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1.
J Environ Manage ; 301: 113825, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34571473

RESUMO

The application of the circular economy concept should utilize the cycles of nature to preserve materials, energy and nutrients for economic use. A full-scale pig farm plant was developed and validated, showing how it is possible to integrate a circular economy concept into a wastewater treatment system capable of recovering energy, nutrients and enabling water reuse. A low-cost swine wastewater treatment system consisting of several treatment modules such as solid-liquid separation, anaerobic digestion, biological nitrogen removal by nitrification/denitrification and physicochemical phosphorus removal and recovery was able to generate 1880.6 ± 1858.5 kWh d-1 of energy, remove 98.6% of nitrogen and 89.7% of phosphorus present in the swine manure. In addition, it was possible to produce enough fertilizer to fertilize 350 ha per year, considering phosphorus and potassium. In addition, the effluent after the chemical phosphorus removal can be safely used in farm cleaning processes or disposed of in water bodies. Thus, the proposed process has proven to be an environmentally superior swine waste management technology, with a positive impact on water quality and ensuring environmental sustainability in intensive swine production.


Assuntos
Esterco , Fósforo , Anaerobiose , Animais , Nitrogênio/análise , Nutrientes , Suínos
2.
Food Chem ; 368: 130815, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34411856

RESUMO

The present investigation aimed at assessing the impact of biological processing techniques on bio-and techno-functional characteristics of foxtail millet (Setaria italica L.). Grains were exposed to soaking, germination, fermentation and combination of aforesaid treatments and significant variation (p < 0.05) in anti-nutritional factors, in vitro starch and protein digestibility, bioactive constituents and associated antioxidant potential was noted. Bioprocessed flours were characterized by altered functional properties due to hydrolytic action of activated enzymes. ATR-FTIR spectra and X-ray diffraction patterns revealed structural variation in macromolecular arrangement, synthesis of bioactive compounds in bioprocessed flours and slight reduction in the crystallinity of starch molecules. Bioprocessed flours exhibited degraded protein matrix; however, only fermentation and combination treatments caused hydrolysis of granular starch. Principal component analysis was employed to validate the differences in processing treatments and observations. The results are suggestive that bioprocessed flours could serve as potential ingredients with improved techno-and bio-functionality in valorized cereal products.


Assuntos
Setaria (Planta) , Farinha , Germinação , Nutrientes , Setaria (Planta)/genética , Amido
3.
Food Chem ; 368: 130826, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34454369

RESUMO

The safety and quality of aquatic foods are a public concern due to their content of pollutants, such as arsenic. A formula is derived for quantifying the benefit-risk ratio (HQ) of the essential polyunsaturated fatty acids vs. arsenic in Chinses mitten crabs. Among these arsenic species, the proportion of inorganic arsenic, which is extremely harmful to the human body, is<5%, and its level does not exceed the national standard limit. Meanwhile, comparing with the HQ from the original method, the HQs from groups 0 min, 5 min, 15 min are significantly higher(p < 0.05). This suggests the original assessment method could underestimate the risk of eating crabs. Eating steamed crabs is easier to digest essential fatty acids (EFAs) than eating raw crabs, and it also protects consumers against arsenic exposure. To achieve a good balance of dietary benefits and risks, the steaming duration of the crabs should exceed 30 min.


Assuntos
Arsênio , Braquiúros , Animais , China , Digestão , Humanos , Nutrientes , Medição de Risco
4.
Food Chem ; 367: 130752, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384988

RESUMO

Berry seeds are rich source of high quality oil containing valuable compounds such as polyunsaturated fatty acids and therefore, have been gaining increasing significance as potential source of nutrients for food, cosmetic or pharmaceutical industry. Supercritical carbon dioxide extraction of seeds was performed, for which oxidative stability analyzes and determinations of fatty acids, selected microelements and toxic metals were carried out. An attempt was made to evaluate unclassified scCO2 oil extracts from berry seeds, taking into account the lack of legislative documents specifying the required contents of metals and biologically active ingredients. The obtained extracts are products with the consistency of liquid oil. The total fatty acid content range from 59% to 98%, with unsaturated fatty acids predominating and very good n-3/n-6 fatty acids ratio. The analyzed samples were taken systematically from one extraction sequence also determining the acid and the peroxide values in subsequent fractions.


