An approach to calculating allowable watershed pollutant loads

To improve the management of discharge pollutants loads in the reservoirs’ watershed, an approach of the allowable pollutants loads calculation and its allocation, based on the water environment model, was proposed. Establishment of the approach framework was described at first. Under the guidance of this framework, two major steps were as follows: modeling and scenario analysis were involved and should be applied to support the decision of discharge loads management; Environmental Fluid Dynamic Code (EFDC) model was selected as the kernel model in this framework. In modeling step, spatial discretization for establishing cell map in model, data preprocessing, parameter calibration and uncertainty analysis (which is considered as the significantly relevant factor of the margin of safety (MOS)), were conducted. As a result of the research, the model-based approach presented as a combination of estimation and precise calculation, which contributed to scenario analysis step. Some integrated modules, such as scenario simulation, result analysis and plan optimization were implemented as cycles in the scenario analysis. Finally, allowable pollutant loads under various conditions were calculated. The Chaihe Reservoir in Liaoning Province, China was used as a case study for an application of the approach described above. Results of the Chaihe reservoir water quality simulation, show good agreement with field data and demonstrated that the approach used in the present study provide an efficient and appropriate methodology for pollutant load allocation.     

不同喷油策略对柴油-四氢呋喃混合燃料燃烧和排放的影响

为了解决环境污染和能源短缺等问题,本研究针对四氢呋喃作为一种含氧替代燃料展开研究.在一台六缸增压柴油机上开展了不同喷油策略下四氢呋喃和柴油混合燃料对柴油机燃烧和排放的影响研究,所用3种燃料分别为：纯柴油、5%四氢呋喃和95%柴油、15%四氢呋喃和85%柴油混合燃料（混合比例均为体积比）,以原机国六脉谱图为基准调节主喷时刻和喷油压力.结果表明,添加5%四氢呋喃使燃油消耗率增加,有效热效率降低,当加入15%四氢呋喃后燃油消耗率进一步升高,有效热效率相比于添加5%四氢呋喃有一定程度改善,但仍低于纯柴油燃料;当喷油压力高于100 MPa时,混合燃料的燃油消耗率和有效热效率随喷油压力的提高基本保持不变.四氢呋喃加入使小负荷下NO_x、CO和HC排放增加;大负荷下使NO_x排放增加,CO和HC排放逐渐降低,各工况下的碳烟排放均降低.由此可见,柴油-四氢呋喃混合燃料的有效热效率相比于纯柴油降低了1%~2%,加入四氢呋喃可有效降低碳烟排放和改善部分工况下的气体污染物排放.     

烧结烟气活性炭脱硫研究

研究了烧结烟气脱硫剂活性炭的反应原理。根据烧结厂烟气参数,在活性炭烧结烟气脱硫试验装置中,研究了活性炭粒度,烟气温度及活性炭质量对烧结烟气脱硫率的影响。研究结果表明:利用活性炭脱硫效率可以达到95.5%以上,为进一步工业应用奠定了基础。     

好氧填埋技术对渗滤液水质变化的影响

垃圾填埋场产生大量渗滤液,而一般厌氧型填埋场产生渗滤液中含有很高浓度的有机物。因此,渗滤液成为填埋场的难题。通过试验模拟垃圾的好氧填埋过程,并在此过程中对垃圾产生渗滤液中的COD、BOD5和NH 4+-N进行连续监测,通过试验初步得出:在好氧填埋条件下,垃圾堆体产生渗滤液中有机物和NH 4+-N浓度得到较大程度降低。渗滤液中COD、BOD5和NH 4+-N的降解率分别高达98.99%、99.94%和99.78%。     

好氧反硝化菌种DF2的分离鉴定及生理生化特性分析

分离了新型的高效反硝化细菌并研究其生物脱氮效率。通过观察形态学、生理生化鉴定和16SrRNA基因同源分析来鉴定菌种,致力于研究微生物污水脱氮处理的实际效果和克服反硝化过程中有害中间产物的积累。利用BTB培养基从水平潜流人工湿地基质中初步筛选出了9株平板阳性菌,革兰阴阳性均有。经试验研究发现该9种菌株在好氧条件下均具有一定的脱氮能力,其中以DF2和DF3 2种菌株脱氮能力最为显著,在3 d时间内NOX--N去除率达到了95%以上,NO2--N仅有微量积累;而其它7种菌株对NO3--N的去除率可以达到98%以上,但是NO2--N积累比较严重,积累量达到了NO3--N去除的50%~70%左右。经测序分析鉴定DF2和DF3分别属于德克斯氏菌属（Derxia）和假单胞菌属（Pseudomonadaceae）。德克斯氏菌属作为除氮的反硝化菌属在以往的研究中鲜有报道,该菌在好氧条件下可以合成周质NAR的亚基基因（napA）。     

Vitamin D mediates the association between acrylamide hemoglobin biomarkers and obesity

Environmental Science and Pollution Research - Mediation analysis aims to discover the role of intermediate variables from exposure to disease. The current study was performed to evaluate how...     

Evaluation of phoxim toxicity on aquatic and zebrafish intestinal microbiota by metagenomics and 16S rRNA gene sequencing analysis

Environmental Science and Pollution Research - Phoxim is one of the main organophosphorus pesticides used in agricultural production. However, little information is known about how it affects the...     

Alteration of dominant cyanobacteria in different bloom periods caused by abiotic factors and species interactions

Freshwater cyanobacterial blooms have drawn public attention because they threaten the safety of water resources and human health worldwide. Heavy cyanobacterial blooms outbreak in Lake Taihu in summer annually and vanish in other months. To find out the factors impacting the cyanobacterial blooms, the present study measured the physicochemical parameters of water and investigated the composition of microbial community using the 16S rRNA gene and internal transcribed spacer amplicon sequencing in the months with or without bloom. The most interesting finding is that two major cyanobacteria, Planktothrix and Microcystis, dramatically alternated during a cyanobacterial bloom in 2016, which is less mentioned in previous studies. When the temperature of the water began increasing in July, Planktothrix appeared first and showed as a superior competitor for M. aeruginosa in NO₃^?-rich conditions. Microcystis became the dominant genus when the water temperature increased further in August. Laboratory experiments confirmed the influence of temperature and the total dissolved nitrogen (TDN) form on the growth of Planktothrix and Microcystis in a co-culture system. Besides, species interactions between cyanobacteria and non-cyanobacterial microorganisms, especially the prokaryotes, also played a key role in the alteration of Planktothrix and Microcystis. The present study exhibited the alteration of two dominant cyanobacteria in the different bloom periods caused by the temperature, TDN forms as well as the species interactions. These results helped the better understanding of cyanobacterial blooms and the factors which contribute to them.     

Cobalt exposure in relation to cardiovascular disease in the United States general population

Environmental Science and Pollution Research - Cobalt exposure has adverse health effects on the cardiovascular system in occupational and laboratory studies, but these effects have not been...