Modeling effect of remaining nitrate on phosphorus removal in SBR

2001 ◽  
Vol 43 (3) ◽  
pp. 175-182 ◽  
Author(s):  
A. A. Kazmi ◽  
M. Fujita ◽  
H. Furumai
Keyword(s):  
Phosphorus Removal ◽  
Shock Loading ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Dynamic Changes ◽  
Model Simulations ◽  
Steady State Operation ◽  
Consumption Rates ◽  
Removal System ◽  
P Removal

Nitrate shock loading experiments were conducted in a bench scale SBR to investigate the effect of nitrate on phosphorus removal. After achieving satisfactory phosphorus removal under steady state operation, initial NO3-N concentration amounting to 10 and 20 mg /L was fed at the beginning of the cycle. It was observed that, 10 mg/L of NO3-N suppressed phosphorus release during the feed and mix phases. Organic consumption for denitrification lead to limited PHA storage by phosphorus removing bacteria, resulting in less PO4-P removal. For 20 mg/L, influent organic substrate was not sufficient even for complete denitrification, thus leading to the presence of higher NO3-N and PO4-P in effluent. To explain the dynamics of the nutrient removal system under the transient loading, a SBR model based on IAWQ ASM2 was implemented. After adjusting PHA contents, model simulations well predicted dynamic changes of nitrate and phosphate concentrations during a cycle. Based on the model simulations, competition of COD substrate among denitrification, fermentation and oxygen respiration were investigated by calculating their consumption rates during mixing phase. In addition, a nitrate disappearance model was proposed and implemented in conjunction with a settling model to predict remaining and effluent nitrate in a cycle of SBR. Furthermore, integrated model simulations highlighted the effect of remaining nitrate on phosphorus release considering different options of reactions in settling phase.

Phosphorus Release Kinetics in Biofilm Reactors

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza
Keyword(s):  
Phosphorus Removal ◽  
Release Kinetics ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biofilm Reactor ◽  
Substrate Uptake ◽  
Biofilm Reactors ◽  
Initial Substrate ◽  
Linear Behaviour ◽  
Substrate Concentrations

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.

Combined denitrification and excess biological phosphorus removal in discontinuous operated biofilm systems

2002 ◽  
Vol 46 (4-5) ◽  
pp. 193-200 ◽  
Author(s):  
D. Brandt ◽  
C. Sieker ◽  
W. Hegemann
Keyword(s):  
Phosphorus Removal ◽  
P Uptake ◽  
Organic Substrate ◽  
Treated Wastewater ◽  
Biological Phosphorus Removal ◽  
P Release ◽  
Different Types ◽  
Immobilized Biomass ◽  
Biological Phosphorus ◽  
P Removal

The sorption-denitrification-P-removal (S-DN-P) process combines biological excess P-removal (BEPR) and denitrification using immobilized biomass. The accumulation of denitrifying polyP organisms is achieved by sequencing anaerobic/anoxic conditions. The immobilized biomass is in alternating contact with primary treated wastewater (anaerobic sorption-phase) and nitrified wastewater (denitrification phase). In the sorption phase, P-release takes place and readily biodegradable organic substrate, e.g. volatile fatty acid, is taken up and stored by polyP accumulating organisms (PAO). In addition to this, other organic matter is physically/chemically adsorbed in the biofilm structures. In the denitrification phase, the biomass denitrifies the stored and adsorbed organic substrate and, at the same time, P-uptake and polyP formation occurs. This paper presents results of investigations at laboratory and half-technical scale. At laboratory scale different types of carriers were tested regarding their suitability for the S-DN-P-process. In half-technical scale a biofilter and a moving bed reactor (MBR) were tested. In the biofilter a stable removal of nitrate and phosphate was achieved. However, it was not possible to achieve similar results in the MBR process. Especially the release and uptake of phosphate showed no clear tendency although the uptake of acetate was good. Reasons for this could be the accumulation of glycogen accumulating organisms which impair the metabolism of PAO.

Effect of continuous addition of an organic substrate to the anoxic phase on biological phosphorus removal

1998 ◽  
Vol 38 (1) ◽  
pp. 97-105 ◽  
Author(s):  
J. Meinhold ◽  
H. Pedersen ◽  
E. Arnold ◽  
S. Isaacs ◽  
M. Henze
Keyword(s):  
Phosphorus Removal ◽  
Phosphate Uptake ◽  
P Uptake ◽  
Organic Substrate ◽  
Organic Substrates ◽  
Biological Phosphorus Removal ◽  
P Release ◽  
Influence Of Substrate ◽  
Biological Phosphorus ◽  
P Removal

