High Nutrient Concentrations Research Articles

Root-associated functional microbiome endemism facilitates heavy metal resilience and nutrient poor adaptation in native plants under serpentine driven edaphic challenges.

Serpentine soils are characterized by high concentrations of heavy metals (HMs) and limited essential nutrients with remarkable endemic plant diversity, yet the mechanisms enabling plant adaptation to thrive in such harsh environments remain largely unknown. Full-length 16S rRNA amplicon sequencing, coupled with physiological and functional assays, was used to explore root-associated bacterial community composition and their metabolic and ecological functions. The results revealed that serpentine plant species exhibited significantly higher metal transfer factor values compared to non-serpentine plant species, particularly evident in Bidens pilosa, Miscanthus floridulus, and Leucaena leucocephala. The serpentine root-associated microbes showed a higher utilization of carboxylic acid, whereas carbohydrate utilization was higher in the non-serpentine site. Zymomonas mobilis and Flavabacterium sp. exhibited high resistance to heavy metal concentrations, showing greater adaptability, while, Staphylococcus carnosus showed sensitivity to HMs, showing limited adaptability. Moreover, Ni, Cr, and Co resistance genes were found, while nitrogen and phosphorous metabolism genes were less abundant in the serpentine site compared to the non-serpentine site. Furthermore, Flavobacterium sp. had a strong positive relationship with Cd and Cu, Zymomonas mobilis with Ni, and Cr, Streptomyces sp. with Co, and Staphylococcus carnosus with N and P cycling. These findings underscore critical role of root-associated bacterial communities and distinctive soil conditions of serpentine habitats in fostering ecological adaptation of native plant species to the challenges posed by HMs and nutrient deficiencies.

Characterization of Parthenium (Parthenium hysterophorus L.) Compost for Plant Nutrient Contents at Ginir District of Bale Zone, South-Eastern Ethiopia

Parthenium (Parthenium hysterophorus L.) characterization in the southeast of Ethiopia, in the Oromia Region, the compost for Major Plant Nutrient Contents experiment was carried out in the Ginir District of the Bale Zone. As a result, the purpose of this research was to evaluate the quality and nutrient content of compost made from parthenium combined with wheat byproduct and farmyard manure. Before they began to bloom, the parthenium plants were harvested and cut into smaller pieces. As a result, parthenium compost was made using three different methods, including parthenium biomass plus farmyard manure, parthenium biomass plus crop residue, and parthenium biomass plus both farmyard manure and crop residue. Important chemical characteristics like pH, EC, OC, TN, available P, CEC, and exchangeable bases (Ca, Mg, K, and Na) and micronutrients (Fe, Mn, Cu, and Zn) were examined using standard practice laboratory techniques. The compost had high plant nutrients and significantly varied among the three Parthenium compost preparation techniques, according to the results of the final laboratory analysis of the prepared and harvested Parthenium compost. As a result, Parthenium compost provides multiple benefits, including high nutrient content, weed control, and the general environmental friendliness of using organic fertilizers.

Diatom Communities in the Littoral Sediments of the Robert Island`s Lakes, South Shetland Islands, Antarctica

The study area is situated at Robert Island, which is located in the South Shetland Islands in the northwest of the Antarctic Peninsula. The diatom samples were taken as part of the Turkish Antarctic Expedition (TAE-II) which took place between March and April 2018. The samples were collected from the surface of sediments (c. 5 cm) at a depth of approximately 20 cm, 50–100 cm from the littoral zones of an inland glacial lake (L1) and three coastal lakes (L2, L3 and L4) situated on glacier-free area on Robert Island. The main objective of this study was to reveal the diversity and the abundance of diatom communities in the littoral sediments of the lakes on Robert Island. The lakes are shallow and oligotrophic freshwater lakes, although the coastal lagoons have a high conductivity and nutrient concentration. Twenty-six diatom taxa belonging to Achnanthes (1), Fragilaria (1), Frustulia (1), Gomphonema (1), Halamphora (1), Hantzschia (1), Hippodonta (1), Humidophila (2), Luticola (3), Melosira (1), Nitzschia (4), Pinnularia (3), Planothidium (2), Psammothidium (2), Stauroneis (1) and Stephanopterobia (1) were identified in the samples from these lakes. The coastal lake L2 showed the highest richness of diatom communities among the in studied lakes, with 21 identified taxa.

