scholarly journals The Past, Present, and Future of Phosphorus Removal Structures

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 797
Author(s):  
Chad J. Penn
Keyword(s):  
Phosphorus Removal ◽  
Special Issue ◽  
Dissolved Phosphorus ◽  
The Past ◽  
P Removal

The purpose of this special issue is to explore current challenges and develop a better understanding of the processes that control dissolved phosphorus (P) removal among P removal structures [...]

scholarly journals Performance of Field-Scale Phosphorus Removal Structures Utilizing Steel Slag for Treatment of Subsurface Drainage

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 443 ◽  
Author(s):  
Chad Penn ◽  
Stan Livingston ◽  
Vinayak Shedekar ◽  
Kevin King ◽  
Mark Williams
Keyword(s):  
Surface Runoff ◽  
Phosphorus Removal ◽  
Algal Blooms ◽  
Pore Space ◽  
Steel Slag ◽  
Tile Drainage ◽  
Dissolved Phosphorus ◽  
Water Ph ◽  
Induced Flow ◽  
P Removal

Reducing dissolved phosphorus (P) losses from legacy P soils to surface waters is necessary for preventing algal blooms. Phosphorus removal structures containing steel slag have shown success in treating surface runoff for dissolved P, but little is known about treating subsurface (tile) drainage. A ditch-style and subsurface P removal structure were constructed using steel slag in a bottom-up flow design for treating tile drainage. Nearly 97% of P was delivered during precipitation-induced flow events (as opposed to baseflow) with inflow P concentrations increasing with flow rate. Structures handled flow rates approximately 12 L s−1, and the subsurface and ditch structures removed 19.2 (55%) and 0.9 kg (37%) of the cumulative dissolved P load, respectively. Both structures underperformed relative to laboratory flow-through experiments and exhibited signs of flow inhibition with time. Dissolved P removal decreased dramatically when treated water pH decreased <8.5. Although slag has proven successful for treating surface runoff, we hypothesize that underperformance in this case was due to tile drainage bicarbonate consumption of slag calcium through the precipitation of calcium carbonate, thereby filling pore space, decreasing flow and pH, and preventing calcium phosphate precipitation. We do not recommend non-treated steel slag for removing dissolved P from tile drainage unless slag is replaced every 4–6 months.

scholarly journals Utilization of Steel Slag in Blind Inlets for Dissolved Phosphorus Removal

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1593
Author(s):  
Javier M. Gonzalez ◽  
Chad J. Penn ◽  
Stan J. Livingston
Keyword(s):  
Phosphorus Removal ◽  
Steel Slag ◽  
N Cycling ◽  
Organic N ◽  
Particulate Phosphorus ◽  
Total N ◽  
Dissolved Phosphorus ◽  
Surface Drainage ◽  
P Removal ◽  
Blind Inlet

Blind inlets are implemented to promote obstruction-free surface drainage of field depressions as an alternative to tile risers for the removal of sediment and particulate phosphorus (P) through an aggregate bed. However, conventional limestone used in blind inlets does not remove dissolved P, which is a stronger eutrophication agent than particulate P. Steel slag has been suggested as an alternative to limestone in blind inlets for removing dissolved P. The objectives of this study were to construct a blind inlet with steel slag and evaluate its ability to remove dissolved P, nitrogen (N), and herbicides. A blind inlet was constructed with steel slag in late 2015; data from only 2018 are reported due to inflow sampling issues. The blind inlet removed at least 45% of the dissolved P load and was still effective after three years. The dissolved P removal efficiency was greater with higher inflow P concentrations. More than 70% of glyphosate and its metabolite, and dicamba were removed. Total N was removed in the form of organic N and ammonium, although N cycling processes within the blind inlet appeared to produce nitrate. Higher dissolved atrazine and organic carbon loads were measured in outflow than inflow, likely due to the deposition of sediment-bound particulate forms not measured in inflow, which then solubilized with time. At a cost similar to local aggregate, steel slag in blind inlets represents a simple update for improving dissolved P removal.