Assuntos
Ácidos Graxos , Frutas , Nutrientes , Estresse Oxidativo , Extratos Vegetais , Óleos Vegetais
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120461, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34649123

RESUMO

Hazelnut oil (HO), which is not widely used because its healthy properties are not fully known yet, is an excellent nutrient due to its high content of monounsaturated fatty acids and antioxidants. In this study, the effects of thermal processing on the quality of HO in comparison to extra virgin olive oil (EVOO), which is one of the healthiest and heat-resistant oils, were investigated using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Oil samples were heated at a frying temperature (180 °C) for 24 h in periods of 8 h per day and alterations in the spectra of these oils sampled every 2 h were evaluated. The heating process caused decreases in the areas of the bands at 3007 and 722 cm-1 and the area ratios of 3007/2854 and 722/2854 cm-1 and increases in the areas of the bands at 987 and 965 cm-1 and the area ratio of 965/2854 cm-1 in both oils suggesting the conjugation and cis-trans isomerization of unsaturated fatty acids. In addition, heating caused increases in the areas of the bands at 3475 and 1744 cm-1 and the ratios of 3475/2854 cm-1 and 1744/2854 cm-1, a shift to a lower value in the wavenumber and a broadening of the 1744 cm-1 band indicating the formation of primary and secondary oxidation products in the heated oils, which were also supported by chemical studies. Most of these changes began earlier in EVOO and all occurred to a higher extent, revealing that HO has a higher thermal stability than EVOO. Principal component analysis and hierarchical cluster analysis confirmed that HO is more resistant to heat than EVOO. These results showed that HO is superior to EVOO and it could be used for frying as a healthier and cheaper oil alternative. This study also indicated that oil oxidation could be monitored easily and rapidly via ATR-FTIR spectroscopy.


Assuntos
Corylus , Nutrientes , Azeite de Oliva/análise , Óleos Vegetais , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Sci Total Environ ; 803: 150019, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34500267

RESUMO

Reducing nitrogen (N) losses from cropping systems to aquatic ecosystems is a global priority. In Australia, N losses from sugarcane production in catchments adjacent to the Great Barrier Reef (GBR) are threatening the health of this World Heritage-listed coral reef ecosystem. N losses from sugarcane can be reduced by improving fertiliser management. However, little is known about the contribution of organic sources of N, such as mill mud. We used more than 10 years of data from two of the main Australian sugarcane regions, a high (Wet Tropics) and moderate (Mackay Whitsundays) rainfall area, to calibrate and validate a model to predict dissolved inorganic nitrogen (DIN) losses in runoff from both inorganic and organic fertilisers. DIN losses in runoff were well simulated (RMSE = 0.37 and 2.0 kg N ha-1 for the Wet Tropics and Mackay Whitsunday regions, respectively). Long-term simulations of rate and fertiliser deductions to account for N from organic sources showed that adopting best management practices for organic fertiliser (applying ≤50 wet t ha-1 mill mud) can significantly reduce DIN in runoff losses compared with applications of 150 wet t ha-1. Simulations of typical farmer practices in relation to fallow management (bare fallow vs. legume fallow) and organic fertiliser placement (buried in a fallow but surface applied to a green cane trash blanket in ratoons) showed that inorganic fertiliser rates need to be adjusted to account for N inputs from both mill mud and legume crops. Rates of application of organic N had a larger impact on DIN runoff losses than placement or timing of application. This work presents a DIN in runoff modelling algorithm that can be coupled with nitrogen models readily available in agricultural models to assess the impact of nutrient management on the quality of water leaving agricultural systems.


