scholarly journals Using Steel Slag for Dissolved Phosphorus Removal: Insights from a Designed Flow-Through Laboratory Experimental Structure

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1236 ◽  
Author(s):  
Linhua Wang ◽  
Chad Penn ◽  
Chi-hua Huang ◽  
Stan Livingston ◽  
Junhua Yan

Steel slag, a byproduct of the steel making process, has been adopted as a material to reduce non-point phosphorus (P) losses from agricultural land. Although substantial studies have been conducted on characterizing P removed by steel slag, few data are available on the removal of P under different conditions of P input, slag mass, and retention time (RT). The objective of this study was to investigate P removal efficiency as impacted by slag mass and RT at different physical locations through a horizontal steel slag column. Downstream slag segments were more efficient at removing P than upstream segments because they were exposed to more favorable conditions for calcium phosphate precipitation, specifically higher Ca2+ concentrations and pH. These results showed that P is removed in a moving front as Ca2+ and slag pH buffer capacity are consumed. In agreement with the calcium phosphate precipitation mechanism shown in previous studies, an increase in RT increased P removal, resulting in an estimated removal capacity of 61 mg kg−1 at a RT of 30 min. Results emphasized the importance of designing field scale structures with sufficient RT to accommodate the formation of calcium phosphate.

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 443 ◽  
Author(s):  
Chad Penn ◽  
Stan Livingston ◽  
Vinayak Shedekar ◽  
Kevin King ◽  
Mark Williams

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.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1593
Author(s):  
Javier M. Gonzalez ◽  
Chad J. Penn ◽  
Stan J. Livingston

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.


Author(s):  
Norwardatun Abd Roni ◽  
◽  
Suraya Hani Adnan ◽  
Nuramidah Hamidon ◽  
Tuan Noor Hasanah Tuan Ismail ◽  
...  

The high levels of phosphorus (P) removal occurring through human activities contributes to Eutrophication. Therefore, it is important to understand the quantity of P flows of the different filter materials. This paper provides an overview on the different filter media used for P removal from wastewater also the conventional wastewater treatment system for phosphorus removal. The filter materials consist of natural materials, industrial by-products and man-made products. Most filters have been investigated in batch and column studies in laboratory. The results from these overview vary for every filters and recycled concrete aggregates (RCA) have demonstrated promising properties with regard to P removal capacity. The chemical composition of the adsorption media is a critical factor. Because phosphorus is removed via sorption and precipitation processes, Calcium (Ca), Iron (Fe) and Aluminium (Al) content is important in efficient P removal. Thus filter media should be selected very carefully. In such systems, appropriate pre-treatment will also allow for a longer lifetime of the filter media, by decreasing the risk of clogging and allowing one to use finer reactive filter media with higher sorption capacity. The usage of these alternatives filters materials will ease the environmental problems that are currently perceived globally.


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

2010 ◽  
Vol 29 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Hee-Jung Kim ◽  
Ri-Bi Yoo ◽  
Seok-Soon Han ◽  
Sun-Hee Woo ◽  
Moon-Soon Lee ◽  
...  

1987 ◽  
Vol 66 (2) ◽  
pp. 462-466 ◽  
Author(s):  
F.G. Oppenheim ◽  
D.I. Hay ◽  
D.J. Smith ◽  
G.D. Offner ◽  
R.F. Troxler

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.


2006 ◽  
Vol 309-311 ◽  
pp. 333-336
Author(s):  
Emiko Amaoka ◽  
Erik Vedel ◽  
Satoshi Nakamura ◽  
Yusuke Moriyoshi ◽  
Jukka I. Salonen ◽  
...  

We investigated the electrical polarizability of MgO and B2O3 containing bioactive glass (MBG). The MBG material with good manufacturing properties but low bioactivity was electrically polarized at a high dc field. The electrical polarizability of MBG was evaluated by thermally stimulated depolarization current (TSDC) measurements and immersion in simulated body fluid (SBF). The early precipitation of calcium phosphate on the negatively charged surface of the treated MBG demonstrated the increased bioactivity of the material and confirmed its polarizability. It is suggested that the electrical interactions between the polarized MBG and ions in SBF promoted the formation of the calcium phosphate precipitation. Accordingly, the increased bioactivity of the MBG in SBF is suggested to demonstrate the conversion of MBG into electrovector ceramics by the polarization treatment.


2017 ◽  
Author(s):  
Marco Tadeu Gomes Vianna ◽  
Marcia Marques

The excessive release of phosphorus (P) by discharge of domestic and industrial effluents is directly associated with the eutrophication of water bodies. Therefore, an efficient removal of P from effluents is required. The method most commonly used for P removal from wastewater is chemical precipitation. However, this technique is relatively expensive and demands a proper disposal for the sludge. Therefore, the development of new materials with low cost but high P removal efficiency has been investigated. The introduction of exotic species in aquatic environments is considered a serious environmental problem in different parts of the world. Considering that, many of these species have high concentrations of carbonates in their exoskeleton composition, which is potentially useful in water treatment, particularly for P removal the use of such material as adsorbent has been tested. The present study aimed to investigate the capacity of the exoskeleton of exotic species in powder form to remove orthophosphates from water comparing the raw material (RCS), with physically modified (CSA) and chemically modified (CSC) material. To study the orthophosphates removal efficiency, a factorial design with central composite rotational design (CCRD) was applied. In order to optimize the P removal, the influence of the independent variables adsorbent/adsorbate ratio, pH and temperature was investigated with the kinetic control associate at each configuration obtained by CCRD. The P removal capacity of RCS varied from 125.0 mgP kg-1 to 1002.5 mgP kg-1; the removal capacity of CSA varied from 237.5 mgP kg-1 to 1540.0 mgP kg-1. The removal capacity of CSC varied from 5212.5 mgP kg-1 to 12672.5 mgP kg-1. Based on the preliminary results, the exoskeleton powder showed to be a potentially sustainable alternative as adsorbent material (mostly the chemically modified form CSC) useful in several applications, such as the treatment of urban and industrial wastewaters to prevent eutrophication of water bodies and population control of exotic species due to the commercial exploitation. 


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