Artificial indoor streams as a method to investigate the impact of chemicals on lotic communities

The potential hazard of chemicals on aquatic communities are generally evaluated by standardised single-species bioassays. Safety assessment is based on results gained from organisms adapted to lentic systems and biological interactions in ecosystems are neglected. While lotic communities are often at first in contact with chemicals, it is astonishing that microcosms with lentic communities are mainly used as a bridge between laboratory bioassays and outdoor aquatic systems. Hence, we established five artificial indoor streams to simulate abiotic factors of small rivers. The closed-circuit system was filled with nutrients added to tap water. Washed pebbles were used as sediment. The dynamics of a simple biocoenoses consisting of aufwuchs, Lumbriculus variegatus Asellus aquaticus and Gammarus fossarum was investigated. The dynamic of aufwuchs and periphyton was determined as dry weight and chlorophyll-a, respectively and qualitatively by pigment pattern. The abundance of different developmental stages of L. variegatus was determined at the end of the experiment as well as the population dynamics of G. fossarum and A. aquaticus. Survival rates of gammarids and juveniles per female were investigated and data were used for modelling the population dynamics. The experiment was carried out to investigate the performance of the established artificial streams and the developed approaches to investigate effects of chemicals on a basic lotic community. The prime reason to establish this approach was to close a gap between complex artificial stream systems and laboratory single species tests to assess the impact of chemicals on the aquatic environment.     

混床填色谱柱在有机氯农药残留分析中的应用

在植物粮食、土壤有机氯农药残留监测，使用涂有ＯＶ－１７和ＱＦ－１固定液的白色载体ＣｈｒｏｍｏｓｏｒｂＷ，该种色谱柱对六六六的四种异构体分离比较好，但对ＤＤＴ的四种异构体分离不理想，采用红色载体ＣｈｒｏｍｏｓｏｒｂＰ和白色载体ＣｈｏｍｏｓｏｒｂＷ湿床填充的色谱柱，分离有机氯农药８种组份仅需１５分钟，提高了有机氯农药的分离分析效果。     

论炼油厂液氨质量及出路

炼油厂生产液氨，作为综合利用产品给社会带来益处，但液氨质量不好无法出厂，放火矩烧不仅浪费资源，同时造成大气污染。为解决炼油厂液氨出路，首先通过技术攻关解决液氨质量问题，并试用气氨作为燃料获得成功，达到既可生产液氨，又可作为锅炉燃料，彻底解决了炼油厂液氨出路。     

二氧化氯预氧化工艺处理微污染黄河水研究

对二氧化氯预氧化工艺替代预加氯系统处理低温、含异味和较高色度的黄河原水进行了综合研究.与预氯化、混凝沉淀系统相比,二氧化氯预氧化、混凝沉淀系统对藻类的去除率提高了30%～40%,使嗅和味的阈值降低了10～20,但CODmn和氨氮的去除率的变化不明显.由于进水色度变化较大,对色度的去除率变化也不明显.运行证明,该系统改造后对降低以微污染黄河水为水源的北方给水处理厂冬季运行过程中的出水嗅和味的阈值、增加藻类的去除率具有明显的效果,同时,运行费用也较低.     

膜电解氢自养MBBR反应器深度转化水中高氯酸盐

建立膜电解电化学氢自养MBBR反应器（移动床生物膜反应器）用于去除水中高氯酸盐,微生物利用阴极电解产生的氢气将高氯酸根还原为氯离子,而后氯离子在阳极发生氧化析氯反应生成活性氯进一步提升出水水质,从而实现高氯酸根的深度转化.利用该反应器研究了高氯酸根的转化过程及相关影响因素,结果表明：进水ClO₄^-浓度为（4.98±0.091）mg/L,维持HRT（水力停留时间）为4h,施加电流由6mA增加至15mA,反应器对高氯酸根的去除率由（39.75±2.09）%增加至（98.99±0.05）%,总出水活性氯浓度由（0.057±0.003）mg/L增加至（0.070±0.002）mg/L,pH值稳定在7.96~8.11,浊度较低为（0.89±0.27）NTU.进一步增大施加电流（20mA）,导致阴极室溶液pH值超过9.5,进而影响微生物活性,去除率急剧下降至（30.75±1.19）%.利用扫描电子显微镜（SEM）观察反应器内微生物形貌,发现反应器内微生物均附着于填料表面,以短杆菌为主,增殖缓慢.运用高通量测序技术对接种及运行第24d的微生物群落结构展开分析.结果显示,反应器运行过程中,菌群多样性下降,Thauera菌属为主要的氢自养还原优势菌属,其丰度达到8.25%.     