Assuntos
Nitrogênio , Saccharum , Agricultura , Algoritmos , Austrália , Ecossistema , Monitoramento Ambiental , Nitrogênio/análise , Nutrientes , Fósforo/análise
7.
Food Chem ; 369: 130958, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34479011

RESUMO

The aim of this study was to determine the influence of the microwave heating method (MWH) on selected determinants of the nutritional value of human milk (HM) and compare to the effect exerted by the standard convection heating (CH) method, including holder pasteurization (HoP). It was showed that using MWH under conditions assumed to ensure microbiological safety, changes in the level of the nutrients were not observed. In these conditions concentration of fatty acids (FAs), lipid peroxides (LP) and α-lactalbumin (α-La) were on a similar level as in raw milk, and furosine was not formed. MWH treatment of HM led to slight increase in the malonaldehyde (MDA) and protein carbonyls (PC) content. However, MDA content in HM as a result of MWH was lower than after application CH.


Assuntos
Calefação , Leite Humano , Convecção , Humanos , Micro-Ondas , Nutrientes , Pasteurização
8.
Food Chem ; 369: 130900, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34496317

RESUMO

Thermal process is the most important way of treating foods. Heat energy inputted into the natural food system induces the depolymerization of multi-scale structures of matrix, and causes the intramolecular and intermolecular interactions of different nutrients. It attacks and breaks the original polymeric molecule structures and the functional properties of macronutrients such as carbohydrates, proteins and lipids. Micronutrients such as vitamins and other novel functional ingredients are also thermally converted. The heat-induced conversions of nutrients are slightly or totally with discrepancy in simple-, simulated- and real-food systems, respectively. Thus, this review aims to extensively summarize the heat-induced structural characteristics, thermal conversion pathways and pyrolysis mechanism of nutrients both in simple and complex food matrices. The structural change of each nutrient and its thermal reaction kinetics depend on the molecule structure and polymeric characteristic of the unit substances in the system.


Assuntos
Temperatura Alta , Nutrientes , Alimentos , Micronutrientes , Estrutura Molecular , Vitaminas
9.
Chemosphere ; 286(Pt 1): 131660, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34315078

RESUMO

Biochar mediated pollutant removal is gaining attention because of high efficiency of the process. However, effective recycling avenues of the pollutant-saturated biochars are scarce in the knowledge base; while such materials can be a new source of long-range contamination. Therefore, potential of vermitechnology for eco-friendly recycling of pollutant-loaded biochar was assessed by using arsenic-saturated native (NBC) and exfoliated (EBC) biochars as feedstocks for the first time. Interestingly, the bioavailable arsenic fractions (water soluble and exchangeable) considerably reduced by 22-44 % with concurrent increment (~8-15 %) of the recalcitrant (residual and organic bound) fractions in the biochar-based feedstocks. Consequently, ~2-3 folds removal of the total arsenic was achieved through vermicomposting. The earthworm population growth (2.5-3 folds) was also highly satisfactory in the biochar-based feedstocks. The results clearly imply that Eisenia fetida could compensate the arsenic-induced stress to microbial population and greatly augmented microbial biomass, respiration and enzyme activity by 3-12 folds. Moreover, biochar-induced alkalinity was significantly neutralized in the vermibeds, which remarkably balanced the TOC level and nutrient (N, P, and K) availability particularly in EBC + CD vermibeds. Overall, the nutrient recovery potential and arsenic removal efficiency of vermitechnology was clearly exhibited in NBC/EBC + CD (12.5:87.5) feedstocks. Hence, it is abundantly clear that vermitechnology can be a suitable option for eco-friendly recycling of pollutant-saturated sorbing agents, like biochars.


