Search Results (3,593)

Decentralized biomethane is vital for the energy transition; however, small-scale plants face significant energy penalties. This study evaluates the mass and energy balance of a TRL 6 pilot biorefinery treating pig manure, integrating anaerobic digestion with a microalgae-based photobioreactor coupled to an absorption column for biogas upgrading (>93 vol% CH₄, dry basis). A Life Cycle Inventory (LCI) was used to compared a theoretical mesophilic design (Scenario I, 35 °C) against an experimental psychrophilic baseline (Scenario II, avg. 12 °C). The results indicate that while winter mesophilic heating consumes 58% of gross energy production, the passive psychrophilic strategy eliminates this demand, ensuring a positive Net Energy Balance year-round. Both scenarios achieved competitive Specific Energy Consumption (SEC) (1.20 vs. 4.17 kWh·m⁻³ CH₄), while upgrading reached peak efficiency at a 10 min Hydraulic Residence Time. Furthermore, solar-synchronized load-shifting allowed for 100% electrical self-sufficiency. We conclude that although passive operation offers a superior Energy Return on Investment during cold periods (average EROI of 2.35 vs. 1.44 under winter mesophilic conditions), active mesophilic heating yields a 3-fold revenue increase, making it the superior economic choice despite the thermal penalty. Full article

Bioconversion of lignocellulosic biomass into edible, nutrient-rich products using low-cost forestry waste offers substantial ecological and economic benefits. Composting forestry waste as a substrate for oyster mushroom (Pleurotus ostreatus) cultivation is an effective recovery strategy. However, the specific microbial-driven mechanisms by which nitrogen sources regulate lignocellulose degradation and compost quality during forestry waste composting for Pleurotus ostreatus substrate preparation remain to be elucidated. We evaluated three organic nitrogen sources (bran, soybean meal, and chicken manure) and one inorganic source (diammonium phosphate, DAP) during composting of forest-waste-based substrates. Composting performance and cultivation outcomes were assessed using physicochemical analyses, lignocellulose degradation measurements, high-throughput sequencing of bacterial 16S rRNA and fungal ITS, and biological efficiency. Organic nitrogen sources enhanced compost temperature and lignocellulose degradation by providing sustained nitrogen release, promoting stable colonization of core microbial communities and cooperative bacteria–fungi networks. In contrast, inorganic nitrogen resulted in slower heating, minimal lignocellulose degradation (0.75%), and unstable, competition-dominated microbial networks. Nitrogen sources indirectly shaped microbial communities by regulating the C/N ratio, pH, and electrical conductivity. Lignocellulose degradation and bacterial diversity significantly influenced mushroom biological efficiency, with bacterial diversity strongly regulating degradation rates. The forest waste–bran treatment achieved the highest biological efficiency (78.35%). These findings offer a practical strategy for optimizing forestry waste bioconversion into fungal protein. Full article

The accelerating frequency of emerging infectious diseases (EIDs) in livestock poses a significant threat to global food security, as well as to animal and public health. While wastewater-based surveillance (WBS) has advanced significantly for human health surveillance, its application to livestock production systems remains fragmented and lacks standardization. This review synthesizes current evidence on livestock wastewater-based surveillance (L-WBS) as an early-warning sentinel for emerging viral pathogens, evaluating their dynamics, economic impacts, biosecurity measures, and One Health implications. Existing studies demonstrate that L-WBS effectively detects emerging viral pathogens in agricultural effluent, swine manure, and municipal wastewater systems serving livestock regions, frequently preceding clinical outbreak recognition. We further conceptualized a multifactorial framework linking environmental drivers such as climate and ecological disruption and agricultural intensification to pathogen emergence dynamics. Economic assessments show substantial direct losses (approximately US$ 950 per H5N1-infected dairy cow and US$ 25.9 billion in African swine fever virus (ASFV)-related damages across China) alongside indirect costs from biosecurity implementation, workforce disruption, and supply-chain instability. We recommend prioritizing methodological standardization through unified sampling and extraction protocols, integration of next-generation sequencing for genomic surveillance, and cross-sectoral policy frameworks to operationalize L-WBS as a global early-warning infrastructure for mitigating zoonotic spillover and livestock-dependent community resilience. Full article

