Effects of operational factors on soluble microbial products in a carrier anaerobic ba ed reactor treating dilute wastewater

The effects of feed strength, hydraulic residence time （HRT）, and operational temperatures on soluble microbial product （SMP） production were investigated, to gain insights into the production mechanism. A carrier anaerobic baffled reactor （CABR） treating dilute wastewater was operated under a wide range of operational conditions, namely, feed strengths of 300-600 mg/L, HRTs of 9- 18 h, and temperatures of 10-28℃. Generally, SMP production increased with increasing feed strength and decreasing temperature. At high temperature （28℃）, SMP production increased with decreasing HRT. As the temperature was decreased to 18 and 10℃, the SMP production was at its peak for 12 h HRT. Therefore, temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand （SCOD） ratio was found at high temperature and long HRT because of complete volatile fatty acid degradation. SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR. As a secondary metabolite, some SMP could be consumed at lower feed strength.     

Lims系统发展历史及在环境监测站的应用

介绍了Lims系统的发展历史和最新概况,阐述了Lims系统在环保系统的实验室应用意义:提高监测站综合监测能力和分析水平,建立起快速高效的质量监督信息化平台,确保监测工作更好地为管理、科研及客户服务。应该具有的主要功能:实验室管理和业务流程控制。系统实施的主要步骤:需求调研、信息收集、详细需求设计、软件设计、运行调试等。关键词:     

金沙江下游梯级电站开发影响区域的资源开发与产业可持续发展

金沙江下游是我国长江经济带的重要组成部分,也是西南地区生态建设和区域经济社会发展的中心。“西电东送”骨干工程的向家坝、溪洛渡、白鹤滩、乌东德四大水电站均分布在这一江段。通过对该区域资源开发和产业发展的现状、问题和发展前景进行分析,得到如下主要结论：（1）该区域农业资源丰富多样,矿产资源分布广泛且优势矿种地位突出,旅游资源待开发潜力巨大,但是资源开发却面临着勘探开发程度不够、浪费污染严重、资金交通制约和生态环境脆弱等几大问题;（2）区域产业经济发展迅速但总体水平低,部门结构中以种植业为主的农牧业占主导,林牧业和特色产业有待进一步开发,产业发展面临着部类和区域不均衡、结构矛盾突出以及效益低下等问题的困扰。在此基础上,提出该区域必须以梯级电站和水能开发为契机,切实抓好移民工作,立足资源优势,主打“特色”和“品牌”战略,经济效益和社会生态效益并重,寻找区域资源开发和产业可持续发展的道路。     

西湖和东苕溪沉积物重金属化学形态分析

不同赋存形态重金属的环境行为和生态效应不同,水体沉积物中重金属的迁移转化及其潜在环境危害更大程度上取决于其赋存形态.本研究在西湖和东苕溪设置12个采样点采集沉积物样品,采用改进BCR分步提取法,提取了重金属污染物的4种化学形态,分别为弱酸提取态、可还原态、可氧化态及残渣态.结果表明:沉积物中Cd以弱酸提取态为主,对外界...     

Effects of climate change on water resources in Tarim River Basin, Northwest China

Based on hydrology, temperature, and precipitation data from the past 50 years, the effects of climate change on water resources in Tarim River Basin in Northwest China were investigated. The long-term trends of the hydrological time series were detected using both parametric and nonparametric techniques. The results showed that the increasing tendency of the temperature has a 5% level of significance, and the temperature increased by nearly 1℃ over the past 50 years. The precipitation showed a significant increase in the 1980s and 1990s, and the average annual precipitation exhibited an increasing trend with a magnitude of 6.8 mm per decade. A step change occurred in both the temperature and precipitation time series around 1986. The streamflow from the headwater of the Tarim River exhibited a significant increase during the last 20 years. The increase in temperature, precipitation, and streamflow may be attributed to global climate change.     

