Spatial distribution and comparative evaluation of phosphorus release rate in benthic sediments of an estuary dam

2021 ◽  
Author(s):  
Yongsik Song ◽  
Yong-Hoon Jeong ◽  
Chang-Min Shin ◽  
Dong-Heui Kwak
Keyword(s):  
Spatial Distribution ◽  
Release Rate ◽  
Comparative Evaluation ◽  
Phosphorus Release ◽  
Benthic Sediments

PIXE MICROBEAM IN LOCALIZING METALS RELEASED FROM DENTAL AND ORTHOPEDIC IMPLANTS

2005 ◽  
Vol 15 (03n04) ◽  
pp. 187-193
Author(s):  
PIETRO PASSI ◽  
ANGELA ZADRO ◽  
SILVIO GALASSINI ◽  
GIULIANO MOSCHINI ◽  
PAOLO ROSSI ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Release Rate ◽  
Pure Titanium ◽  
Orthopedic Implants ◽  
Elemental Distribution ◽  
Commercially Pure Titanium ◽  
Metal Release ◽  
Hip Prostheses ◽  
Commercially Pure ◽  
Release Processes

The release of metals and other elements from dental and orthopedic implants into the tissues has been a matter of numerous studies. However, the conditions that favor such a phenomenon have not been completely understood so far. PIXE microbeam technique has been applied to study the spatial distribution of the elements released from the implants. Subjects of interest have been implants made from commercially pure titanium, Ti -6 Al -4 V alloy and 316 LWM surgical steel. Block sections of five dental implants, as well as tissues surrounding one metal spine plate and two hip prostheses, have been examined. Rabbit bones containing copper inclusions have been taken for microbeam analysis to complete the study about the metal release processes. Samples from the tissues and bone slices have been analyzed using PIXE microbeam setup at National Laboratories of Legnaro, Italy. Traces of the implant metals, including titanium but with the exception of vanadium, were found in the surrounding tissues and maps of their elemental distribution at different distances from the contact surface with implants have been obtained. The origin and the differences of the release rate of the observed metals have been discussed.

scholarly journals Comparative Evaluation of Pre-treatment Methods to Enhance Phosphorus Release from Digestate

2016 ◽  
Vol 8 (3) ◽  
pp. 659-667 ◽  
Author(s):  
Céline Vaneeckhaute ◽  
Aga T. Zeleke ◽  
Filip M. G. Tack ◽  
Erik Meers
Keyword(s):  
Comparative Evaluation ◽  
Phosphorus Release ◽  
Treatment Methods ◽  
Pre Treatment

Phosphate release from waste stabilisation pond sludge: significance and fate of polyphosphate

2011 ◽  
Vol 63 (8) ◽  
pp. 1689-1694 ◽  
Author(s):  
N. Powell ◽  
A. Shilton ◽  
S. Pratt ◽  
Y. Chisti
Keyword(s):  
Release Rate ◽  
Phosphorus Removal ◽  
Algal Bloom ◽  
Chemical Precipitation ◽  
Phosphorus Release ◽  
Common View ◽  
Phosphate Release ◽  
Initial Release ◽  
Polyphosphate Accumulation ◽  
The Common

Net phosphorus removal from waste stabilisation pond (WSP) systems is governed by the rate of phosphorus incorporation into the sludge layer and the rate of phosphorus release from this sludge back to the overlying wastewater. Luxury uptake of phosphorus by microalgae has been shown to occur under WSP conditions in the laboratory; however, the significance of this mechanism and the fate of polyphosphate contained in the settled solids have not previously been investigated. In this work the analysis of sludge samples from three WSP showed that up to 71% of the total phosphorus in the sludge was in the form of polyphosphate. This indicates that polyphosphate accumulation could potentially be an important mechanism for phosphorus sequestration in WSP and challenges the common view that chemical precipitation is the predominant phosphorus removal mechanism in these systems. The release of phosphate from WSP sludge samples was monitored in the laboratory. The samples from two different pond systems had release rates in the order of 4.3 μgP/gTSS.d. However, the third sample which was collected during an algal bloom had a release rate of 12.4 μgP/gTSS.d. Phosphate release from fresh microalgal sludge grown under laboratory conditions was also studied and was shown to have a release rate of 160 μgP/gTSS.d. Analysis of polyphosphate during the experiments on laboratory grown microalgal sludge showed that polyphosphate was indeed degraded resulting in phosphate release. Interestingly, after the initial release phase phosphorus was assimilated by the biomass and some polyphosphate was reformed. It is likely that this is due to bacterial growth in the sludge.

