Restoring phosphorus from water to soil: Using calcined eggshells for P adsorption and subsequent application of the adsorbent as a P fertilizer

Chemosphere ◽  
2022 ◽  
Vol 287 ◽  
pp. 132267
Author(s):  
Jae-In Lee ◽  
Jeong-Man Kim ◽  
Soo-Cheul Yoo ◽  
Eun Hea Jho ◽  
Chang-Gu Lee ◽  
...  
2020 ◽  
pp. 339-342
Author(s):  
V.F. Bez’yazychny ◽  
M.V. Timofeev ◽  
R.V. Lyubimov ◽  
E.V. Kiselev

The theoretical justification for the hardening process of the surface layer of machine parts for combined methods of surface hardening with subsequent application of strengthening coatings, as well as reducing or increasing the fatigue limit due to the fretting process is presented.


2019 ◽  
Vol 47 (7) ◽  
pp. 1-9 ◽  
Author(s):  
Zhongyang Wang ◽  
Yi Li ◽  
Zheng Jin ◽  
Timothy Tamunang Tamutana

Self-serving bias is individuals' belief that leads them to blame external forces when bad things happen and to give themselves credit when good things happen. To evaluate how underlying evaluative associations toward the self or others differ between individuals, and/or how the regulation mechanism of the influence of such associations differs, we used a multinomial process model to measure the underlying implicit self-esteem in these processes with 56 Chinese undergraduate students. The results indicated that participants assessed themselves as being better than others when their performance was followed by a desirable outcome. Subsequent application of the quadruple processes showed that both activation of positive associations toward self and regulation of the associations played important roles in attitudinal responses. Our findings may provide a supplementary explanation to that of previous results, promoting understanding of the mechanism underlying self-serving bias.


2021 ◽  
Vol 13 (3) ◽  
pp. 1232
Author(s):  
Natalie Szeligova ◽  
Marek Teichmann ◽  
Frantisek Kuda

The subject of the work is the research on relevant factors influencing participation in the success of brownfield revitalization, especially in the territory of small municipalities. Research has so far dealt with the issue of determining disparities in the municipalities of the Czech Republic, not excluding small municipalities, but their subsequent application has usually been presented in larger cities. The focus on smaller municipalities or cities was usually addressed only in general. The introduction provides an overview of theoretical knowledge in the field of brownfield revitalization. Defining the level of knowledge of the monitored issues is an essential step for the purposes of more effective determination of disparities. Disparities will be determined on the basis of information on localities that have been successfully revitalized. The identified disparities are then monitored in the territory of small municipalities. For the purposes of processing, it was determined that a small municipality or city is an area with a maximum of 5000 inhabitants. Using appropriately selected statistical methods, an overview of disparities and their weights is determined, which significantly affect the success of revitalization. In small municipalities, the issue of brownfields is not emphasized but, in terms of maintaining community strength and reducing population turnover, the reuse of brownfields is a crucial theme.


Membranes ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 64 ◽  
Author(s):  
Tobias Gienau ◽  
Artjom Ehrmanntraut ◽  
Matthias Kraume ◽  
Sandra Rosenberger

Membrane filtration of biological suspensions is frequently limited by fouling. This mechanism is well understood for ultrafiltration of activated sludge in membrane bioreactors. A rather young application of ultrafiltration is the recovery of nutrients from anaerobic digestates, e.g., from agricultural biogas plants. A process chain of solid/liquid separation, ultrafiltration, and reverse osmoses separates the digestate into different products: an organic N-P-fertilizer (solid digestate), a recirculate (UF retentate), a liquid N-K-fertilizer (RO retentate) and water. Despite the preceding particle removal, high crossflow velocities are required in the ultrafiltration step to overcome fouling. This leads to high operation costs of the ultrafiltration step and often limits the economical application of the complete process chain. In this study, under-stoichiometric ozone treatment of the ultrafiltration feed stream is investigated. Ozone treatment reduced the biopolymer concentration and apparent viscosity of different digestate centrates. Permeabilities of centrate treated with ozone were higher than without ozone treatment. In a laboratory test rig and in a pilot plant operated at the site of two full scale biogas plants, ultrafiltration flux could be improved by 50–80% by ozonation. Nutrient concentrations in the fertilizer products were not affected by ozone treatment.


2005 ◽  
Vol 85 (1) ◽  
pp. 81-93 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
P. G. Jefferson ◽  
B. G. McConkey ◽  
...  

