The Summary of Nitritation Process in Mainstream Wastewater Treatment

The application of the mainstream partial nitritation/anammox (PN/A) process is promising due to the huge cost reduction compared to traditional biological nitrogen removal. However, the nitrite production rate (NPR) of a biological nitritation pre-treatment process is relatively lower than the nitrite consumption rate in a pure anammox reactor with a high nitrogen loading rate (NLR). Thus, the NPR is the rate-limiting step for operating the PN/A process with a higher NLR. Various studies have attempted to improve mainstream NPR. A comprehensive review of these processes is needed for the actual application of the PN/A process. This study focuses on: (1) various nitrite production processes that have emerged in recent years; (2) the main microbial species and characteristics involved in biological nitritation; (3) the existing problems and the N2O emission problem of these processes; and (4) a proposed novel and promising PN/A process facilitated with photocatalyst oxidation. This review is expected to provide references and a basis for the research on the nitritation step of the application of the mainstream PN/A process

The Summary of Nitritation Process in Mainstream Wastewater Treatment

The application of the mainstream partial nitritation/anammox (PN/A) process is promising due to the huge cost reduction compared to traditional biological nitrogen removal. However, the nitrite production rate (NPR) of a biological nitritation pre-treatment process is relatively lower than the nitrite consumption rate in a pure anammox reactor with a high nitrogen loading rate (NLR). Thus, the NPR is the rate-limiting step for operating the PN/A process with a higher NLR. Various studies have attempted to improve mainstream NPR. A comprehensive review of these processes is needed for the actual application of the PN/A process. This study focuses on: (1) various nitrite production processes that have emerged in recent years; (2) the main microbial species and characteristics involved in biological nitritation; (3) the existing problems and the N2O emission problem of these processes; and (4) a proposed novel and promising PN/A process facilitated with photocatalyst oxidation. This review is expected to provide references and a basis for the research on the nitritation step of the application of the mainstream PN/A process

Research Progress on Anaerobic Digestion of Cellulose Waste Based on Bibliometric Analysis

The bibliometric method was used in this study to analyze current advances in the anaerobic digestion (AD) of cellulose waste. The result shows that the number of articles increased rapidly after 2010, suggesting a growing interest in this field. The USA and China were the top two countries with the highest number of published articles. AD of cellulose waste is being actively explored in many countries, and partnerships between countries are being actively formed. The top three subject categories were Environmental Sciences & Ecology, Engineering, Energy & Fuels. The most widely published and influential journals were Bioresource Technology, Water Science and Technology, and Waste Management. The co-occurrence and trend analysis of author keywords indicates that current research is primarily focused on pretreatment and co-digestion. Microbial community analysis plays a crucial role in elucidating the mechanisms, and life cycle analysis (LCA) could evaluate the impact on the environment at different stages. Microbial community analysis and LCA will be the hotspots in the future. To some extent, this study helps to understand the current global status and trends of the related research

A Comparison of Three-Dimensional Speckle Tracking Echocardiography Parameters in Predicting Left Ventricular Remodeling

Three-dimensional speckle tracking echocardiography (3D STE) is an emerging noninvasive method for predicting left ventricular remodeling (LVR) after acute myocardial infarction (AMI). Previous studies analyzed the predictive value of 3D STE with traditional models. However, no models that contain comprehensive risk factors were assessed, and there are limited data on the comparison of different 3D STE parameters. In this study, we sought to build a machine learning model for predicting LVR in AMI patients after effective percutaneous coronary intervention (PCI) that contains the majority of the clinical risk factors and compare 3D STE parameters values for LVR prediction. We enrolled 135 first-onset AMI patients (120 males, mean age 54 ± 9 years). All patients went through a 3D STE and a traditional transthoracic echocardiography 24 hours after reperfusion. A second echocardiography was repeated at the three-month follow-up to detect LVR (defined as a 20 percent increase in left ventricular end-diastolic volume). Six models were constructed using 15 risk factors. A receiver operator characteristic curve and four performance measurements were used as evaluation methods. Feature importance was used to compare 3D STE parameters. 26 patients (19.3%) had LVR. Our evaluation showed that RF can best predict LVR with the best AUC of 0.96. 3D GLS was the most valuable 3D STE parameters, followed by GCS, global area strain, and global radial strain (feature importance 0.146, 0.089, 0.087, and 0.069, respectively). To sum up, RF models can accurately predict the LVR after AMI, and 3D GLS was the best 3D STE parameters in predicting the LVR