Phosphate Precipitation in Biofilms and Flocs

1983 ◽  
Vol 15 (3-4) ◽  
pp. 65-85 ◽  
Author(s):  
Erik Arvin ◽  
Gert Holm Kristensen
Keyword(s):  
Mathematical Model ◽  
Calcium Phosphate ◽  
Carbon Source ◽  
Practical Interest ◽  
Calcium Bicarbonate ◽  
Fixed Film ◽  
Phosphate Phase ◽  
Film Reactor ◽  
Calcium Phosphate Precipitation ◽  
Apatitic Phase

The experiments have confirmed that denitrification in biofilms may lead to calcium phosphate precipitation inside the biofilms due to the increased pH created by the denitrification reaction. This has been shown in a laboratory fixed film reactor with well defined geometry and feed with well defined substrates. The phosphate precipitate was in one case found similar to a carbonate containing apatitic phase. It accumulated in the bio-film to 9.3% P based on dry solids. A mathematical model has been developed relating the phosphate to nitrate molar removal rates to the concentration of phosphate, calcium, bicarbonate, the solubility of the solid phosphate phase and the type of carbon source used for denitrification. The model was supported by the experiments. The experiments show that the biofilm precipitation may be of significant practical interest, but factors as filamentous growth on the biofilm surface or precipitation of an easy soluble amorphous calcium phosphate can also make the biofilm precipitation insignificant. The precipitation effect is expected to be feasible in floes, if a homogeneous biomatrix with a thickness of more than approx. 100 µm exist in the floc substructure.

Starting-Up of an Anaerobic Fixed-Film Reactor

1983 ◽  
Vol 15 (8-9) ◽  
pp. 305-308 ◽  
Author(s):  
M S Salkinoja-Salonen ◽  
E.-J Nyns ◽  
P M Sutton ◽  
L van den Berg ◽  
A D Wheatley
Keyword(s):  
Fixed Film ◽  
Film Reactor

Tertiary nitrification in pilot-plant plug-flow fixed-film reactors with long-term ammonium deficiency

1994 ◽  
Vol 29 (10-11) ◽  
pp. 61-67 ◽  
Author(s):  
M. Fruhen ◽  
K. Böcker ◽  
S. Eidens ◽  
D. Haaf ◽  
M. Liebeskind ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Effective Means ◽  
Plug Flow ◽  
Nitrification Rate ◽  
Industrial Project ◽  
Transfer Processes ◽  
Fixed Film ◽  
Film Reactor ◽  
Observation Period

The objective of this study is to investigate to what extent the nitrification capacity of a pilot-plant fixed-film reactor changes during extensive periods of nutrient supply deficiency. The examined pilot-plant was an upflow reactor filled with swelling clay of medium grain size (6 to 8 mm). The experiments revealed that the maximum nitrification rate remained practically constant during the first weeks after the onset of unregulated ammonium supply. The capacity declined slowly, dropping to approximately 66% of the initial capacity after about ten weeks. Still ammonium peaks of up to 8 mg/l were readily nitrified throughout the entire period of the experiment. The reduction in nitrification capacity during the observation period did not result from decay processes of biomass but from the reactor becoming blocked and thus hampering transfer processes. It could be observed that the detached organisms attached again further up. This semi-industrial project demonstrated that a plug-flow fixed-film reactor can be used as effective means of tertiary nitrification.

Evidence of calcium phosphate supersaturation in the loop of Henle

1996 ◽  
Vol 270 (4) ◽  
pp. F604-F613 ◽  
Author(s):  
J. R. Asplin ◽  
N. S. Mandel ◽  
F. L. Coe
Keyword(s):  
Calcium Phosphate ◽  
Calcium Concentration ◽  
Loop Of Henle ◽  
X Ray ◽  
Ion Interactions ◽  
Collecting Ducts ◽  
Phosphate Phase ◽  
Dietary Phosphate ◽  
Calcium Phosphate Phase

We have used published rat micropuncture data to construct a matrix of ion concentrations along the rat nephron. With an iterative computer model of known ion interactions, we calculated relative supersaturation ratios in all nephron segments. The collecting ducts and urine showed expected supersaturation with stone-forming salts. Fluid in the thin segment of the loop of Henle may be supersaturated with calcium carbonate and calcium phosphate under certain conditions. Because calculations cannot predict the actual course of crystallization, we made solutions to mimic, in vitro, presumed conditions in the loop of Henle. The solid phases that formed were analyzed by X-ray powder diffraction, electron microprobe, and infrared spectroscopy. All samples were identified as poorly crystallized or immature apatite. The descending limb of Henle's loop creates a unique condition as it extracts water but not sodium, bicarbonate, calcium, or phosphate, giving a calcium concentration at the bend of 3 mM, pH 7.4, and a phosphate concentration that varies from 0.8 to 48 mM, depending on parathyroid hormone and dietary phosphate. We conclude that conditions in the thin segment potentially could create a solid calcium phosphate phase, which may initiate nucleation of calcium oxalate salts in the collecting ducts, potentiating nephrolithiasis and nephrocalcinosis.

scholarly journals Modelling simultaneous removal of trichlorfon and glucose in a hybrid bioreactor containing magnetically immobilized biomass

1998 ◽  
Vol 38 (4-5) ◽  
pp. 179-186 ◽  
Author(s):  
Guang Hao Chen ◽  
Hiroaki Ozaki ◽  
Yutaka Terashima
Keyword(s):  
Mathematical Model ◽  
Carbon Source ◽  
Experimental Results ◽  
Simultaneous Removal ◽  
Industrial Wastewaters ◽  
Suspended Biomass ◽  
Immobilized Biomass

