Technologies for the recovery of nutrients, water and energy from human urine: A review

Patel, Asfak; Mungray, Alka A.; Mungray, Arvind Kumar

doi:10.1016/j.chemosphere.2020.127372

Cited by 97 publications

(36 citation statements)

References 132 publications

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“…60 In addition, we assume N input from the recycling of a substantial fraction (70%) of human N excretion. Patel et al 61 and Martin et al 62 have recently reviewed the available technologies for recovering nutrients from source-separated human urine, which contains 80% of N excretion, 44 and have advocated for reusing them as fertilizers. Note that this reuse would imply that the current prohibition of human excreta in the European organic farming regulation would be lifted.…”

Section: A B B Amentioning

confidence: 99%

Reshaping the European agro-food system and closing its nitrogen cycle: The potential of combining dietary change, agroecology, and circularity

et al. 2021

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After World War II, the evolution of Europe's agro-food system has been marked by intensified use of synthetic fertilizers, territorial specialization, and integration in global food and feed markets. This evolution led to increased nitrogen (N) losses to aquatic environments and the atmosphere, which, despite increasing environmental regulations, continues to harm ecosystems and human well-being. Here, we explore how these N losses can be drastically reduced in a scenario synergistically operating three levers: (1) a dietary change toward less animal products and an efficient recycling of human excreta; (2) the generalization of region-specific organic crop rotation systems involving N 2 -fixing legumes, making it possible to do without synthetic N fertilizers; and (3) the reconnection of livestock with cropping systems allowing optimal use of manure. This scenario demonstrates the possibility to feed the projected European population in 2050 without imports of feed and with half the current level of environmental N losses.

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Section: A B B Amentioning

confidence: 99%

Reshaping the European agro-food system and closing its nitrogen cycle: The potential of combining dietary change, agroecology, and circularity

et al. 2021

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“…In the case of a bilayer membrane, the thickness of the cation-exchange layer is much less than the thickness of the substrate membrane; therefore, we will consider β c → 0, then substituting Equations (11) and (12) into Equation (10), we obtain the full expression for the limiting current of the bilayer membrane with one thin layer:…”

Section: The Nature Of the Limiting Current On Bilayer Membranementioning

confidence: 99%

“…The areas of application of membrane processes are steadily expanding. One of the new vectors for the development of electromembrane technologies is the processing of ampholyte-containing solutions [7][8][9] and the recovery of nutrients from the waste products of humans and animals [10,11].…”

Section: Introductionmentioning

confidence: 99%

Water Splitting and Transport of Ions in Electromembrane System with Bilayer Ion-Exchange Membrane

et al. 2020

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Bilayer ion-exchange membranes are mainly used for separating single and multiply charged ions. It is well known that in membranes in which the layers have different charges of the ionogenic groups of the matrix, the limiting current decreases, and the water splitting reaction accelerates in comparison with monolayer (isotropic) ion-exchange membranes. We study samples of bilayer ion-exchange membranes with very thin cation-exchange layers deposited on an anion-exchange membrane-substrate in this work. It was revealed that in bilayer membranes, the limiting current’s value is determined by the properties of a thin surface film (modifying layer). A linear regularity of the dependence of the non-equilibrium effective rate constant of the water-splitting reaction on the resistance of the bipolar region, which is valid for both bilayer and bipolar membranes, has been revealed. It is shown that the introduction of the catalyst significantly reduces the water-splitting voltage, but reduces the selectivity of the membrane. It is possible to regulate the fluxes of salt ions and water splitting products (hydrogen and hydroxyl ions) by changing the current density. Such an ability makes it possible to conduct a controlled process of desalting electrolytes with simultaneous pH adjustment.

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“…Urine may be sterilized by heat, pressure, or ultraviolet light, but these methods require energy. Alternatively, storage at low pH for weeks to months can inactivate viruses, inhibit pathogens, combat the rise in pH due to urea hydrolysis, and reduce ammonia volatilization (Hellström et al, 1999;Patel et al, 2020). If acidic conditions are maintained, no N is lost during the sterilization process.…”

Section: Sterilizationmentioning

confidence: 99%

Optimizing Nitrogen Fixation and Recycling for Food Production in Regenerative Life Support Systems

Langenfeld

Kusuma

Wallentine

et al. 2021

Front. Astron. Space Sci.

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Nitrogen (N) recycling is essential for efficient food production in regenerative life support systems. Crew members with a high workload need 90–100 g of protein per person per day, which is about 14 g of N, or 1 mole of N, per person per day. Most of this N is excreted through urine with 85% as urea. Plants take up N predominantly as nitrate and ammonium, but direct uptake as urea is possible in small amounts. Efficient N recycling requires maintenance of pH of waste streams below about 7 to minimize the volatilization of N to ammonia. In aerobic reactors, continuous aerobic conditions are needed to minimize production and volatilization of nitrous oxide. N is not well recycled on Earth. The energy intensive Haber–Bosh process supplies most of the N for crop production in terrestrial agriculture. Bacterial fixation of dinitrogen to ammonium is also energy intensive. Recycling of N from plant and human waste streams is necessary to minimize the need for N fixation. Here we review approaches and potential for N fixation and recycling in regenerative life support systems. Initial estimates indicate that nearly all the N from human and plant waste streams can be recovered in forms usable for plants.

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Technologies for the recovery of nutrients, water and energy from human urine: A review

Cited by 97 publications

References 132 publications

Reshaping the European agro-food system and closing its nitrogen cycle: The potential of combining dietary change, agroecology, and circularity

Reshaping the European agro-food system and closing its nitrogen cycle: The potential of combining dietary change, agroecology, and circularity

Water Splitting and Transport of Ions in Electromembrane System with Bilayer Ion-Exchange Membrane

Optimizing Nitrogen Fixation and Recycling for Food Production in Regenerative Life Support Systems

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