Exploration of Converting Food Waste into Value-Added Products via Insect Pretreatment-Assisted Hydrothermal Catalysis.

The environmental burden of food waste (FW) disposal coupled with natural resource scarcity has aroused interest in FW valorization; however, transforming FW into valuable products remains a challenge because of its heterogeneous nature. In this study, a two-stage method involving black soldier fly (BSF)-based insect pretreatment and subsequent hydrothermal catalysis over a single-atom cerium-incorporated hydroxyapatite (Ce-HAP) was explored to convert FW into high added-value furfurals (furfural and 5-hydroxymethylfurfural). FW consisting of cereal, vegetables, meat, eggs, oil, and salt was initially degraded by BSF larvae to generate homogeneous BSF biomass, and then, crucial parameters impacting the conversion of BSF biomass into furfurals were investigated. Under the optimized conditions, 9.3 wt % yield of furfurals was attained, and repeated trials confirmed the recyclability of Ce-HAP. It was proved that the revenue of furfural production from FW by this two-stage method ranged from 3.14 to 584.4 USD/tonne. This study provides a potential technical orientation for FW resource utilization.

Morphology-Tailored Hydroxyapatite Nanocarrier for Rhizosphere-Targeted Phosphorus Delivery.

High hydrophilicity and soil fixation collectively hamper the delivery of phosphorus (P) released from conventional chemical phosphorus fertilizers (CPFs) to plant rhizosphere for efficient uptake. Here, a phosphorus nutrient nanocarrier (PNC) based on morphology-tailored nanohydroxyapatite (HAP) is constructed. By virtue of kinetic control of building blocks with designed calcium phosphate intermediates, rod-like and hexagonal prism-like PNCs are synthesized, both having satisfactory hydrophobicity (water contact angle of 105.4- 132.9°) and zeta potential (-17.43 to -58.4 mV at pH range from 3 to 13). Greenhouse experiments demonstrate that the P contents increase by up to 183% in maize rhizosphere and up to 16% in maize biomass when compared to the CPF. Due to the water potential gradient driven by photosynthesis and transpiration, both PNCs are stably transported to maize rhizosphere, and they are capable to counteract soil fixation prior to uptake by plant roots. Within the synergies of the HAP morphological characteristics and triggered phosphate starvation response, root anatomy confirms that two pathways are elucidated to enhance plant P replenishment from the PNCs. Together with structure tunability and facile synthesis, our results offer a new nanodelivery prototype to accommodate plant physiological traits by tailoring the morphology of HAP.

Molecular dynamics simulation study of covalently bound hybrid coagulants (CBHyC): Molecular structure and coagulation mechanisms.

Covalently-bound organic silicate-aluminum hybrid coagulants (CBHyC) have been shown to efficiently remove low molecular weight organic contaminants from wastewater. However, the interaction dynamics and motivations during the coagulation of contaminant molecules by CBHyC are limited. In this study, a molecular dynamics (MD) simulation showed that CBHyC forms core-shell structure with the aliphatic carbon chains gather inside as a core and the hydrophilic quaternary ammonium-Si-Al complexes disperse outside as a shell. This wrapped structure allowed the coagulant to diffuse into solutions easily and capture target contaminants. The adsorption of anionic organic contaminants (e.g., diclofenac) onto the CBHyC aggregates was driven equally by van der Waals forces and electrostatic interactions. Cationic organic contaminants (e.g., tetracycline) were seldom bound to CBHyC because of substantial repulsive forces between cationic molecules and CBHyC. Neutrally-charged organic molecules were generally bound through hydrophobic interactions. For adenine and thymine deoxynucleotide, representatives of antibiotic resistance genes, van der Waals forces and electrostatic interaction became the dominant driving force with further movement for adenine and thymine, respectively. Driving forces between target contaminant and coagulant directly affect the size and stability of formed aggregate, following the coagulation efficiency of wastewater treatment. The findings of this study enrich the database of aggregation behavior between low molecular weight contaminants and CBHyC and contribute to further and efficient application of CBHyC in wastewater treatment.

