Model based evaluation of plant improvement strategies for biological nutrient removal

1999 ◽  
Vol 39 (4) ◽  
pp. 45-53 ◽  
Author(s):  
H. M. van Veldhuizen ◽  
M. C. M. van Loosdrecht ◽  
F. A. Brandse
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Adequate Description ◽  
Control Scheme ◽  
Detailed Simulation ◽  
High Fraction ◽  
Biokinetic Parameters ◽  
P Removal

An activated sludge model for biological N- and P-removal was developed, which describes anoxic and aerobic P-uptake based on bacterial metabolism. This model was tested in practice on two wastewater treatment plants, which are BCFS®-processes, which contain activated sludge with a high fraction of denitrifying P-removing bacteria (DPB's). The model appeared to be able to give an adequate description of the performance of these treatment plants under different conditions. If the process parameters are well defined almost no calibration of the biokinetic parameters was necessary. In the simulation of Dalfsen wwtp, which has a complex control scheme, it was possible to give an adequate simulation of the control actions and the concentration profiles in a rather simple way, showing that detailed simulation of these controllers was not necessary. With the calibrated model it was possible to analyse bottlenecks and give suggestions for upgrading of the concerned treatments plants. The simulation results were used in decisions on investments.

Difficulties and developments in biological nutrient removal technology and modelling

1999 ◽  
Vol 39 (6) ◽  
pp. 1-11 ◽  
Author(s):  
George A. Ekama ◽  
Mark C. Wentzel
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Filamentous Bulking ◽  
Recent Developments ◽  
Removal Technology ◽  
Hydrolysis Of ◽  
Activated Sludge Systems ◽  
P Removal

Filamentous bulking and the long sludge age required for nitrification are two important factors that limit the wastewater treatment capacity of biological nutrient removal (BNR) activated sludge systems. A growing body of observations from full-scale plants indicate support for the hypothesis that a significant stimulus for filamentous bulking in BNR systems in alternating anoxic-aerobic conditions with the presence of oxidized nitrogen at the transition from anoxic to aerobic. In the DEPHANOX system, nitrification takes place externally allowing sludge age and filamentous bulking to be reduced and increases treatment capacity. Anoxic P uptake is exploited in this system but it appears that this form of biological excess P removal (BEPR) is significantly reduced compared with aerobic P uptake in conventional BNR systems. Developments in the understanding of the BEPR processes of (i) phosphate accumulating organism (PAO) denitrification and anoxic P uptake, (ii) fermentation of influent readily biodegradable (RB)COD and (iii) anaerobic hydrolysis of slowly biodegradable (SB)COD are evaluated in relation to the IAWQ Activated Sludge Model (ASM) No.2. Recent developments in BEPR research do not yet allow a significant improvement to be made to ASM No. 2 that will increase its predictive power and reliability and therefore it remains essentially as a framework to guide further research.

New Process Design for Biological Nutrient Removal

1992 ◽  
Vol 25 (4-5) ◽  
pp. 445-448 ◽  
Author(s):  
J. Wanner ◽  
J. S. Čech ◽  
M. Kos
Keyword(s):  
Activated Sludge ◽  
Process Design ◽  
Laboratory Experiments ◽  
Biological Process ◽  
Biological Nutrient Removal ◽  
Organic Substances ◽  
Anaerobic Reactor ◽  
New Process ◽  
Denitrification Reactor ◽  
P Removal

A new arrangement of the biological process for efficient COD, N and P removal has been proposed. The process consists of the anaerobic reactor where organic substances from waste water are sequestered into activated sludge, the nitrification reactor where ammonia-rich supernatant is oxidized, and the denitrification reactor where oxidized supernatant is mixed with the activated sludge separated from the anaerobic reactor. Laboratory experiments confirmed favorable characteristics of the proposed system.