Assuntos
Arsênio , Poluentes do Solo , Carvão Vegetal , Nutrientes , Solo , Poluentes do Solo/análise
10.
Chemosphere ; 286(Pt 2): 131742, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34352544

RESUMO

Dissolved oxygen (DO) and carbon stock in substrate medium play a vital role in the nutrient removal mechanism in a constructed wetland (CW). This study compiles the results of dynamics of DO, ammonium N (NH4+-N), nitrate (NO3-N), sulfate (SO4-2), phosphate (PO4-3), chemical oxygen demand (COD), in three setups of vertical-flow constructed wetlands (TFCWs) (SB: substrate + biochar; SBP: substrate + biochar + Colocasia esculenta plantation; SP: substrate + Colocasia esculenta (SP), operated with tidal flow cycles. Experimental analyses illustrated the continuous high DO level (2.743-5.66 mg L-1) in SB and SBP after the I and II cycle of tidal flow (72 h flooding and 24 h dry phase). COD reduction efficiencies increased from 15.75 - 61.86% to 48.55-96.80% after tidal operation among operating TFCWs. N (NH4+-N) and N (NO3-N) removal were found to be 88.16%, and 76.02%; 49.32, and 57.85%; and 40.23%, and 48.94 % in SBP, SP and SB, respectively. The theory of improved nitrification and adsorption through biochar amended substratum was proposed for TFCW systems. PO4-3 and SO4-2 removal improved from 22.63 to 80.50%, and 19.69 to 75.20%, respectively after first tidal operation in all TFCWs. The microbial inhabitation on porous biochar could promote the transformation of available P into microbial biomass and also helped by the plant uptake process while SO4-2 reduction in TFCWs could be mainly due to sulfate-reducing bacterial activity and nitrate reduction process, mainly facilitated by high DO and biochar addition in such setups. The study suggests that effluent re-circulation through tidal operation and biochar supplementation in the substratum could be an effective mechanism for the improvement of the working efficiencies of CWs operated with low energy input systems.


Assuntos
Águas Residuárias , Áreas Alagadas , Carvão Vegetal , Desnitrificação , Nitrogênio/análise , Nutrientes , Eliminação de Resíduos Líquidos
11.
Chemosphere ; 286(Pt 3): 131800, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34399258

RESUMO

Chemical fertilizers are used in modern agricultural practice to increase plant output. They possess anthropogenic compounds which are hazardous, result in poor soil quality, poor crop nutrition and pollutes the water table. Currently, food crops that lack in micro-nutrients (Zn, silicates and Se) can be enriched with micronutrients by use of fertilizers. Eco-friendly bio-fertilizers have been proved to provide a known population of microorganisms that create a mutual benefit to the plants & the rhizosphere soil. Nanomaterials are often used in plant fertilizer formulation, allowing for controlled release and targeted delivery of beneficial nanoscale components, as well as to boost plant production and reduce environmental pollutants. In the present study we identified a multipotent micronutrient solubilizing bacterium (MSB) - Pseudomonas gessardi and Pseudomonas azotoformans as a bio-fertiliser. Comparative study of the formulated MSB, with nanocomposite prepared with the soya chunks as natural carrier material and chemically synthesized cerium oxide was performed on the growth of fenugreek for its effectiveness. The SEM images of nanocomposite showed the non-uniform distribution of CeO2 in bio-inoculant with an average size of 25.24 nm. The current study deals with increase in the shoot and root length of the fenugreek plant with only 75 ppm of CeO2 in nanocomposite, thereby preventing bioaccumulation of Ce in soil. This work gives a potential use of CeO2 nanocomposite with MSB bio-inoculants which could be applied to soil deficient with the micronutrients that can enhance the crop yield.