The continuous introduction of a biological phosphorus removal (BPR) promoting organic substrate to the denitrifying reactor of a BPR process is examined through a series of batch experiments using acetate as model organic substrate. Several observations are made regarding the influence of substrate availability on PHA storage/utilization and phosphate uptake/release. Under anoxic conditions PHB is utilized and phosphate is taken up, indicating that at least a fraction of the PAO can denitrify. The rates of anoxic P-uptake, PHB utilization and denitrification are found to increase with increasing initial PHB level. At low acetate addition rates the P-uptake and PHB utilization rates are reduced compared to when no acetate is available. At higher acetate addition rates a net P-release occurs and PHB is accumulated. For certain intermediate acetate addition rates the PHB level can increase while a net P-release occurs. Whether the introduction of BPR promoting organic substrates to the denitrifying reactor is detrimental to overall P-removal appears to be dependent on the interaction between aerobic P-uptake, which is a function of PHB level, and the aerobic residence time.

The Effect of Organic Compounds on Biological Phosphorus Removal

1991 ◽  
Vol 23 (4-6) ◽  
pp. 585-594 ◽  
Author(s):  
Z. H. Abu-ghararah ◽  
C. W. Randall
Keyword(s):  
Organic Acids ◽  
Organic Compounds ◽  
Phosphorus Removal ◽  
Phosphorus Uptake ◽  
Phosphorus Release ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
University Of Cape Town ◽  
Biological Phosphorus ◽  
Removal System

The effect of influent organic compounds on the performance of a biological nutrient removal system was investigated using a pilot plant system operated as a UCT (University of Cape Town) process. The system was fed domestic sewage and operated at a sludge age of 13 days. The effects of separate addition of formic, acetic, propionic, butyric, isobutyric, valeric, and isovaleric acid on phosphorus release under anaerobic conditions, and phosphorus uptake under aerobic conditions, were studied. The effects of the organic acid additions on the removal of nitrogen and COD, and changes in SOUR and MLSS, were also studied. All added substrates, except formic acid, caused significant increases in phosphorus release in the anaerobic stage, and subsequent phosphorus uptake in the aerobic stage with an increase in phosphorus removal efficiency. It was also found that the branched organic acids, isobutyric and isovaleric, caused more phosphorus release in the anaerobic stage and better phosphorus removal efficiencies in the system, compared with the nonbranching forms of the same organic acids. The most recent biochemical model, proposed by Comeau et al. (1986) and Wentzel et al. (1986) was also tested using the data collected in this investigation. Both models, in most cases, overestimated the ratios of phosphorus release to volatile fatty acid utilized. All added substrates caused no change in either COD or TKN removals. For engineering applications, it is suggested by this research, that at least 20 mg COD equivalent of acetic acid is needed for the removal of 1 mg phosphorus.

Acetate injection into anaerobic settled sludge for biological P-removal in an intermittently aerated reactor

2001 ◽  
Vol 44 (1) ◽  
pp. 77-85 ◽  
Author(s):  
K. H. Ahn ◽  
H. Yoo ◽  
J. W. Lee ◽  
S. K. Maeng ◽  
K. Y. Park ◽  
...  
Keyword(s):  
Phosphorus Removal ◽  
Carbon Sources ◽  
Phosphorus Uptake ◽  
Phosphorus Release ◽  
Optimal Values ◽  
High Degree ◽  
The Relationship ◽  
Residual Nitrate ◽  
Floc Model ◽  
P Removal

Injecting acetate into the sludge layer during the settling and decanting periods was adopted to enhance phosphorus release inside the sludge layer during those periods and phosphorus uptake during the subsequent aeration period in a KIST Intermittently Decanted Extended Aeration (KIDEA) process. The relationship among nitrification, denitrification and phosphorus removal was investigated in detail and analyzed with a qualitative floc model. Dependencies of nitrification on the maximum DO level during the aerobic phase and phosphorus release on residual nitrate concentration during the settling phase were significant. High degree of nitrification resulted that phosphorus release inside the sludge layer was significantly interfered with nitrate due to the limitation of available acetate and the carbon sources from influent. Such limitation was related to the primary utilization of organic substance for denitrification in the outer layer of the floc and the retarded mass transfer into the inner layer of the floc. Nevertheless, effects of acetate injection on both denitrification and phosphorus release during the settling phase were significant. Denitrification rate after acetate injection was two times as high as that before acetate injection, and phosphorus release reached about 14 mg PO43--P/g MLVSS/hr during the decanting phase after the termination of denitrification inside the sludge layer. Extremely low level of maximum DO (around 0.5 mg/L) during the aerobic phase may inhibited nitrification, considerably, and thus nearly no nitrate was present. However, the absence of nitrate increased when the phosphorus release rate was reached up to 33 mg PO43--P/g MLVSS/hr during the settling and decanting phase, and nearly all phosphorus was taken up during subsequent aerobic phase. Since the sludge layer could function as a blocking layer, phosphorus concentrations in the supernatant was not influenced by the released phosphorus inside the sludge layer during the settling and decanting period. Phosphorus removal was directly (for uptake) and indirectly (for release) dependent on the median and maximum DO concentration during the aerobic phase, and those optimal values may exist within the range from 0.2 to 0.6 mg/L and 0.4 to 1.2 mg/L, respectively.

