Kinetics of Biological Phosphorus Release

1985 ◽  
Vol 17 (11-12) ◽  
pp. 57-71 ◽  
Author(s):  
M. C. Wentzel ◽  
P. L. Dold ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Flow Regime ◽  
Mass Fraction ◽  
Phosphorus Release ◽  
P Uptake ◽  
Process Conditions ◽  
Anaerobic Reactor ◽  
P Release ◽  
Wide Range ◽  
Biological Phosphorus ◽  
Kinetics Of

Experimental observations indicate that the magnitude of biological excess P uptake is linked strongly to the magnitude of P release in the anaerobic reactor. A theory describing the kinetics of P release is presented in terms of the readily biodegradable COD in the influent, the non-polyP heterotrophic mass, the anaerobic mass fraction and the reactor flow regime. Observed P release conforms well to that predicted over a wide range of wastewater characteristics and process conditions.

Full Scale Investigations on Enhanced Biological Phosphorus Removal – P-Release in the Anaerobic Reactor

1994 ◽  
Vol 29 (7) ◽  
pp. 153-156 ◽  
Author(s):  
D. Wedi ◽  
P. A. Wilderer
Keyword(s):  
Phosphorus Removal ◽  
Full Scale ◽  
Process Conditions ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Anaerobic Reactor ◽  
P Release ◽  
Acinetobacter Sp ◽  
Biological Phosphorus ◽  
P Removal

Most of the fundamental processes responsible for enhanced biological phosphorus removal (EBPR) were obtained through laboratory tests under defined conditions with pure or enriched cultures. Acinetobacter sp. was identified as the most important group of bacteria responsible for bio-P removal. Full scale data showed, however, that laboratory results do not match full scale results well enough. There is a lack of data on the effects of sub-optimal process conditions such as inadequate availability of volatile fatty acids (VFA), high nitrate recycle, storm water inflow or low temperatures. In this paper the results of full scale experiments on P-release are presented and compared with theoretical values. Measurements at a full scale Phoredox-system showed a surprisingly low P-release in the anaerobic reactor. Only 4 to 10% of the phosphorus in the activated sludge was released in the bulk liquid. With laboratory batch-tests, a maximum of 20% of the P in the sludge could be released. It is assumed that under the prevailing process conditions either the fraction of Acinetobacter sp. was very small, or bacteria other than Acinetobacter sp. were responsible for the P-removal, or most of the phosphorus was bound chemically but mediated by biological processes.

Phosphorus release and uptake during start-up of a covered and non-aerated sequencing batch reactor with separate feeding of VFA and sulfate

2012 ◽  
Vol 65 (5) ◽  
pp. 840-844 ◽  
Author(s):  
D. Wu ◽  
T. Hao ◽  
H. Lu ◽  
H. K. Chui ◽  
M. C. M. van Loosdrecht ◽  
...  
Keyword(s):  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
P Uptake ◽  
Sulfur Cycle ◽  
Biological Phosphorus Removal ◽  
P Release ◽  
Start Up ◽  
Uptake Rates ◽  
Biological Phosphorus ◽  
P Removal

This study explored a sulfur cycle-associated biological phosphorus (P) removal process in a covered and non-aerated sequencing batch reactor (SBR) fed with volatile fatty acid (VFA) and sulfate separately. During the 60-day start-up, both phosphate release and uptake rates increased, while poly-phosphate cyclically increased and decreased accordingly. The P-release and P-uptake rates were associated with VFA uptake and sulfate reduction. The average ratio of potassium to phosphate during the P-uptake and P-release was also determined to be 0.29–0.31 mol K/mol P, which is close to a reported value (0.33) for biological phosphorus removal. All this evidence confirmed there was biological P removal in this reactor, in which metabolism could be different from conventional biological P removal.

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.

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.

