Phosphorus retention and sorption by constructed wetland soils in Southeast Ireland

Dunne, E. J.; Culleton, N.; O’Donovan, Grace; Harrington, Rory; Daly, Karen

doi:10.1016/j.watres.2005.09.007

Cited by 74 publications

(26 citation statements)

References 25 publications

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“…In an earlier study conducted by the author [17], the first order rate constant noted was in the range of 0.096-0.34 d -1 (0.004 -0.014 h -1 ) which agrees with the 0.083 -0.575 d -1 range reported by [2]. In an observation, an increase in the amount of medium, the reaction rate constant increases.,indicating that the responses is faster with more medium present, as there are presumably more sites for sorption.…”

Section: B Kinetics Studysupporting

confidence: 86%

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Batch Sorption Experimental Study for Phosphorus Removal Mechanisms Using Wetland Gravel Medium

Paul¹,

Anderson²

2016

IJEP

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Abstract-Sorption experiments conducted for estimation of the phosphorus sorption capacity for the local gravel. The tests performed for two different concentrations of the influent phosphorus solution i.e. 4mg/L and 8 mg/L. Experimental results were then modeled using Langmuir and Freundlich equation. Batch isotherm studies show that the P sorption study follows the Freundlich isotherm rather than the Langmuir isotherm. Additionally, ultimate sorption capacities were calculated, and observed that the gravel medium has a sorption capacity in the range of 17mg/kg ~ 22 mg/kg of the gravel. The ultimate quantity estimated was more by using the Freundlich isotherm as compared to the Langmuir isotherm. Also, the sorption capacity was more in the case for the higher concentration effluent (8mg/L) than, the lower one (4mg/L). During the design phase of the wetland system, batch isotherm studies represent a useful criterion for practical considerations of the application of the media. Therefore, the information will enable to short-list materials for wetland or filter design.

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Section: B Kinetics Studysupporting

confidence: 86%

“…Studies conducted by various researchers show that phosphorus removal is unpredictable in constructed wetlands (CW). On the other hand, treatment of wastewater for other parameters is satisfactory [2]. These inconsistencies are probably due to the limited understanding of the removal mechanisms resulting in the inefficient design of the wetland systems [3].…”

mentioning

confidence: 99%

Batch Sorption Experimental Study for Phosphorus Removal Mechanisms Using Wetland Gravel Medium

Paul¹,

Anderson²

2016

IJEP

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“…An experiment using wetland soils has also shown that P concentration of the water has the potential to change the retention capacity of the CW. When P concentrations in water are low, P may be released from Stevens and Quinton 2009 Critical Reviews in Environmental Science and Technology 39 478-520 34 soil pore water into water column; however, as P concentration in overlying waters increased, retention by the soils also increased (47).…”

Section: Constructed Wetlandsmentioning

confidence: 99%

Diffuse Pollution Swapping in Arable Agricultural Systems

Stevens

Quinton

2009

Critical Reviews in Environmental Science and Technology

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“…Quantification of phosphate levels in culture medium and accumulated by N. punctiforme WT, PstB1-overexpressing, and PstB1 ؊ strains after 64 h. Nostoc punctiforme WT, PstB1-overexpressing, and PstB1 Ϫ cells (ϳ1,000 mg [wet weight] of each) were pelleted, washed five times in sterile ddH 2 O, and then resuspended in modified Allen and Arnon solution without P i and purged for 72 h. Triplicate cultures of 100 mg of purged cells were then resuspended in 25 ml of Allen and Arnon medium containing 0.8 mM P i for 64 h. Cells (3 ϫ 10 5 ) from each treatment were collected and dried in a heating block at 60°C for 8 h or until the pellets weighed ϳ25 mg. Cell pellets were digested in nitric acid, and total P levels analyzed for each sample using inductively coupled plasma mass spectrometry (ICP-MS).…”

Section: Methodsmentioning

confidence: 99%

“…For example, diazotrophs like cyanobacteria are unable to fix atmospheric nitrogen in lowphosphate environments (1). A low abundance of P i is typical of soils after intensive plant cropping, and even if abundant, P i is often complexed to soil constituents, making it unavailable to many organisms in this environment (2). In aquatic systems, P i is relatively less soluble than in soils, making it a key growth-limiting factor (3).…”

mentioning

confidence: 99%

Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme

Hudek

Premachandra

Webster

et al. 2016

Appl Environ Microbiol

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In bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacterium Nostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified. pstB1 was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined that pstB1 mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed when pstB2, pstB3, and pstB4 mRNA levels increased, particularly in cells starved of phosphate. The overexpression of pstB1 increased phosphate uptake by N. punctiforme and was shown to functionally complement the loss of PstB in E. coli PstB knockout (PstB ؊ ) mutants. The knockout of pstB1 in N. punctiforme did not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in the pstB2, pstB3, and pstB4 mRNA levels. This study provides novel in vivo evidence that PstB1 plays a functional role in phosphate uptake in N. punctiforme. IMPORTANCECyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons in Nostoc punctiforme and functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genes pstB2, pstB3, and pstB4 show alterations in expression to compensate for the deletion of pstB1. The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria like N. punctiforme, allowing them to thrive in low-phosphate environments. P hosphorus (P) is a crucial element for the survival and growth of all organisms, and it is commonly associated with oxygen in the form of inorganic phosphates (PO 4 Ϫ and P i ) in the environment. Phosphate has a central role in many of the metabolic and energy-producing pathways in ...

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Phosphorus retention and sorption by constructed wetland soils in Southeast Ireland

Cited by 74 publications

References 25 publications

Batch Sorption Experimental Study for Phosphorus Removal Mechanisms Using Wetland Gravel Medium

Batch Sorption Experimental Study for Phosphorus Removal Mechanisms Using Wetland Gravel Medium

Diffuse Pollution Swapping in Arable Agricultural Systems

Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme

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