Phosphorus release rate and plant response in some calcareous soils

2009 ◽  
Vol 55 (1) ◽  
pp. 91-103 ◽  
Author(s):  
Farzaneh Sadate Biabanaki ◽  
Alireza R. Hosseinpur
Keyword(s):  
Release Rate ◽  
Calcareous Soils ◽  
Phosphorus Release ◽  
Plant Response

Use of phosphorus release batch tests for modelling an EBPR pilot plant

2002 ◽  
Vol 45 (6) ◽  
pp. 99-106 ◽  
Author(s):  
E. Tykesson ◽  
H. Aspegren ◽  
M. Henze ◽  
P.H. Nielsen ◽  
J. Ia C. Jansen
Keyword(s):  
Release Rate ◽  
Phosphorus Removal ◽  
Pilot Plant ◽  
Phosphorus Content ◽  
Phosphorus Release ◽  
Biological Phosphorus Removal ◽  
Batch Tests ◽  
Initial Release ◽  
Analysis Programme ◽  
Biological Phosphorus

The aim of this study was to evaluate how routinely performed phosphorus release tests could be used when modelling enhanced biological phosphorus removal (EBPR) using activated sludge models such as ASM2d. A pilot plant with an extensive analysis programme was used as basis for the simulations. Without any calibration the prediction of phosphorus removal was poor and the initial release rates from the simulations were not similar to those found from the laboratory tests. A period with low organic loading was chosen as a calibration period. In this period averages of daily influent measurements were used as influent parameters. First, calibration was performed in order to fit effluent COD and MLVSS in the sludge. Next, the phosphorus content in the sludge was decreased to the measured level by decreasing the fermentation rate. Finally, the initial phosphorus release rate was calculated from a simulated batch test and the PHA uptake rate was increased to fit this release rate with the average initial rates from laboratory batch tests performed during the period. The calibrated model was verified with data from the subsequent period where acetate was dosed.

Microbial effects on phosphorus release in aquatic sediments

2008 ◽  
Vol 58 (6) ◽  
pp. 1285-1289 ◽  
Author(s):  
Ting-Lin Huang ◽  
Xiao-Chun Ma ◽  
Hai-bing Cong ◽  
Bei-Bei Chai
Keyword(s):  
Ion Exchange ◽  
Release Rate ◽  
Phosphorus Release ◽  
Source Water ◽  
Aquatic Sediments ◽  
Iron Respiration ◽  
Microbial Effects

Microbial effects on phosphorus release were studied for the sediments of Tianjin source water by controlling DO and pH. The results show that: (1) In sterilised water, phosphorus began to release when pH = 9.1 and the stable release rate was 9.51 mg/(d·m2). It indicates that microorganisms may utilise anaerobic iron respiration to release Fe-P. (2) With unsterilised water, phosphorus release rate is 2.14 mg/(d·m2) when pH = 6.5, 8.60 mg/(d·m2) when pH is uncontrolled, and gets to 8.51 mg/(d·m2) when pH = 9.1. This indicates that microorganisms can dissolve insoluble phosphates to accelerate the ion exchange of OH− and PO43−, which are derived from iron-bound ortho-P and aluminium-bound ortho-P.

scholarly journals Heat release rate correlation and combustion noise in premixed flames

2011 ◽  
Vol 681 ◽  
pp. 80-115 ◽  
Author(s):  
N. SWAMINATHAN ◽  
G. XU ◽  
A. P. DOWLING ◽  
R. BALACHANDRAN
Keyword(s):  
Spatial Distribution ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Time Scale ◽  
Reaction Rate ◽  
Laminar Flame ◽  
Premixed Flames ◽  
Length Scale ◽  
Turbulent Premixed Flames

The sound emission from open turbulent flames is dictated by the two-point spatial correlation of the rate of change of the fluctuating heat release rate. This correlation in premixed flames can be represented well using Gaussian-type functions and unstrained laminar flame thermal thickness can be used to scale the correlation length scale, which is about a quarter of the planar laminar flame thermal thickness. This correlation and its length scale are observed to be less influenced by the fuel type or stoichiometry or turbulence Reynolds and Damkohler numbers. The time scale for fluctuating heat release rate is deduced to be about τc/34 on an average, where τc is the planar laminar flame time scale, using direct numerical simulation (DNS) data. These results and the spatial distribution of mean reaction rate obtained from Reynolds-averaged Navier–Stokes (RANS) calculations of open turbulent premixed flames employing the standard model and an algebraic reaction rate closure, involving a recently developed scalar dissipation rate model, are used to obtain the far-field sound pressure level from open flames. The calculated values agree well with measured values for flames of different stoichiometry and fuel types, having a range of turbulence intensities and heat output. Detailed analyses of RANS results clearly suggest that the noise level from turbulent premixed flames having an extensive and uniform spatial distribution of heat release rate is low.

Sign in / Sign up

Export Citation Format

Share Document