Assuntos
Fertilizantes , Nanocompostos , Produtos Agrícolas , Fertilizantes/análise , Micronutrientes , Nutrientes , Pseudomonas , Solo , Microbiologia do Solo
12.
Chemosphere ; 286(Pt 3): 131827, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34403897

RESUMO

Precision farming using nanoparticles is a cutting-edge technology for safe cultivation of crop plants in marginal areas afflicted with environmental/climatic stresses like salinity, drought, extremes of temperature, ultraviolet B stress or polluted with xenobiotics like toxic heavy metals and fluoride. Major cereal crops like rice, wheat, maize, barley, sorghum and millets which provide the staple food for the entire global population are mainly glycophytes and are extremely susceptible to abiotic stress-induced oxidative injuries. Nanofertilization/exogenous spraying of beneficial nanoparticles alleviates the oxidative damages in cereals by altering the homeostasis of phytohormones like abscisic acid, gibberellins, cytokinins, auxins, salicylic acid, jasmonic acid and melatonin and by triggering the synthesis of gasotransmitter nitric oxide. Signaling cross-talks of nanoparticles with plant growth regulators enable activation of the defence machinery, comprising of antioxidants, thiol-rich compounds and glyoxalases and restrict xenobiotic mobilization by suppressing the expression of associated transporters. Accelerated nutrient uptake and grain biofortification under the influence of nanoparticles result in optimum crop productivity under sub-optimal conditions. However, over-dosing of even beneficial nanoparticles promotes severe phytotoxicity. Hence, the concentration of nanoparticles and mode of administering need to be thoroughly standardized before large-scale field applications, to ensure sustainable cereal cultivation with minimum ecological imbalance.


Assuntos
Grão Comestível , Nanopartículas , Homeostase , Nanopartículas/toxicidade , Nutrientes , Estresse Fisiológico , Xenobióticos/toxicidade
13.
Sci Total Environ ; 803: 150070, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525689

RESUMO

To suffice the escalating global energy demand, microalgae are deemed as high potential surrogate feedstocks for liquid fuels. The major encumbrance for the commercialization of microalgae cultivation is due to the high costs of nutrients such as carbon, phosphorous, and nitrogen. Meanwhile, the organic-rich anaerobic digestate which is difficult to be purified by conventional techniques is appropriate to be used as a low-cost nutrient source for the economic viability and sustainability of microalgae production. This option is also beneficial in terms of reutilize the organic fraction of solid waste instead of discarded as zero-value waste. Anaerobic digestate is the side product of biogas production during anaerobic digestion process, where optimum nutrients are needed to satisfy the physiological needs to grow microalgae. Besides, the turbidity, competing biological contaminants, ammonia and metal toxicity of the digestate are also potentially contributing to the inhibition of microalgae growth. Thus, this review is aimed to explicate the feasibility of utilizing the anaerobic digestate to cultivate microalgae by evaluating their potential challenges and solutions. The proposed potential solutions (digestate dilution and pre-treatment, microalgae strain selection, extra organics addition, nitrification and desulfurization) corresponding to the state-of-the-art challenges are applicable as future directions of the research.


Assuntos
Microalgas , Anaerobiose , Biocombustíveis , Nutrientes , Fósforo
14.
Sci Total Environ ; 802: 149862, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34461473

RESUMO

Complete ammonia oxidizing (comammox) bacteria are frequently detected in wastewater biological nutrient removal (BNR) systems. This study identified "Candidatus Nitrospira nitrosa"-like comammox bacteria as the predominant ammonia oxidizers (97.5-99.4%) in a lab-scale BNR system with acetate and sludge fermentation liquid as external carbon sources. The total nitrogen and phosphorus removals of the system were 75.9% and 86.9% with minimal N2O emission (0.27%). Low ammonia concentration, mixotrophic growth potentials and metabolic interactions with diverse heterotrophs collectively contributed to the survival of comammox bacteria in the system. The recovered draft genomes of comammox bacteria indicated their potentials in using acetate and propionate but not butyrate. Acetate and propionate indeed stimulated the transcription of comammox amoA genes (up-regulated by 4.1 folds compared with no organic addition), which was positively correlated with the ammonia oxidation rate of the community (r = 0.75, p < 0.05). Comammox bacteria could provide vitamins/cofactors (e.g., cobalamin and biotin) to heterotrophs (e.g., Burkholderiaceae), and in return receive amino acids (e.g., phenylalanine and tyrosine) from heterotrophs, which they cannot synthesize. Compared with comammox bacteria, ammonia oxidizing bacteria (AOB) exhibited lower metabolic versatility, and lacked more pathways for the synthesis of amino acids and vitamin/cofactors, leading to their washout in the studied system. BNRs with comammox bacteria as the major nitrifiers hold great potentials in achieving superior performance at low aeration cost and low N2O emission and at full-scale plants.