Effect of anaerobic digestion and liming on plant availability of phosphorus in iron- and aluminium-precipitated sewage sludge from primary wastewater treatment plants

2017 ◽  
Vol 75 (7) ◽  
pp. 1743-1752 ◽  
Author(s):  
Emilio Alvarenga ◽  
Anne Falk Øgaard ◽  
Lasse Vråle
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Negative Impact ◽  
Limited Resource ◽  
Primary Treatment ◽  
P Uptake ◽  
Lime Treatment ◽  
Plant P Uptake ◽  
P Removal

More efficient plant utilisation of the phosphorus (P) in sewage sludge is required because rock phosphate is a limited resource. To meet environmental legislation thresholds for P removal from wastewater (WW), primary treatment with iron (Fe) or aluminium (Al) coagulants is effective. There is also a growing trend for WW treatment plants (WWTPs) to be coupled to a biogas process, in order to co-generate energy. The sludge produced, when stabilised, is used as a soil amendment in many countries. This study examined the effects of anaerobic digestion (AD), with or without liming as a post-treatment, on P release from Fe- and Al-precipitated sludges originating from primary WWTPs. Plant uptake of P from Fe- and Al-precipitated sludge after lime treatment but without AD was also compared. Chemical characterisation with sequential extraction of P and a greenhouse experiment with barley (Hordeum vulgare) were performed to assess the treatment effects on plant-available P. Liming increased the P-labile fraction in all cases. Plant P uptake increased from 18.5 mg pot−1 to 53 mg P pot−1 with liming of Fe-precipitated sludge and to 35 mg P pot−1 with liming of the digestate, while it increased from 18.7 mg pot−1 to 39 and 29 mg P pot−1 for the Al-precipitated substrate and digestate, respectively. Thus, liming of untreated Fe-precipitated sludge and its digestate resulted in higher P uptake than liming its Al-precipitated counterparts. AD had a negative impact on P mobility for both sludges.

Biological nitrogen and phosphorus removal in UCT-type MBR process

2009 ◽  
Vol 59 (11) ◽  
pp. 2093-2099 ◽  
Author(s):  
H. Lee ◽  
J. Han ◽  
Z. Yun
Keyword(s):  
Phosphorus Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Anoxic Zone ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Nitrate Inhibition ◽  
Biological Nitrogen ◽  
P Removal ◽  
Production Characteristics

A lab-scale UCT-type membrane bio-reactor (MBR) was operated for biological nitrogen (N) and phosphorus (P) removal simultaneously. In order to examine biological nutrient removal (BNR) characteristics of MBR, the lab unit was fed with a synthetic strong and weak wastewater. With strong wastewater, a simultaneous removal of N and P was achieved while application of weak wastewater resulted in a decrease of both N and P removal. Recycled nitrate due to the limited organic in weak wastewater operation probably caused a nitrate inhibition in anaerobic zone. In step feed modification with weak wastewater, both N and P removal capability recovered in the system, indicating that the allocation of COD for denitrification at anoxic zone was a key to increase the biological P removal. In addition, the analysis on the specific P uptake rate in anoxic zone demonstrated that denitrifying phosphorus accumulating organism (dPAO) played an important role to remove up to 40% of P along with N. The sludge production characteristics of UCT-type MBR were similar to ordinary activated sludge with BNR capability.

scholarly journals Quantification of biologically and chemically bound phosphorus in activated sludge from full-scale plants with biological P-removal

2021 ◽  
Author(s):  
Francesca Petriglieri ◽  
Jette F. Petersen ◽  
Miriam Peces ◽  
Marta Nierychlo ◽  
Kamilla Hansen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Mass Balance ◽  
Wastewater Treatment Plants ◽  
Raman Microspectroscopy ◽  
Full Scale ◽  
P Fractions ◽  
P Content ◽  
Total P ◽  
P Removal