Concentrations of additive arsenic in Beijing pig feeds and the residues in pig manure

The swine industry in China has grown rapidly over last two decades. Great amount of pig manure is generated in China, which can be used as organic fertilizers on agricultural lands. Meanwhile, the organic arsenic compounds have been used as feed additives for swine disease control and weight improvement. Once the excessive additives are released in the environment, arsenic may compromise food safety and environmental quality. There is a growing public concern about the arsenic residues accumulation in pig manure, however, little work has been done to investigate the exact arsenic content in pig feed and the residues in manure in China This study investigates the concentrations of arsenic in 29 pig feed samples and 29 manure samples collected from eight pig farms in the Chaoyang district, Beijing city. The detected rate of arsenic in 29 couples of samples was 100%. The concentrations of arsenic in pig feeds and manures ranged from 0.15 to 37.8 mg/kg and 0.42 to 119.0 mg/kg, respectively. The result showed that arsenic concentration in pig manure will be greatly elevated when the arsenic in pig feed was largely increased. The loading rates of pig manure in fourteen Beijing counties and districts were in the range of 2.7–57.2 t/ha yr. Accordingly, the potential soil arsenic increase rates resulting from land application of pig manure might range between 11.8 and 78.9 μg/kg yr. Despite these findings, it is too early to draw the conclusion that arsenic pollution from pig manure is serious in Beijing farmland; therefore, longitudinal studies about the chemical form transformation and the environmental behaviors of pig manure arsenic are required in order to come up with more definitive conclusions.     

李仙江流域梯级电站开发对生态环境的影响及防治措施

李仙江流域梯级电站开发建设即有单个电站对生态环境的影响特征，又有影响的累积性、群体性、系统性、波及性和潜在性。分析了流域梯级电站开发建设对植被、生物多样性、鱼类、水文、水质等产生的影响，提出了相应的防治措施。     

氧化沟不同曝气模式对氮磷去除性能的优化与比较

采用轮流搅拌-曝气SBR系统模拟氧化沟的运行方式,探讨分点曝气和分段曝气对氮磷的去除效果.结果表明,在供气量相同的条件下,分点曝气系统溶氧效率高,一个循环的好氧区比分段曝气系统长,但是分段曝气溶解氧(DO)的有效利用率(用于除氮除磷)高,二者硝化能力相当,氨氮(NH4+-N)去除率分别为96.68%和97.03%,硝化菌活性(以NH4+-N/MLVSS计)分别为4.65和4.66 mg.(g.h)-1.在缺氧区和好氧区比例皆为1时,分点曝气在2、4、7个分区时总氮(TN)去除率分别为60.14%、47.93%和33.7%;总磷(TP)去除率分别为28.96%、23.75%和24.31%,即分区越少,对TN和TP的去除皆有利,但是更利于TN的去除;而分段曝气只有1个分区,其TN和TP的去除率分别为64.21%和49.09%,分段曝气对氮磷的去除效果优于分点曝气,但对提高TP的去除率更有利.对于分段曝气,在满足硝化效果的前提下,增大缺氧区与好氧区的比例,氮磷的去除效率增加.当缺氧区与好氧区的比例由1∶1增大至1.8∶1,其TN和TP的去除率分别提高到73.94%和54.18%.继续增加缺氧区的比例,将影响硝化和运行的稳定,从而影响氮磷的去除效果.     

Macroscale and microscale analysis of Anammox in anaerobic rotating biological contactor

Inoculated with conventional anaerobic activated sludge, the Anammox process was successfully developed in an anaerobic rotating biological contactor (AnRBC) fed with a low ratio of C/N synthetic wastewater. Operated in a single point feed mode, the AnRBC removed 92.1% (n = 126) of the influent N at the highest surface load of 12 g/(m².day). The biomass increased by 25% and 17.1 g/(m².day) of maximum N removal surface load was achieved by elevating flow rate with another feed point. Fluorescence in situ hybridization and polymerase chain reaction analysis indicated that the Anammox genus Candidatus Kuenenia stuttgartiensis dominated the community. Both Anammox and denitrifying activity were detected in biofilm by the application of microelectrodes. In the outer layer of the biofilm (0-2500 μupm), nitrite and ammonium consumed simultaneously in a ratio of 1.12/1, revealing the occurrence of Anammox. In the inner layer (> 2500 μupm), a decrease of nitrate was caused by denitrification in the absence of nitrite and ammonium.     

疫情期间《消防工程学》在线教学课堂的建设

为做到疫情期间“停课不停教、停课不停学”,本文针对线上教学的特点,基于“六步网课教学法”理论,为《消防工程学》在线教学课堂设计了一种将课前准备和预习、课中学习和互动以及课后复习和督导融为一体的“三位一体”式教学方法,同时为在线教学构建科学的课程考评体系、配置丰富的资源、组建合理的教学团队以及制定有力的课程保障措施。教学实践显示,《消防工程学》在线教学课堂的建设效果显著,实现线上教学与线下教学的同质等效。