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

Five Years and Count(er)ing: Memoir after Memoir

CounterText ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 26-32
Author(s):  
Norbert Bugeja
Keyword(s):  
Guest Editor ◽  
Arab Countries ◽  
National Museum ◽  
Terror Attack ◽  
Special Issue ◽  
The Past ◽  
Personal Perspectives ◽  
The Moment ◽  
Ongoing Project

In this retrospective piece, the Guest Editor of the first number of CounterText (a special issue titled Postcolonial Springs) looks back at the past five years from various scholarly and personal perspectives. He places particular focus on an event that took place mid-way between the 2011 uprisings across a number of Arab countries and the moment of writing: the March 2015 terror attack on the Bardo National Museum in Tunis, which killed twenty-two people and had a profound effect on Tunisian popular consciousness and that of the post-2011 Arab nations. In this context, the author argues for a renewed perspective on memoir as at once a memorial practice and a political gesture in writing, one that exceeds concerns of genre and form to encompass an ongoing project of political re-cognition following events that continue to remap the agenda for the region. The piece makes a brief final pitch for Europe's need to re-cognise, within those modes of ‘articulacy-in-difficulty’ active on its southern borders, specific answers to its own present quandaries.

Reframing the Sciences of the Long Eighteenth Century

2020 ◽  
Vol 50 (1-2) ◽  
pp. 58-66
Author(s):  
Giuliano Pancaldi
Keyword(s):  
Eighteenth Century ◽  
History Of Science ◽  
Science Policy ◽  
Special Issue ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
History Of ◽  
Long Eighteenth Century ◽  
Past Half

Here I survey a sample of the essays and reviews on the sciences of the long eighteenth century published in this journal since it was founded in 1969. The connecting thread is some historiographic reflections on the role that disciplines—in both the sciences we study and the fields we practice—have played in the development of the history of science over the past half century. I argue that, as far as disciplines are concerned, we now find ourselves a bit closer to a situation described in our studies of the long eighteenth century than we were fifty years ago. This should both favor our understanding of that period and, hopefully, make the historical studies that explore it more relevant to present-day developments and science policy. This essay is part of a special issue entitled “Looking Backward, Looking Forward: HSNS at 50,” edited by Erika Lorraine Milam.

Full Scale Investigations on Enhanced Biological Phosphorus Removal – P-Release in the Anaerobic Reactor

1994 ◽  
Vol 29 (7) ◽  
pp. 153-156 ◽  
Author(s):  
D. Wedi ◽  
P. A. Wilderer
Keyword(s):  
Phosphorus Removal ◽  
Full Scale ◽  
Process Conditions ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Anaerobic Reactor ◽  
P Release ◽  
Acinetobacter Sp ◽  
Biological Phosphorus ◽  
P Removal

Most of the fundamental processes responsible for enhanced biological phosphorus removal (EBPR) were obtained through laboratory tests under defined conditions with pure or enriched cultures. Acinetobacter sp. was identified as the most important group of bacteria responsible for bio-P removal. Full scale data showed, however, that laboratory results do not match full scale results well enough. There is a lack of data on the effects of sub-optimal process conditions such as inadequate availability of volatile fatty acids (VFA), high nitrate recycle, storm water inflow or low temperatures. In this paper the results of full scale experiments on P-release are presented and compared with theoretical values. Measurements at a full scale Phoredox-system showed a surprisingly low P-release in the anaerobic reactor. Only 4 to 10% of the phosphorus in the activated sludge was released in the bulk liquid. With laboratory batch-tests, a maximum of 20% of the P in the sludge could be released. It is assumed that under the prevailing process conditions either the fraction of Acinetobacter sp. was very small, or bacteria other than Acinetobacter sp. were responsible for the P-removal, or most of the phosphorus was bound chemically but mediated by biological processes.

Enhanced biological phosphorus removal process implemented in membrane bioreactors to improve phosphorous recovery and recycling

2003 ◽  
Vol 48 (1) ◽  
pp. 87-94 ◽  
Author(s):  
B. Lesjean ◽  
R. Gnirss ◽  
C. Adam ◽  
M. Kraume ◽  
F. Luck
Keyword(s):  
Phosphorus Removal ◽  
Theoretical Calculations ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
P Limitation ◽  
Batch Tests ◽  
P Content ◽  
On Line ◽  
Biological Phosphorus ◽  
P Removal