The Influence of Lipase Enzyme Level and Ca(OH)2 Usage in the Production of Protected Lemuru Fish Oil Supplement on the Texture, Nutrient Content, and Fatty Acid Value of the Product

The scarcity of feed energy source to ruminant can be anticipated by adding oil to the feed. However, the effect of adding oil to the feed more than 7% will reduce the activity of fiber-degrading microbes because fat is toxic. In addition, fat in the feed will easily undergo biohydrogenation by rumen microbes so that it will reduce its function. Making fat protection feed using lemuru fish oil with a combination of lipase enzymes and Ca(OH)2 can be a solution because it aims to protect fat from biohydrogenation in the rumen. The experiment used a completely randomized design method with a 3×2 factorial pattern with factors 1) lipase enzyme (0%, 0.5%, and 1%) and factor 2) Ca(OH)2 (20% and 25%). The product results obtained showed that the product quality was in good condition with the product hardness criteria at number 4 (hard). Analysis of variance showed no significant effect on interaction,enzyme factor and Ca(OH)2 factor (P>0.05) on DM, OM, CF and acid number where the combination of L1K20 treatment (1% enzyme and 20% Ca(OH)2) produced the highest DM content of 90.25±1.12%; OM 81.98±1.35%; CF 14.62±0.53%; and the lowest acid number of 0.54±.0.06 mg KOH/g sample. The conclusion that can be given is that the use of a combination of 1% lipase enzyme and 20% Ca(OH)2 in fat protection products produces good quality products in terms of product hardness, high nutrient content and low acid number according to the standard fatty acid number below 1 mg KOH/g sample.

Characterization of biochar produced from paperboard sludge: A sustainable approach for waste management and resource recovery

The pulp and paperboard industry are a significant industrial sector that consumes large quantities of fresh water and generates substantial volumes of wastewater. Treating this wastewater produces a considerable amount of sludge, which poses serious environmental challenges. This study proposes a sustainable solution by converting paperboard sludge (PBS) into biochar through slow pyrolysis at temperatures ?00°C, offering an alternative approach to waste management and resource conservation. The physicochemical analysis of paperboard sludge biochar (PBSB) revealed a neutral pH of 7.49, electrical conductivity of 0.09 dS m-1, an organic carbon content of 38.12%, and a calcium carbonate (CaCO3) content of 24.5%. Proximate analysis of PBSB revealed an increased fixed carbon content of 10.27 %, total organic carbon (TOC) of 7.13%, and reduced volatile matter and moisture levels. Micronutrients viz., iron (Fe) (5.06 mg L-1), Manganese (Mn) (419.3 mg L-1), Copper (Cu) (26.3 mg L-1), and Zinc (Zn) (66.1 mg L-1), were also observed in PBSB. FTIR analysis identified various carbon-containing functional groups, including C-Cl, C-N, C-C, H-C=O, C-H, and -C?C-H, indicating substantial chemical transformations during pyrolysis. Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) analysis revealed that PBSB consists of fine particles with a coarse, fluffy, spongy, porous structure, making it ideal for water adsorption. Elemental analysis through x-ray diffraction (XRD) showed high carbon and oxygen content and significant amounts of aluminosilicates, carbonates, and nutrients like phosphorus and potassium, suggesting PBSB as a potential slow-release fertilizer. This research highlights the potential of biochar derived from paperboard waste as a sustainable solution for effective waste management and resource recovery.

