覆压及水分对含瓦斯煤体渗吸特性的影响研究

为研究外加水分条件下受载含瓦斯煤体的渗吸特性,利用自主设计的含瓦斯煤体等压渗吸实验装置对煤体中水分及瓦斯的运移进行连续监测,并在瓦斯压力恒定不变的条件下研究覆压及外加水分对煤体渗吸距离、渗吸速度以及瓦斯置换量的影响。结果表明:水分在煤体中的渗吸距离随时间增长先是快速增加,而后缓慢增大。在相同外加水分条件下,相同时刻水分的渗吸速度随覆压增大而增大;在相同覆压条件下的煤体,相同时刻水分的渗吸速度随外加水分的增大而增大;渗吸过程中水分置换出来的瓦斯量随时间变化分为3个阶段,在第1个阶段覆压和外加水分的变化对瓦斯置换量影响不大,之后的2个阶段瓦斯置换量随着外加水分和覆压的增大而增大,并逐渐达到1个极限值。     

Influencing factors and improvement paths of green water use efficiency in the Yellow River Basin: a new perspective based on ecogeographical divisions

Environmental Science and Pollution Research - Exploring the influencing factors and improvement paths of green water use efficiency (GWUE) based on different regions is very important for the...     

放射性废液桶内干燥装置加热方式初步研究

针对放射性废液桶内干燥装置的研制,就装置的加热方式对目前加热结合桶内干燥装置的要求进行了对比筛选,初步选择微波和热风组合加热方式,在此基础上对微波和热风加热方式进行了试验验证。结果表明,虽然热风加热耗时太长,且微波加热存在盲区,但是两种加热方式干燥模拟废液的效果良好,能够相互补充,因此建议采用微波-热风组合加热方式进行深入研究。     

煤的加水热模拟气特征对比

为探讨煤成气的生成特征和演化规律 ,对两种不同有机质类型煤进行了加水热模拟生气实验研究。认为 ,有机质类型对于煤的热模拟气生成特征和烃气产率有决定作用。非烃气中的氢气、一氧化碳与二氧化碳含量之间呈负相关 ,这与水参与反应有关。甲烷的形成与水的作用关系密切。不同的热模拟气在成熟 -高成熟演化阶段差异明显 ,有机质类型越差 ,热模拟气中甲烷相对越多 ,干燥系数相对越大 ,异丁烷 /正丁烷越高 ;反之 ,甲烷相对越少 ,干燥系数越小 ,异丁烷 /正丁烷低 ,区别越明显。演化程度增加时 ,热模拟气之间的差别减小。总烃气和甲烷的产率随温度升高而增加 ,而重烃有产率高峰存在 ,正好对应于生油窗的底界     

Tracking Cryptosporidium in urban wastewater treatment plants in a cold region: Occurrence,species and infectivity

• Cryptosporidium in WWTPs in a cold region was investigated in different seasons. • The overall removal efficiency of Cryptosporidium in WWTPs was over 84%. • The infectivity rate declined below 53% in effluents mainly due to disinfection. • The infectivity of Cryptosporidium increased with a seasonal drop in temperature. • Low temperature promotes binding protein retention and virulence genes expression. This study investigated the occurrence, species, infectivity and removal efficiency of Cryptosporidium spp. across typical wastewater treatment train. Samples from different process units were collected seasonally and synchronously from four wastewater treatment plants (WWTPs) in Northeastern China. Live Cryptosporidium oocysts were identified in most samples from both influent (97.50%) and effluent (90.00%) wastewaters of the four WWTPs, at an average density of 26.34 and 4.15 oocysts/L, respectively. The overall removal efficiency was 84.25%, and oocysts were mainly removed (62.01%) by the modified secondary sedimentation process. Ten Cryptosporidium species were identified in the effluent samples. C. andersoni, C. bovis, and C. ryanae were the three most prevalent species. Oocyst viability assays indicated no reduction of excystation rate during the primary and secondary wastewater treatments (varied in the range of 63.08%–68.50%), but the excystation rate declined to 52.21% in the effluent after disinfection. Notably, the Cryptosporidium oocysts showed higher infection intensity in the cold season (winter and spring) than that in summer and autumn. The influences of environmental temperature on virulence factors of Cryptosporidium were further examined. It was observed that more extracellular secretory proteins were bound on the oocyst surface and several virulence genes were expressed relatively strongly at low temperatures, both of which could facilitate oocyst adhesion, invasion, and host immune evasion. This research is of considerable interest since it serves as an important step towards more accurate panoramic recognition of Cryptosporidium risk reduction in WWTPs, and especially highlights the potential health risk associated with Cryptosporidium in cold regions/seasons.     

