Phosphorus removal in constructed wetlands: can suitable alternative media be identified?

2005 ◽  
Vol 51 (9) ◽  
pp. 267-273 ◽  
Author(s):  
C.A. Arias ◽  
H. Brix
Keyword(s):  
Constructed Wetlands ◽  
Binding Capacity ◽  
Chemical Properties ◽  
Full Scale ◽  
Suitable Alternative ◽  
Limited Application ◽  
The Media ◽  
Full Scale Tests ◽  
Physical And Chemical ◽  
P Removal

Removal of phosphorous in constructed wetlands is limited by the capacity of the media to adsorb, bind or precipitate the incoming P. To enhance P removal and the life span of constructed wetlands the approach might be to use natural sands rich in calcium or iron, to use an alternative ‘artificial’ medium with high P-binding capacity, or to establish external P-binding filters after the wetland. Our studies focused on the evaluation of calcium-rich materials potentially useful as P-binding media. The materials tested included calcite products, natural sands and seashells. Tests included assessment of physical and chemical properties of the materials, extractions in P-spiked water at different P concentrations to determine P-binding equilibrium isotherms, and column experiments. In addition, full-scale tests were performed with calcite in an external filter. The result showed that equilibrium isotherm is an indicator of the potential P-sorption capacity of the media, although the value is of limited application for the determination of the binding capacity in full-scale systems. The columns showed that the materials do bind phosphorus. However, the binding capacities are still insufficient for the establishment of external P-removal filter; the volumes of the filters would be too large to be of practical use.

Two Typical Cases Analysis of Casing Connection Pullout

2012 ◽  
Vol 524-527 ◽  
pp. 1651-1655
Author(s):  
Zhi Yong Pan ◽  
Chun Feng ◽  
Hua Jia Zhang ◽  
Dong Feng Li ◽  
Peng Yang
Keyword(s):  
Chemical Properties ◽  
Comprehensive Analysis ◽  
Full Scale ◽  
Physical And Chemical Properties ◽  
Dimension Measurement ◽  
Full Scale Tests ◽  
Physical And Chemical ◽  
Macroscopic Analysis ◽  
And Chemical Properties

Research on a round thread casing connection pullout case and a buttress thread casing connection pullout accident was carried out combining relative theorys with tests. Macroscopic analysis and dimension measurement and material’s physical and chemical properties were checked for casings and couplings. Thread inspection and full-scale tests were done for casing simples that are same lot with pullout casing. Comprehensive analysis was carried out on these results. Two cases history showed that casing connection dropout may take place if make-up location cann’t reach standard location or make-up torque is too little even if the quality of casing and coupling are in accordance with corresponding standards.

Media selection for sustainable phosphorus removal in subsurface flow constructed wetlands

2001 ◽  
Vol 44 (11-12) ◽  
pp. 47-54 ◽  
Author(s):  
H. Brix ◽  
C.A. Arias ◽  
M. del Bubba
Keyword(s):  
Sorption Capacity ◽  
Constructed Wetlands ◽  
Binding Capacity ◽  
Subsurface Flow ◽  
P Sorption ◽  
P Sorption Capacity ◽  
The Media ◽  
Subsurface Flow Constructed Wetlands ◽  
Clay Aggregates ◽  
P Removal

Sorption of phosphorus (P) to the bed sand medium is a major removal mechanism for P in subsurface flow constructed wetlands. Selecting a sand medium with a high P-sorption capacity is therefore important to obtain a sustained P-removal. The P-removal capacities of 13 Danish sands were evaluated and related to their physico-chemical characteristics. The P-removal properties of sands of different geographical origin varied considerably and the suitability of the sands for use as media in constructed reed beds thus differs. The P-sorption capacity of some sands would be used up after only a few months in full-scale systems, whereas that of others would subsist for a much longer time. The most important characteristic of the sands determining their P-sorption capacity was their Ca-content. Also the P-binding capacities of various artificial media were tested (light-expanded-clay-aggregates (LECA), crushed marble, diatomaceous earth, vermiculite and calcite). Particularly calcite and crushed marble were found to have high P-binding capacities. It is suggested that mixing one of these materials into the sand or gravel medium can significantly enhance the P-sorption capacity of the bed medium in a subsurface-flow constructed wetland system. It is also possible to construct a separate unit containing one of these artificial media. The media may then be replaced when the P-binding capacity is used up.