Application of fertigation using biotreated agro-industrial wastewater (with Bacillus paramycoides MT477810) on the growth of two vegetables Capsicum annuum (var. Astra) and Lycopersicon esculentum (var. Kristina)

ABSTRACT This research explored the use of the fertigation technique with treated agro-industrial wastewater to enhance the growth of Capsicum annuum (var. Astra) and Lycopersicon esculentum (var. Kristina). The wastewater, collected from Bajwa Agro Industries in Lahore, was biotreated using the bacterial strain Bacillus paramycoides MT477810, with a 10% inoculum incubated at 37 °C for 48 h. The bacterial strain achieved an 87% decolorization of the wastewater. Physicochemical analysis before and after biotreatment showed reductions in pH (60%), EC (22%), salinity (16%), turbidity (48%), COD (40%), BOD (73%), TDS (62%), and TSS (25%). The two vegetable varieties were fertigated with both biotreated and untreated wastewater to assess their effects on seed germination and plant growth. Results indicated a significant reduction in phytotoxicity (over 50%) in plants grown with biotreated wastewater. Additionally, plants irrigated with biotreated wastewater showed a 9–30% increase in fresh and dry weights compared to those irrigated with untreated wastewater. Nutritional analysis revealed that crops irrigated with treated wastewater had 12–48% higher nutrient content. These findings emphasize the effectiveness of biological wastewater treatment and fertigation in reducing pollutants and enhancing nutrient availability for vegetable crops.

Effects of Straw Management and Nitrogen Application Rate on Soil's Physicochemical Properties and Rice Yield in Saline-Sodic Paddy Fields.

Straw return plays a vital role in crop yield and sustainable agriculture. Extensive research has focused on the potential to enhance soil fertility and crop yield through straw return. However, the potential impacts of straw return on saline-sodic soils have been relatively neglected due to the unfavorable characteristics of saline-sodic soils, such as high salinity, poor structure, and low nutrient contents, which are not conducive to crop growth. Therefore, a two-year field experiment was conducted to assess the effects of straw management (retention or removal) with nitrogen fertilizers (0, 90, 180, 270, and 360 kg N ha-1) on soil aggregates, soil chemical properties, and rice yields in saline-sodic soil. The results showed that straw return with nitrogen fertilization significantly decreased the soil exchange sodium percentage (ESP) and the percentage and organic carbon contribution of silty clay particles and also significantly increased the soil aggregate stability, organic matter (SOM), and percentage and organic carbon contribution of macroaggregates. However, there was no significant difference between 270 kg N ha-1 and 360 kg N ha-1 for all soil indicators under straw return. Straw return significantly increased rice grain yield by 5.77% (two-year average) compared to straw removal. The highest grain yield of 8.01 t ha-1 (two-year average) was obtained from straw return combined with 270 kg N ha-1. However, since this experiment was conducted for only two years, the positive effects of long-term straw return on soil and rice yield could have been greater. Therefore, the application of 270 kg N ha-1 in the early stages of straw return is a promising management practice for improving saline-sodic soils and increasing rice yields.

Weed nutrient content in commercial orange orchards in the region of Manaus, Amazonas

Weeds compete for nutrients causing productivity losses with crops, so the quantification of nutrients in these plants can indicate their nutrient absorption efficiency. In this research we aim to identify weed species representative of three commercial orange orchards (Citrus sinensis L.) in the region of Manaus (AM), and to determine their potential for nutrient absorption. A survey of the floristic composition of orchards was carried out from August to October in 2019, and the phytosociological indicators of species were identified. The main species were selected according to the Importance Value Index (IVI). Weeds and C. sinensis leaves samples were analyzed to obtain nutrient contents. Weeds showed competitive potential in commercial orange orchards, once they had a high nutrient content in their dry matter. Weeds with greater amounts of nutrients were Alternanthera Ficoidea (L.) P. Beauv. (N, K, Mg, Cu, Mn and Zn), Commelina benghalensis L. (P, S and Fe), Pseudelephantopus spiralis (Less.) Cronquist (N, P, K, Mg, Fe and Zn), Acalypha arvensis Poepp. (P and Ca), Cyperus diffusus Vahl (Fe and Mn) and Stachytarpheta cayennensis (Rich.) Vahl (Mg and Zn).

Composition and dynamics of macroinvertebrates community in relation to physicochemical parameters of hydrogeologically connected wetlands in Abbay River basin, Ethiopia.