Assessment of the long-term impact of fertilizers and other management factors on crop production and environmental sustainability of cropping systems in the semi-arid Canadian prairies is needed. This paper discusses the long-term influence of N and P fertilizers on crop production, N uptake and water use of hard red spring wheat (Triticum aestivum L.), and the effect of the preceding crop type [flax (Linum usitatissimum L.) and fall rye (Secale cereale L.)] on wheat grown on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan. We analysed 36 yr of results (1967–2002) from eight crop rotation-fertility treatments: viz., fallow-wheat receiving N and P (F-W, N + P), three F-W-W treatments fertilized with (i) N + P, (ii) P only, and (iii) N only; two other 3-yr mixed rotations with N + P (i) F-flax-W (F-Flx-W) and (ii) F-fall rye-W (F-Rye-W); and two continuous wheat rotations (Cont W), one receiving N + P and the other only P. Growing season weather conditions during the 36-yr period were near the long-term mean, but the first 22 yr were generally drier than normal while the last 14 yr (1989–2002) had average to above-average growing conditions. This was partly responsible for grain and N yield being greater in the latter period than in the first 22 yr. The 36-yr average response of wheat grown on fallow to P fertilizer was 339 kg ha-1, while the response to N fertilizer over this period was only 123 kg ha-1. The 36-yr average response of wheat grown on stubble to N was 344 kg ha-1 for F-W-(W) and 393 kg ha-1 for Cont W. Neither flax nor fall rye influenced the yield response of the following wheat crops. Annualized grain production for F-W (N + P), F-W-W (+ N) and F-W-W (+ P) rotations were similar (1130 kg ha-1 yr-1); this was about 15% lower than for F-W-W (N + P), 40% lower than for Cont W (N + P), and 5% lower than for Cont W (+ P). Annualized aboveground N yield for Cont W (N + P) was 57% higher than for Cont W (+ P). Regressions were developed relating straw to grain yields for wheat, flax and fall rye. The amount of NO3-N left in the soil was directly related to amount of N applied and inversely to N removed in the crop. Thus, F-(W)-W (+ N) left about 28% more NO3-N in the rooting zone than F-(W)-W (N + P), while F-W-(W) (N + P) left 20% more than F-W-(W) (+ P), and Cont W (N + P) left 39% more than Cont W (+ P). F-Rye-W (N + P) left much less NO3-N in the soil than any other fallow-containing system and similar amounts to Cont W (N + P). Key words: Yields, grain protein, N and P fertilizer, straw/grain regressions, water use, soil nitrate


1986 ◽  
Vol 66 (1) ◽  
pp. 105-119 ◽  
Author(s):  
B. I. WAGAR ◽  
J. W. B. STEWART ◽  
J. O. MOIR

A sequential phosphorus (P) fractionation procedure was used to measure the changes in the labile and stable forms of inorganic and organic P following single broadcast P applications to Canadian Chernozemic soils under cereal cropping. Approximately half of the fertilizer residues remained in plant-available forms (resin, NaHCO3). In a Black Waskada clay loam 8 yr after the application of 200 and 400 kg P ha−1, residual fertilizer P consisted of resin-P, 30–40%; HCl-P, 25–30%; residue-P, 10–15%; NaOH-P, 10–15%, NaHCO3-P, 10%; and aggregate protected P, 3%. The residues in a Dark Brown Sutherland clay 5 yr after the application of 160 kg P ha−1 were: resin-P, 35%; NaOH-P, 30–40%; NaHCO3-P, 15%; HCl-P, 0–5%; H2SO4-P, 5%; and aggregate protected P, 5%. The soils differed in the quantity of fertilizer recovered in inorganic HCl-extractable forms. In the Sutherland soil the change from wheat-fallow to continuous wheat cropping produced a build-up of organic P which occurred with and without the addition of P fertilizer. Key words: Residual P, P transformations, Labile Pi; labile Po, stable Pi stable Po


Author(s):  
N Banerjee ◽  
D Dini ◽  
D A Hills

This paper provides a set of ‘maps’ showing the response of three example frictional complete contacts (with edge angle of 60°, 90°, and 120°) subject to a constant normal load and the subsequent application of cyclic shear and bulk tension, the latter present in only one body. The maps define the region of full adhesion, the nature of violations, and conditions under which they arise.


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