A/O工艺在高氨氮废水中的应用

介绍了采用A/O工艺处理高氨氮废水的工程实例。通过近一个月的调试,出水氨氮均在5 mg/L以下,COD在50 mg/L以下;该工艺耐冲击,且处理效果稳定,处理后的出水各项指标均达到了《合成氨工业水污染物最高允许排放限值》（GB 13458-2001）的要求。     

江西省冬季大气典型污染过程的气象成因研究

选取2019年1月江西省两次大气污染过程为研究对象,利用常规气象观测资料、美国国家环境预报中心（NCEP）再分析资料、全球资料同化系统（GDAS）气象数据和空气质量数据,分别从局地气象要素变化、地面天气形势、大气动力和热力条件及污染潜在源区等进行分析,对比两次污染过程形成机制.两次污染过程地面天气形势分别为冷锋前部型和低压倒槽型.冷锋前部型污染形成主要原因为冷空气南下在江西省减弱辐合导致上游细颗粒物输送并堆积,西北风增大细颗粒物浓度降低.低压倒槽型污染形成原因为较长时间处于高湿、小风或静风、逆温下的污染累积.对两次过程中污染较为严重的九江市进行分析,冷锋前部型九江市近地面主要受西风影响,低压倒槽型主要受东北风影响,低压倒槽型九江市风速多在2 m·s^-1以下.两次污染期间大于3 m·s^-1的风速有利于污染物清除.长时间高湿、小风（< 2 m·s^-1）及风场辐合,是低压倒槽型九江市重污染维持较长时间的重要原因.低压倒槽型大气垂直结构较冷锋前部型稳定.低压倒槽型垂直湍流弱、低层风速小于2 m·s^-1,且存在多层逆温和深厚的湿区,冷锋前部型存在明显下沉运动,逆温强度明显弱于低压倒槽.九江市PM_2.5污染潜在贡献源主要来自河南东部、山东西部和安徽西北部;低压倒槽型九江市潜在源区主要位于江西省内及与江西省接壤的湖北东南部、安徽西南部.     

Construction and application of comprehensive drought monitoring model considering the influence of terrain factors: a case study of southwest Yunnan,China

Environmental Science and Pollution Research - Droughts in winter and spring are one of the most prominent natural disasters in the Yunnan Province in China. They occur frequently, with long...     

Integrating CVOR-GWLR-Circuit model into construction of ecological security pattern in Yunnan Province,China

Environmental Science and Pollution Research - In the traditional construction of ecological security pattern, the minimum cost path is extracted as the ecological corridor based on the minimum...     

潘北煤矿通风系统阻力测定及现状评价分析

以潘北煤矿2014年通风系统改造为例，对其通风网络系统运行现状进行了测定和解算分析，分析结果表明矿井部分工作面存在通风风量分配不合理现象；部分巷道通风阻力较高，如1121(3)上顺槽阻力损失高达561 Pa,占系统总阻力30.8%。通过对矿井通风网络分析解算，提出科学合理的通风系统优化改造方案，为矿井通风系统能够安全、高效运行提供基础依据参考。     

Airborne black carbon variations during the COVID-19 lockdown in the Yangtze River Delta megacities suggest actions to curb global warming

Environmental Chemistry Letters - Airborne black carbon is a strong warming component of the atmosphere. Therefore, curbing black carbon emissions should slow down global warming. The 2019...     

Study on the threshold relationship between landscape pattern and water quality considering spatial scale effect—a case study of Dianchi Lake Basin in China

Environmental Science and Pollution Research - It is of great significance to analyze the threshold relationship between landscape pattern and water quality for watershed water environment...     

Higher sequestration of wheat versus maize crop carbon in soils under rotations

Environmental Chemistry Letters - In the context of climate change, soil is a major pool of stable carbon on earth, yet knowledge on soil carbon turnover is limited. The difference in 13C/12C...     

Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity and reducibility

• The optimum SCR activity was realized by tuning the acid pretreatment. • Optimized catalysts showed NO_x conversion above 90%. • The NH₃ and NO adsorption capacity of Al-O₃-Fe is stronger than Fe-O₃-Fe. • The formation of almandine consumes Fe³⁺ and Al³⁺ and weakens their interaction. Red mud (RM), as an alkaline waste, was recently proved to be a promising substitute for the SCR catalyst. Dealkalization could improve the acidity and reducibility of red mud, which were critical for SCR reaction. However, the dealkalization effect depended on the reaction between acid solution and red mud. In this study, we realized the directional control of the chemical state of active sites through tuning the acid pretreatment (dealkalization) process. The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid. When the pH values of red mud were 3 and 5 (CRM-3 and CRM-5), activated catalysts showed NO_x conversion above 90% at 275°C–475°C. The high initial reaction rate, Ce³⁺/(Ce³⁺ + Ce⁴⁺) ratio, and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst. Meanwhile, more Fe³⁺ on the CRM-3 surface improved the NH₃ adsorption. There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts. DFT results showed that the adsorption capacity of the Al-O₃-Fe for NH₃ and NO is stronger than that of Fe-O₃-Fe, which enhanced the NO_x conversion of the catalyst. However, the almandine was formed in CRM-4, consumed part of Fe³⁺ and Al³⁺, and the interaction between Al and Fe was weakened. Also, deposited almandine on the catalyst surface covered the active sites, thus leading to lower NH₃-SCR activity.     

Correction to: Higher sequestration of wheat versus maize crop carbon in soil under rotations

Environmental Chemistry Letters -