Phosphorus is a non-renewable resource critical for global food security, yet its natural reserves are rapidly depleting. Meanwhile, the poultry industry generates vast amounts of nutrient-rich waste that pose serious environmental risks if not managed properly. While valorizing these wastes offers a sustainable raw material alternative, investigating the environmental impacts of recovering them as a phosphorus source is crucial. This study evaluates phosphorus recovery from poultry litter via acid leaching following Hydrothermal Carbonization (HTC) and pyrolysis processes holistically. By conducting a Life Cycle Assessment (LCA) using this specific substrate and method combination, this work aims to provide comprehensive environmental insights. The impact assessment reveals that the total Global Warming Potential (GWP) is 6.00 kg CO₂ eq for the pyrolysis scenario and 4.18 kg CO₂ eq for the HTC scenario. Methodologically, a ‘system expansion’ approach was applied to integrate the avoided burdens from poultry manure management into the system boundaries. Furthermore, the inventory analysis revealed that chemical consumption (specifically NaOH and H₂SO₄) in the production process is the dominant factor not only for Global Warming Potential (GWP) but also across other environmental impact categories evaluated. The findings clearly indicate that chemical intensity predominantly determines the environmental performance across carbon footprint, acidification and other environmental impact categories. Full article

Low-concentration methane emissions from landfills, manure management, wastewater treatment, and ventilation streams are difficult to mitigate using conventional capture and oxidation because of high air-to-fuel ratios, variable flows, and unfavorable economics. Methanotrophic bioreactors provide an aerobic biological route to oxidize methane at ambient conditions and, in selected cases, enable valorization into biomass and bioproducts. This review synthesizes methanotrophic reactor technologies for dilute methane, emphasizing the design and operational constraints that control performance. We classify systems into (i) fixed-film gas–solid configurations (biofilters, biocovers, biotrickling filters, and bioscrubbers), (ii) suspended-growth gas–liquid reactors (stirred tanks, bubble columns, and loop/airlift designs), (iii) membrane-based and intensified contactors that decouple methane and oxygen delivery and enhance mass transfer, and (iv) hybrid and in situ approaches for diffuse sources. This review presents key metrics and discusses how mass transfer, moisture and temperature control, nutrient supply, and microbial ecology interact to define achievable removal. We further summarize recent techno-economic and life-cycle studies to identify dominant cost drivers, particularly air handling and gas–liquid transfer, and the concentration regimes where biological oxidation is competitive with catalytic or thermal alternatives. Full article

This study targets key challenges in ameliorating the plow-layer soil of coastal saline soils. A field experiment under a wheat–maize rotation was established with six treatments: CK, control with no organic inputs; A1, 45 t ha⁻¹ organic manure; A2, 45 t ha⁻¹ organic manure + microbial inoculant; A3, 45 t ha⁻¹ organic manure + microbial inoculant + plastic-film mulching; A4, 90 t ha⁻¹ organic manure; and A5, 135 t ha⁻¹ organic manure. By applying high rates of organic manure alone or in combination with microbial inoculation and mulching, we aimed to strengthen soil water–salt regulation, improve plow-layer soil quality, and ultimately promote crop growth and yield formation. We further quantified treatment-induced shifts in soil physicochemical properties and linked them to crop growth and yield responses. The results indicated that, compared with CK, plow-layer soil organic carbon increased by 45.56% and 107.91% under A3 and A4, respectively, while soil salinity decreased by 70.57% and 67.42%. All manure-based treatments increased yield relative to CK, with the highest yields achieved under A3 and A4: wheat yield reached 7628.16 and 7888.01 kg ha⁻¹, and maize yield reached 8828.29 and 8716.01 kg ha⁻¹, respectively. Overall, high-rate organic manure—especially when integrated with microbial inoculation and plastic mulching—substantially enhanced soil fertility while alleviating salinity stress, resulting in an integrated “fertility build-up–salinity reduction–yield enhancement” amelioration effect. This technology package offers a feasible pathway for improving coastal saline farmland and stabilizing productivity under rotation systems, with strong potential for further on-farm demonstration and wider adoption. Full article