This paper focuses on a simultaneous removal of trichlorfon and glucose that was added as carbon source for degradation requirement of trichlorfon. A hybrid bioreactor, having both suspended and magnetically immobilized biomass, was used for investigating this removal of both substances. To evaluate the respective roles of these two types of biomass, a mathematical model was developed and also verified well with experimental results. It has been found that the suspended biomass plays a key role in removing both substances in the system. This is due to complete coexistence of both trichlorfon-degrading and glucose-removing bacteria completely in each type of the biomass. Such a system would be applicable to the treatment of complex industrial wastewaters that contain easily biodegradable organics as well as refractory pollutants.

scholarly journals Transfection of Capsaspora owczarzaki  using calcium-phosphate precipitation v1 (protocols.io.p4adqse)

protocols.io ◽  
2018 ◽  
Author(s):  
Helena Parra ◽  
N ria ◽  
Alberto Perez ◽  
Aleksandra Kozyczkowska ◽  
Sebasti n
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Precipitation

scholarly journals Assessing the Impact of Regional Budget Expenditures on Average Wages

2020 ◽  
Vol 16 (1) ◽  
pp. 61-69
Author(s):  
Denis M. Zhuravlyov
Keyword(s):  
Mathematical Model ◽  
Economic System ◽  
Labour Market ◽  
Model Performance ◽  
Practical Interest ◽  
Qualitative Assessment ◽  
Average Wage ◽  
Software Application ◽  
Regional Budget ◽  
The Impact

The author discusses the development of an economic-mathematical model for assessing the impact of regional budget expenditures on the average wage for solving the problems of analyzing macroeconomic indicators and forming strategic planning tools for the development of the regional socioeconomic system. The Object of the Study - expenses of the regional budget of the constituent entity of the Rossiyskaya Federatsiya, aimed at developing and maintaining the infrastructure contributing to the provision of comfortable working conditions for citizens. The Subject of the Study - methods of economic and mathematical modelling, processes of formation of the average wage. The Purpose of the Study. Development of an economic and mathematical model for assessing the impact of regional budget expenditures on the average wage level for quantitative and qualitative assessment of the effectiveness of the totality of measures arising in the process of its implementation. The Main Provisions of the Article. The labour market is the basis of a market economy and indicator, the importance of which makes it possible to draw conclusions both about the state of the economy as a whole and about the success of the reforms and transformations, in particular. His condition directly affects the performance indicators of the socio-economic system of the region: productivity, profitability, growth, etc. Research and identification of factors that have a significant impact on the processes of formation and functioning of the labor market is of not only theoretical, but practical interest. The following tasks have been solved: the economic and mathematical models are formalized; the layout of the indices characterizing the object of study; the corresponding mathematical apparatus is selected; software application developed; the proof of model performance is performed. As a methodological apparatus, methods of regression and correlation analysis were used. As a result, an economic-mathematical model of the category «labour market efficiency» was obtained, the functionality of which is sufficient to substantiate causal relationships between indicators that determine the nature of its functioning. Using the obtained results in practice, it is possible to reasonably form a system of priority long-term guidelines for the development of the socio-economic system of the region, drawn up in the form of relevant program documents. The developed software can be used as a module of a decision support system in the formation and development of a strategy for the region’s accelerated development.

Biological nitrification kinetics in a fixed-film reactor

1996 ◽  
Vol 58 (1) ◽  
pp. 41-48 ◽  
Author(s):  
M.F. Hamoda ◽  
M.O. Zeidan ◽  
A.A. Al-Haddad
Keyword(s):  
Fixed Film ◽  
Nitrification Kinetics ◽  
Film Reactor ◽  
Biological Nitrification

Molecular Basis of Salivary Proline-rich Protein and Peptide Synthesis: Cell-free Translations and Processing of Human and Macaque Statherin mRNAs and Partial Amino Acid Sequence of their Signal Peptides

1987 ◽  
Vol 66 (2) ◽  
pp. 462-466 ◽  
Author(s):  
F.G. Oppenheim ◽  
D.I. Hay ◽  
D.J. Smith ◽  
G.D. Offner ◽  
R.F. Troxler
Keyword(s):  
Calcium Phosphate ◽  
Macaca Fascicularis ◽  
Electrophoretic Analysis ◽  
Proteolytic Processing ◽  
Oral Environment ◽  
Reticulocyte Lysate ◽  
Polyprotein Precursor ◽  
Phosphate Salts ◽  
Calcium Phosphate Precipitation

Acidic proline-rich phosphoproteins and phosphopeptides are abundant components of parotid and submandibular salivary secretions in man and in the subhuman primate, Macaca fascicularis. The major acidic proline-rich proteins and the proline-rich phosphopeptide, statherin, of man and macaques have been shown to be potent inhibitors of calcium phosphate precipitation and are thought to function in the oral environment by maintaining saliva supersaturated with respect to calcium phosphate salts. Little is known about the biosynthesis of these proline-rich phosphoproteins and peptides, and the aim of the present work was to determine the structural relationship between statherin precursors and native human and macaque statherin. RNA was isolated from human submandibular gland, and poly(A+) mRNA was selected by affinity chromatography on oligo(dT) cellulose and translated in a reticulocyte lysate. Electrophoretic analysis of the translation products revealed that this mRNA directed the synthesis of a large number of polypeptides with M,s ranging from 5000 to 70,000. Immunoprecipitates, prepared with an antiserum directed against human statherin, contained a single component with a Mr of 7800, approximately 2000 daltons larger than native statherin. Radiosequencing of the in vitro precursor of statherin in immunoprecipitates demonstrated the presence of a 19-residue signal peptide. These results suggest that statherin is derived from a unique structural gene, and does not result from proteolytic processing of a large polyprotein precursor.

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