scholarly journals Internal phoshorus loading potential of a semiarid reservoir: an experimental study

2021 ◽  
Vol 33 ◽  
Author(s):  
Hérika Cavalcante ◽  
Fabiana Araújo ◽  
Vanessa Becker ◽  
José Etham de Lucena Barbosa
Keyword(s):  
Acidic Ph ◽  
Alkaline Ph ◽  
Release Rates ◽  
Tropical Reservoir ◽  
Reservoir Sediment ◽  
P Fractionation ◽  
P Release ◽  
Water And Sediment ◽  
Fractionation Analysis ◽  
Total P

Abstract: Aim To determine the internal P loading potential of semiarid tropical reservoir sediment while verifying the driving factors that affect P release rates. Methods An experiment was performed with water and sediment from the reservoir Boqueirão de Parelhas in Brazil. The effects of three variables on P release were studied: air temperature (region average of 28 °C and 32 °C, simulating an increase of 4 °C), pH (region average of pH 8, more acidic pH 6 and more alkaline pH 10) and oxygen (presence and absence). In addition, P fractionation analysis was performed on the P forms in the sediment. Results It was found that the minimum P release was in an oxic treatment at pH 6 and temperature 28 °C (0.22 mg m-2 d-1 ± 0.13) and the maximum P release in an anoxic treatment at pH 10 and temperature 32 °C (2.1 mg m-2 d-1 ± 0.15). The total P in the sediment was 597 mg kg-1, and the major P form in the sediment was NaOH-rP, the P bound to aluminum, corresponding to 42% of the total P. Conclusion These results allow us to confirm that the sediment of the Boqueirão reservoir is susceptible to the release of P bound to aluminum due to the prevalence of this form in its sediments concomitant with the high temperatures and alkaline pH of the water. This scenario can be aggravated by climate change.

CHANGES WITH TIME IN FORM AND AVAILABILITY OF RESIDUAL FERTILIZER PHOSPHORUS IN A CATENARY SEQUENCE OF CHERNOZEMIC SOILS

1975 ◽  
Vol 55 (2) ◽  
pp. 149-159 ◽  
Author(s):  
J. M. SADLER ◽  
J. W. B. STEWART
Keyword(s):  
Available P ◽  
P Availability ◽  
Reaction Products ◽  
Monoammonium Phosphate ◽  
P Fractionation ◽  
Inorganic P ◽  
P Transformation ◽  
Fractionation Analysis ◽  
Ap Horizon ◽  
Total P

Granular monoammonium phosphate (500 μg P/g soil) was applied in the field to three soils of an Oxbow catena. Changes in P form during the ensuing 2½ yr were determined by total P and modified inorganic P fractionation analysis; an index of available P was obtained by NaHCO3 extraction. The original soils were very low in NH4Cl-soluble P and available P; inorganic P apparently existed as sparingly soluble minerals. After application, most of the fertilizer P remained in the Ap horizon. In the Calcareous and Orthic profiles after 2 mo, 52 and 67%, respectively, of applied P recovered as inorganic P remained in available forms, mainly as NH4Cl-P. Subsequently in the Calcareous profile, NH4Cl-P underwent conversion to NH4F-soluble forms, causing a further 70% reduction in P availability. In the Orthic profile, the only apparent change with time was a decline to 41% in P availability. Applied P transformation to H2SO4-P was minimal in both soils. In the Gleysol profile, only 31% of P in the inorganic reaction products, which consisted mainly of NH4F-P and NaOH-NaCl-P, remained as available P after 2 mo. However, no further reduction in P availability occurred with time. Results indicated that an appreciable portion of residual fertilizer P in Chernozemic soils may persist for years in readily available forms. Soil pH strongly influenced residual P form and availability.

