scholarly journals Hydroxyapatite Precipitation and Accumulation in Granules and Its Effects on Activity and Stability of Partial Nitrifying Granules at Moderate and High Temperatures

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1710
Author(s):  
Yong-Qiang Liu ◽  
Simone Cinquepalmi
Keyword(s):  
High Temperature ◽  
Calcium Phosphate ◽  
Granular Sludge ◽  
Phosphate Removal ◽  
Ammonium Oxidation ◽  
Mineral Contents ◽  
Research Attention ◽  
Oxidation Rates ◽  
P Content ◽  
Removal And Recovery

Precipitation and accumulation of calcium phosphate in granular sludge has attracted research attention recently for phosphate removal and recovery from wastewater. This study investigated calcium phosphate accumulation from granulation stage to steady state by forming heterotrophic granules at different COD/N ratios at 21 and 32 °C, respectively, followed by the transformation of heterotrophic granules to partial nitrifying granules. It was found that mature granules accumulated around 60–80% minerals in granules, much higher than young granules with only around 30% ash contents. In addition, high temperature promoted co-precipitation of hydroxyapatite and calcite in granules with more calcite than hydroxyapatite and only 4.1% P content, while mainly hydroxyapatite was accumulated at the moderate temperature with 7.7% P content. The accumulation of minerals in granules at the high temperature with 75–80% ash content also led to the disintegration and instability of granules. Specific ammonium oxidation rates were reduced, as well, from day 58 to day 121 at both temperatures due to increased mineral contents. These results are meaningful to control or manipulate granular sludge for phosphorus removal and recovery by forming and accumulating hydroxyapatite in granules, as well as for the maintenance of microbial activities of granules.

Simultaneous COD, nitrogen, and phosphate removal by aerobic granular sludge

2005 ◽  
Vol 90 (6) ◽  
pp. 761-769 ◽  
Author(s):  
M.K. de Kreuk ◽  
J.J. Heijnen ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Granular Sludge ◽  
Phosphate Removal ◽  
Aerobic Granular Sludge ◽  
Nitrogen And Phosphate Removal

scholarly journals Phosphate removal and recovery using immobilized phosphate binding proteins

2018 ◽  
Vol 1 ◽  
pp. 100003 ◽  
Author(s):  
Kaushik Venkiteshwaran ◽  
Nilisha Pokhrel ◽  
Faten Hussein ◽  
Edwin Antony ◽  
Brooke K. Mayer
Keyword(s):  
Binding Proteins ◽  
Phosphate Removal ◽  
Phosphate Binding ◽  
Removal And Recovery

Mineral partitioning in milk and milk permeates at high temperature

2011 ◽  
Vol 79 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Divina D Kaombe ◽  
Yanhong Du ◽  
Michael J Lewis
Keyword(s):  
High Temperature ◽  
Calcium Phosphate ◽  
Temperature Dependence ◽  
Casein Micelle ◽  
Soluble Phase ◽  
Ionic Calcium ◽  
Separation Temperature ◽  
Two Temperatures ◽  
Lower Temperature ◽  
Mineral Partitioning

The soluble phase of milk was separated at 20 and 80°C using ultrafiltration. The resulting permeates were then subjected to further ultrafiltration and dialysis at close to these two temperatures. It was found that pH, Ca2+ and soluble Ca decreased as the separation temperature increased both in original UF permeates and in dialysates obtained from these permeates, but P decreased only slightly. The major reason for these changes was due to the precipitation of calcium phosphate/citrate complexes onto the casein micelle with concomitant release of H+. The pH of both permeates and dialysates from milk at 20°C were slightly higher than for milk. When UF permeates collected at 20 and 80°C, were each dialysed at both these temperatures, the dialysate collected at 80°C showed much less temperature dependence for pH and ionic calcium compared with that collected at 20°C. This is in contrast to milk, which shows considerable temperature dependence for pH and ionic calcium. Further experiments revealed that the pH and Ca2+ concentration of permeates showed high temperature dependence above the temperature at which they were separated, but a much lower temperature dependence below that temperature. These findings suggest that dialysis and UF of milk at high temperature provide the best means yet for estimating the pH and ionic calcium of milk at that temperature.

scholarly journals Phosphate removal and recovery from water using nanocomposite of immobilized magnetite nanoparticles on cationic polymer

2016 ◽  
Vol 37 (16) ◽  
pp. 2099-2112 ◽  
Author(s):  
Ahmad Abo Markeb ◽  
Amanda Alonso ◽  
Antonio David Dorado ◽  
Antoni Sánchez ◽  
Xavier Font
Keyword(s):  
Magnetite Nanoparticles ◽  
Cationic Polymer ◽  
Phosphate Removal ◽  
Removal And Recovery

Biomimetic Mineralization and Bioactivity of Phosphorylated Chitosan

2005 ◽  
Vol 288-289 ◽  
pp. 429-432 ◽  
Author(s):  
Zhi Qing Chen ◽  
Quan Li Li ◽  
Quan Zen ◽  
Gang Li ◽  
Hao Bin Jiang ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Crystal Nucleation ◽  
Osteoblast Proliferation ◽  
Biomimetic Mineralization ◽  
P Content ◽  
Proliferation And Differentiation ◽  
Nucleation Growth