AbstractLarge amounts of phosphorus (P) are present in activated sludge from municipal wastewater treatment plants, where it exists in the form of metal salt precipitates or biologically bound into the biomass as nucleic acids, cell membrane components, and the extracellular polymeric substances or, in special polyphosphate-accumulating organisms (PAOs), as intracellular polyphosphate. Only recently, methods that reliably allow an absolute quantification of the different P-fractions, such as sequential extraction, Raman microspectroscopy, solid-state 31P magic angle spinning (MAS) NMR, and solution state 31P NMR have been developed. This study combines these techniques to obtain a comprehensive P mass-balance of activated sludge from four wastewater treatment plants with enhanced biological phosphate removal (EBPR). The total content of P and various cations was measured by chemical analysis (ICP-OES), and different P fractions were extracted for chemical characterization. Chemically bound P constituted 38-69% of total P, most likely in the form of Fe, Mg, or Al minerals, while organically bound P constituted 7-9%. By using Raman microspectroscopy and solution state 31P NMR and 31P MAS NMR spectroscopy before and after anaerobic P-release experiments, poly-P was quantified and constituted 22-54% of total P in the activated sludges and was found in approx. 25% of all bacterial cells. Moreover, Raman microspectroscopy in combination with fluorescence in situ hybridization (FISH) was used to quantify the species-specific intracellular poly-P of known PAO genera (Tetrasphaera, Ca. Accumulibacter, Dechloromonas) and other microorganisms known to possess high level of poly-P, such as the filamentous Ca. Microthrix. They were all abundant, as measured by quantitative-FISH and amplicon sequencing, and accumulated large amount of poly-P, depending on their cell-size, contributing substantially to the P-removal. Interestingly, in all four EBPR plants investigated, only 1-13% of total poly-P was stored by unidentified PAO, highlighting that most PAOs in the full-scale EBPR plants investigated are now known.HighlightsExhaustive P mass-balance of main organic and inorganic P-species in four EBPR plantsQuantification of poly-P of FISH-defined PAO and other species with high P contentTotal P content was 36-50 mgP/gSS of which 31-62% was in biomass and as poly-PA high fraction of all cells (25-30%) contained a high content of poly-PKnown PAOs contained almost all poly-P in the EBPR plants investigated

Contribution of P-bacteria in biological nutrient removal processes to overall effects on the environment

2001 ◽  
Vol 44 (1) ◽  
pp. 67-76 ◽  
Author(s):  
X. Hao ◽  
J. J. Heijnen ◽  
Y. Qian ◽  
M. C.M. van Loosdrecht
Keyword(s):  
Energy Consumption ◽  
Co2 Emissions ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Net Energy ◽  
Positive Effects ◽  
Ch4 Production ◽  
Obligate Aerobic ◽  
Energy Consumption Simulation ◽  
P Removal

P-bacteria can combine denitrification and P-uptake. This category of P-bacteria is abbreviated DPB. Use of DPB in BNR processes, instead of obligate aerobic PAOs, reduces oxygen consumption. Moreover, less COD is needed for the nitrogen removal. Non-required COD can be removed by presettling and used for methanation. This leads to a lower sludge production. As a result, CO2 emissions are reduced owing to less net energy consumption. Simulation for a planned WWTP with the BCFS® process indicates that DPB can save 53-59% of required COD. The optimal ratios of COD/N and COD/P for simultaneous N and P removal are determined to be 3.9~4.5 and 32.2~35.2 at 12~20°C. 80-95% of particulate COD can be removed from the influent, thereby CH4 production is increased by 154-271%, and the total volume of reactors can be reduced by about 50% compared to a minimised process design. Less net energy consumption over the whole WWTP contributes to a net reduction of the total CO2 emissions up to 16-21%. The energy production from CH4 is excessive enough to balance the energy consumption from aeration, dewatering and incineration. It is concluded that contribution of P-bacteria to saving COD has overall positive effects on the environment.

