燃煤过程中微量元素砷和硒形态转化的热力学平衡模拟

砷和硒是煤中的易挥发有毒微量元素。由于砷和硒在燃煤烟气中的浓度极低以及实验条件的限制 ,目前化学热力学平衡分析已成为预报烟气中砷和硒等有毒元素形态分布的主要理论分析方法。本文综述了热力学平衡分析方法应用于砷和硒在燃煤过程中形态转化和平衡分布等方面的研究进展。首先用于热力学平衡分析的是只含有砷或硒一种微量元素和煤中主量元素及氯元素的简单体系 ,并假设烟气中只有理想气体组成的气相和纯凝聚相的理想模型。然而是否考虑砷和硒与其他微量、主量或次量元素的相互作用 ,砷和硒所有可能存在的反应 ,以及在熔融相砷和硒与熔融物的结合会严重地影响模型的预报结果 ,因此 ,目前热力学平衡体系已发展成为含有包括砷和硒在内的多个微量元素和煤中所有主量、次量元素 ,以及包括熔融相在内的非理想多相复杂体系     

Full-scale experience for nitrogen removal from piggery waste.

The nitrogen-removal performances of three full-scale piggery wastewater treatment plants, with different organic and nitrogen loads, at the capacity ranges of 95 to 130 m3/d, were compared in this study. Plants 1 and 2 can be characterized as the modification of anoxic-aerobic operating systems, while an anaerobic and anoxic-aerobic system was used in plant 3. The influent piggery wastewater concentration for plant 1 was relatively lower, but with higher organic and nitrogen loads, resulting in higher chemical oxygen demand (COD) and ammonium-nitrogen in effluent. Plant 2 was operated with strong piggery wastewater, resulting in a higher operating temperature. The high temperature could inhibit the nitrifying activity in plant 2. Although plant 3 was operated with a higher influent total COD-to-total Kjeldahl nitrogen ratio (TCOD:TKN), an additional external carbon source was required to polish the final effluent to remove nitrogen. Influent COD in plant 3 was used in the anaerobic-anoxic reactor for both methane (CH4) production and denitrification. Based on various mass balances, including caloric, COD, and alkalinity, the key elements for the successful nitrogen removal from the piggery waste were reactor temperature (less than 35degrees C), influent TCOD:TKN (greater than 6), and alkalinity-to-TKN ratio (greater than 3).     

超滤分离、浓缩、脱盐青霉素酰化酶的研究

本文用中空纤维超滤膜对青霉素酰化酶进行了分离、浓缩的研究、实验了不同种类的膜、不同的酶活浓度、不同运行时间和不同压力等因素对膜透水量、截留率和酶的回收率的影响。结果表明:采用超滤技术分离、浓缩、脱盐青霉素酰化酶工艺,具有操作简单,酶的比活高,回收率高和省能等特点,适用于工业化生产。     

污水塘自净作用及环境因素的影响

本文研究了在自然状况下污水塘的净化作用及其效率,通过对总氮、总磷、COD_(Cr)和BOD_5等在进、出水中的含量与水温进行回归分析,建立了三者之间的相关性方程。同时讨论了水温对污水塘的自净效率的影响。     

抚仙湖流域主要生态安全问题识别

对抚仙湖的水质污染、水环境安全、生物多样性环境安全、湖泊湿地与环境安全、水资源4方面进行了安全问题识别,在此基础上开展抚仙湖生态资源环境安全问题识别,包括农业耕作土污染的环境安全问题、土壤侵蚀（水土流失）环境安全问题。结果表明：抚仙湖的生态安全面临一定的威胁,必须采取有效措施,切实解决生态环境问题,维护湖泊生态安全。     

Relation of hepatic EROD activity and CYP1A level in Sebastiscus marmoratus exposed to benzo[a]pyrene

This study was designed to investigate the in vivo effects of benzo[a]pyrene (BaP) on hepatic ethoxyresorufin-O-deethylase (EROD) activity and its correlation with cytochrome P450 1A (CYP1A) protein levels in Sebastiscus marmoratus, which were exposed through a water column to BaP (10, 100, 1000 ng/L, respectively) or were treated with intraperitoneal injections of BaP (0.5, 1, 5, 10 mg/kg, respectively) every 7 d. The results showed that after 25 d of waterborne exposure to 1000 ng/L BaP, fish hepatic CYP1A levels and EROD activity were significantly induced. In contrast, EROD activity was not altered 7 d after second ip injections, whereas, CYP1A protein levels were increased. Dose-dependent increase of biliary BaP metabolites demonstrated that the catalytic activity of CYP1A was induced by treatment with BaP. The lowest observable effect concentration with regard to biliary BaP metabolites (100 ng/L) was much lower than that with reference to EROD activity (1000 ng/L). The results suggest that biliary polycyclic aromatic hydrocarbon (PAH) metabolites were shown to better reflect the contamination gradients of PAHs than EROD activity. It appeared to be necessary to measure CYP1A protein levels to complement the EROD activity in relevant toxicological assessments.     