Biological Phosphorus Removal in Fixed Films Reactors

1992 ◽  
Vol 25 (12) ◽  
pp. 165-174 ◽  
Author(s):  
R. Franci Gonçalves ◽  
F. Rogalla
Keyword(s):  
Retention Time ◽  
Phosphorus Removal ◽  
Hydraulic Retention Time ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biological Phosphorus Removal ◽  
Removal Process ◽  
Fixed Film ◽  
Film Reactor ◽  
Biological Phosphorus

Possible procedures to achieve biological phosphorus removal in a fixed film reactor are discussed and the feasibility of phosphorus removal process in a fixed film reactor under continous flow is demonstrated. The behaviour of an upflow aerated filter operating under continuous feed and alternate aerobic/anaerobic conditions is analyzed. The influence of the duration of anaerobic and aerobic contact periods and of organic substrate loadings on the phosphorus removal process is verified. During the anaerobic state, the longer the duration, or the higher the substrate load, the better the phosphorus release and consequently the higher the uptake in the aerobic phase. The excess of accumulated phosphorus in the aerobic phase over released phosphorus in the anaerobic phase approaches 33 %. For each mg of phosphorus released, 5 mg filtered COD are consumed. Continuous phosphorus removal on two biofilters in series was performed by alternating aeration conditions, always introducing the influent to the anaerobic reactor.The tests carried out on laboratory scale showed that this system carrys out complete nitrification and removal of 80% of the phosphorus with a maximum hydraulic retention time of 5 hours. The hydraulic retention time and the residence time of the biomass in the reactor are independent and, therefore, the time the bacteria are exposed to alternate A/O conditions can be optimized. The very low concentrations of suspended solids in the effluent of the biofilter enable residual levels below 1 mg PO4-P/l to be obtained. Further investigations are carried out on full scale and to introduce denitrification in the same reactor.

Nitrification, Denitrification and Biological Phosphate Removal in Sequencing Batch Reactors Treating Piggery Wastewater

1992 ◽  
Vol 26 (5-6) ◽  
pp. 977-985 ◽  
Author(s):  
G. Bortone ◽  
S. Gemelli ◽  
A. Rambaldi ◽  
A. Tilche
Keyword(s):  
Chemical Precipitation ◽  
Phosphorus Release ◽  
High Ratio ◽  
Organic Substrate ◽  
Phosphate Removal ◽  
Limiting Factor ◽  
High Concentration ◽  
Piggery Wastewater ◽  
N Removal ◽  
P Removal

In Italy, because of the high concentration of animals in many agricultural areas, not all piggery manure can be landspread. Considering their chemical characteristics - high concentration in organics and nutrients -processes providing the removal of COD, N & P have to be adopted. Other aspects have to be considered with regard to cost saving and simple management. In order to study a simple andreliable treatment system, two 51 bench-scale SBRs were built. Each reactor treated 500 ml/d of clarified (after centrifugation) piggery wastewater. A cycle with the following alternating phases of reaction was chosen: first denitrification and phosphorus release, first oxidation-nitrification, second denitrification and second oxidation-nitrification. The systems showed good flexibility and enhanced removal of COD, N and P was easily reached modifying the duration of each phase. The best efficiency in N removal has been noticed in the reactor in which the feeding distribution was done in the two denitrification phases, allowing a better use of the organic substrate for the denitrifying bacteria. This confirmed that the limiting factor, in the removal of N from piggery wastewater, is represented by the too high ratio TKN/COD. Anyway good removals of COD (~93%), N (88-93%) and P(~95%) were obtained in both reactors. A relevant concentration of unbiodegradable COD - at the adopted HRT, SRT and reaction temperature - was still present in the effluent of both reactors (~300 mg/l). Track studies allowed the evaluation of the nitrification and denitrification kinetic constants. Their values were higher than the ones reported in the literature. No inhibition of the nitrifying activity due to high concentration of N-NH4 (>80 mg N/l), was observed. Specific studies on biological phosphate removal have been carried out. In spite of the high concentration of P in the biomass and the low concentration of P in the effluent, showing a surplus biological P removal, no P release was observed; this might have been masked by biologically induced chemical precipitation. In fact, piggery wastewaters are rich in metals and a high concentration of metal-bound P was analytically observed. However, a high concentration of polyphosphates has been analytically determined in the biomass. This should confirm the presence in the microbial community of bacteria performing the surplus P removal.

Sign in / Sign up

Export Citation Format

Share Document