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Journal ArticleDOI: 10.1016/J.CHEMOSPHERE.2021.130097

Novel sorbent shows promising financial results on P recovery from sludge water.

04 Mar 2021-Chemosphere (Pergamon)-Vol. 276, pp 130097-130097
Abstract: For several decades, researchers have been struggling to obtain minimum phosphorus (P) capture costs to meet the parameters for discharging wastewater into the watercourse. Findings from ongoing practices suggest that the Modified University of Cape Town process is currently the cheapest P capture method in the USA, whereas struvite precipitation seems to be the most cost effective method in the rest of the developed world. P sorption via biochars is becoming widespread in developing countries because this technique allows for the turning of voluminous biowaste into fertilizer with soil improving properties. Nevertheless, the reliability of this technology fluctuates throughout the year according to biowaste characteristics. For the first time, it has been proposed to use broken cellulose casings, which are readily available in increasing quantities worldwide. The sorbent obtained was subsequently activated by calcium chloride (CaCl2), whose cost is irrelevant as it would be used for agronomical purposes anyway. Pilot scale experiments show that this novel sorbent is capable of capturing 31.8 kg P t−1 from sludge water that contains 52.5 mg of extractable P L−1. More importantly, it was reported that the novel sorbent captures P, mostly in calcium phosphates (CaP) forms (191.5 g CaP t−1), which are the most valuable for plant nutrition. Enough evidence was obtained to claim that the ongoing technological race to meet the P discharge standards at the lowest cost possible should also reflect the agronomic value of P to plant nutrition to increase its competitiveness.

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Topics: Sorbent (50%)

24 results found

Open accessJournal ArticleDOI: 10.3390/EN14123468
11 Jun 2021-Energies
Abstract: There is wide consensus that Spirulina can serve as a tool for wastewater management and simultaneously provide feedstock for biorefining. However, the economic aspects associated with its use remain a significant challenge. Spirulina cultivated in wastewater decreased the concentrations of both ammonia and nitrate and also served as a biodiesel source. The oil obtained in the feedstock was subjected to transesterification and turned into biodiesel. The biodiesel was subsequently analyzed in a test motor (water-cooled, four-stroke, single-cylinder compression ignition with injection). The tests were conducted at a constant 1500 rpm, and the output power was 3.7 kW. Mixtures of diesel and biodiesel were also enriched with carbon nanotubes (CNTs). The amount of CNTs added to the diesel was 30 mg L−1. The algae and de-oiled biomass were characterized using XRD analysis, and an ultrasonicator was used to mix the CNTs with diesel and spirulina blends. A series of tests were conducted at different load conditions (25%, 50%, 75%, and 100%) for all fuel blends. Test results were compared with a neat diesel engine with a CR of 17.5:1. Among the fuel blends, the B25 reported improved brake thermal efficiency and reduced emissions. The outcomes are a reduction in thermal efficiency of 0.98% and exhaust gas temperature of 1.7%. The addition of Spirulina biodiesel blends had a positive impact on the reduction of greenhouse gas emissions, including reductions of 16.3%, 3.6%, 6.8%, and 12.35% of CO, NOx, and smoke, respectively. The specific fuel consumption and CO2 emissions were reduced by 5.2% and 2.8%, respectively, for B25 fuel blends compared to plain diesel and B50. Concerning cost competitiveness, vigorous research on microalgae for the production of biodiesel can cut production costs in the future.

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Topics: Diesel fuel (63%), Biodiesel (61%), Diesel engine (57%) ... show more

11 Citations

Journal ArticleDOI: 10.1007/S10668-021-01636-1
Abstract: The most common drinking water clarification technology worldwide is based on precipitation using the floccules of iron(III) oxide-hydroxide FeO(OH). The coagulation sludge obtained is usually mixed with biowaste and composted. Inexperienced farmers are interested in these composts, in the expectation that the smallest fractions of the precipitated organic matter together with the colloidal particles of clay captured during the clarification process might increase the level of soil organic matter as well as cation-exchange capacity (CEC) of soil and increase crop yields. Nevertheless, those who have used these composts observed that plants on treated soil show signs of phosphorus (P) insufficiency, despite having been fertilized appropriately. It has been published recently that the traces of iron (Fe) from the FeO(OH) turn the soil P into Fe phosphates (FeP), which makes P not readily available to agricultural plants. A 6-year field-scale experiment was carried out and was accompanied by robust analyses on soils and yields. It was confirmed that the traces of Fe from the coagulation sludge worsen the availability of soil P to plants. However, for the first time, evidence has been obtained concerning the fact that the Fe also damages the efficiency of P fertilizers applied afterward. A questionnaire was conducted among drinking water treatment plant operators and regulators to identify a reason why similar practices have not been banned yet. The results showed a growing awareness of the issue among experts, but politicians seem to prefer putting off unpopular measures. We recommend abandoning the application of these composts onto arable land and the revitalization of the affected fields using biochar activated by calcium and aluminum phosphates (CaP and AlP) so that the problem is not delayed to such an extent that its solution would become a problem for future generations.