The significance of microbial Fe(III) reduction in the activated sludge process

1996 ◽  
Vol 34 (5-6) ◽  
pp. 129-136 ◽  
Author(s):  
Per Halkjær Nielsen
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Reduction Rate ◽  
Treatment Plant ◽  
Anaerobic Conditions ◽  
Phosphate Release ◽  
Floc Structure ◽  
Acetate Formation ◽  
Nitrate And Nitrite ◽  
P Removal

The significance of microbial Fe(III) reduction in activated sludge was evaluated with regard to: its importance as electron acceptor; as a producer of acetate during anaerobic conditions; for phosphate release; and for its role in the floc structure. Potential Fe(III) reduction rates were measured in 6 wastewater treatment plants with and without biological P-removal and found to be in the range of 0.9-5.4 mgFe/gVSS h. Assuming an incomplete oxidation of organic matter leading to acetate formation, Fe(III) reduction was a major acetate source, providing substrate to phosphorus-accumulating organisms (PAO) during anaerobic conditions. The observed high potential Fe(III) reduction rate might also be responsible for a significant chemical phosphate release due to reduction of Fe(III) to Fe(II) in clarifies, sludge storage tanks and anaerobic tanks in plants with biological P-removal. Investigation of the concentrations of Fe(II) in a full-scale treatment plant in anaerobic tanks, oxic/anoxic tanks and return sludge indicated that both reduction and reoxidation took place in the treatment plant. Reoxidation of Fe(II) to Fe(III) in activated sludge was shown to take place with oxygen and probably also during anoxic conditions with nitrate and nitrite as electron acceptors. The results indicate that Fe may be more involved in important processes in activated sludge than hitherto assumed, so a better understanding of Fe interactions in activated sludge is desirable.

Modelling of full-scale wastewater treatment plants with different treatment processes using the Activated Sludge Model no. 3

2001 ◽  
Vol 44 (1) ◽  
pp. 49-56 ◽  
Author(s):  
M. Wichern ◽  
F. Obenaus ◽  
P. Wulf ◽  
K.-H. Rosenwinkel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Biological Phosphorus Removal ◽  
Activated Sludge Model ◽  
Treatment Processes ◽  
Biological Phosphorus ◽  
P Removal

In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.

Comparison of aerobic and anoxic phosphorus uptake in ndbepr systems (uct and enbnras)

2002 ◽  
Vol 46 (4-5) ◽  
pp. 201-207 ◽  
Author(s):  
S.M. Vermande ◽  
S. Sötemann ◽  
G. Aguilera Soriano ◽  
M. Wentzel ◽  
J.M. Audic ◽  
...  
Keyword(s):  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Mass Fraction ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
P Release ◽  
University Of Cape Town ◽  
The University ◽  
P Removal

Two Nitrification-Denitrification Biological Excess Phosphorus Removal (NDBEPR) systems have been operated for 8.5 months in order to compare their Biological Excess Phosphorus Removal (BEPR) performance. One of these systems, i.e. the University of Cape Town (UCT) system, exhibits mainly aerobic P uptake while the External Nitrification Biological Nutrient Removal Activated Sludge (ENBNRAS) system is characterised by high anoxic P uptake. It was observed that when operating with predominantly aerobic P uptake, the UCT system released more P than the ENBNRAS system, even though it had a lower anaerobic mass fraction. However, when the influent TKN/COD was high, i.e. >0.1, anoxic P uptake also occurred in the UCT system and P release dropped to lower levels than in the ENBNRAS. Accordingly, P uptake of the UCT system was 5 mg P/l influent higher than that of the ENBNRAS system, when it was predominantly aerobic, but 9 mg P/l influent lower when anoxic P uptake occurred. As a result, the UCT system achieved superior P removal when aerobic P uptake was predominant (23% higher), but when high influent TKN/COD promoted anoxic P uptake the P removal of the UCT system was poorer than that of the ENBNRAS system. This study clearly showed that anoxic P uptake is not beneficial to NDBEPR systems.

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