Evaluation of In-situ Sludge Reduction and Enhanced Nutrient Removal in an Integrated Repeatedly Coupling Aerobic and Anaerobic and Oxic-setting-anaerobic System

Aiming to achieve simultaneous good performances of in-situ sludge reduction and effluent quality,an integrated repeatedly coupling aerobic and anaerobic and oxic-setting-anaerobic system( r CAA + OSA) is developed to reduce sludge production and enhance nutrient removal. Considering the mechanism of in-situ sludge reduction in this r CAA +OSA system,the combined effect of energy uncoupling metabolism and sludge cryptic growth maybe attributed to the higher reduction of biomass. Results show that the maximal sludge reduction in this r CAA + OSA system is obtained when the hydraulic retention time( HRT) is controlled at6. 5 h,which an increase in 16. 67% reduction in excess sludge is achieved compared with OSA system( HRT of 6. 5 h). When compared the performances of effluent qualities,the enhanced nutrient removal efficiencies also can be observed in this r CAA + OSA system. Three-dimensional excitation emission matrix( 3D-EEM)fluorescence spectroscopy is applied to characterize the effluent organic matters( Ef OM) under different HRTs in the OSA and the r CAA+OSA systems. Analyses of 3D-EEM spectra show that more refractory humic-like and fulvic-like components are observed in the effluent of the OSA system. On the basis of these results,simultaneous enhanced in-situ sludge reduction and improved nutrient removal can be obtained in the r CAA +OSA systems.

Effects of Ultrasonic and Acid Pretreatment on Food Waste Disintegration and Volatile Fatty Acid Production

This study aims at investigating the effects of ultrasonic and acid pretreatment on food waste( FW)disintegration and volatile fatty acid( VFA) production. Single-factor experiments are carried out to obtain optimal conditions of individual ultrasonic and acid pretreatment,and response surface method( RSM) is applied to optimize the conditions of the combination of ultrasonic and acid( UA) pretreatment. Results show that the optimal acid,ultrasonic and UA pretreatments conditions are individual pH 2,individual ultrasonic energy density of 1. 0 W / mL and the combination of ultrasonic energy density1. 11 W / mL and pH 1. 43,respectively. Correspondingly,the maximum disintegration degrees( DD) of 46. 90%,57. 38% and68. 83%are obtained by acid,ultrasonic and UA pretreatments,respectively. After optimizing pretreatment conditions,batch experiments are operated to produce VFA from raw and pretreated FW under anaerobic fermentation process. Both the maximum VFA production( 976. 17 mg COD / gV S) and VFA / SCOD( 72. 89%) are obtained with ultrasonic pretreatment, followed by UA pretreatment, non-pretreatment and acid pretreatment,respectively. This observation demonstrates that a higher acidity on acid and UA pretreatments inhibits the generation of VFA. Results suggest that ultrasonic pretreatment is preferable to promote the disintegration degree of FW and VFA production.

Unlocking the potential of thin-film composite reverse osmosis membrane performance:Insights from mass transfer modeling

Thin-film composite(TFC)reverse osmosis(RO)membranes have attracted considerable attention in water treatment and desalination processes due to their specific separation advantages.Nevertheless,the trade-off effect between water flux and salt rejection poses huge challenges to further improvement in TFC RO membrane performance.Numerous research works have been dedicated to optimizing membrane fabrication and modification for addressing this issue.In the meantime,several reviews summarized these approaches.However,the existing reviews seldom analyzed these methods from a theoretical perspective and thus failed to offer effective optimization directions for the RO process from the root cause.In this review,we first propose a mass transfer model to facilitate a better understanding of the entire process of how water and solute permeate through RO membranes in detail,namely the migration process outside the membrane,the dissolution process on the membrane surface,and the diffusion process within the membrane.Thereafter,the water and salt mass transfer behaviors obtained from model deduction are comprehensively analyzed to provide potential guidelines for alleviating the trade-off effect between water flux and salt rejection in the RO process.Finally,inspired by the theoretical analysis and the accurate identification of existing bottlenecks,several promising strategies for both regulating RO membranes and optimizing operational conditions are proposed to further exploit the potential of RO membrane performance.This review is expected to guide the development of high-performance RO membranes from a mass transfer theory standpoint.