Optimising the A/O cycle for phosphorus removal in a submerged biofilter under continuous feed

2000 ◽  
Vol 41 (4-5) ◽  
pp. 503-508 ◽  
Author(s):  
R.F. Gonçalves ◽  
F. Rogalla
Keyword(s):  
Phosphorus Removal ◽  
Organic Substrate ◽  
P Element ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
P Release ◽  
Continuous Feed ◽  
Biological Phosphorus ◽  
Total P ◽  
Selection Of

This work describes laboratory scale research about Enhanced Biological Phosphorus Removal (EBPR) in a submerged biofilter under Anaerobic/Oxic (A/O) alternation and continuous feed. Its main purpose is to detail the behaviour of the reactor throughout the anaerobic and the aerobic phases of the A/O cycle, to study the importance of the anaerobic phase in the selection of the EBPR bacteria in the biofilm and to evaluate the consumption and the importance of the organic substrate during the anaerobic phase. The mass balance over the Phosphorus (P) element indicates that long anaerobic phases (6 h) are more efficient than short ones (3 h) as a selector of EBPR bacteria in biofilms. In both comparisons, thespecific mass of P released in a 6 h period represents almost 50% more than the amount of P release in the shorter period (3 h). However, the presence of rapidly biodegradable COD in the influent of the anaerobic phase is a more effective selector, more important than the duration of the anaerobic phase: by doubling the amount of acetic acid in the influent, a similar 50% increase of P-release can be achieved at short anaerobic periods of 3 h. The effect of the strategy adopted in this study, focusing on selecting EBPR bacteria in biofilm, is shown by the P levels of 4% (total P/SST) in the sludge removed from the BF by backwashing in all periods.

Two modes of phosphate transport by turtle urinary bladder

1980 ◽  
Vol 238 (1) ◽  
pp. F31-F36 ◽  
Author(s):  
J. P. Johnson ◽  
S. Green ◽  
J. H. Schwartz
Keyword(s):  
Urinary Bladder ◽  
Phosphate Transport ◽  
Phosphate Concentration ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
The Difference

The effects of changes in pH and addition of CO2/HCO3- on transepithelial phosphate transport were studied in turtle urinary bladder. Net mucosa-to-serosa flux of phosphate (JP) was determined as the difference between unidirectional 32P fluxes in the absence of transepithelial electrochemical gradients. With 5 mM phosphate in HCO3--free Ringer at pH 8.4, JP was 21.8 +/- 7.4 nmol . 8 cm-2 . h-1. There was a slight increase in JP with isohydric addition of 10 mM HCO3-. Addition of 5% CO2, which reduced pH to 7.3, did not affect JP. At pH 8.4, JP was not affected by ouabain or dinitrophenol and increased progressively as phosphate concentration was raised between 0.5 and 10 mM. At pH 6.2 in the absence of exogenous CO2 and HCO3-, JP was undectable. With 2.5 mM HCO3- and 5% CO2 at pH 6.5, JP was 61.3 +/- 16.0 and decreased to 30.6 +/- 1.6 nmol . 8 cm-2 . h-1 when pH was raised to 7.2 by increasing HCO3- to 10 mM. At pH 6.5 JP was inhibited by both ouabain and dinitrophenol. These results suggest that at acidic pH, JP results from the tranport of H2PO4-. The transport of H2PO4- is CO2 dependent and inhibited by ouabain and dinitrophenol. In contrast, at alkaline pH, JP results from the transport of HPO4(2-), which is neither CO2 dependent nor inhibited by ouabain or dinitrophenol.

scholarly journals Changes in the concentration of selected metals in sediments of the River Chotla in northwest Poland in its section affected by various anthropogenic factors

2015 ◽  
Vol 15 (2) ◽  
pp. 77-82
Author(s):  
Małgorzata Włodarczyk ◽  
Hanna Siwek ◽  
Anna Buchwał ◽  
Edyta Rafacz
Keyword(s):  
Bottom Sediment ◽  
Interstitial Water ◽  
Anthropogenic Factors ◽  
Alkaline Ph ◽  
River Section ◽  
Water And Sediment ◽  
Fish Breeding ◽  
Accumulation Of Metals ◽  
Water Accumulation ◽  
The Village