Phosphorylated chitosans were synthesized as templates to manipulate hydroxyapatite (HA) crystal nucleation, growth and microstructure. Two kinds of insoluble phosphorylated chitosan were soaked in saturated Ca(OH)2 solution for 4 d and in 1.5× SBF (simulated body fluid) solutions for 14 d at 37 °C for biomimetic mineralization. A lower [P]-content of phosphorylated chitosan promoted greater mineralization than higher [P]-content. Phosphorylated chitosan inhibited osteoblast proliferation and differentiation in vitro, while calcium phosphate phosphorylated chitosan composites did not.

scholarly journals Performance and adsorption mechanism of a magnetic calcium silicate hydrate composite for phosphate removal and recovery

2018 ◽  
Vol 2017 (2) ◽  
pp. 578-591 ◽  
Author(s):  
Lihong Peng ◽  
Hongliang Dai ◽  
Yifeng Wu ◽  
Zheqin Dai ◽  
Xiang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Magnetic Separation ◽  
Adsorption Kinetics ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Phosphate Removal ◽  
Separation Technique ◽  
Phosphate Adsorption ◽  
X Ray ◽  
Removal And Recovery

Abstract A novel magnetic calcium silicate hydrate composite (Fe3O4@CSH) was proposed for phosphorus (P) removal and recovery from a synthetic phosphate solution, facilitated by a magnetic separation technique. The Fe3O4@CSH material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), zeta-potential and magnetic curves. The chemical composition and structure of Fe3O4@CSH and the successful surface loading of hydroxyl functional groups were confirmed. Phosphate adsorption kinetics, isotherm, and thermodynamic experiments showed that adsorption reaches equilibrium at 24 h, with a maximum adsorption capacity of 55.84 mg P/g under optimized experimental conditions. Adsorption kinetics fitted well to the pseudo second-order model, and equilibrium data fit the Freundlich isotherm model. Thermodynamic analysis provided a positive value for ΔH° (129.84 KJ/mol) and confirmed that phosphate adsorption on these materials is endothermic. The P-laden Fe3O4@CSH materials could be rapidly separated from aqueous solution by a magnetic separation technique within 1 min. A removal rate of more than 60% was still obtained after eight adsorption/desorption cycles, demonstrating the excellent reusability of the particles. The results demonstrated that the Fe3O4@CSH materials had high P-adsorption efficiency and were reusable.

scholarly journals Vitamin B12-dependent biosynthesis ties amplified 2-methylhopanoid production during oceanic anoxic events to nitrification

2020 ◽  
Vol 117 (52) ◽  
pp. 32996-33004
Author(s):  
Felix J. Elling ◽  
Jordon D. Hemingway ◽  
Thomas W. Evans ◽  
Jenan J. Kharbush ◽  
Eva Spieck ◽  
...  
Keyword(s):  
Nutrient Loading ◽  
Model Organism ◽  
Fold Increase ◽  
Conclusive Evidence ◽  
Marine Cyanobacteria ◽  
Ammonium Oxidation ◽  
Oxidation Rates ◽  
Ammonia Oxidizing Archaea ◽  
Anoxic Events ◽  
Geologic Record

Bacterial hopanoid lipids are ubiquitous in the geologic record and serve as biomarkers for reconstructing Earth’s climatic and biogeochemical evolution. Specifically, the abundance of 2-methylhopanoids deposited during Mesozoic ocean anoxic events (OAEs) and other intervals has been interpreted to reflect proliferation of nitrogen-fixing marine cyanobacteria. However, there currently is no conclusive evidence for 2-methylhopanoid production by extant marine cyanobacteria. As an alternative explanation, here we report 2-methylhopanoid production by bacteria of the genus Nitrobacter, cosmopolitan nitrite oxidizers that inhabit nutrient-rich freshwater, brackish, and marine environments. The model organism Nitrobacter vulgaris produced only trace amounts of 2-methylhopanoids when grown in minimal medium or with added methionine, the presumed biosynthetic methyl donor. Supplementation of cultures with cobalamin (vitamin B12) increased nitrite oxidation rates and stimulated a 33-fold increase of 2-methylhopanoid abundance, indicating that the biosynthetic reaction mechanism is cobalamin dependent. Because Nitrobacter spp. cannot synthesize cobalamin, we postulate that they acquire it from organisms inhabiting a shared ecological niche—for example, ammonia-oxidizing archaea. We propose that during nutrient-rich conditions, cobalamin-based mutualism intensifies upper water column nitrification, thus promoting 2-methylhopanoid deposition. In contrast, anoxia underlying oligotrophic surface ocean conditions in restricted basins would prompt shoaling of anaerobic ammonium oxidation, leading to low observed 2-methylhopanoid abundances. The first scenario is consistent with hypotheses of enhanced nutrient loading during OAEs, while the second is consistent with the sedimentary record of Pliocene–Pleistocene Mediterranean sapropel events. We thus hypothesize that nitrogen cycling in the Pliocene–Pleistocene Mediterranean resembled modern, highly stratified basins, whereas no modern analog exists for OAEs.

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