Assuntos
Esgotos , Águas Residuárias , Amônia , Bactérias/genética , Carbono , Fermentação , Nitrificação , Nutrientes , Oxirredução , Filogenia
15.
Sci Total Environ ; 802: 149657, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464797

RESUMO

The decomposition of organic matter mediated by soil enzymes is the key process that transports carbon from the soil into the atmosphere. To better understand the effect of global warming on organic matter decomposition, we evaluated the temperature sensitivity (Q10) of invertase (EC3.2.1.26), ß-glucosidase (EC3.2.1.21), urease (EC3.1.1.5), acid phosphatase (EC3.1.3.2), and arylsulfatase (EC3.1.6.1) activities in red soil from the subtropical region and black soil from the mid-temperate region at 5, 15, 25, 35, and 45 °C. Further, the in-situ stoichiometry of the products released by enzymes was modelled. All of the enzyme activities in the tested soils increased with the increasing temperature (1.1-8.9 fold per 10 °C), indicating an enhanced degradation of the organic substrate with warming. In the lower temperature range (5-25 °C), Q10 of the enzyme activities in the red soil evaluated in terms of total enzyme activity index were more prominent than that in black soil (1.53 and 3.46 vs 1.16 and 3.19). Changes in the in-situ stoichiometry of enzyme products with warming indicated that, in colder months (Jan. to Apr. and Oct. to Dec.), the microbial nutrient demand in the red soil exhibited the following order, N > P > S > C. While in the black soil, it suggested that there is increasing microbial demand for only N and S. In the warmer months (May to Sep.), the microbial nutrient demands in the two soils were opposite to the colder months. The results suggested differential changes in microbial nutrient limitation with warming, which has significant implications for the carbon stocks management in farmlands under the changing global climate.


Assuntos
Microbiologia do Solo , Solo , Carbono , Fazendas , Aquecimento Global , Nutrientes
16.
J Sci Food Agric ; 102(1): 167-174, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34080199

RESUMO

BACKGROUND: Nowadays a significant amount of land contaminated with toxic elements is being used for agriculture, posing a serious risk of crop contamination and toxicity. Several methodologies are being used to remediate soil contamination, including the use of amendments such as biochar. This work evaluated the effects of biochar combined with different fertirrigations (water, a conventional fertilizer solution, or a fertilizer solution with a commercial biostimulant derived from leonardite) on the availability of toxic elements and nutrients for pepper cultivated in a soil contaminated with As, Cd, Pb, and Zn. RESULTS: Irrigation with fertilizer solutions improved plant growth regardless of the biochar amendment. Biochar decreased the bioavailability of Cu and Pb in soil and the Cu content in pepper leaves. Combined with fertilization, biochar also decreased plant As and Pb content. Biochar combined with biostimulant decreased the bioavailable content of Cd in soil and its uptake by pepper plants. CONCLUSION: The use of biochar and biostimulant presented advantages for plant production in a non-suitable scenario of nutrient scarcity and contamination. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Capsicum/metabolismo , Carvão Vegetal/química , Produção Agrícola/métodos , Fertilizantes/análise , Nutrientes/química , Poluentes do Solo/metabolismo , Adsorção , Transporte Biológico , Cádmio/química , Cádmio/metabolismo , Capsicum/química , Capsicum/crescimento & desenvolvimento , Chumbo/análise , Chumbo/química , Chumbo/metabolismo , Nutrientes/metabolismo , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Solo/química , Poluentes do Solo/química , Zinco/química , Zinco/metabolismo
17.
Sci Total Environ ; 804: 150146, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509828

