Floc management enables integrated anammox and enhanced biological phosphorus removal for sustainable ultra-efficient nutrient removal
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Pilot-scale partial nitrification and anaerobic ammonium oxidation system for nitrogen removal from municipal wastewater
Partial nitrification has the advantages of saving energy and reducing the need for carbon sources in municipal wastewater treatment. However, for municipal wastewater with low ammonia, start-up and maintenance of partial nitrification is a worldwide challenge. Here we developed a pilot-scale double sludge system consisting of two sequencing batch reactors for partial nitrification (12 m2) and denitrification/anaerobic ammonium oxidation (denitrification/anammox, 8.4 m2) to treat municipal wastewater. Partial nitrification was maintained at no ammonium remaining with a nitrite accumulation rate of 87.7%. This study found that partial nitrification system effluent chemical oxygen demand increased from 24.8 mg L−1 to 64.9 mg L−1 accompanied by transformation from complete nitrification to partial nitrification. In the denitrification/anammox system, the reduction of nitrite to nitrogen required about 40% less carbon consumption than nitrate. High nitrogen removal was achieved with effluent total inorganic nitrogen of 2.7 mg L−1 without carbon addition. This work provided a pilot-scale demonstration of low-carbon high-nitrogen removal.
Fibrous super-bridging agents simultaneously improve contaminants removal and sludge dewatering via a very compact three-in-one process
A compact three-in-one water treatment process, combining a flocculant, a fibrous super-bridging agent, and a screen-based floc retention system, simultaneously improves water treatment and sludge dewatering. The presence of fibrous materials allows for the formation of very large flocs, efficient floc separation via screening (without settling), and sludge dewatering through a compact press-filter system. The implementation of this three-in-one process is possible due to the formation of very large fiber-based flocs. The sludge containing fibers was subsequently dewatered using a screen-based press filter without further chemical addition. The use of fibers also significantly improved the removal of total organic carbon, nanoplastics, and microplastics. This three-in-one process could be used for decentralized water treatment in drinking water and wastewater applications in small cities, marginalized communities, and developing countries. The compact process, which also performs sludge dewatering, would reduce the risks associated with mismanaged sludge to the environment and human health.
Sustainable supply chain management practices and performance: The moderating effect of stakeholder pressure
Currently, sustainable supply chain management practices have become an important strategy for firms to improve performance and gain competitive advantage. However, there is a current debate over the performance outcomes of sustainable supply chain management practices. Additionally, the role of stakeholder pressure is frequently overlooked. Drawing on Natural Resources-Based View and Stakeholder Theory, this study aims to elucidate the ambiguous connection between sustainable supply management, sustainable process management, stakeholder pressure and performance, and investigate the mediation role of sustainable process management and the moderation effect of stakeholder pressure. Our analysis, based on data collected from 235 Chinese manufacturing firms, reveals significant insights. First, stakeholder pressure positively moderates the relationship between sustainable process management and performance, while negatively moderates the relationship between sustainable supply management and performance. Second, sustainable process management has a complete mediation effect on the relationship between sustainable supply management and performance. The conclusion not only explains the inconsistent relationship between sustainable supply chain management practice and performance, but also reveals clearly the relationship between sustainable supply management and sustainable process management. Besides, it also highlights the difference in performance outcomes of sustainable supply management and sustainable process management under stakeholder pressures, and has valuable guidance to the practice of sustainable supply chain management in Chinese manufacturing firms.
Separate orexigenic hippocampal ensembles shape dietary choice by enhancing contextual memory and motivation
The hippocampus (HPC) has emerged as a critical player in the control of food intake, beyond its well-known role in memory. While previous studies have primarily associated the HPC with food intake inhibition, recent research suggests a role in appetitive processes. Here we identified spatially distinct neuronal populations within the dorsal HPC (dHPC) that respond to either fats or sugars, potent natural reinforcers that contribute to obesity development. Using activity-dependent genetic capture of nutrient-responsive dHPC neurons, we demonstrate a causal role of both populations in promoting nutrient-specific intake through different mechanisms. Sugar-responsive neurons encoded spatial memory for sugar location, whereas fat-responsive neurons selectively enhanced the preference and motivation for fat intake. Importantly, stimulation of either nutrient-responsive dHPC neurons increased food intake, while ablation differentially impacted obesogenic diet consumption and prevented diet-induced weight gain. Collectively, these findings uncover previously unknown orexigenic circuits underlying macronutrient-specific consumption and provide a foundation for developing potential obesity treatments.
Microbial controls over soil priming effects under chronic nitrogen and phosphorus additions in subtropical forests
The soil priming effect (PE), defined as the modification of soil organic matter decomposition by labile carbon (C) inputs, is known to influence C storage in terrestrial ecosystems. However, how chronic nutrient addition, particularly in leguminous and non-leguminous forests, will affect PE through interaction with nutrient (e.g., nitrogen and phosphorus) availability is still unclear. Therefore, we collected soils from leguminous and non-leguminous subtropical plantations across a suite of historical nutrient addition regimes. We added 13C-labeled glucose to investigate how background soil nutrient conditions and microbial communities affect priming and its potential microbial mechanisms. Glucose addition increased soil organic matter decomposition and prompted positive priming in all soils, regardless of dominant overstory tree species or fertilizer treatment. In non-leguminous soil, only combined nitrogen and phosphorus addition led to a higher positive priming than the control. Conversely, soils beneath N-fixing leguminous plants responded positively to P addition alone, as well as to joint NP addition compared to control. Using DNA stable-isotope probing, high-throughput quantitative PCR, enzyme assays and microbial C substrate utilization, we found that positive PE was associated with increased microbial C utilization, accompanied by an increase in microbial community activity, nutrient-related gene abundance, and enzyme activities. Our findings suggest that the balance between soil available N and P effects on the PE, was dependent on rhizosphere microbial community composition. Furthermore, these findings highlight the roles of the interaction between plants and their symbiotic microbial communities in affecting soil priming and improve our understanding of the potential microbial pathways underlying soil PEs.
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