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Topics: Soil organic matter (57%), Soil fertility (56%), Soil water (52%) ... show more

6 Citations

Journal ArticleDOI: 10.1016/J.RSER.2021.111371
Abstract: Anaerobic fermentation (AF) is a widely used process for the transformation of organic waste into biogas. However, despite its ubiquitous use, it has several limiting factors, including low yield, redox imbalance, high concentration of inhibitors, and a long retention time. Integration of pyrolysis with AF improves efficiency and facilitates effective biomass utilization in a closed-loop approach. Research trends emphasize the inclusion of biochar derived from biomass to improve the stability and efficiency of AF and facilitate biogas up-gradation (H2S removal). However, there is a lack of consolidated scientific understanding regarding the complex interactions of biochar and AF microbial communities, in addition to its potential amendment advantages. Therefore, this review summarizes biomass utilization for biochar production using various pyrolysis methods and its use as an effective inclusion material to improve AF performance. Specifically, the influence of biochar amendments in AF is discussed in terms of microbial colonization, direct interspecies electron transfer, minimization of organic load, and buffering maintenance. Moreover, the role of AF digestate biochar in nutrient recycling and utilization as a soil conditioner is elaborated. The progressive integration of pyrolysis and AF offers the complete decoupling of biomass, enhances AF performance, and promotes the establishment of a sustainable bioprocess by inducing the circular bioeconomy.

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Topics: Biochar (61%), Digestate (50%)

5 Citations

Open accessJournal ArticleDOI: 10.3390/MATH9161962
17 Aug 2021-
Abstract: To fill in the literature flaws that have not been detected in previous studies, this research, therefore, examines the driving factors of proactive environmental strategy (PES). First, this research proposes how corporate social responsibility (CSR) predicts the agricultural company’s PES through the intermediary mechanism of green organization identification (GOI) of the top management team (TMT) according to symbolic context and theory of high-level echelon, to solve the first gap in exploring what factors can drive the PES. Second, this research proposes a multi-level growth curve model (MGCM) to solve how individuals adjust their behavioral intentions over time according to their translation and understanding of their use environment, because past studies consist of almost cross-sectional properties. Third, past research has also neglected the multi-level framework, leading to hierarchical reasoning bias. Therefore, this research believes that the MGCM can fill in the multi-level gap. Finally, this research collected 400 TMT employees from 100 different agricultural companies in Taiwan in three-stage time for six months. The results show that CSR will significantly lead to more growth in GOI, and more growth in GOI will lead to more growth in PES adoption. The research results can not only advance the agricultural sustainability literature but also serve as a guide for agricultural companies to implement PES.

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3 Citations

Journal ArticleDOI: 10.1080/15567036.2021.1933267
Abstract: Biological plants such as algae have a great potential of fixating CO2 from flue gases or atmospheric air and converting it into useful biomass. This is because CO2 is part of their photosynthesis ...

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Topics: Biomass (59%), Flue gas (55%), Photosynthesis (54%) ... show more

2 Citations


47 results found

Open accessJournal ArticleDOI: 10.1016/J.SUSMAT.2016.06.002
Sabino De Gisi1, Giusy Lofrano1, Giusy Lofrano2, Mariangela Grassi2  +1 moreInstitutions (2)
Abstract: Low-cost by-products from agricultural, household and industrial sectors have been recognized as a sustainable solution for wastewater treatment. They allow achieving the removal of pollutants from wastewater and at same time to contribute to the waste minimization, recovery and reuse. Despite numerous reviews have been published in the last few years, a direct comparison of data obtained using different sorbents is difficult nowadays because of inconsistencies in the data presentation. In this context, the aim of the study was to revise the current literature concerning the application of low-cost adsorbents for wastewater treatment highlighting, systematically, both adsorbents characteristics and adsorption capacities. For this scope, low-cost sorbents have been divided into the following five groups: (i) Agricultural and household wastes, (ii) industrial by-products, (iii) sludge, (iv) sea materials, (v) soil and ore materials and (vi) novel low-cost adsorbents. The affinity of sorbents in removing various pollutants, their applications on real wastewater, costs and considerations on their reuse after adsorption processes, has been discussed. Finally, in order to better highlights the affinity of sorbents for more pollutants (dyes, heavy metals, biorecalcitrant compounds, nitrogen and phosphate compounds), simple methodological tools such as “adsorbents-pollutants” matrices have been proposed and applied. In this manner, the adsorbent candidates for replacing commercial activated carbons have been identified.