未来10年保定市大气PM2.5的健康效益预测

分别设定保定市2020年、2025年及2030年PM_2.5浓度的不同目标情景,并考虑人口发展趋势,采用IER模型对各区县低、中、高目标情景下归因于PM_2.5污染的过早死亡人数进行评估.结果表明,以2017年大气PM_2.5浓度为基线,按照高中低3种预测情景,在2020年、2025年和2030年分别能避免的过早死亡人数高达1582~3840人、5244~7902人和12602~23558人,主要分布在市中心（莲池区、竞秀区和清苑区）及其东南区域.随着老龄化问题越来越严重,环境质量改善获得的健康收益愈加突出,心血管系统疾病（中风和缺血性心脏病）的归因死亡人数多于呼吸系统疾病（肺癌、慢阻肺疾病以及急性下呼吸道感染）.当PM_2.5浓度高于20μg/m³时,中风的归因死亡人数最高;当PM_2.5浓度小于10μg/m³时,缺血性心脏病的归因死亡人数最高.建议保定市在制定PM_2.5污染防控政策时重点关注人群密集的市区及东南方向地区,并考虑大气污染不同阶段导致的过早死亡疾病类型进行针对性的宣教和防控.     

A collaborative strategy for enhanced reduction of Cr(VI) by Fe(0) in the presence of oxalate under sunlight: Performance and mechanism

Nanometer-size zero-valent iron (NZVI) is an efficient reducing agent, but its surface is easily passivated with an oxide layer, leading to reaction inefficiency. In our study, oxalate (OA) was introduced into this heterogeneous system of NZVI, which could form ferrioxalate complexes with the NZVI surface-bound Fe³⁺ and dissolved Fe³⁺ in the solution. Photolysis of ferrioxalate complexes can facilitate the generation of Fe²⁺ from Fe³⁺ and CO₂^?- radical, both species have strong reduction capacity. Hence, a “photo-oxalate-Fe(0)” system through sunlight induction was established, which not only prohibited the formation of a surface passivation layer, but also displayed a synergetic mechanism of ferrioxalate photolysis to enhance reduction, exhibiting remarkably higher degradation activity (several times faster) toward the model pollutant Cr(VI) than the mechanism with NZVI alone. Factor tests suggested that both NZVI dosage and OA content markedly affected the reduction rate. Low pH was beneficial to the reduction efficiency. Moreover, recyclability experiment showed that the reduction rate decreased from 0.21706 to 0.03977 min^?1 after three cycles of reuse due to the NZVI losing reaction activity generally, but the system still maintained considerable reduction capacity. Finally, a mechanism was revealed whereby NZVI would transform to Fe oxides after the exhaustion of its reductive power, and the photolysis of ferrioxalate to promote the cycling of iron species played the predominant role in providing extra reduction ability. These features confirm that introduction of OA into Cr(VI) reduction by NZVI through sunlight induction is advantageous and promising.     

基于远程通讯技术的混动公交车SCR系统运行及NOx排放特征

SCR技术是降低包括常规、混合动力公交车在内的重型柴油车NO_x排放的重要手段.基于无线远程通讯技术,对杭州市秋冬季11辆实际运行的混合动力公交车SCR系统的运行和NO_x排放特性进行了研究.分别研究了混合动力公交车内燃机模式下车速及发动机运行工况和环境温度对SCR催化器后温度、尿素喷射量和SCR催化器后NO_x排放浓度的影响.结果表明,安装有SCR系统的混合动力公交车有(32.4±4)%的运行时间处于内燃机模式下,模式下平均有(26.9±11)%的运行时间SCR没有工作;SCR系统正常工作的混合动力公交车的NO_x平均减排率约为59%;SCR系统未达到运行要求而不工作和SCR催化器低温转化效率低是造成公交车NO_x排放较高的主要原因;当车速高于40 km·h-1时,SCR催化器后温度上升至230℃以上,SCR系统的工作比例和尿素喷射量上升的同时NO_x排放大幅下降;进入冬季,随着环境温度的降低,混合动力公交车SCR催化器出口温度降低的同时,平均尿素喷射量降低导致NO_x排放恶化.     

污水厂中微塑料的污染及迁移特征研究进展

合成聚合物的广泛使用和持久性污染使得微塑料（<5mm）成为近年来受到广泛关注的一种新型污染物,污水的大量排放是淡水和海洋环境微塑料的主要来源之一,而污水处理厂也成为微塑料进入淡水与海洋环境的一个重要途径.通过系统调研,追溯污水处理厂中微塑料的来源,综述污水处理厂中微塑料的迁移和污染特征的研究进展,分析国内外污水处理厂中微塑料的特征和去除效果的差异性,为开展国内污水处理厂中微塑料污染研究与监督工作提供参考,并展望未来污水处理厂工艺的发展及改进方向.