Transcriptomic analysis reveals the significant effects of fertilization on the biosynthesis of sesquiterpenes in Phoebe bournei.

Phoebe bournei is a potential medicinal plant. Its essential oils (Eos) are mainly composed of sesquiterpenes that has potential activities of anti-bacteria and anti-tumors. In this study, we evaluated the effects of compost and compound fertilizer on the total amount and main components of Eos in P. bournei, we also studied the molecular mechanism undergoing this process by deep sequencing the genes involved in the biosynthesis of sesquiterpenes. Fertilization enhanced the total amount of main components in Eos from both leaves and twigs. Bicyclogermacrene, the primary sesquiterpene in the leaf EO, was significantly increased under compost treatment, while bicyclogermacrene and δ-cadinene (the second most abundant sesquiterpene) were decreased under compound fertilizer treatment. The two fertilizers had no significant effect on the abundance of the primary (+) - δ-cadinene in the twig EO, but had a positive effect on the second most abundant sesquiterpene copaene. Significant differences were observed in the number of differentially expressed genes (DEGs) with the leaves showing greater number of DEGs as compared to the twigs after compost treatment. Terpenoid backbone biosynthesis (TBB) is a key pathway of sesquiterpenes synthesis. The expression of genes regulating several important enzymes in TBB was altered after fertilization. After the compost treatment, the expression of the leaf DXS gene (ACQ66107.1), being closely related to the sesquiterpene biosynthesis in P. bournei leaves, was decreased. Compost and compound fertilizer altered the expression of the two important branch-point enzymes (FPPS and GGPPS) genes (ART33314.1 and ATT59265.1), which contributed to the changes of the total amount and components of P. bournei sesquiterpenes. This study provides a new insight into the future use of P. bournei for Eos.

An electrochemical sensor based on a MOF/ZnO composite for the highly sensitive detection of Cu(ii) in river water samples.

Cu(ii) ions are one of the most common forms of copper present in water and can cause bioaccumulation and toxicity in the human body; therefore, sensitive and selective detection methods are required. Herein, a copper ion sensor based on a UiO-66-NH2/ZnO composite material is proposed. The UiO-66-NH2/ZnO nanocomposite was prepared by an ultrasonic mixing method. The morphology and structure of the nanocomposite were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensitivity to Cu(ii) is 6.46 µA µM-1 and the detection limit is 0.01435 µM. The composite material is rich in -OH and -NH2 groups, which are active sites for Cu(ii) adsorption. The UiO-66-NH2/ZnO-modified electrode has good repeatability and anti-interference ability. The sensor was successfully used for the determination of Cu(ii) in an actual water sample.

A Comparative Study of the Effect of Different Carbon-Reduction Policies on Outsourcing Remanufacturing.

To facilitate the green transformation of enterprises and realize low-carbon development, governments have adopted the policies of carbon emission constraint and carbon trade to promote enterprises' low-carbon production. Although the two policies aim to reduce carbon emissions, they have different effects on enterprises' production. Meanwhile, the development of remanufacturing caters to the low-carbon economy. Therefore, this article establishes the game models between an original equipment manufacturer (OEM) and a remanufacturer under carbon-emission-constraint and carbon-trade policies, analyzing the production decisions of enterprises under different policies to compare the influence of the two policies on outsourcing remanufacturing. The main conclusions of the article are as follows: (1) Both carbon-emission-constraint and carbon-trade policies increase the unit retail price of remanufactured and new products, reducing the new products sales volume. However, the sales volume of remanufactured products only decreases if the discount rate is less than the rate of carbon emissions of the two products. (2) The upper limit of carbon emissions can affect the unit outsourcing cost. The unit cost of outsourcing under the carbon-emission-constraint policy is only higher when the upper limit of carbon emissions is less than a certain threshold, and the discount rate is larger than the proportion of carbon emissions for both products; otherwise, the unit outsourcing cost under the carbon-trade policy is higher. (3) Both policies lessen the total environmental implication. When the upper limit of carbon emissions is less than a particular threshold, the environmental effect of the two manufacturers under the carbon-emission-constraint policy is smaller; otherwise, the environmental impact is smaller under the carbon-trade policy.