The enhanced biological phosphorus removal (EBPR) process was adapted to membrane bioreactor (MBR) technology. One bench-scale plant (BSP, 200-250 L) and two pilot plants (PPs, 1,000-3,000 L each) were operated under several configurations, including pre-denitrification and post-denitrification without addition of carbon source, and two solid retention times (SRT) of 15 and 26 d. The trials showed that efficient Bio-P removal can be achieved with MBR systems, in both pre- and post-denitrification configurations. EBPR dynamics could be clearly demonstrated through batch-tests, on-line measurements, profile analyses, P-spiking trials, and mass balances. High P-removal performances were achieved even with high SRT of 26 d, as around 9 mgP/L could be reliably removed. After stabilisation, the sludge exhibited phosphorus contents of around 2.4%TS. When spiked with phosphorus (no P-limitation), P-content could increase up to 6%TS. The sludge is therefore well suited to agricultural reuse with important fertilising values. Theoretical calculations showed that increased sludge age should result in a greater P-content. This could not be clearly demonstrated by the trials. This effect should be all the more significant as the influent is low in suspended solids.

scholarly journals Introduction to the Special Issue on New Longitudinal Data for Retirement Analysis and Policy

2021 ◽  
pp. 1-5
Author(s):  
Marco Angrisani ◽  
Anya Samek ◽  
Arie Kapteyn
Keyword(s):  
Big Data ◽  
Academic Research ◽  
Cost Effective ◽  
Research Data ◽  
Data Sources ◽  
Special Issue ◽  
Administrative Records ◽  
The Past ◽  
Survey Questionnaires ◽  
Internet Panels

The number of data sources available for academic research on retirement economics and policy has increased rapidly in the past two decades. Data quality and comparability across studies have also improved considerably, with survey questionnaires progressively converging towards common ways of eliciting the same measurable concepts. Probability-based Internet panels have become a more accepted and recognized tool to obtain research data, allowing for fast, flexible, and cost-effective data collection compared to more traditional modes such as in-person and phone interviews. In an era of big data, academic research has also increasingly been able to access administrative records (e.g., Kostøl and Mogstad, 2014; Cesarini et al., 2016), private-sector financial records (e.g., Gelman et al., 2014), and administrative data married with surveys (Ameriks et al., 2020), to answer questions that could not be successfully tackled otherwise.

scholarly journals Special Issue “Molecular Basis of Inherited Diseases in Companion Animals”

Genes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Steven G. Friedenberg ◽  
Danika L. Bannasch
Keyword(s):  
Molecular Basis ◽  
Companion Animals ◽  
Special Issue ◽  
Inherited Diseases ◽  
The Past

The study of inherited diseases in companion animals has exploded over the past 15 years since the publication of the first dog genome in 2005 [...]

scholarly journals Play! A Special Issue

Sexualities ◽  
2021 ◽  
pp. 136346072110136
Author(s):  
Caroline Bem ◽  
Susanna Paasonen
Keyword(s):  
Video Games ◽  
Sexual Pleasure ◽  
Special Issue ◽  
Sexuality Studies ◽  
The Past ◽  
Sexual Representation ◽  
The Social ◽  
Sexual Play ◽  
Sex Toys

Sexuality, as it relates to video games in particular, has received increasing attention over the past decade in studies of games and play, even as the notion of play remains relatively underexplored within sexuality studies. This special issue asks what shift is effected when sexual representation, networked forms of connecting and relating, and the experimentation with sexual likes are approached through the notion of play. Bringing together the notions of sex and play, it both foregrounds the role of experimentation and improvisation in sexual pleasure practices and inquires after the rules and norms that these are embedded in. Contributors to this special issue combine the study of sexuality with diverse theoretical conceptions of play in order to explore the entanglements of affect, cognition, and the somatic in sexual lives, broadening current understandings of how these are lived through repetitive routines and improvisational sprees alike. In so doing, they focus on the specific sites and scenes where sexual play unfolds (from constantly morphing online pornographic archives to on- and offline party spaces, dungeons, and saunas), while also attending to the props and objects of play (from sex toys and orgasmic vocalizations to sensation-enhancing chemicals and pornographic imageries), as well as the social and technological settings where these activities occur. This introduction offers a brief overview of the rationale of thinking sex in and as play, before presenting the articles that make up this special issue.

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