Phosphorus removal by apatite in horizontal flow constructed wetlands for small communities: pilot and full-scale evidence

2011 ◽  
Vol 63 (8) ◽  
pp. 1629-1637 ◽  
Author(s):  
N. Harouiya ◽  
S. Martin Rue ◽  
S. Prost-Boucle ◽  
A. Liénar ◽  
D. Esser ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Particle Surface ◽  
Full Scale ◽  
Retention Capacity ◽  
Small Communities ◽  
Lab Experiments ◽  
Apatite Mineral ◽  
Kinetics Of ◽  
P Removal

Phosphorus (P) removals in constructed wetlands (CWs) have received particular attention in recent decades by using specific materials which promote adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilot units and a full-scale plant over a 2 year period. P retention kinetics of two qualities of apatites are presented and discussed. In this work apatite appears to have high retention capacity (>80% of P removal) and is still an interesting way for P removal in CWs for limiting the risk of eutrophication downstream of small communities. Nevertheless, the apatite quality appears to be of great importance for a reliable and long term P removal. The use of materials with low content of apatite mineral (40–50%) seems to be not economically relevant.

scholarly journals Effect of Media Containing Processed Fiber, Fertilization, and Fumigation on Appearance and Growth in Containerized Woody Perennial Plants

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 658c-658
Author(s):  
Sanliang Gu ◽  
Leslie H. Fuchigami ◽  
Victor Sahakian
Keyword(s):  
Plant Species ◽  
Woody Plant ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Perennial Species ◽  
Rooted Cuttings ◽  
Woody Perennial ◽  
The Media ◽  
Physical And Chemical ◽  
And Chemical Properties

Applicability of processed fiber (methane digested cow manure) as a substitute for peatmoss for production of various containerized perennial woody plant species with various fertilization and fumigation practices was investigated in this study. Liner plants of five species and rooted cuttings of 41 species were potted in various media containing processed fiber as the replacement of peatmoss with or without fertilization and fumigation, with commercial mix as control. Plants varied in their responses to the media, fertilization, and/or fumigation. Most plant species performed well in the media containing processed fiber. The physical and chemical properties of processed fiber, either alone or mixed with other media components, were satisfactory for producing woody perennial species even with less fertilization and no fumigation.

The light-controlling of temperature-responsivity in stimuli-responsive polymers

2019 ◽  
Vol 10 (42) ◽  
pp. 5686-5720 ◽  
Author(s):  
Amin Abdollahi ◽  
Hossein Roghani-Mamaqani ◽  
Bahareh Razavi ◽  
Mehdi Salami-Kalajahi
Keyword(s):  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Temperature Responsive ◽  
The Media ◽  
Physical And Chemical ◽  
And Chemical Properties

Light-controlling of phase separation in temperature-responsive polymer solutions by using light-responsive materials for reversible controlling physical and chemical properties of the media with an out-of-system stimulus with tunable intensity.

Removing phosphorus with Ca-Fe oxide granules – a possible wetlands filter material

2013 ◽  
Vol 45 (3) ◽  
pp. 368-378 ◽  
Author(s):  
Egle Saaremäe ◽  
Martin Liira ◽  
Morten Poolakese ◽  
Toomas Tamm
Keyword(s):  
Constructed Wetlands ◽  
Chemical Properties ◽  
Phosphate Removal ◽  
Batch Experiment ◽  
Phosphorus Adsorption ◽  
Mass Unit ◽  
Fe Oxide ◽  
P Sorption ◽  
Flow Through ◽  
P Removal

Phosphorus (P) is one of the nutrients causing eutrophication in many of our waterways. In the present study, we investigated Sachtofer PR Ca-Fe oxide granules as a potential P sorption material (PSM) for constructed wetlands. We found the P sorption with various experiments as follows: the 24 h batch experiment with the highest initial concentration of 50 mgP L−1 yielded 0.48 mgP g−1 P removal per mass unit, the kinetic P removal batch experiment of 600 h duration yielded 1.25 mgP g−1, the maximum phosphorus adsorption capacity estimated from the Langmuir equation yielded 23.78 mgP g−1, and the long term flow-through experiment with drainage ditch water yielded indicative saturated sorption of 1.4 mgP g−1. Flow-through experiments revealed that phosphate removal was rapid and the efficiency was 10–70%, depending on the retention time and age of granules. Possible weaknesses of this material for sorption filter systems were found to include the loss of mass caused by the rapid dissolution of gypsum, increased sulfate and calcium concentrations in the water, and rapidly changing hydraulic conductivity. Considering hydraulic and chemical properties, further pilot experiments are necessary to develop technical solutions for optimal use of Ca-Fe oxide granules in sorption filter systems at constructed wetlands.

scholarly journals Effect of Biochar Amendment in Woodchip Denitrifying Bioreactors for Nitrate and Phosphate Removal in Tile Drainage Flow

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2883
Author(s):  
Rasa Vismontienė ◽  
Arvydas Povilaitis
Keyword(s):  
Chemical Properties ◽  
Pilot Scale ◽  
Drainage Water ◽  
Tile Drainage ◽  
Phosphate Removal ◽  
Retention Capacity ◽  
N Removal ◽  
Physical And Chemical ◽  
P Removal ◽  
Biochar Amendment

