Investigating inhibiting factors affecting seed germination index in kitchen waste compost products: Soluble carbon, nitrogen, and salt insights.

The seed germination index (GI) serves as the principal determinant that impedes the integration of aerobic composting products into agricultural lands. The current research work predominantly focuses on exploring the correlation between physical and chemical indicators of the compost products and GI, neglecting the fundamental cause. This study systematically analyzed the composition of GI aqueous extracts from compost products derived from kitchen waste under various composting methodologies, with nitrogen, carbon, and inorganic salt as critical factors. The analytical work concluded that acetic acid, formic acid, and ammonium were the inhibitory factors influencing GI. Validation experiments introduced inhibitory factors, yielding a functional relationship formula depicting GI variations due to a single influential factor. This study conclusively identified acetic acid as the primary constraint, establishing that its inhibitory concentration corresponded to 70 % GI stands at 85 mg/L. This study will provide guidelines for the future research on enhancing aerobic composting techniques.

Directed regulation of anammox communities based on exogenous siderophores for highly efficient nitrogen removal.

It is expected that the quicker domestication of anaerobic ammonia oxidation (anammox) communities and the enhancement of their nitrogen transformation capability can be achieved through targeted regulation of anammox communities. Iron cast a vital role in the growth and metabolism of anammox bacteria. Specific siderophores offer promising prospects for the targeted regulation of anammox communities by facilitating the efficient utilization of iron. Two siderophores-enterobactin and putrebactin-exclusively for Ca. Brocadia and Ca. Kuenenia were developed to specifically regulate anammox communities towards different directions, respectively. Anammox communities in the reactors evoluted targetedly towards Ca. Brocadia-dominated communities and Ca. Kuenenia-dominated communities, respectively, leading to a maximum increase in community nitrogen removal capacity by 84.64±0.55% and 210.26±0.57%, respectively, under different nitrogen concentrations. It was indicated that siderophores could regulate anammox communities by redistributing iron resources in a targeted manner based on the analyses of transcriptome and proteome. This study provides novel insights into the rational selection and utilization of exogenous siderophores as an effective implement to manipulate anammox communities and create communities with high nitrogen removal ability fleetly.

Affinity difference determines the assembly and interaction mode of anammox community reconstructed by siderophores.

Anammox community is the core of anammox process. The constancy of the anammox community determines the stability of the anammox process and the ability of withstand environmental impact. Community stability is influenced by the assembly and interaction mode of the community. This study aimed to explore the assembly, interaction mode, and stability of anammox community influenced by two siderophores (enterobactin and putrebactin) specific for Ca. Brocadia and Ca. Kuenenia as produced in our previous research. Siderophores improved the stability of the anammox community, among which vulnerability dropped by 30.02 % and 72.53 % respectively. Enterobactin and putrebactin altered the succession speed and assembly pattern of communities, with a respective increase of 9.77 % and 80.87 % in the deterministic process of anammox community assembly, respectively. Enterobactin and putrebactin reduced the dependence of Ca. Brocadia and Ca. Kuenenia on companion bacteria by 60 items and 27 items respectively. The affinity of different siderophore-Fe with bacterial membrane receptors caused variations in community reconstruction, with Ca. Brocadia and Ca. Kuenenia exhibiting the highest affinity with enterobactin-Fe (-11.4 kcal/mol) and putrebactin-Fe (-9.0 kcal/mol), respectively. This study demonstrated how siderophores can enhance the stability of anammox process by regulating assembly and interaction mode of anammox community, while also revealing the underlying molecular mechanisms.

Analogical Assessment of Train-Induced Vibration and Radiated Noise in a Proposed Theater.

This study presents the analogical assessment of the train-induced vibration and radiated noise in a proposed theater. The theater is to be constructed in a region with crowded metro lines, and the assessment is implemented in an analogical building with comparable structural type and metro condition. Prior to the assessment, the comparability of the analogical building with the theater is validated using the train-induced ground vibration. With the same horizontal distance from the metro line, the train-induced vibration level in the analogical building is 9 dB higher than that in the construction site of the theater. Such results indicate that the lack of soil layers may lead to a dramatic increase in train-induced vibration in the building. In the staircase of the analogical building, the train-induced radiated noise reached 55 dB (A), which is 10 dB (A) higher than the daytime allowable level. As the most important indicator, the noise rating number in the cinema of the analogical building is NR-43, which put forward an enormous challenge on the construction of the theater with a denoise demand of 23 dB. The analogical method applied in this study provides an effective and practical way for the assessment of train-induced vibration and radiated noise in proposed vibration-sensitive buildings. The assessment results that provide necessary reference and support for the anti-vibration design will help guarantee the stage effect of the theater.