As a frequently used product with antimicrobial activity, consumed allicin might be discharged and concentrated in waste-activated sludge (WAS). However, the influence of allicin (as an exogenous pollutant) on WAS fermentation has not been clearly revealed. This study aimed to disclose the impacts of allicin on volatile fatty acid (VFA) generation during WAS fermentation. The results showed that the appropriate presence of allicin (10 mg/g TSS) significantly enhanced the VFA yield (1894 versus 575 mg COD/L in the control) with increased acetate proportion (24.3%). Further exploration found that allicin promoted WAS solubilization, hydrolysis and acidification simultaneously. Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism (i.e., CAZymes), membrane transport (i.e., gtsA and ytfT), substrate metabolism (i.e., yhdR and pfkC) and fatty acid synthesis (i.e., accA and accD) were all highly expressed. Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions, thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment. Moreover, the variations in fermentative microbes and their contributions to the upregulation of functional genes (i.e., ytfR, gltL, INV, iolD and pflD) for VFA generation were disclosed. Overall, the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors.

Mechanisms of allicin exposure for the sludge fermentation enhancement: Focusing on the fermentation processes and microbial metabolic traits

Metatranscriptomic insights of the metabolic process enhancement during food wastes fermentation driven by linear alkylbenzene sulphonates

As a frequently used product with antimicrobial activity, consumed allicin might be discharged and concentrated in waste-activated sludge (WAS). However, the influence of allicin (as an exogenous pollutant) on WAS fermentation has not been clearly revealed. This study aimed to disclose the impacts of allicin on volatile fatty acid (VFA) generation during WAS fermentation. The results showed that the appropriate presence of allicin (10 mg/g TSS) significantly enhanced the VFA yield (1894 versus 575 mg COD/L in the control) with increased acetate proportion (24.3%). Further exploration found that allicin promoted WAS solubilization, hydrolysis and acidification simultaneously. Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism (i.e., CAZymes), membrane transport (i.e., gtsA and ytfT), substrate metabolism (i.e., yhdR and pfkC) and fatty acid synthesis (i.e., accA and accD) were all highly expressed. Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions, thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment. Moreover, the variations in fermentative microbes and their contributions to the upregulation of functional genes (i.e., ytfR, gltL, INV, iolD and pflD) for VFA generation were disclosed. Overall, the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors. 

Antagonistic effects of surfactants and CeO2 nanoparticles co-occurrence on the sludge fermentation process: Novel insights of interaction mechanisms and microbial networks.

Joint effects of carbon nanotubes and copper oxide nanoparticles on fermentation metabolism towards Saccharofermentans acetigenes: Enhancing environmental adaptability and transcriptional expression.

Anaerobic fermentation metabolism of Moorella thermoacetica inhibited by copper nanoparticles: Comprehensive analyses of transcriptional response and enzyme activity

The invention provides a membrane-loaded biological deodorization reactor and a deodorization method. A membrane-loaded biological deodorization reactor comprises a reactor body, a plurality of membrane assemblies, a plurality of backwashing aerators, a first gas supply unit and a second gas supply unit, the membrane assembly and the backwashing aerators are arranged in the reactor body; the firstair supply unit is communicated with the membrane assemblies, and the second air supply unit is communicated with the backwashing aerators; and the backwashing aerators are arranged towards the membrane assemblies. According to the method, the membrane thickness of the biological membrane can be adjusted, the metabolic activity of efficient degradation microorganisms is high, the removal efficiency of sulfur-containing malodorous organic pollutants is high, and the oxygen utilization efficiency is high.

Membrane-loaded biological deodorization reactor and deodorization method

The invention provides a purification system and a purification method for sulfur-containing organic waste gas. The purification system comprises an absorption tower and a membrane-loaded biological deodorization reactor which are communicated with each other, the membrane-loaded biological deodorization reactor comprises a reactor body, a plurality of membrane assemblies, a plurality of backwashing aerators, a first gas supply unit and a second gas supply unit, the first air supply unit is communicated with the membrane assemblies, and the second air supply unit is communicated with the backwashing aerators; and the backwashing aerators are arranged towards the membrane assemblies. The purification method comprises the following steps: 1) absorbing to-be-treated sulfur-containing organicwaste gas by spraying liquid; 2) introducing the to-be-treated waste liquid and sludge obtained in the step 1) into a membrane-loaded biological deodorization reactor, and domesticating activated sludge under the condition of oxygen supply pressure; and 3) after domestication of the activated sludge is completed, continuously introducing the waste liquid to be treated, and carrying out membrane-loaded biological deodorization under the conditions of oxygen supply pressure and aeration. According to the invention, the removal efficiency of sulfur-containing malodorous organic pollutants is greater than or equal to 99.9%, and the oxygen utilization efficiency is greater than or equal to 99%.

Purification system and purification method for sulfur-containing organic waste gas

The invention relates to the field of water treatment, in particular to a biological nitrogen and phosphorus removal method and system for sewage. The method comprises the following steps: 1) performing anaerobic treatment on a to-be-treated water body; 2) carrying out anoxic treatment on the water body obtained by anaerobic treatment; 3) carrying out aerobic treatment on the water body obtained by anoxic treatment; 4) carrying out oxygen elimination treatment on the water body obtained by aerobic treatment; 5) refluxing a part of supernatant of the water body obtained by oxygen elimination treatment to the step 2) for anoxic treatment; 6) carrying out membrane-based biological treatment on part of supernatant of the water body obtained by oxygen elimination treatment; 7) carrying out precipitation treatment on a lower-layer mud-water mixture of the water body obtained by the oxygen elimination treatment; 8) refluxing part of the water body obtained by the membrane-based biological treatment to the step 1) for anaerobic treatment; and 9) refluxing part of the water body obtained by the membrane-based biological treatment to the step 3) for aerobic treatment. The method is good in removal effect of total nitrogen and total phosphorus pollutants, simple and convenient to operate, low in energy consumption and stable in up-to-standard emission.

Wu Jing

Papers

Anaerobic fermentation metabolism of Moorella thermoacetica inhibited by copper nanoparticles: Comprehensive analyses of transcriptional response and enzyme activity

Membrane-loaded biological deodorization reactor and deodorization method

Purification system and purification method for sulfur-containing organic waste gas

Biological nitrogen and phosphorus removal method and system for sewage