Assessing the macroinvertebrate assemblage in relation to physicochemical parameters can provide insight into the ecological state of aquatic environments. Therefore, this study aimed to assess macroinvertebrate assemblage of hydrogeologically connected wetlands in relation to physicochemical water quality parameters. Data were collected between June 2022 and April 2023 from twelve purposively selected sampling sites following established procedures. A total of 1,211 macroinvertebrates were collected from 18 orders and 44 families. The majority (72.83%) are generally pollution-tolerant families of the order Hemiptera, Odonata, Coleoptera and Diptera. There was significant spatio-temporal variation (P < 0.05, One-way ANOVA) in total macroinvertebrate abundance and bioindices. There were more individual macroinvertebrates collected during the dry season. The CCA and correlation analysis indicated that the physicochemical parameters had an effect on the distribution and abundance of macroinvertebrates. The size of the wetlands andthe intensity of anthropogenic interventionmight also result difference in macroinvertebrate abundance across the wetlands. The higher nutrient concentrations, the low DO level, the higher abundance of tolerant taxa and the medium Shannon_Hvalue (range: 2.13 to 2.68) all indicate the wetlands' poor ecological status. Therefore, regular water quality monitoring, identification of the macroinvertebrate at the lower taxonomic level and the development of macroinvertebratebased multimetric indices are recommended for their sustainable management.

Growth, Filtration and Respiration Under Superfluous Feeding in Single-Osculum Halichondria panicea Sponges

Filter-feeding sponges capture suspended food particles from ambient water, but little is known about the response of sponges to high food concentrations causing superfluous feeding. Here, through several experimental assays, we studied the relationship between algal concentration in the water column, filtration rate, respiration rate, and specific growth rate in single-osculum Halichondria panicea demosponge explants. Laboratory experiments showed that sponge explants filter the ambient seawater at a maximum rate when exposed to naturally (low) algal concentrations, whereas high algal concentrations resulted in superfluous feeding and reduced filtration rates. Explants maintained at algal concentrations above the incipient overloading concentration level showed that growth rates were in fair agreement with the maximum possible weight-specific growth rate of about 4% d−1. Although the filtration rate became reduced due to overloading, the oxygen extraction efficiency increased, and therefore superfluous feeding did not cause reduced growth. This suggests that H. panicea and probably other sponges have adapted to low algal concentrations, displaying continuous maximum filtration rates. Osculum closure reflects a protection mechanism rather than a physiological regulatory response to high algal concentrations.

Using Aquaculture Waste Sludge and Agricultural By-products to Produce Organic Fertilizer

The study was conducted to turn aquaculture sludge and agricultural by-products into organic fertilizer as part of the circular production. The main raw materials included sludge from catfish ponds after harvest and organic materials from agricultural by-products (25% from growing cordyceps, 25% from growing oyster mushrooms, 25% from peanut shells, and 25% from coconut fiber). The aquaculture sludge (AS) and agricultural by products (ABP) are mixed at five different ratios: 10% AS + 90% ABP; 30% AS + 70% ABP; 50% AS + 50% ABP; 70% AS + 30% ABP, and 90% AS + 10% ABP. The results showed that the experiment with the ratio of 30% AS + 70% ABP optimized the decomposition of organic compounds and produced organic fertilizer with higher nutrient content than the other four mixing ratios. Comparing the quality of organic fertilizer produced with the organic fertilizer quality standards of the Ministry of Agriculture and Rural Development, 15/18 biochemical indicators have met the regulations. The results of the study can provide a guideline for the local people to optimize organic fertilizer production utilizing aquaculture sludge and agricultural byproducts, save input costs for agricultural production, and contribute to reducing waste to the natural environment.

Technical Feasibility Analysis of Processing Food Waste into Organic Fertilizer with Black Soldier Fly Composting Method

Food waste is a major issue in Indonesia, accounting for 41.97% of waste generated. This untreated waste can lead to the production of greenhouse gases. However, food waste has the potential to be composted due to its high nutrient content. The purpose of this study was to analyze the technical feasibility of processing food waste using the Black Soldier Fly (BSF) composting method for organic fertilizer production. The study used variations of fish waste and reject milk as composting mixtures, with percentages of 100% food waste, 70% food waste and 30% cow manure, and 30% food waste and 70% fish waste. The dimensions of the BSF composting reactor were 56 cm x 43 cm x 20 cm. The research was conducted for 15 days with the addition of local microorganisms (MoL) to accelerate the degradation process. Various parameters such as pH, moisture content, C-Organic, nitrogen, phosphorus, and potassium were analyzed. The results showed that all variations met the required compost quality standards, it which was technically feasible to be used as organic fertilizer using the BSF composting method. The results of this study can improve the circular economy because compost and bsf larvae products have many benefits if traded.

