scholarly journals Phosphorus Recovery from Sewage Sludge Using Acidithiobacilli

Author(s):  
Surendra K. Pradhan ◽  
Helvi Heinonen-Tanski ◽  
Anna-Maria Veijalainen ◽  
Sirpa Peräniemi ◽  
Eila Torvinen

Sewage sludge contains a significant amount of phosphorus (P), which could be recycled to address the global demand for this non-renewable, important plant nutrient. The P in sludge can be solubilized and recovered so that it can be recycled when needed. This study investigated the P solubilization from sewage sludge using Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans. The experiment was conducted by mixing 10 mL of sewage sludge with 90 mL of different water/liquid medium/inoculum and incubated at 30 °C. The experiment was conducted in three semi-continuous phases by replacing 10% of the mixed incubated medium with fresh sewage sludge. In addition, 10 g/L elemental sulfur (S) was supplemented into the medium in the third phase. The pH of the A. thiooxidans and A. ferrooxidans treated sludge solutions was between 2.2 and 6.3 until day 42. In phase 3, after supplementing with S, the pH of A. thiooxidans treated sludge was reduced to 0.9, which solubilized and extracted 92% of P. We found that acidithiobacilli supplemented with S can be used to treat sludge, i.e., achieve hygienization, removal of heavy metals, and solubilization and recovery of P.

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdul Hasan Saragih

This classroom research was conducted on the autocad instructions to the first grade of mechinary class of SMK Negeri 1 Stabat aiming at : (1) improving the student’ archievementon autocad instructional to the student of mechinary architecture class of SMK Negeri 1 Stabat, (2) applying Quantum Learning Model to the students of mechinary class of SMK Negeri 1 Stabat, arising the positive response to autocad subject by applying Quantum Learning Model of the students of mechinary class of SMK Negeri 1 Stabat. The result shows that (1) by applying quantum learning model, the students’ achievement improves significantly. The improvement ofthe achievement of the 34 students is very satisfactory; on the first phase, 27 students passed (70.59%), 10 students failed (29.41%). On the second phase 27 students (79.41%) passed and 7 students (20.59%) failed. On the third phase 30 students (88.24%) passed and 4 students (11.76%) failed. The application of quantum learning model in SMK Negeri 1 Stabat proved satisfying. This was visible from the activeness of the students from phase 1 to 3. The activeness average of the students was 74.31% on phase 1,81.35% on phase 2, and 83.63% on phase 3. (3) The application of the quantum learning model on teaching autocad was very positively welcome by the students of mechinary class of SMK Negeri 1 Stabat. On phase 1 the improvement was 81.53% . It improved to 86.15% on phase 3. Therefore, The improvement ofstudent’ response can be categorized good.


2019 ◽  
Author(s):  
Sony Widyawan ◽  
Darul Prayogo ◽  
Rukman . ◽  
Diajeng Ayu D P ◽  
Abdul Rokhim

Transportation problems are one of the issues faced in Depok, especially at intersections. The problems of traffic congestion and conflict often occur at intersections, especially at Depok intersection in which one of the efforts made to reduce the conflicts is made by managing the intersection. The method used in analyzing intersection performance is the use of calculations at IHCM, while the analysis of traffic conflicts to determine the seriousness of traffic conflicts is to use traffic conflict techniques (TCT) compared to the conflicts. Recommendations are made with a scheme using the selection of 3 phases and 3.5 phases then making a comparison with the third phase and choosing the most appropriate scenario. From the recommendation scheme made using the VISSIM 10 PTV software, the most appropriate scheme is obtained by using three-phase settings. The results of phase 3 simulations are effective in reducing the number of traffic conflicts and service levels are still in good condition.


Author(s):  
Sony Widyawan ◽  
Rukman Rukman

The problemof transportation isone of the problems faced in Depok, especially atintersections. Problems of traffic congestion and conflicts often occur at signalizedintersections, especially at the intersection of four signalized Depok Depok City where one ofthe efforts made to reduce conflicts in Depok intersection is done by setting the intersection.The methods used in the analysis of the performance of the intersection is the use ofcalculation on IHCM, while the traffic conflict analysis to determine the level of seriousnessof traffic conflicts is by using traffic conflict Technique (TCT) is compared to that conflictVisSim 10. Recommendation is done by using a scheme using a 3-phase elections and 3.5phase and then make a comparison with the third phase (existing) and selected the mostappropriate scenario. From the scheme of recommendations that were made by using thesoftware PTV VISSIM 10 obtained the most appropriate scheme that uses three-phasearrangement. The results of the simulation phase 3 was effective at reducing the number oftraffic conflicts and service levels are still in good condition


