scholarly journals Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

2019 ◽  
Vol 11 (19) ◽  
pp. 5490 ◽  
Author(s):  
Stefano Freguia ◽  
Maddalena Logrieco ◽  
Juliette Monetti ◽  
Pablo Ledezma ◽  
Bernardino Virdis ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Human Urine ◽  
Modern Society ◽  
Electrical Current ◽  
Nutrient Recovery ◽  
Self Healing ◽  
Recovery System ◽  
Current Densities ◽  
Self Powered ◽  
Process Controls

Nutrient recovery from source-separated human urine has been identified by many as a viable avenue towards the circular economy of nutrients. Moreover, untreated (and partially treated) urine is the main anthropogenic route of environmental discharge of nutrients, most concerning for nitrogen, whose release has exceeded the planet’s own self-healing capacity. Urine contains all key macronutrients (N, P, and K) and micronutrients (S, Ca, Mg, and trace metals) needed for plant growth and is, therefore, an excellent fertilizer. However, direct reuse is not recommended in modern society due to the presence of active organic molecules and heavy metals in urine. Many systems have been proposed and tested for nutrient recovery from urine, but none so far has reached technological maturity due to usually high power or chemical requirements or the need for advanced process controls. This work is the proof of concept for the world’s first nutrient recovery system that powers itself and does not require any chemicals or process controls. This is a variation of the previously proposed microbial electrochemical Ugold process, where a novel air cathode catalyst active in urine conditions (pH 9, high ammonia) enables in situ generation of electricity in a microbial fuel cell setup, and the simultaneous harvesting of such electricity for the electrodialytic concentration of ionic nutrients into a product stream, which is free of heavy metals. The system was able to sustain electrical current densities around 3 A m–2 for over two months while simultaneously upconcentrating N and K by a factor of 1.5–1.7.

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

Self‐Healing, Flexible, and Tailorable Triboelectric Nanogenerators for Self‐Powered Sensors based on Thermal Effect of Infrared Radiation

2020 ◽  
Vol 30 (16) ◽  
pp. 1910723 ◽  
Author(s):  
Xingyi Dai ◽  
Long‐Biao Huang ◽  
Yuzhang Du ◽  
Jiancheng Han ◽  
Qiuqun Zheng ◽  
...  
Keyword(s):  
Thermal Effect ◽  
Infrared Radiation ◽  
Self Healing ◽  
Self Powered ◽  
Triboelectric Nanogenerators

Highly Robust and Self-Powered Electronic Skin Based on Tough Conductive Self-Healing Elastomer

ACS Nano ◽  
2020 ◽  
Vol 14 (7) ◽  
pp. 9066-9072 ◽  
Author(s):  
Xiaochen Xun ◽  
Zheng Zhang ◽  
Xuan Zhao ◽  
Bin Zhao ◽  
Fangfang Gao ◽  
...  
Keyword(s):  
Self Healing ◽  
Electronic Skin ◽  
Self Powered

Nutrient recovery options from human urine: A choice for large scale application

2020 ◽  
Vol 24 ◽  
pp. 219-231 ◽  
Author(s):  
Yitayal Addis Alemayehu ◽  
Seyoum Leta Asfaw ◽  
Tadesse Alemu Terfie
Keyword(s):  
Human Urine ◽  
Large Scale ◽  
Nutrient Recovery

scholarly journals Air-breathing cathode self-powered supercapacitive microbial fuel cell with human urine as electrolyte

2020 ◽  
Vol 353 ◽  
pp. 136530
Author(s):  
Carlo Santoro ◽  
Xavier Alexis Walter ◽  
Francesca Soavi ◽  
John Greenman ◽  
Ioannis Ieropoulos
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Human Urine ◽  
Air Breathing ◽  
Self Powered

Influence of Surface Roughness on Friction and Contact Resistance in Sliding Electrical Contacts

2007 ◽  
Author(s):  
Dinesh G. Bansal ◽  
Jeffrey L. Streator
Keyword(s):  
Surface Roughness ◽  
Contact Resistance ◽  
Coefficient Of Friction ◽  
Electrical Contact ◽  
Electrical Current ◽  
Electrical Contacts ◽  
Sliding Electrical Contacts ◽  
The Coefficient Of Friction ◽  
Current Densities

An experiment is conducted to investigate the role of surface roughness on the coefficient of friction and contact resistance of sliding electrical contacts. A hemispherical pin is sliding along both smooth and rough 2-meter rail surface. Tests are performed at both low and moderate sliding speed and for a range of electrical current densities, ranging from 0 to about 12 GA/m2. It was found that surface roughness had a significant influence on the coefficient of friction, with the smoother surfaces exhibiting higher coefficients of friction. Contact resistance, on the other hand, did not show as strong an effect of surface roughness, except for a few parameter combinations. At the higher current densities studied (>10 GA/m2), it was found that the contact resistance values tended to be on the order of 1 mΩ, independent of load, speed and roughness. This convergence may be due to presence of liquid metal film at the interface, which established ideal electrical contact.

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