Clinical characteristics, prescription patterns, and persistence associated with sacubitril/valsartan adoption: A STROBE-compliant study.

ABSTRACT: Sacubitril/valsartan (sac/val) was launched in China in 2018; however, the adoption of sac/val in real-world clinical practice has yet to be described.This study aimed to analyze real-world treatment patterns of sac/val using data from 3 tertiary hospitals in China.A non-interventional, retrospective cohort study of patients with Heart failure (HF) prescribed sac/val from 3 tertiary hospitals in China between January 1, 2018 and June 30, 2020 was conducted. The analysis included sac/val dose titration patterns and persistence during 6 months post-index.A total of 267 patients were included, with a mean age of 63.9 ±â€Š13.1 years. At index, 27% of patients were prescribed sac/val 12/13 mg b.i.d., 63.7% were prescribed 24/26 mg b.i.d., 4.5% were prescribed the target dose of 49/51 mg b.i.d., and 4.8% were not prescribed according to the recommended dose. During the 6 months post-index, 8.3% of patients had only 1 dose titration record. Good therapeutic persistence was observed across sac/val doses, and only 15.7% of patients discontinued sac/val during the 6 months post-index.In China, the majority of patients prescribed sac/val are not initiated on the recommended dose nor up-titrated according to drug instruction. Notably, good persistence with sac/val is observed in the real-world cohort study.

Composition and profiles of volatile organic compounds during waste decomposition by the anaerobic bacteria purified from landfill.

Volatile organic compounds (VOCs) become concerned pollutants in landfill gases, and their composition and concentration varied significantly during waste decomposition. Many environmental factors are known to affect VOC emissions, while the effect of indigenous bacteria in wastes on VOC production remains elusive. In this study, a simplified anaerobic degradation experiment, with the single substrate and the purified bacteria from a landfill, was set up to measure the degradation process and the dynamic changes of VOCs. The experiment excluded the abiotic factors for VOC variation. The two isolated bacteria, identified as Sporanaerobacter acetigenes and Clostridium sporogenes, could anaerobically ferment amino acids by Stickland reaction. They produced 51 and 57 species of VOCs in the experiment, respectively. The concentration changes of VOCs over bacterial growth and fermentation were clustered into four types by principal component analysis: three profiles were regular, similar to the variation of nitrate, hydrogen sulfide, and the major fermentation products (carbon dioxide, ammonium, and volatile organic acids), respectively; while one profile was unique to any degradation indicator. The various concentration profiles indicated different origins for VOCs, possibly from the extracellular environment, fermentation, and secondary reactions. The findings provide insights into the understanding of VOC diversity and variability during waste decomposition.

Metabolic patterns reveal enhanced anammox activity at low nitrogen conditions in the integrated I-ABR.