Combined effects of hypoxia and ammonia to Daphnia similis estimated with life-history traits

The degradation of cyanobacterial blooms often causes hypoxia and elevated concentrations of ammonia, which can aggravate the adverse effects of blooms on aquatic organisms. However, it is not clear how one stressor would work in the presence of other coexistent stressors. We studied the toxic effects of elevated ammonia under hypoxia using a common yet important cladoceran species Daphnia similis isolated from heavily eutrophicated Lake Taihu. A 3?×?2 factorial experimental design was conducted with animals exposed to three un-ionized ammonia levels under two dissolved oxygen levels. Experiments lasted for 14 days and we recorded the life-history traits such as survival, molt, maturation, and fecundity. Results showed that hypoxia significantly decreased survival time and the number of molts of D. similis, whereas ammonia had no effect on them. Elevated ammonia significantly delayed development to maturity in tested animals and decreased their body sizes at maturity. Both ammonia and hypoxia were significantly detrimental to the number of broods, the number of offspring per female, and the number of total offspring per female, and significantly synergistic interactions were detected. Our data clearly demonstrate that elevated ammonia and hypoxia derived from cyanobacterial blooms synergistically affect the cladoceran D. similis.     

城市污水厂污泥倾倒对海洋生物的毒性研究

以广州市和佛山市的5个城市污水处理厂的污泥为实验对象,选取费氏弧菌、蒙古裸腹溞、卤虫、裸项栉鰕虎鱼仔鱼4种不同营养级的海洋生物为受试对象,结合化学分析方法,研究广州区域周边污水污泥浸出液的生物毒性效应。结果显示各污水污泥浸出液的毒性均较大,且浸出液的Cu污染浓度较高;广州市污水污泥对4种受试生物的毒性效应要高于佛山市。从污泥毒性对受试生物的选择性方面分析,发现卤虫筛分能力强且灵敏度高,而费氏弧菌则相关性好且方法简捷。研究结果为反映城市污泥的生物毒性强度和选择合适毒性评价受试生物提供基础数据。     

Mn/GO复合催化剂催化氧化NO

针对尾气中NO浓度高且传统方法脱除NO代价高的问题,研究了锰固载氧化石墨诱导单过硫酸氢钾(PMS)催化氧化并吸收NO方法。通过浸渍法在氧化石墨上负载了Mn3O4制得Mn/GO催化剂,以此为催化剂催化PMS氧化NO。研究了p H、PMS投加量、催化剂投加量以及温度等因素对NO氧化率的影响。结果表明,该系列Mn/GO催化剂可以有效地诱导PMS氧化NO,热处理时间为7 h时催化效果最佳。同时,对Mn/GO(7 h)的FT-IR、XRD、SEM、EDS以及XPS表征可知,Mn3O4是主要的锰氧化物,并成功负载在GO表面。     

高氨废水短程硝化特性简

采用SBR装置,针对高氨废水的特点,在高氨条件下,以高氨低氧为转化手段,实现高氨废水短程硝化过程中亚硝化菌的驯化与积累。控制温度为28~31℃,曝气量为15~60 L/h,pH控制在7.8~8.2的条件下连续运行78 d。实验结果表明,运行11 d后实现了短程硝化,从11 d至78 d属于系统氨氮负荷提高期。在运行过程中,氨氮污泥负荷从开始的0.023 kg/（kg·d）逐步上升为0.3 kg/（kg·d）,最高时达到0.34 kg/（kg·d）,此时氨氮去除率仍维持90%以上。为观察驯化后短程硝化菌的形态,取驯化好的污泥进行电镜扫描,结果表明,污泥中的细菌形态主要以球状菌为主。     

Green growth and environmental sustainability in China: the role of environmental taxes

Environmental Science and Pollution Research - This study aims to investigate the impact of environmental-related taxes on green growth and CO2 emissions in China covering the time 1996–2019....