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Topics: Wastewater (54%), Sewage treatment (51%)

771 Citations

Journal ArticleDOI: 10.1016/J.CHEMOSPHERE.2017.03.072
01 Jul 2017-Chemosphere
Abstract: Biochar produced by thermal decomposition of biomass under oxygen-limited conditions has received increasing attention as a cost-effective sorbent to treat metal-contaminated waters. However, there is a lack of information on the roles of different sorption mechanisms for different metals and recent development of biochar modification to enhance metal sorption capacity, which is critical for biochar field application. This review summarizes the characteristics of biochar (e.g., surface area, porosity, pH, surface charge, functional groups, and mineral components) and main mechanisms governing sorption of As, Cr, Cd, Pb, and Hg by biochar. Biochar properties vary considerably with feedstock material and pyrolysis temperature, with high temperature producing biochars with higher surface area, porosity, pH, and mineral contents, but less functional groups. Different mechanisms dominate sorption of As (complexation and electrostatic interactions), Cr (electrostatic interactions, reduction, and complexation), Cd and Pb (complexation, cation exchange, and precipitation), and Hg (complexation and reduction). Besides sorption mechanisms, recent advance in modifying biochar by loading with minerals, reductants, organic functional groups, and nanoparticles, and activation with alkali solution to enhance metal sorption capacity is discussed. Future research needs for field application of biochar include competitive sorption mechanisms of co-existing metals, biochar reuse, and cost reduction of biochar production.

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Topics: Biochar (69%), Sorption (60%)

686 Citations

Open accessJournal ArticleDOI: 10.1111/GCBB.12018
01 Mar 2013-Gcb Bioenergy
Abstract: Biochar was produced by fixed-bed slow pyrolysis from various feedstock biomasses under a range of process conditions. Feedstocks used were pine wood, wheat straw, green waste and dried algae. Process conditions varied were the highest treatment temperature (HTT) and residence time. The produced chars were characterized by proximate analysis, CHN-elemental analysis, pH in solution, bomb calorimetry for higher heating value, N2 adsorption for BET surface area and two biological degradation assays (oxygen demand, carbon mineralization in soil). In proximate analysis, it was found that the fixed carbon content (expressed in wt% of dry and ash-free biochar) in the biochar samples strongly depended on the intensity of the thermal treatment (i.e. higher temperatures and longer residence times in the pyrolysis process). The actual yield in fixed carbon (i.e. the biochar fixed carbon content expressed as wt% of the dry and ash-free original feedstock biomass weight) was practically insensitive to the highest treatment temperature or residence time. The pH in solution, higher heating value and BET surface positively correlated with pyrolysis temperature. Finally, soil incubation tests showed that the addition of biochar to the soil initially marginally reduced the C-mineralization rate compared against the control soil samples, for which a possible explanation could be that the soil microbial community needs to adapt to the new conditions. This effect was more pronounced when adding chars with high fixed carbon content (resulting from more severe thermal treatment), as chars with low fixed carbon content (produced through mild thermal treatment) had a larger amount of volatile, more easily biodegradable, carbon compounds.

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Topics: Biochar (70%), Pyrolysis (58%), Compounds of carbon (53%) ... show more

494 Citations

Journal ArticleDOI: 10.1080/15435075.2013.841163
Abstract: Limits set by the Kyoto protocol brings Czech Republic billions of EUR from carbon emissions trading. The Ministry of Environment wants to invest the aforementioned revenue into energy savings and other projects like subsidies on the purchase of stoves for solid biofuels in regions with the most polluted air. Surprisingly, charcoal is not supported. Robust analysis of solid biofuels was made according to valid standards and routine chemical procedures. Data shows that there is no reason for charcoal to be rejected. It was confirmed that solid biofuels do not achieve the quality of black coal. The Czech Ministry of Environment argues that charcoal is not supported because of its high price per ton. The ecological criteria and price per energy should be also taken into account as analyzed in detail. Within the discussed ethical context, an improper form of support may affect market in a short term.

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Topics: Kyoto Protocol (52%)

235 Citations

Journal ArticleDOI: 10.1016/J.BIORTECH.2017.09.136
Qi Yang1, Xiaolin Wang1, Wei Luo1, Jian Sun1  +8 moreInstitutions (1)
Abstract: Excessive discharge of phosphate (P) into the surface water is the key factor to cause the eutrophication, so its removal has aroused much attention in recent years. In this study, different iron modification (chemical co-precipitation of Fe3+/Fe2+ or FeCl3 impregnation) was used to improve the phosphate adsorption capacity of waste activated sludge (WAS)-based biochar. Comparative tests demonstrated that the FeCl3-impregnated WAS-based biochar exhibited much superior phosphate adsorption capacity (111.0mg/g) in all as-prepared samples and performed well even under the interferences with pH and coexisting ions. X-ray diffraction (XRD) analyzes indicated that the iron in FeCl3-impregnated WAS-based biochar existed mainly in amorphous phase, as hematite and amorphous hydroxides forms, which was of great benefit to the phosphate adsorption. Besides, ligand exchange plays important role in the adsorption of phosphate. The WAS-based biochar kept over 60% phosphate removal efficiency after five recycles.

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Topics: Biochar (61%), Adsorption (56%), Phosphate (56%) ... show more

176 Citations

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