Preliminary assessment of the data appropriateness of electronic health records for real-world studies:A survey of hospitals in a developing region in China

To the Editor:Assessment of data appropriateness is a process to answer whether electronic health records(EHRs)from routine healthcare practices couldt intended study purposes,for example,available to be proceeded,with enough individual records,with relevant information able to be extracted from records,etc.[1-3]This has been increasingly underscored as a prerequisite when using EHRs(one important type of real-world data[RWD])for scientic purposes.[4-6]Although controversies remain on the denitions,types and assessment methods of the dimensions of RWD appropriateness,the latest ofcial guidelines(i.e.,from the U.S.Food and Drug Administration[FDA][4]and China National Medical Products Administration[NMPA][6])suggest that the assessment start from a preliminary stage on variable existence,and subsequently deepen into the issue of data value(such as missing value,outliers,etc.),as the preliminary assessment is the foundation of the overall RWD appropriateness.[7]Little is known about the appropriateness of EHRs in developing regions,which feature high visit volumes and a great number of hospitals.Therefore,this study aimed to preliminarily investigate RWD appropriateness from hospitals in developing regions from the perspective of core variables’comparison.

Dissolved oxygen in aeration-driven piezo-catalytic for antibiotics pollutants removal in water

The misuse of antibiotics and oxygen-lacking in aquaculture causes serious water environmental problems.Herein,a piezoelectic odd-layered MoS_(2)is prepared and applied to piezo-catalytic remove tinidazole(TNZ)and other antibiotic pollutants with aeration as a piezo-driving force.About 89.6%of TNZ can be degraded by MoS_(2)under aeration in the presence of dissolved oxygen with a reaction rate constant of0.15 min^(-1),which is 2.4 times higher than that under N2atmosphere and quiescence conditions.Quenching experiments and electron paramagnetic resonance(EPR)tests identify that singlet oxygen(^(1)O_(2))and superoxide radical(O_(2)^(·-))are dominant reactive oxygen species in MoS_(2)/aeration system.These results demonstrate that MoS2can trigger a piezoelectric effect and produce charge carriers to generate reactive oxygen species with dissolved oxygen(DO)for contaminant degradation with the turbulence and water bubbles rupture driven by aeration.

Mechanism of powdered activated carbon enhancing caproate production

Caproate, produced by microbial chain elongation process, is potential to replace the diversified fossilbased products, contributing to carbon neutrality. However, its production performance is far from industrial application, so the cost-effective enhancement measures are highly needed. This study confirmed powdered activated carbon(PAC) has a significant effect on enhancing caproate production performance.The production, yield, and selectivity of caproate were improved by more than 1-fold by the optimized PAC dosage of 15 g/L, comparing with control. Mechanism investigation from a new visual angle showed that PAC accelerated ethanol oxidation to generate acetyl-Co A, and simultaneously boosted the efficiency of reverse β oxidation(RBO) by promoting the timely reaction of butyrate and acetyl-Co A to synthesis caproate. The addition of PAC also shifted the microbial community by enriching more caproateproducing bacteria but eliminating irrelevant ones. Furthermore, metagenomic analysis revealed that PAC effectively up-regulated the functional genes encoding key enzymes responsible for ethanol oxidation and RBO pathway, which was the root cause for the improved caproate production. This study presented the intrinsic insights into the mechanism of PAC promoting caproate generation, laying a foundation to the scale production of caproate.

Enhanced utilization efficiency of peroxymonosulfate via water vortex-driven piezo-activation for removing organic contaminants from water

The efficient activation and utilization of peroxymonosulfate(PMS)in PMS-based advanced oxidation processes is a high-priority target for the removal of organic contaminants.This work introduces a water vortex-driven piezoelectric effect from few-odd-layered MoS_(2)into the PMS activation to remove benzotriazole(BTR)and other organic contaminants from the water.Approximately 91.1%of BTR can be removed by the MoS_(2)piezo-activated PMS process with a reaction rate constant of 0.428 min
1,which is 2.09 times faster than the sum of the individual MoS_(2),water vortex,and piezocatalysis rates.Meanwhile,the PMS utilization efficiency reached 0.0147 in the water vortex-driven piezo-activation system,which is 3.97 times that of the sum from the vortex/PMS and MoS_(2)/PMS systems.These results demonstrate that the presence of MoS_(2)under a water vortex can trigger a piezoelectric potential and generate abundant free electrons to activate PMS to generate various active species for degradation of organic contaminants.