Abstract The purpose of the paper was to assess the changes in the concentration of selected metals in the bottom sediment and interstitial water of the River Chotla in northwest Poland. The research was conducted on the river section flowing through Zaspy Małe and a salmonid fish breeding farm. Samples of water and bottom sediment were taken in four control and measurement points, located above and below the village and on a backwater above the trouteries and below the fish breeding ponds. The pH and the concentration of the metals potassium, iron, calcium, manganese and zinc were determined in the water and sediment samples. The lowest concentrations of the metals were found in the samples collected above and below Zaspy Małe, while the highest concentrations of metals in the water and sediment were found in the samples taken in the backwater, above the fish breeding ponds. Exceptions were calcium and potassium, with the highest concentrations of metals in the water being found in the samples taken below the fish breeding ponds. The content of metals in sediments of the analysed section of the River Chotla was mainly determined by the content of organic matter, which varied as it is dependent on water accumulation processes and the operation of nearby fishery facilities. The slightly alkaline pH facilitated long-lasting accumulation of metals in sediments.

scholarly journals Phosphorus forms in leaves and their relationships with must composition and yield in grapevines

2017 ◽  
Vol 52 (5) ◽  
pp. 319-327 ◽  
Author(s):  
Rogério Piccin ◽  
Rafael da Rosa Couto ◽  
Roque Júnior Sartori Bellinaso ◽  
Luciano Colpo Gatiboni ◽  
Lessandro De Conti ◽  
...  
Keyword(s):  
The Other ◽  
Available P ◽  
Anthocyanin Content ◽  
P Fractionation ◽  
Cabernet Franc ◽  
Phosphorus Forms ◽  
Yield Parameters ◽  
P Content ◽  
Total P

Abstract: The objective of this work was to evaluate phosphorus forms in grape leaves and their relationships with must composition and yield in grapevines grown in a Typic Hapludalf with different available P contents. Two experiments were carried out with Vitis viniferacultivars, one with 'Tannat' and the other with 'Cabernet Franc' grapes. Experiment 1 consisted of two vineyards of 'Tannat', with the following P content in the soil: V1, 11.8 mg kg-1 P; and V2, 34.6 mg kg-1 P. Experiment 2 consisted of two vineyards of 'Cabernet Franc', with the following P content in the soil: V1, 16.0 mg kg-1 P; and V2, 37.0 mg kg-1 P. Leaves were collected at flowering (FL) and veraison (V), and, after their preparation, P forms were evaluated. Yield and must composition were assessed. The highest yield was observed in V2 of experiment 1 and in V2 of experiment 2. Total P content and P forms in leaves at FL and V have no relationship with yield parameters; however, total P content in leaves has a relationship with anthocyanin content in the must of 'Tannat' grapevines. Therefore, P fractionation in leaves predicts neither grapevine yield nor must composition.

scholarly journals A Comparative Electrochemical-Ozone Treatment for Removal of Phenolphthalein

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. M. García-Orozco ◽  
C. E. Barrera-Díaz ◽  
G. Roa-Morales ◽  
Ivonne Linares-Hernández
Keyword(s):  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Ozone Treatment ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Diamond Electrodes ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Electrochemical Processes ◽  
Density Values

The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at 5±0.5 mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.

scholarly journals Effect of using inoculant on elephant grass silage with additives

2020 ◽  
Vol 42 ◽  
pp. e50533
Author(s):  
Ana Rebeca Pires da Silva ◽  
Fabio Jacobs Dias ◽  
João Paulo Ferreira Rufino ◽  
Ewerton de Souza Tanaka ◽  
Maycom Marinho Lopes
Keyword(s):  
Experimental Design ◽  
Crude Protein ◽  
Dry Matter ◽  
Acidic Ph ◽  
Elephant Grass ◽  
Test Results ◽  
Alkaline Ph ◽  
Nutritional Content ◽  
Grass Silage ◽  
Silage Production