The transition towards a circular bioeconomy in developing regions is frequently hindered by operational failures caused by feedstock discontinuity. Whilst biochemical potential is traditionally the primary selection criterion, this study postulates that logistic reliability serves as the governing constraint. To validate this strategic reorientation, a decision-making framework was developed and applied to a representative tropical agro-industrial region. A sensitivity analysis comparing objective, subjective and neutral weighting scenarios identified annual residue production as the dominant factor. Results established cattle manure as the universal baseload substrate essential for mitigating seasonality, outweighing higher-yielding but intermittent agricultural residues. Spatial analysis revealed distinct territorial vocations, identifying a high-availability rice–livestock cluster in the south suitable for centralised industrial plants and dispersed cassava–livestock nodes in the centre favourable for decentralised digestion. Furthermore, the assessment of energy autonomy demonstrated that the prioritised co-digestion scenarios could cover local residential electricity demand between 1.5 times and 81 times. Crucially, residues favoured by expert judgement proved logistically unfeasible despite superior theoretical yields. This data-driven approach demonstrates that successful substrate selection must transcend theoretical yield maximisation to prioritise supply chain reliability, providing a robust roadmap for de-risking bioenergy investments and ensuring regional energy autonomy. Full article

The application of leguminous green manure (GM) can enhance the soil inorganic phosphorus (Pi) pool, offering considerable benefits for crop cultivation in slightly and moderately saline-alkali soils. To optimize its agronomic potential, systematic and science-based fertilization strategies are required. In this study, we researched the changes in the content, movement distance, and accumulation of Pi fractions at the GM microsites in coastal saline-alkali soils of differing salinity levels (slightly vs. moderately) following the application of Sesbania GM at two rates (30 and 60 t ha⁻¹) over 14- and 28-day incubation periods. The results indicated that GM application significantly (p < 0.05) increased the accumulation of all Pi fractions—including aluminum-bound phosphorus (Al-P), iron-bound phosphorus (Fe-P), occluded phosphorus (O-P), and forms of calcium-bound Pi (Ca-P: Ca₂-P, Ca₈-P, and Ca₁₀-P)—at the manure microsite, with the magnitude of increase declining with distance from the manure site. Further analysis revealed positive correlations between GM rate, two incubation periods and Pi-fraction movement distance, indicating that the observed effects were significantly influenced by incubation period, GM rate, and soil salinity-alkalinity. While temporal dynamics governed the rates of Pi movement and transformation, elevated salinity-alkalinity partially inhibited these processes. This study provides practical insights for improving GM utilization efficiency on saline-alkali soils. These results support optimized GM application to enhance P efficiency and reduce fertilizer reliance in saline systems. Full article

This study evaluated the effects of fly ash (F) and effective microorganisms (EM) on nutrient dynamics and heavy metal transformations during vermicomposting of camel manure (CM). Four treatments (CM, CM + F, CM + EM, and CM + F + EM) were arranged in a completely randomized design and monitored over 12 weeks. Significant (p < 0.05) treatment and time interactions were observed for pH, NH₄-N, Mn, Pb, and Mo. The addition of EM resulted in a greater decline in pH compared to other treatments. After 12 weeks, Olsen P increased from 300.62 to 398.71 mg/kg in CM + EM, while NH₄-N increased markedly from 22.74 to 86.62 mg/kg. In contrast, NO₃/NO₂-N declined in EM-amended treatments but increased in the control and CM + F. Trace metal concentrations generally increased due to mass reduction during vermicomposting yet remained within internationally acceptable limits. Germination index (GI) values varied significantly among crops and treatments, ranging from phytotoxic to non-phytotoxic responses. Although CM + EM produced superior nutrient enrichment, several vegetables exhibited GI values below 50%, indicating potential phytotoxicity for sensitive crops. In case of established crops for which nutrient supply outweighs early phytotoxic concerns, CM + EM represents the most agronomically beneficial option. Future studies should explore blending CM + EM and CM + F with stabilizing amendments such as biochar to optimize nutrient availability while minimizing salinity and phytotoxic risks. Full article