RESUMO

Sewage effluent discharged from wastewater treatment plants (WWTPs) is a major driver of nitrogen (N) and phosphorus (P) enrichment, but tertiary treatment methods such as P-stripping have previously been shown to mitigate eutrophication risk. The aim of this study was to evaluate the impacts of sewage effluent discharged from WWTPs with contrasting classifications of tertiary treatment on nutrient dynamics across the River Wensum catchment, UK. River water samples were collected from 20 locations across the catchment at monthly intervals between October 2010 and September 2013, with 677 samples collected in total and analysed for a suite of hydrochemical parameters. The 20 sampling locations were divided into four classifications based on the type of upstream WWTP: (1) no WWTP; (2) WWTPs without P-stripping; (3) WWTPs with and without P-stripping; (4) WWTPs with P-stripping. Results revealed substantial overlaps in riverine nutrient composition making differentiation between classifications difficult. The majority of N (>97%) and P (~75%) was present in dissolved bioavailable forms across all sites and there was no significant difference in total N speciation between classifications. Total P (TP) speciation did, however, reveal higher proportions of particulate P at sites with no WWTP, indicating a greater P contribution of agricultural origin. Ratios of total dissolved to particulate P (TDP:TPP) and chloride concentrations proved effective discriminators of agricultural and sewage P, respectively, but phosphate­boron ratios (PO4:B) were ineffective discriminators in this catchment. Most importantly, there was no evidence that P-stripping reduced overall TP concentrations downstream of WWTPs, despite evidence of a per capita reduction, nor reduced the proportion of dissolved P released. These findings were attributed to P-stripping facilities serving larger populations and thus releasing greater effluent P load, thereby demonstrating that the presence of tertiary P-stripping alone is insufficient to overcome population pressures and ensure that rivers achieve good hydrochemical status.


Assuntos
Esgotos , Poluentes Químicos da Água , Monitoramento Ambiental , Nutrientes , Fósforo/análise , Reino Unido , Poluentes Químicos da Água/análise
18.
Sci Total Environ ; 804: 150134, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509849

RESUMO

Establishing a sustainable vegetation cover is one of the most important steps in progressive rehabilitation and final closure of ore-processing residues and tailings facilities. Sustainable rehabilitation partly depends on establishing and maintaining a supply of plant-available nutrients, but few long term field studies demonstrating the success or failure of rehabilitation of degraded land such as mineral processing tailings have been reported. Bauxite-processing residues are a highly sodic, highly alkaline, nutrient-poor by-product generated from alumina extraction, and pose many challenges for successful rehabilitation. This study investigated long term performance of rehabilitation established on bauxite-processing residue storage areas (RSAs) by comparing the nutrient content of the vegetation cover with nutrient concentrations in the underlying residue sand. Five plant species having diverse physiology were selected from rehabilitation varying in age from 1 to 10 years old; these being: Hardenbergia comptoniana - a vigorous growing legume ground cover/creeper), Acacia cochlearis and A. rostellifera - legume shrubs tolerant of sandy, alkaline conditions, Grevillea crithmifolia - a drought-tolerant proteaceous shrub tolerant of alkaline soil, and Spyridium globulosum - a robust, fast-growing shrub, commonly found on alkaline coastal soils. Gypsum incorporation reduced the pH and soluble aluminium levels in residue sand, but also acted as a long-term source of nutrients for the vegetation cover. Legume species contained more nitrogen than non-legumes (2.5% N and 1.5% N, respectively), and decomposition of surface litter increased organic carbon and total and mineral nitrogen contents of the residue sand over time. Nutrient cycling maintained a supply of macro- and micro- nutrients for the vegetation cover, and 10-year old rehabilitation exhibited characteristics similar to an analogue site. This study highlighted the importance of organic matter accumulation, developing a functional microbial community, and a diverse plant species mix on transforming the residue sand characteristics and encouraging nutrient cycling as key mechanisms for establishing a sustainable vegetation cover and functional ecosystem on residue sand embankments.