2020 ◽  
Author(s):  
Adriana Klein ◽  
Roseli de Deus Lopes ◽  
Rodrigo Suigh

BACKGROUND EasySeating is a mobile health (mHealth) app that supports the prescription of wheelchair and postural support devices (WPSD). It can be used by occupational therapists (OT) and physiotherapists (PT) who prescribe WPSD. The app offers a standardization of the prescription procedure, showing images, metrics and details that guide the prescriber to decide on the best equipment. It was developed with an iterative mixed-methods evaluation approach. Objective: The aim of this study was to investigate the processes involved in the prescription of WPSD and to propose, develop and evaluate a mHealth to support OT and PT prescribers. OBJECTIVE The aim of this study was to investigate the processes involved in the prescription of WPSD and to propose, develop and evaluate a mHealth to support OT and PT prescribers. METHODS This study was divided into three phases and was carried out as an iterative process composed of user consulting/testing (using a mixed-methods evaluation approach), system (re)design and software development. The first phase consisted of the collection of qualitative and quantitative data to map and understand the users requirements and of the development of the first prototype (v1) of the app. This data collection was performed through semi-structured interviews with 14 OT and PT prescribers, 5 specialized technicians and 5 WPSD users. The second phase aimed at improving the overall functionality of the app and consisted in the development, test and evaluation of the prototypes v1, v2, v3 and v4. A total of 59 prescribers tested and evaluated these prototypes by means of open interviews, semi-structured questionnaires and focus groups. The third phase focused in the usability aspects of the app. It consisted in the development and test of the prototype v5. Eight technology specialists assessed its usability through heuristics evaluation. RESULTS Data collected in phase one indicated there is a lack of standardization on the prescription of postural support devices (PSD). A divergent nomenclature for the PSDs was also found and classified in eight categories. These information guided the development of the first prototype of the EasySeating app. Phase two results pointed that the prescribers value the insertion of the app into their clinical practice, as it accelerates and increases the quality of the evaluation process and improves the organization of the prescription information. Significant suggestions for the improvement of the app were given during the users tests, including the use of images to represent the PSDs. The usability tests from the third phase revealed two strong issues that must be solved: the need of greater feedback and failures in the persistence of the input data. CONCLUSIONS This study demonstrated that there is a lack of systematization of the WPSD prescription process. The evaluation of the developed EasySeating app demonstrated that there is a potential to standardize, integrate and organize the WPSD prescription information, supporting and facilitating the decision making process of the prescribers. CLINICALTRIAL This study was approved by the Research Ethics Board of the Universidade de São Paulo (registered protocol n°53929516.6.0000.0065) URL - http://plataformabrasil.saude.gov.br/login.jsf


2019 ◽  
Vol 29 (2) ◽  
pp. 104-125

Three phases in Foucault’s examination of authorship and free speech were essential to him throughout his life. They can be linked to such texts as the three lectures “What is an Author?” (first phase), “What is Critique?,” and “What is Revolution?” (second phase), and the two lecture courses, “Fearless Speech,” and “The Courage of Truth” (third phase). Initially, Foucault merely describes the founders of discursivity (hence, “superauthors”), among whom he reckoned only Marx and Freud, as the sole alternative to his own conceptualization of the author function, which is exhibited en masse in contemporary society. He then modifies his views on superauthorship by making Kant the paradigm and by linking his own concept of free speech to a Kan-tian critical attitude. However, Foucault claims only the half of Kant’s philosophical legacy that is related to the study of the ontology of the self.The article advances the hypothesis that the sovereign power of speech, which can be found in Marx and Heidegger and in generally in the concept of “superauthorship,” becomes unacceptable for Foucault. During the third phase, the danger of a tyrannical use of free speech compels Foucault to make a number of fruitful but questionable choices in his work. He focuses on a single aspect of free speech in which a speaker is in a weaker position and therefore has to overcome his fear in order to tell the truth. Foucault associates this kind of free speech with the ancient Greek notion of parrhesia, which according to his interpretation means “fearless speech”; however, this reading is not always supported by the ancient Greek sources. Foucault’s deliberations bring him to the radical conclusion that free speech transforms into performative “aesthetics of existence.” Foucault’s main motivation for pursuing this line of thought all through his life was to investigate his own abilities and powers as an author


Author(s):  
Michael P. DeJonge

If, as Chapter 12 argues, much of Bonhoeffer’s resistance thinking remains stable even as he undertakes the novel conspiratorial resistance, what is new in his resistance thinking in the third phase? What receives new theological elaboration is the resistance activity of the individual, which in the first two phases was overshadowed by the resistance role played by the church. Indeed, as this chapter shows, Bonhoeffer’s conspiratorial activity is associated with what he calls free responsible action (type 6), and this is the action of the individual, not the church, in the exercise of vocation. As such, the conspiratorial activity is most closely related to the previously developed type 1 resistance, which includes individual vocational action in response to state injustice. But the conspiratorial activity differs from type 1 resistance as individual vocational action in the extreme situation.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2697
Author(s):  
Gabriel Gerner ◽  
Luca Meyer ◽  
Rahel Wanner ◽  
Thomas Keller ◽  
Rolf Krebs

Phosphorus recovery from waste biomass is becoming increasingly important, given that phosphorus is an exhaustible non-renewable resource. For the recovery of plant nutrients and production of climate-neutral fuel from wet waste streams, hydrothermal carbonization (HTC) has been suggested as a promising technology. In this study, digested sewage sludge (DSS) was used as waste material for phosphorus and nitrogen recovery. HTC was conducted at 200 °C for 4 h, followed by phosphorus stripping (PS) or leaching (PL) at room temperature. The results showed that for PS and PL around 84% and 71% of phosphorus, as well as 53% and 54% of nitrogen, respectively, could be recovered in the liquid phase (process water and/or extract). Heavy metals were mainly transferred to the hydrochar and only <1 ppm of Cd and 21–43 ppm of Zn were found to be in the liquid phase of the acid treatments. According to the economic feasibility calculation, the HTC-treatment per dry ton DSS with an industrial-scale plant would cost around 608 USD. Between 349–406 kg of sulfuric acid are required per dry ton DSS to achieve a high yield in phosphorus recovery, which causes additional costs of 96–118 USD. Compared to current sewage sludge treatment costs in Switzerland, which range between 669 USD and 1173 USD, HTC can be an economically feasible process for DSS treatment and nutrient recovery.


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