Increasing global demand for animal-based protein has created a critical environmental management challenge regarding manure accumulation in intensive livestock production. Gasification offers a sustainable solution by converting organic residues into renewable synthetic gas (syngas) and carbon-rich biochar. This study systematically evaluated the performance of three major types of animal waste—dairy manure, poultry litter, and swine manure—against a lignocellulosic control (wood veneer waste) in a top-lit updraft (TLUD) gasifier. Three airflow rates (10, 15, and 20 L min⁻¹) were studied. The results indicated that increasing airflow significantly elevated the gasifier flame front temperatures, with poultry litter achieving the highest peak temperature (825.5 °C), followed by swine manure and dairy manure (753.7 and 727.0 °C, respectively) at 20 L min⁻¹ airflow. While dairy manure exhibited the fastest linear burning rate (25.7 mm/min), poultry litter demonstrated the highest mass consumption rate (32.8 g/min). Feedstock chemistry drove distinct reaction pathways in syngas composition. Poultry litter emerged as the superior feedstock for H₂ production, achieving a peak H₂ concentration of 10.78% at 20 L min⁻¹, which attributed to a synergistic combination of outstanding temperature, moisture content and catalytic alkali metals that promoted steam reforming and water–gas shift reactions. CO production was dominated by wood veneer (17.6%), which was driven by the dominance of elemental carbon and fixed solid (FS) content that favored partial oxidation and a Boudouard reaction. These findings suggest that while airflow regulates thermal kinetics, the specific energy profile of the produced syngas is fundamentally determined by the physiochemical properties of the biomass precursor. Full article

Aerobic composting shows state-dependent dynamics in key parameters such as temperature, moisture content, oxygen concentration, and pH, and these variables are strongly coupled over time. This coupling makes accurate state identification and process regulation challenging when relying on single-parameter thresholds or experience-based control. To enable robust recognition of composting states throughout the process, we propose an IRRTO-optimized CNN–LSTM–attention model (IRRTO–CNN–LSTM–attention). The model uses a convolutional neural network (CNN) to extract discriminative multivariate features, a long short-term memory (LSTM) network to model temporal dependencies, and an attention module to adaptively emphasize informative features. To address the hyperparameter selection challenge, the Rapidly-exploring Random Tree Optimizer (RRTO) was introduced and further enhanced via four strategies (fluctuating attenuation adaptive regulation, dual-mode guided update, dynamic dimension adaptive perturbation, and dual-mechanism adaptive perturbation regulation), forming the improved IRRTO. The proposed approach was validated using sensor data from windrow composting of pig manure and corn straw. The IRRTO–CNN–LSTM–attention model achieved an overall accuracy of 98.31% in classifying the four states (mesophilic/heating, thermophilic, cooling, and abnormal) on the independent test set, which was 3.39 percentage points higher than the RRTO-based model. These results suggest that the proposed method can accurately identify composting states and support early warning and state-specific regulation in practical aerobic composting systems. Full article

The growing demand for sustainable soil management strategies has intensified interest in hydrochar (HC), a waste-derived amendment produced via hydrothermal carbonization (HTC). This review synthesizes recent advances in HC production, characterization, and agri-environmental applications within a waste-to-resource framework. It covers studies conducted mainly over the last decade, encompassing a wide range of feedstocks, including agricultural residues, sewage sludge, animal manures, and food waste. HTC is typically performed at 130–280 °C under autogenous pressure (2–15 MPa), generating HCs with low intrinsic surface area (<50 m²g⁻¹) and oxygen-containing functional groups that govern nutrient dynamics and soil interactions. Reported application rates vary broadly between 10 and 60 t ha⁻¹, with most experiments conducted under greenhouse conditions. Positive effects on soil pH, cation exchange capacity, water retention, and phosphorus availability are frequently observed. However, plant responses vary according to the type of stimulation promoted by HC, as well as its processing conditions, application rates, and the soil characteristics in which it is applied. Advanced molecular-level analyses (e.g., FT-ICR-MS, GC-MS, and ¹³C-NMR) have provided mechanistic insights into carbon stability, nutrient release, and interaction with soil organic matter. Reusing HTC process water offers an additional pathway for nutrient recovery, although concerns about phytotoxic compounds remain. Despite promising short-term results, long-term field evaluations and standardized assessment protocols are still limited. This review integrates structural, functional and agri-environmental perspectives to identify critical knowledge gaps and guide the optimized and context specific use of hydrochar in sustainable agricultural systems. At the same time, it emphasizes its role in advancing carbon sequestration and in operationalizing resource-circular strategies, thereby underscoring its broader practical and strategic relevance. Full article