Study on the effects of extreme climate and human activities on the growth mechanisms of Zostera japonica in the Yellow River estuary

Zostera japonica, as one of the major seagrasses in the Yellow River Estuary, plays a critical ecological role, particularly in providing habitat for marine organisms, stabilizing sediment, and contributing significantly to carbon sequestration. In recent years, Zostera japonica seagrass beds have receded extensively due to multiple impacts of natural factors and human activities. This study investigates the complex effects of extreme climate events and human activities on the growth mechanisms of Zostera japonica in the Yellow River Estuary using a combination of field sampling, laboratory analysis, and quantitative calculations. The result shows that there are significant differences in sediment characteristics between the north and south shores, with the south shore having finer sediments and higher nutrient content, which support more robust seagrass growth. The Water and Sediment Regulation Scheme (WSRS) dramatically alters water quality by reducing salinity and increasing turbidity, thus inhibiting photosynthesis and disrupting the physiological functions of Zostera japonica. Additionally, WSRS introduces an increase in heavy metals, which could potentially impact plant health and stress levels. Extreme weather events, particularly Super Typhoon Lekima, further compound these impacts by causing soil erosion, uprooting seagrass beds, and reducing biomass and seed production. The interplay of WSRS, climate change, and anthropogenic activities necessitates integrated management strategies to mitigate adverse effects and enhance habitat resilience. This study underscores the need for specific management strategies, such as controlling heavy metal inflows, implementing sediment stabilization techniques, and regulating freshwater discharge during key growth periods, to mitigate adverse effects and enhance habitat resilience for Zostera japonica in the Yellow River Estuary.

Effect of Nitrogen and Boron Fertilization on Nutrient Content and Uptake by Mustard Crop in Chitrakoot Area

This study assessed the impact of nitrogen (N) and boron (B) fertilization on yield, nutrient composition, and nutrient uptake in Indian mustard (Brassica juncea) in Chitrakoot, Madhya Pradesh, India. A field trial featuring 13 treatments combined reduced nitrogen levels, nano-urea applications, and different boron doses, using a randomized block design with three replications. Treatment T12 [½ recommended nitrogen dose (RDN) + two nano-urea sprays + 1.25 kg B ha⁻¹] achieved the highest seed yield (1523.81 kg ha⁻¹), surpassing the control (100% NPK as per RDF) which yielded 958.73 kg ha⁻¹. T12 also had the highest nutrient concentrations 2.78% nitrogen, 0.482% phosphorus, and 0.74% potassium as well as the highest nutrient uptake, with nitrogen at 42.36 kg ha⁻¹, phosphorus at 7.34 kg ha⁻¹, and potassium at 11.28 kg ha⁻¹. These results indicate that combining nano-urea with boron, especially at elevated boron levels, can significantly improve yield and nutrient absorption in mustard, highlighting its potential for sustainable farming in semi-arid areas.

Performance evaluation of a brewery wastewater treatment plant: A case of Heineken Brewery, Addis Ababa, Ethiopia

Untreated wastewater from the brewing industry poses significant environmental risks due to its high organic content. Therefore, this study evaluates the wastewater treatment system at Heineken Brewery in Addis Ababa, Ethiopia. Key parameters analyzed include COD, BOD₅, TSS, pH, ammonia (NH₃), total nitrogen (TN), total phosphorus (TP), electrical conductivity (EC), temperature, turbidity, and volatile fatty acids (VFA). These parameters were analyzed following the procedures of the American Public Health Association's standard. The treatment system demonstrated notable efficiency, with influent temperature decreasing from 29.37 °C to 25.35 °C, remaining well below the acceptable limit of 40 °C. The pH dropped from a mean of 9.3 to 7.5, aligning with the acceptable range of 6–9. COD and BOD₅ were significantly reduced by 97.2 %, achieving levels well below discharge limits of 250 mg/L and 60 mg/L, respectively. TSS levels decreased by 95.7 %, with a mean of 32.3 mg/L. However, TP and TN removal efficiencies were lower at 49.4 % and 57.6 %, respectively, with TP slightly exceeding the limit of 5 mg/L. The system effectively reduced VFA by 94.3 % and turbidity by 71.5 %. While parameters such as pH, temperature, TN, NH₄-N, and EC were within acceptable limits, the high nutrient concentrations in the final effluent indicate potential environmental contamination if discharged untreated. Overall, while the treatment plant shows commendable pollutant removal efficiency, further optimization is needed for improved nutrient management.