This study aimed to evaluate the use of inoculant on silage of elephant grass, wet brewery waste and buriti meal at different silo opening times. The experimental silage tested was composed of 50% elephant grass, 30% wet brewery waste, and 20% buriti meal. The experimental design was randomized block in a factorial arrangement (2 x 4), where the treatments consisted of the use or not of inoculant during silage processing, and four silo opening times (7, 14, 21, and 28 days). Data collected were firstly subjected to ANOVA and subsequent Tukey’s test. Results were considered significant at p ≤ 0.05. The use of inoculant in silage production provided more acidic pH (p < 0.05) and higher (p < 0.05) effluent losses. Longer silo opening times resulted in more alkaline pH (p < 0.05) and higher (p < 0.05) effluent losses. The use of inoculant in silage production and longer silo opening times provided higher (p < 0.05) content of ash, crude protein, and fats, and lower (p < 0.05) content of dry matter and fiber (neutral and acid detergent). However, there was no interaction between the factors evaluated in this study. It was concluded that the inoculant may be used in the production of elephant grass silages, wet brewery waste, and buriti meal, providing a more acidic pH, higher effluent losses, lower contents of dry matter and fiber, and higher nutritional content. As the opening time was extended up to 28 days, there was more alkaline pH, higher effluent losses, lower dry matter and fiber content, and higher nutritional content.

scholarly journals Role of Groundwater-Borne Geogenic Phosphorus for the Internal P Release in Shallow Lakes

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1783 ◽  
Author(s):  
Catharina S. Nisbeth ◽  
Søren Jessen ◽  
Ole Bennike ◽  
Jacob Kidmose ◽  
Kasper Reitzel
Keyword(s):  
Lake Sediment ◽  
Trophic State ◽  
Driving Factor ◽  
Original Source ◽  
Depth Profiles ◽  
P Release ◽  
Order Of Magnitude ◽  
The One ◽  
Total P

This study explores the under-investigated issue of groundwater-borne geogenic phosphorus (P) as the potential driving factor behind accumulation of P in lake sediment. The annual internally released P load from the sediment of the shallow, hypereutrophic and groundwater-fed lake, Nørresø, Denmark, was quantified based on total P (TP) depth profiles. By comparing this load with previously determined external P loadings entering the lake throughout the year 2016–2017, it was evident that internal P release was the immediate controller of the trophic state of the lake. Nevertheless, by extrapolating back through the Holocene, assuming a groundwater P load corresponding to the one found at present time, the total groundwater P input to the lake was found to be in the same order of magnitude as the total deposit P in the lake sediment. This suggests that groundwater-transported P was the original source of the now internally cycled P. For many lakes, internal P cycling is the immediate controller of their trophic state. Yet, this does not take away the importance of the external and possibly geogenic origin of the P accumulating in lake sediments, and subsequently being released to the water column.

Tensile, physical, and microstructure properties of glycine treated cotton fibers

2017 ◽  
Vol 88 (12) ◽  
pp. 1356-1366 ◽  
Author(s):  
Rechana Remadevi ◽  
Stuart Gordon ◽  
Xungai Wang ◽  
Rangam Rajkhowa
Keyword(s):  
Linear Density ◽  
Cotton Fibers ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
X Ray Diffraction ◽  
Density Measurements ◽  
X Ray ◽  
Acidic Conditions ◽  
Improved Strain ◽  
Control Samples

In this paper, the effect of aqueous glycine treatments at different pH on the tensile properties of cotton fibers is reported. The effects on linear density and X-ray diffraction crystallinity were also evaluated. Glycine treated fibers at alkaline pH (i.e. at pH 11) produced fibers with higher linear density than control (untreated) and glycine treatments at acidic pH. The same treatment also increased strain values in cotton fibers by as much as 36%. Interestingly, similar changes in strain were observed under acidic conditions, especially at pH4, although the changes were smaller. Specific stress values normalized by the linear density measurements were not significantly different from control samples. The results of this research demonstrated improved strain properties of cotton fibers after aqueous glycine treatment at suitable conditions.

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