Cattle manure composting is an effective strategy for recycling agricultural waste. However, the presence of lignocellulosic materials in cattle manure–maize straw mixtures can limit the degradation efficiency during composting. This study investigated the effects of microbial inoculation on composting performance using three treatments: a lignocellulose-degrading microbial consortium (MC1), a commercial microbial inoculant (BS1), and a non-inoculated control (CK). The results showed that the MC1-treated pile entered the thermophilic phase (>50 °C) earlier than the BS1-treated pile. After 49 days of composting, the lignocellulose degradation rates in the MC1, BS1, and CK treatments were 46.25%, 37.5%, and 29.8%, respectively. Based on compost maturity indicators, including temperature, C/N ratio, pH, and electrical conductivity (EC), the composting period required to reach maturity was shortened by 8 days in the MC1 treatment compared with the BS1 treatment (37 vs. 45 days). Microbial community analysis indicated that MC1 inoculation increased the relative abundance of key microbial groups, particularly Ascomycota and Firmicutes, thereby enhancing lignocellulose degradation and accelerating composting. These findings provide insights into the application of lignocellulose-degrading microbial inoculants for improving cattle manure composting efficiency. Full article

Biochar and plant growth-promoting rhizobacteria (PGPR) are promising for coastal saline–alkali soil remediation, but their combined effect is often limited by nutrient scarcity. This study investigated whether nutrient-laden biochar (saturated with livestock wastewater) synergizes with a PGPR inoculant (Paenibacillus mucilaginosus PM12) to enhance maize productivity by reshaping the rhizosphere microbiome. A field experiment included five treatments: control (CK), sheep manure biochar alone (BC), nutrient-laden biochar (NBC), BC + PGPR (MBC), and NBC + PGPR (MNBC). The MNBC treatment showed the most pronounced improvements, increasing maize yield by 52.5% compared to CK, while reducing soil pH by 0.30 units and enhancing soil organic matter, total nitrogen, and available phosphorus. Metagenomic analysis revealed that MNBC uniquely enriched beneficial genera (e.g., Nocardioides) and saprotrophic Basidiomycota, while suppressing pathogenic Fusarium. This restructuring elevated the genetic potential for nitrogen transformation, phosphorus solubilization, and carbon metabolism. Structural equation modeling identified increased soil available phosphorus and total nitrogen as the primary direct drivers of yield enhancement. The integration of nutrient-laden biochar and PGPR creates a synergistic system that reclaims saline–alkali soil by alleviating stress, supplying nutrients, and directing the assembly of a functional microbiome. Full article

Long-term excessive chemical fertilization threatens the sustainability of wheat–maize rotation systems in the North China Plain. Organic substitution is a promising alternative to sustain crop productivity and soil health, yet its underlying mechanisms require clarification. This study investigated the effects of six fertilization treatments (unfertilized [CK], chemical nitrogen [N] alone at 180 kg N ha⁻¹ season⁻¹ [NPK], chemical N 25% substituted by chicken manure per season [NPKM], full manure substitution per season [CM], chemical N 25% substituted by straw return under no tillage per season [NT] and chemical N 25% substituted by straw return under rotary tillage per season [ST]) on soil fertility and crop productivity in a long-term wheat–maize rotation field experiment initiated in 2007. All treatments followed a randomized complete block design with three replicates per treatment. Wheat and maize plants were randomly collected from each plot at the harvest stage of each season, and weighed and measured for yield and N uptake, while soil samples were randomly collected from each plot at maize harvest stage for chemical and enzyme activity analyses. Compared to NPK, organic substitution maintained grain yields while significantly enhancing key soil fertility indicators: soil organic carbon (C) (up to 53.8%), and labile C and N pools including readily oxidizable C (by 120.0%), ammonium N (by 23%) and microbial biomass C (up to 164.5%). It also strongly stimulated the activities of C-acquiring (e.g., β-glucosidase and cellobiohydrolase) and N-cycling (e.g., β-N-acetylglucosaminidase and urease) enzymes by up to 278.7% and 256.3%, respectively. Multivariate analyses identified these enzymes as primary drivers of soil C and N dynamics, with direct positive links to crop yield. In conclusion, long-term organic substitution, particularly full manure substitution, improved yield stability and soil fertility predominantly through an enzymatic-driven stimulation of nutrient cycling and organic matter accumulation, offering a viable strategy to reduce chemical fertilizer inputs and enhance crop production sustainability. Full article