Substrate concentrations greatly influence bacterial growth and metabolism. However, optimal nitrogen concentrations for anammox bacteria in nitrogen-limited environments remain unclear. Here, we observed enhanced nitrogen metabolism and anabolism of anammox bacteria at low nitrogen conditions. Efficient nitrogen removal was achieved at ammonium and nitrite influent concentration of 30 mg/L under HRT of 1 hr, with an average nitrogen removal rate (NRR) of 0.73 kg N/(m3 ·day) in I-ABR composed of four compartments. The highest anammox activity of 6.25 mmol N/ (gVSS·hr) was observed in the fourth compartment (C4) with the lowest substrate levels (ammonium and nitrite of 11.6 mg/L and 7 mg/L). This could be resulted from the highest expression level of genes involved in nitrogen metabolism in C4, which was 1.49-1.67 times higher than that in other compartments. Besides, the second compartment (C2) exhibited the most active anabolism at ammonium and nitrite of 17 mg/L and 13 mg/L, respectively, which contributed to the most active amino acid synthesis and thus the highest EPS (1.35 times higher) in C2. This enhanced amino acid auxotrophy between anammox bacteria with heterotrophs, and consequently, heterotrophs thrived and competed for nitrite. These results hint at the potential application of anammox process in micro-polluted water. PRACTITIONER POINTS: High nitrogen removal and efficient biomass retention at low nitrogen concentrations under short HRT was achieved in I-ABR. Optimal concentrations for anammox nitrogen removal and anabolism were discussed under low nitrogen concentrations. More active anabolism contributed to enhanced amino acid synthesis and thus higher EPS contents. Low substrate levels led to enhanced expression of genes involved in nitrogen metabolism and thus high anammox activity.

Changes in municipal solid waste pore structure during degradation: Analysis of synthetic waste using X-ray computed microtomography.

In solid wastes, pores provide passages for leachate and biogas flows, and room for microbial activities. In this study, the pores in the solid wastes of synthetic solid wastes were measured using X-ray computed microtomography to explore their structural characteristics during degradation. The synthetic municipal solid waste (MSW) column was inoculated with microorganisms obtained from leachate sampling and X-ray digital images of MSW were taken on the 2nd and 260th days after inoculation. The results show that the porosity dropped sharply, and the volume and path number of the connected pores reduced while those of disconnected pores increased. However, the corresponding characteristics in the blank MSWs changed only slightly. For the probability density distributions of the inoculated column, both the pore size (fitted well by y = 0.49e-0.49x, r2 = 0.96) as well as the throat area (fitted well by y = 0.54e-0.54x, r2 = 0.96) changed, depicting an exponential decay at the primary stage and a unimodal distribution at the degraded stage. The pore path length and coordination number also changed. These indicated that the pore structure of MSWs underwent considerable evolution during degradation; the changes can be attributed primarily to microbial activity instead of physical effects.

A survey of municipal solid waste landfills in Beijing during 2009-2011.

The investigation of municipal solid waste (MSW) treatment in China is rare due to its sensitivity and difficulty in terms of access. We chose Beijing, the capital of China, as an example to identify the characteristics of MSW landfill treatments using a 2-month investigation with 20 participants. MSW landfill treatments account for nearly 70% of the annual MSW disposal in Beijing; the landfill processes are equipped with many kinds of technologies and consume a large amount of energy and produce a variety of contaminants. The cover method (the most obvious difference in landfill tamping) mainly includes high-density polyethylene (HDPE) geomembranes with loess and soil alone (i.e., loess or sandy soil). We investigated the actual conditions of landfills and collected data on leachate and landfill gas (LFG) emissions and energy consumption during 2009-2011. The results indicated that the cover method employed by landfills was related to treatment quantity, operation, and especially landfill location. Early large-scale landfills located in plains were covered with HDPE geomembranes, and newly built landfills covered with soil tended to be equipped with HDPE covers. Using HDPE cover also contributed greatly to LFG production due to its impermeability but had no remarkable effect on leachate yield reduction due to the dry climate in Beijing. The potential was reinforced by the potentials of decrement and reuse. The disposal method of LFG can be optimized, and the power generated by the LFG process can meet the landfill demand. The gray water recycled from the leachate could be used in the landfill process.

A Multiscale Model of Oxidation Kinetics for Cu-Based Oxygen Carrier in Chemical Looping with Oxygen Uncoupling.