Assuntos
Óxido de Alumínio , Ecossistema , Nitrogênio/análise , Nutrientes , Solo
19.
Sci Total Environ ; 802: 149851, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464808

RESUMO

In order to meet the global demand of fertilizers for food production, there is an urgent need to recover macronutrients (such as NH4+, PO43-, Ca2+, K+, and Mg2+) from non-conventional sources (e.g., waste streams). Sludge reject water - a by-product produced during the dewatering of anaerobically-stabilized sewage sludge - is considered an ideal feedstock for bioelectrochemical nutrient recovery due to its high nutrient content. However, its low readily available organic matter and alkalinity usually limit electric current generation, resulting in low nutrient recovery. Here, we designed and operated self-powered microbial nutrient recovery cells (MNRCs) to test whether or not the addition of high-strength livestock wastewater could improve the macronutrients recovery from sludge reject water into a liquid concentrate. MNRCs fed with sludge reject water exhibited a low current density generation of 0.98 ± 0.31 A/m3 with approximately 24 ± 2% reduction in chemical oxygen demand (COD) concentration. The NH4+ removal was only 37.1 ± 11% with an up-concentration factor of ~0.43 ± 0.15. Macronutrients recovery and up-concentration were optimized by mixing sludge reject water with livestock wastewater, which its content varied from 10 to 30%. Consequently, the current output and NH4+ up-concentration factor were remarkably increased, peaking at 14.10 ± 1.14 A/m3 and 2.19 ± 0.51, respectively, for MNRCs fed with sludge reject water:livestock wastewater = 70%:30% (v:v). Detailed analysis of the liquid concentrate revealed that it could be efficiently used as a liquid fertilizer to replace chemical fertilizers with comparable agricultural productivity at a lower cost. These results suggest that the MNRC can promote self-powered, chemical-free macronutrients recovery from sludge reject water (and other low-strength wastewater, too) by controlling the availability of organic matter in waste streams.


Assuntos
Esgotos , Purificação da Água , Nutrientes , Eliminação de Resíduos Líquidos , Águas Residuárias , Água
20.
Environ Monit Assess ; 193(12): 799, 2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34773518

RESUMO

Mastering ecological dynamics necessitates identifying the substance cycles in biomass. In terms of sustainable soil productivity, the nutrient content of below-ground biomass is just as significant as the above-ground biomass, which fluctuates depending on land use. Yet, there were limited studies on determining the quantity of plant nutrient stocks, particularly in the below-ground biomass, in rangeland, forest, and plantation areas coexisting in the same ecological zone. In this regard, it is expected that the findings of this study will contribute to the literature. For this purpose in mind, distinct samples were taken from three depth levels (0-10 cm, 10-20 cm, 20-30 cm) to determine root biomass and nutrient stocks of roots in neighboring rangeland, forest, and plantation areas, and roots were divided into diameter classes, and below-ground biomass amounts and nutritional contents of below-ground biomass were determined. According to the results obtained, the total root biomass in the rangelands is 8.02 Mg ha-1, total root biomass was 5.95 Mg ha-1 in forest areas, and in plantation areas, the total root biomass is 6.94 Mg ha-1. Root biomass in the 0-10 cm soil layer constituted 78% of the total biomass. Also, for all land uses, the highest below-ground biomass concentrations were observed for Al, Fe, K, Mg, and Ca. The amounts of Al, Fe, K and Mg in the below-ground biomass followed the sequence of rangeland, plantation, and forest from high to low. Nutrient stocks in below-ground biomass and the effects of increases in root biomass on plant growth should be evaluated by future studies.


Assuntos
Monitoramento Ambiental , Florestas , Biomassa , Nutrientes , Raízes de Plantas , Solo
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