitrogen removal was increased 4–5-fold and the toxic effects on the plants also disappeared. The results show that, in principle, subsurface flow wetlands can also function as an “Anammox bioreactor”. However, the design of a complete process for the treatment of waters with a high ammonia load and, in particular, the realisation of simple technical solutions for partial nitrification have still to be developed.


2003 ◽  
Vol 47 (1) ◽  
pp. 71-76 ◽  
Author(s):  
M. Rodgers ◽  
D. Burke

The aim of this laboratory study was to establish the efficacy of a new experimental biofilm system for the removal of nitrogen from synthetic wastewater. The system consisted of six reactors in series: one anaerobic, one anoxic and four aerobic reactors. In both the anaerobic and anoxic reactors, a plastic cuboid module was repeatedly moved up and down in the wastewater, while being totally submerged at all times. In each of the aerobic reactors, an identical module to that used in the anaerobic and anoxic reactors was intermittently and repeatedly immersed in and lifted out of the wastewater. All the individual reactors had a bulk fluid volume of 28.2 litres and the average temperature of the wastewater was about 10°C. Each module consisted of crossflow corrugated plastic sheets with a surface area of 1.824 m2. The nitrate recycle flow from the fourth aerobic tank to the anoxic tank was twice the inflow to that tank. In the anoxic reactor, filtered COD was removed at an average rate of 2.22 kg COD/m3.d and nitrate-nitrogen was denitrified at a rate of 0.42 kg NO3-N/m3.d. The average nitrification rate in the second aerobic reactor was 0.12 kg NH4-N/m3.d. The new biofilm system was simple to construct and operate.


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