Copper oxide is one of the promising oxygen carrier materials in chemical looping with oxygen uncoupling (CLOU) technology, cycling between Cu2O and CuO. In this study, a multiscale model was developed to describe the oxidation kinetics of the Cu-based oxygen carrier particle with oxygen, including surface, grain, and particle scale. It was considered that the solid product grows with the morphology of disperse islands on the grain surface, and O2 contacts with two different kinds of grain surfaces in the grain scale model, that is, Cu2O surface (solid reactant surface) and CuO surface (solid product surface). The two-stage behavior of the oxidation reaction of the Cu-based oxygen carrier was predicted successfully using the developed model, and the model results showed good agreement with experimental data in the literature. The effects of oxygen partial pressure, temperature, and particle structure on the oxidation performance were analyzed. The modeling results indicated that the transition of the conversion curve occurs when product islands cover most part of the grain surface. The oxygen partial pressure and particle structure have an obvious influence on the duration time of the fast reaction stage. Furthermore, the influence of the external mass transfer and the change of effectiveness factor during the oxidation reaction process were discussed to investigate the controlling step of the reaction. It was concluded that the external mass transfer step hardly affects the reaction performance under the particle sizes normally used in CLOU. The value of the effectiveness factor increases as the reaction goes by, which means the chemical reaction resistance at grain scale increases resulting from the growing number of product islands on the grain surface.

Molecular Insights into the Transformation of Dissolved Organic Matter in Landfill Leachate Concentrate during Biodegradation and Coagulation Processes Using ESI FT-ICR MS.

Landfill leachate concentrate is a type of refractory organic wastewater with high environmental risk. Identification of refractory components and insights into the molecular transformations of the organics are essential for the development of efficient treatment process. In this report, molecular compositions of dissolved organic matter (DOM) in leachate concentrate, as well as changes after anaerobic/aerobic biodegradation and coagulation with salts, were characterized using electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). DOM in leachate concentrate were more saturated and less oxidized with more nitrogen and sulfur-containing substances (accounting for 50.0%), comparing with natural organic matter in Suwannee River. Selectivity for different classes of organics during biodegradation and coagulation processes was observed. Substances with low oxidation degree (O/C < 0.3) were more reactive during biodegradation process, leading to the formation of highly oxidized molecules (O/C > 0.5). Unsaturated (H/C < 1.0) and oxidized (O/C > 0.4) substances containing carboxyl groups were preferentially removed after coagulation with Al or Fe sulfate. The complementary functions of biodegradation and coagulation in the treatment of DOM in leachate concentrate were verified at the molecular level. Lignin-derived compounds and sulfur-containing substances in leachate concentrate were resistant to biodegradation and coagulation treatments. To treat leachate concentrate more effectively, processes aimed at removal of such DOM should be developed.

Estimating municipal solid waste generation by different activities and various resident groups in five provinces of China.

The quantities and composition of municipal solid waste (MSW) are important factors in the planning and management of MSW. Daily human activities were classified into three groups: maintenance activities (meeting the basic needs of food, housing and personal care, MA); subsistence activities (providing the financial support requirements, SA); and leisure activities (social and recreational pursuits, LA). A model, based on the interrelationships of expenditure on consumer goods, time distribution, daily activities, residents groups, and waste generation, was employed to estimate MSW generation by different activities and resident groups in five provinces (Zhejiang, Guangdong, Hebei, Henan and Sichuan) of China. These five provinces were chosen for this study and the distribution patterns of MSW generated by different activities and resident groups were revealed. The results show that waste generation in SA and LA fluctuated slightly from 2003 to 2008. For general waste generation in the five provinces, MA accounts for more than 70% of total MSW, SA approximately 10%, and LA between 10% and 16% by urban residents in 2008. Females produced more daily MSW than males in MA. Males produced more daily MSW than females in SA and LA. The wastes produced at weekends in MA and LA were far greater than on weekdays, but less than on weekdays for SA wastes. Furthermore, one of the model parameters (the waste generation per unit of consumer expenditure) is inversely proportional to per-capita disposable income of urban residents. A significant correlation between gross domestic product (GDP) and waste generation by SA was observed with a high coefficient of determination.