The Pyrolysis of Biosolids in a Novel Closed Coupled Pyrolysis and Gasification Technology: Pilot Plant Trials, Aspen Plus Modelling, and a Techno-Economic Analysis

Pyrolysis is gaining recognition as a sustainable solution for biosolid management, though scaling it commercially presents challenges. To address this, RMIT developed a novel integrated pyrolysis and gasification technology called PYROCO™, which was successfully tested in pilot-scale trials. This study introduces PYROCO™ and its application to produce biochar, highlighting the biochar properties of the results of the initial trials. In addition, an energy analysis using semi-empirical Aspen Plus modelling, paired with a preliminary techno-economic assessment, was carried out to evaluate the feasibility of this technology. The results show that the PYROCO™ pilot plant produced biochar with a ~30 wt% yield, featuring beneficial agronomic properties such as high organic carbon (210–220 g/kg) and nutrient contents (total P: 36–42 g/kg and total N: 16–18 g/kg). The system also effectively removed contaminants such as PFASs, PAHs, pharmaceuticals, and microplastics from the biochar and scrubber water and stack gas emissions. An energy analysis and Aspen Plus modelling showed that a commercial-scale PYROCO™ plant could operate energy self-sufficiently with biosolids containing &gt;30% solids and with a minimum calorific value of 11 MJ/kg. The process generates excess energy for drying biosolids and for electricity generation. Profitability is sensitive to biochar price; prices rise from AUD 300 to AUD 1000 per tonne, the NPV improves from AUD 0.24 million to AUD 4.31 million, and the payback period shortens from 26 to 12 years. The low NPV and high payback period reflect the use of a relatively high discount rate of 8%, chosen to be on the conservative side given the novel nature of the technology.

Chitozan-zeolite Composite Fertilizer Formulations for Enhancing Nutrient Use Efficiency

The experiment was carried out in the Department of Soil Science and Agricultural Chemistry at the College of Agriculture, Vellayani, Kerala, from January to May 2024. Slow release fertilizer formulations (SRF) containing all the major (N, P,K), secondary (Ca, Mg, S) and micronutrients (Zn, B) were prepared using compatible fertilizer materials(urea, diammonium phosphate, muriate of potash, phosphogypsum, magnesium sulphate, zinc sulphate and borax), carrier materials (zeolite and chitosan) which are mixed in five ratios (1:1,1:2,1:3,2:1,3:1) and prepared by two methods namely solid impregnation and solute impregnation. Ten formulations were prepared with different combinations of fertilizer mix, carrier materials and impregnation methods. These formulations were prepared to meet the specific nutrient needs of solanaceous crops (75:40:25 N:P:K kgha-1) and the soil nutrient status. The formulations were characterized for their physical (hygroscopicity, moisture content and stability) and electro-chemical properties (pH, EC) and observed that they are non hygroscopic, non caking and are highly stable. The moisture content of formulations ranged from 2.57 % to 3.92 %, pH 6.30 to 6.81 and EC 10.06 to 16.29 dS m-1. The nutrient content in these formulations were 10.21 to 12.02 % nitrogen, 3.82 to 4.63 % phosphorus, 2.65 to 5.28 % potassium, 5.58 to 6.58 % calcium, 2.46 to 3.08% magnesium, 2.58 to 3.46% sulphur, 1.06 to 1.23% zinc and 0.15 to 0.24% boron. The highest nutrient content was obtained in formulation containing fertilizer mix + C-Z (1:1) prepared by solid impregnation method.