Kinetics of pyrolysis and properties of carbon black from a scrap tire

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
Z. Koreňová ◽  
M. Juma ◽  
J. Annus ◽  
J. Markoš ◽  
L’. Jelemenský
Keyword(s):  
Carbon Black ◽  
Pore Size ◽  
Rubber Particle ◽  
Ash Content ◽  
Process Conditions ◽  
Nitrogen Flow ◽  
Scrap Tire ◽  
Second Stage ◽  
Wide Range ◽  
Kinetics Of

AbstractThe pyrolysis of rubber from the sidewall and tread of a passenger car tire was carried out in a nitrogen flow at a wide range of final temperatures. Derivative thermogravimetric analysis (DTG) was applied to examine the kinetics at the different process conditions of completed pyrolysis. Two characteristic stages were observed in the DTG curves. The first stage corresponded to the decomposition of processing oil, plastifier, and additives, whereas the rubber polymer was decomposed in the second stage. Several properties of the carbon black formed by the pyrolysis such as ash content, specific surface area, and pore size distribution were determined. A change of the internal structure of the rubber particle in the meso-and macroregions of the pore size was observed.

Enhanced biological phosphorus removal in membrane bioreactors

2002 ◽  
Vol 46 (4-5) ◽  
pp. 281-286 ◽  
Author(s):  
C. Adam ◽  
R. Gnirss ◽  
B. Lesjean ◽  
H. Buisson ◽  
M. Kraume
Keyword(s):  
Phosphorus Removal ◽  
P Uptake ◽  
Membrane Bioreactors ◽  
Process Conditions ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Bench Scale ◽  
Plant P Uptake ◽  
Biological Phosphorus ◽  
P Removal

Enhanced biological phosphorus removal (Bio-P) in a membrane bioreactor (MBR) promises several advantages but was never attempted as not compatible with high sludge ages. This article includes description and results of bench-scale investigations on Bio-P removal in an MBR. An MBR bench-scale plant (210 L) was operated in parallel to a conventional WWTP under comparable process conditions. The results show that Bio-P removal is possible in MBR. The effluent qualities of the plants were comparable. The effluent P-concentration was always lower than 0.2 mg PT/L. In the MBR bench-scale plant P-uptake occurred mainly in the anoxic zone. Investigations with P-spiking showed higher Bio-P potential as P-removal increased up to 20-25 mg/L while P/TS rose up to >6%.

Polyhydroxyalkanoate form and polyphosphate regulation: keys to biological phosphorus and glycogen transformations?

2003 ◽  
Vol 47 (11) ◽  
pp. 227-233 ◽  
Author(s):  
A.A. Randall ◽  
Y. Chen ◽  
Y.-H. Liu ◽  
T. McCue
Keyword(s):  
Experimental Studies ◽  
Domestic Wastewater ◽  
P Uptake ◽  
Major Influence ◽  
Biological Phosphorus Removal ◽  
P Release ◽  
P Transformations ◽  
Biological Phosphorus ◽  
P Removal

Experimental studies with both synthetic and real domestic wastewater showed that poly-3-hydroxy-butyrate (3HB) and poly-3-hydroxy-valerate (3HV) formed in direct proportion to the acetate/propionate (Ace/Pro) ratio of the influent wastewater during Enhanced Biological Phosphorus Removal (EBPR). Acetic acid resulted in higher anaerobic phosphorus (P) release, polyhydroxyalkanoate (PHA) yield, 3HB content, and glycogen (CH) degradation. Linear regression showed that anaerobic P release (Prel) and CH degradation (CHdeg) were both a function of Ace→3HB, but not of Pro→3HV. Aerobic P uptake (Pup) correlated best with preceding Prel rather than PHA (but note Prel correlated with Ace→3HB). Aerobic CH formation (CHform) correlated best with CHdeg and 3HB. The results imply the acetate/propionate content of influent has a major influence on PHA, CH, and P transformations. Short-term increases in acetic or propionic acid increased Prel, but were always offset by corresponding changes in Pup to yield the same net P removal as the control reactor. Thus net P removal, and EBPR process performance, was probably a function of the population selected (i.e. XPAO fraction) during long-term cultivation.

Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1362-1363
Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Large Scale ◽  
Hexagonal Phase ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Process Conditions ◽  
Tin Films ◽  
Wide Range ◽  
Fcc Phase ◽  
Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

Sign in / Sign up

Export Citation Format

Share Document