[Community Structure and Succession of Methanogens in Beishenshu Landfill, Beijing].

Methanogens are the key microorganisms for landfill stabilization. RT-PCR and qPCR detecting system were employed to determine the types and abundance of methanogens in 2-15 year-old solid wastes that sampled from Beishenshu Landfill, Beijing. The organic components were almost stable and the pH values were in alkaline range, which indicated that the landfill was in the methanogenic process. Methanobacterials, Methanosaeta, and Methanosarcina were detected, among which Methanosaeta and Methanosarcina are acetoclastic, and Methanobacterials are hydrogenotrophic. As landfill processing, within this time range, although the bacterial abundance was significantly decreased, the amount of methanogens was first increased and then decreased, and finally became stable after being landfilled for 9 years. Methanosarcina was the dominate taxa. Significant correlations were found between the methanogens and the volatile fatty acids, but the correlations between methanogens and larger molecular organic matters were relatively weak or even absent. Taken together, our study revealed that the amount of methanogens were affected by substrates, but hardly influenced by the conversion of large molecules in these wastes landfilled for more than 2 years.

Valley-polarized quantum anomalous Hall effect in silicene.

We find theoretically a new quantum state of matter-the valley-polarized quantum anomalous Hall state in silicene. In the presence of Rashba spin-orbit coupling and an exchange field, silicene hosts a quantum anomalous Hall state with Chern number C=2. We show that through tuning the Rashba spin-orbit coupling, a topological phase transition results in a valley-polarized quantum anomalous Hall state, i.e., a quantum state that exhibits the electronic properties of both the quantum valley Hall state (valley Chern number Cv=3) and quantum anomalous Hall state with C=-1. This finding provides a platform for designing dissipationless valleytronics in a more robust manner.

[Characteristics and influence factors of the energy consumption and pollutant discharge of municipal solid waste transfer stations in Beijing].

In this study, we investigated characteristics and influence factors of energy consumption and pollutant discharge (ECPD) of municipal solid waste transfer stations (MSW TSs) in Beijing by assessing four parameters including the amount of waste recycled, leachate production, water consumption and electricity consumption, based on three years' average data of MSW TSs in Beijing obtained through field investigations from 2009 to 2011. Meanwhile, integral performances of the stations with and without garbage sorting capacities (Sorting TS and Compressing TS) were also analyzed. Results showed that MSW TSs in Beijing differ greatly. For each ton of MSW, masses of waste recycled, leachate productions, water consumptions and electricity consumptions generally fall in the ranges of 12.9 kg x t(-1), 5.8-49.0 kg x t(-1), 40. 3-156.7 kg x t(-1) and 1.75-5.60 kWh x t(-1), respectively. Despite overall the higher energy consumption and more pollutant discharge than Compressing TS, Sorting TS could achieve waste reduction and reuse by recycling part of the municipal solid wastes, as well as the optimization of process by sorting wastes into different ingredients for corresponding waste disposal plants, which could reduce heavy burdens of landfills and extend their lifespans.

Optimization for municipal solid waste treatment based on energy consumption and contaminant emission.

This paper analyzes the characterization of energy consumption and contaminant emissions from a municipal solid waste (MSW) treatment system that comprises transfer station, landfill site, combustion plant, composting plant, dejecta treatment station, and an integrated MSW treatment plant. The consumed energy and energy medium materials were integrated under comprehensive energy consumption (CEC) for comparison. Among typical MSW disposal methods such as combustion, composting, and landfilling, landfilling has the minimum CEC value. Installing an integrated treatment plant is the recommended MSW management method because of its lower CEC. Furthermore, this method is used to ensure process centralization. In landfill sites, a positive linear correlation was observed between the CEC and contaminant removal ratios when emitted pollutants have a certain weight coefficient. The process should utilize the minimum CEC value of 5.3702 kgce/t MSW and consider energy consumption, energy recovery, MSW components, and the equivalent of carbon dioxide emissions.