Effects of Fresh and Composted Azolla on Soil Chemical Properties

The rise in chemical fertilizer use in Malaysia raises concerns about soil degradation and potential long-term yield reductions, highlighting the importance of using organic matter for soil restoration. Azolla has been extensively studied as an alternative soil amendment due to its high nitrogen and nutrient content, as well as its rapid growth. However, the effects of fresh and composted Azolla amendments on soil chemical properties are not yet fully understood. A soil incubation study was thus conducted to determine the effects of fresh and composted Azolla on soil chemical properties over a 3-month incubation period. The soil treatments consisted of non-amended soil (control); fresh Azolla at 3, 6, and 9% w/w; and composted Azolla at 1, 2, and 3% w/w, with soil water holding capacity maintained at 55% throughout the incubation period. The collected soil samples were analyzed for soil pH and electrical conductivity (EC), total carbon (C) and nitrogen (N), available phosphorus, exchangeable bases—potassium (K), calcium, and magnesium, using inductively coupled plasma optical emission spectrometry, and cation exchange capacity (CEC). All data were subjected to variance analysis for statistical analysis. The study revealed significant effects of interaction between soil treatments and incubation periods for all soil parameters. At the end of the incubation period, the soil treated with 3% composted Azolla exhibited higher soil EC, total C and N, exchangeable K, and CEC compared to other soil treatments. The 3% fresh Azolla treatments were also observed to improve the soil’s exchangeable calcium by the end of the incubation period. In conclusion, 3% composted Azolla is best to help restore soil nutrient levels for crop uptake.

Investigation of particle size distribution and ultrafiltration of digestates from short-fibre residues in paper mills

ABSTRACT Industrial digestates from short-fibre residues, generated in paper recycling mills, are driving interest in resource recovery. This study aims to explore their potential for water recovery. Understanding particle dynamics aids in optimizing dewatering for digestate management. The particle size distribution in this study revealed significant fractions: &amp;lt;0.63 μm (6–20%), 0.63–20 μm (38–52%), and &amp;gt;20 μm (11–16%). Pre-treatment with Na4P2O7 and H2O2 enhances settling and lowers total dissolved solids (TDSs) but results in variation of size distribution. Additionally, this study investigates further water reuse in paper mills, focusing on the quality of ultrafiltration (UF) permeate obtained from the digestate of short fibres. UF permeate analysis reveals deviations from freshwater standards in paper mills. Despite effective TS removal, UF permeate falls short of paper mill water standards due to high TDSs, electrical conductivity, and nutrient concentrations, necessitating further downstream treatment with nanofiltration or reverse osmosis. A substantial reduction of permeate flux from 31 to 5 L/(m2·h) over the time indicated fouling and inefficient membrane wash. The silt density index of the UF membrane at 30 min registered 2.1, suggesting potential fouling. Further investigations on optimizing UF operations to enhance permeate flux and exploring alternative UF membranes are required.

Evaluation of Cadmium, Lead, Chromium, and Nickel Content in Various Types of Nuts: Almonds, Cashews, Hazelnuts, Peanuts, and Walnuts - Health Risk of Polish Consumers.

World production and consumption of nuts continue to rise year on year. Nuts, due to their high nutrient content, are becoming increasingly popular among consumers. A potential health risk may result from the consumption of nuts contaminated with metallic trace elements like cadmium or lead. In this research, we measured the content of Cd, Pb, Cr, and Ni in various edible nuts. All elements were detected using the electrothermal atomic absorption spectrometry analytical technique (ETAAS). The study material comprised 69 nut samples including almonds, cashews, hazelnuts, peanuts, and walnuts available on the Polish market. Indicators such as the hazard quotient (HQ) and hazard index (HI) were used to assess the health risk of consumers. The concentrations of elements in all analyzed samples of nuts were as follows: Cd: peanuts > almonds > hazelnuts > walnuts > cashews, Pb: peanuts > almonds > hazelnuts > walnuts > cashews, Ni: cashews > peanuts > walnuts > hazelnuts > almonds, Cr: almonds > cashews & hazelnuts > peanuts > walnuts. Health risk indicators estimated for consumers whose diet is rich in nuts, in which metallic trace elements were recorded, indicate that an unacceptable impact may occur, and the risk of negative health effects (non-cancer) will be moderate to high.