Biochar has received increased attention in environmental applications in recent years. Therefore, three pilot-scale denitrifying bioreactors, one filled with woodchips only and the other two enriched with 10% and 20% by volume of biochar from deciduous wood, were tested under field conditions for the removal of nitrate (NO3-N) and phosphate (PO4-P) from tile drainage water in Lithuania over a 3-year period. The experiment showed the possibility to improve NO3-N removal by incorporating 20% biochar into woodchips. Compared to the woodchips only and woodchips amended with 10% biochar, the NO3-N removal effect was particularly higher at temperatures below 10.0 °C. The results also revealed that woodchips alone can be a suitable medium for PO4-P removal, while the amendment of biochar to woodchips (regardless of 10% or 20%) can lead to large releases of PO4-P and other elements. Due to the potential adverse effects, the use of biochar in woodchip bioreactors has proven to be very limited and complicated. The experiment highlighted the need to determine the retention capacity of biochar for relevant substances depending on the feedstock and its physical and chemical properties before using it in denitrifying bioreactors.

scholarly journals Hydroponic Growth Media (Substrate): A Review

2020 ◽  
pp. 106-113
Author(s):  
S. T. Patil ◽  
U. S. Kadam ◽  
M. S. Mane ◽  
D. M. Mahale ◽  
J. S. Dhekale
Keyword(s):  
Particle Size ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Total Porosity ◽  
Matter Content ◽  
Growth Media ◽  
Medium Temperature ◽  
The Media ◽  
Individual Grains ◽  
Physical And Chemical

From the reviewed literature, it is observed that scientist’s worked on the various substrate medias used for hydroponic system. They also studied about different combinations of the media and their effect on crop growth. The reviewed literature shows that scientists have studied different organic and inorganic media viz. cocopit, saw dust, rice husk vermiculite, perlite, hydroton, pumice, sand etc. It was also found that these media are not easily, cheaply and locally available for users. Beside this, few scientists studied about physical and chemical properties of media such as particle size, porosity, bulk density, wettability, water holding capacity (WHC), Air filled porosity (AFP), Electrical conductivity, pH of these media. The crop specific suitability of combinations of the different media mixtures were also tested and reported by many scientists. It was revealed from reviewed literature that salinity of media caused linear reduction in the water consumption. The size and shape of particle size distribution are useful for estimating the hydraulic properties of the media The substrate under long cultivation period causes increase of organic matter content and microorganism activity which leads to an increased competition for oxygen in the root environment. The optimal EC levels range from 1.5 to 4.0 dSm-1 according to crop and its sensitivity to different salinity levels. It was also observed that level of growing medium temperature close to that of the surrounding air seems more suitable. The ideal substrate should have a total porosity of over 85 percent. Particles of smaller-sized individual grains have a larger specific surface area.

Disinfection of tertiary wastewater effluent prior to river discharge using peracetic acid; treatment efficiency and results on by-products formed in full scale tests

2013 ◽  
Vol 68 (8) ◽  
pp. 1852-1856 ◽  
Author(s):  
Per Overgaard Pedersen ◽  
Erling Brodersen ◽  
David Cecil
Keyword(s):  
Peracetic Acid ◽  
Full Scale ◽  
Treated Wastewater ◽  
Decomposition Products ◽  
Sand Filter ◽  
E Coli ◽  
Log Reduction ◽  
Before And After ◽  
Full Scale Tests ◽  
P Removal

This is an investigation of chemical disinfection, with peracetic acid (PAA), in a tertiary sand filter at a full scale activated sludge plant with nitrification/denitrification and P-removal. The reduction efficiency of Escherichia coli and intestinal enterococci in the sand filter is reported. E. coli log reductions of between 0.4 and 2.2 were found with contact times from 6 to 37 min and with dosing from 0 to 4.8 mg L−1. The average log reduction was 1.3. The decomposition products, bromophenols, chlorophenols and formaldehyde and residual H2O2 were measured before and after the sand filter. The residual H2O2 concentration in the effluent was critical at short contact times and high dosages of PAA due to the discharge limit of 25 μg L−1. The other three products could not be detected at 0.1 μg L−1 levels. The chemical cost of PAA dosing is estimated to be 0.039 US$ m−3 treated wastewater.

Cause Analysis of Round Thread Connection Dropout

2012 ◽  
Vol 479-481 ◽  
pp. 2028-2032
Author(s):  
Zhi Yong Pan ◽  
Sheng Yin Song ◽  
Wen Hong Liu ◽  
Xin Li Han ◽  
Jun Han ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Cause Analysis ◽  
Safety Hazard ◽  
Thread Connection ◽  
The Past ◽  
Dimension Measurement ◽  
Full Scale Tests ◽  
Physical And Chemical ◽  
Great Economy ◽  
And Chemical Properties

Dropout may be happen to round thread connection by main reasons of design and process of product, material’s property, make-up torque or make-up position, field operation problems etc.. Casing’s property has get a high improvement with the development over the past decade in China. But the number of connection dropout accident didn’t declined obviously. These lead to great economy loss and safety hazard had taken place. Research on a round thread connection pullout case was carried out combining relative theorys with tests. Macroscopic analysis and dimension measurement and material’s physical and chemical properties were checked for casings and couplings. Thread inspection and full-scale tests were done for casing simples that are same lot with dropout. Comprehensive analysis was carried out on these results. The results showed that dropout failure was ascribe to two main causes. One is make-up location cann’t reach standard location at field end, and the other is incorrect holding position on coupling in the course of making up.

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