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Electro-Fermentation Technology: Synthesis of Chemicals and Biofuels
Published in Kuppam Chandrasekhar, Satya Eswari Jujjavarapu, Bio-Electrochemical Systems, 2022
Devashish Tribhuvan, V. Vinay, Saurav Gite, Shadab Ahmed
The effluent produced by hydrogen-producing bioreactors are intermediate metabolites that can act as an alternative to the synthetic substrate for hydrogen-producing MECs, which significantly improve the efficiency of MEC and increases the yield (Venkata Mohan et al., 2016); thus, making it economically viable. Hydrogen production by MEC (250 mV) is more energy efficient compared to electrolysis (1.23 V). Also, as the process is carried out in anaerobic conditions, the Coulombic efficiency increases. As a result, an utmost yield of 11 mol of hydrogen/mol of glucose can be obtained at the rate of 1m3hydrogen/day/m3 in the reactor. It was seen that struvite (MgNH4PO4·6H2O) crystallization occurs at the cathode during a bioelectochemical reaction in a single-chamber MEC. Struvite is a phosphate fertilizer that can be used in agriculture. Production of hydrogen can be enhanced by eliminating membranes from dual chambers of MEC. However, this might lead to the utilization of hydrogen by methanogen to make methane.
Effluent Treatment of Semiconductor Industry
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
Additionally, because the chemical precipitation produces very fine CaF2 precipitates, flocculants like polyferric sulfate and polyaluminum chloride need to be added to accelerate the solid separation process (Liu and Liu, 2016). Compared with the precipitation using calcium salts, struvite crystallization can help remove both the TAN and PO4–P, and has been largely considered a promising treatment method to remove nutrients from various types of wastewaters (Barbosa et al., 2016); this process also has several advantages, including the high reaction rate, simple operation, and excellent solid–liquid separation performance. Besides, the struvite thus recovered finds use as a valuable slow-releasing fertilizer. In Japan, struvite has been commercially recovered by Unitika Ltd. and sold to American fertilizer companies. Hence, struvite crystallization appears to be an attractive process to pretreat semiconductor wastewater.
Review of potential ways for resource recovery from human urine
Published in Cândida Vilarinho, Fernando Castro, Maria de Lurdes Lopes, WASTES – Solutions, Treatments and Opportunities II, 2017
J. Santos, E. Cifrian, T. Llano, C. Rico, A. Andrés, C. Alegría
The easiest way to urine recovery is to apply it after storage. This kind of fertilizers are an easy help for the economic and fossil fuel depending regions. This simple method has been studied and tested all around the planet and in all kind of plants, and the results usually show nutrient recovery. The yields of these experiments are similar to the mineral fertilizer ones. To solve the inadequate macronutrient relation, different additives can be added to the urine, but it requires a higher technological level. The most popular components to add are wood ashes, TSP or KCl. In these cases, the yields obtained are similar and even better than the mineral commercial fertilizer. When a source of magnesium is added to the stored human urine a salt called struvite (MgNH4PO4·6H2O) precipitates (Patent WO9951522; Patent US2016185633). Through a basic precipitation reaction, the majority of phosphorus in urine can be crystallized into a white, odorless powder. The struvite can be used as a slow release fertilizer, and different studies show better results than commercial fertilizers, and reducing the volume of the flow to the 2% (Jaatinen et al, 2015; Germer et al., 2011; Liu et al., 2013; Kataki et al., 2016).
Human urine-based fertilizers: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Tristan M. P. Martin, Fabien Esculier, Florent Levavasseur, Sabine Houot
Phosphorus availability depends on many parameters. UBFs are generally compared to calcium superphosphate or other soluble phosphate. However, these two mineral fertilizers have different NUE, which can impact the MFE values of UBFs. Because of its high phosphorus content, struvite is mainly used as a phosphorus fertilizer. Different tests were performed with different crops (e.g., Meyer et al., 2018 for dehydrated alkalinized urine). Phosphorous availability also strongly depends on the soil type. In the case of struvite, its efficiency is much higher in acidic soils than in alkaline soils. The MFE varies more for phosphorous than for nitrogen but also remains close to 100% compare to soluble phosphate. Some of the UBFs as struvite may act as a slow-release fertilizer (Everaert et al., 2017).
Thermal decomposition of struvite in water: qualitative and quantitative mineralogy analysis
Published in Environmental Technology, 2020
Athanasius P. Bayuseno, Wolfgang W. Schmahl
Struvite could be precipitated in wastewater treatments and also may be formed in urine as ‘urine sand’, and in urinary tracts or the kidneys as ‘kidney stones’. When the ambient temperature changes, struvite may be decomposed into other phosphate-bearing minerals through the continuous discharge of ammonia and water [2]. More recently, the struvite formation and decomposition under wet and dry heating for a prolonged time has been discussed in detail [16]. Many phosphate minerals could be possibly formed as a result of struvite decomposition with the ambient temperature changing. This experiment has demonstrated that struvite begins to decompose already at temperatures of 55°C during 24 h, where the thermal decomposition of struvite was controlled by the water dehydration and release of ammonia. This result agrees very well with the previous work reported in the literature [2,16]. Accordingly, the following equation has been proposed for the struvite decomposition reaction (Eq. 1) [16]:
Utilization of struvite recovered from high-strength ammonium-containing simulated wastewater as slow-release fertilizer and fire-retardant barrier
Published in Environmental Technology, 2020
Kaan Yetilmezsoy, Emel Kocak, Havva Melda Akbin, Didem Özçimen
Overall, the studies reveal that the struvite recovery is feasible with an efficiency between 81% and 98.7% for different types of wastewaters (e.g. landfill leachate, synthetic industrial wastewater, anaerobically pretreated poultry manure wastewater, raw semiconductor wastewater, baker’s yeast industry anaerobic effluent, swine wastewater, biocatalytic calcification reactor effluent, synthetic (simulated) fertilizer wastewater, etc.) having an initial ammonium concentration from 80 to 2900 mg/L by applying various chemical combinations and Mg:N:P molar ratios. Moreover, various doses ranging from 0.4 to 11.43 g MAP/kg soil have been applied to evaluate the struvite's slow-release fertilizing potential in the growth of different plants (e.g. medicinal herbs, vegetables) for cultivation periods varying from 11 to 75 days.