超临界CO2和液态CO2及气态N2注入采空区防灭火性能实验

为对比研究超临界态CO_2、液态CO_2和气态N_2注入采空区的防灭火性能,自主研制了模拟采空区残煤自燃过程实验系统,开展了超临界态CO_2、液态CO_2和气态N_2注入采空区防灭火实验。实验结果表明:12 MPa、39℃超临界态CO_2对采空区自燃残煤的降氧降温能力优于6 MPa、30℃液态CO_2优于6 MPa、39℃气态N_2;12 MPa、39℃超临界态CO_2对残煤的降温能力是6 MPa、30℃液态CO_2的1.7倍,是6 MPa、39℃气态N_2的10倍,对采空区的降温能力是液态CO_2的2倍,为气态N_2的8倍;12 MPa、39℃超临界CO_2对采空区的降氧速率比6 MPa、30℃液态CO_2和6 MPa、39℃气态N_2高12.5%;12 MPa、39℃超临界CO_2的降温能力是8 MPa、39℃超临界CO_2的1.7倍,因此适当提高超临界态CO_2的注入压力,防灭火性能更佳。     

ClO_2溶液去除烟气中NO的效果及工程应用

采用实验室规模喷淋脱硝装置对ClO_2溶液去除NO的效果及影响因素进行探讨,通过脱硝产物的测定对ClO_2溶液去除NO的能力及机理进行分析;在此基础上考察ClO_2溶液对供热厂燃煤锅炉烟气的实际脱硝效果。实验结果表明:在液气比为20L/m~3、反应温度为20℃,反应pH为4.0、进气NO质量浓度为250 mg/m~3,ClO_2质量浓度为200 mg/L的条件下,NO去除率达97%以上;ClO_2溶液可将NO氧化吸收为NO_3~-,氧化后产生的NO_x也可被NaOH溶液吸收转化为NO_2~-和NO_3~-;在ClO_2质量浓度为200~500 mg/L,反应pH为5.5~7.0的条件下处理初始NO质量浓度为212~230 mg/m~3的燃煤锅炉烟气,NO去除率为85.7%~94.6%,NO_x去除率为80.4%~88.8%,出口NO_x质量浓度低于46 mg/m~3,远低于GB 13271—2014规定的排放限值。     

Experimental study of the evaporation of spreading liquid nitrogen

The investigation of cryogenic liquid pool spreading is an essential procedure to assess the hazard of cryogenic liquid usage. There is a wide range of models used to describe the spreading of a cryogenic liquid pool. Many of these models require the evaporation velocity, which has to be determined experimentally because the heat transfer process between the liquid pool and the surroundings is too complicated to be modeled. In this experimental study, to measure the evaporation velocity when the pool is spreading, liquid nitrogen was continuously released onto unconfined concrete ground. Almost all of the reported results are based on a non-spreading pool in which cryogenic liquid is instantaneously poured onto bounded ground for a very short period of time. For the precise measurement of pool spreading and evaporation weight with time, a cone-type funnel was designed to achieve a nearly constant liquid nitrogen release rate during discharge. Specifically, three nozzles with nominal flow rates of 3.4 × 10⁻² kg/s, 5.6 × 10⁻² kg/s and 9.0 × 10⁻² kg/s were used to investigate the effect of the release rate on the evaporation velocity. It is noted that information about the release rate is not necessary to measure the evaporation velocity in case of the non-spreading pool. A simultaneous measurement of the pool location using thermocouples and of the pool mass using a digital balance was carried out to measure the evaporation velocity and the pool radius. A greater release flow rate was found to result in a greater average evaporation velocity, and the evaporation velocity decreased with the spreading time and the pool radius.     

Effect of initial temperature on the explosion pressure of various liquid fuels and their blends

In this work, the effect of initial temperature on the explosion pressure, P_ex, of various liquid fuels (isooctane, toluene and methanol) and their blends (isooctane-toluene and methanol-toluene, with three different fuel-fuel ratios) was investigated by performing experiments in a 20-l sphere at different concentrations of vaporized fuel in air. The initial temperature was varied from 333 K to 413 K.Results show that, as the fuel-air equivalence ratio, Φ, is increased, a transition occurs from a “thermodynamics-driven” explosion regime to a “radiant heat losses-driven” explosion regime. The maximum pressure, P_max, is found in the former regime (Φ < 3), which is characterized by a trend of decreasing P_ex with increasing initial temperature. This trend has been explained by thermodynamics. In the latter regime (Φ > 3), P_ex increases with increasing initial temperature. This trend has been addressed to the decrease in emissivity (and, thus, radiant heat losses) with the increase in temperature.     

分散固相萃取/高效液相色谱法测定土霉素菌渣中土霉素的残留量

文章拟建立一种从土霉素菌渣中提取并检测土霉素残留量的高效液相色谱法。用甲醇和冰乙酸作为提取剂提取样品,用分散固相萃取的方法净化样品,净化药剂为石墨化碳黑(GCB)和C18。通过加标回收实验,用高效液相色谱仪检测样品中土霉素含量。选用的色谱柱为PLRP-S,流动相为甲醇和0.05 mol/L草酸,两者比例为35:65(V:V)。检测波长为355 nm,柱温30℃。经检测,土霉素在0.1~2 000 mg/L范围内线性相关系数大于0.999,线性良好。1.0,4.0及8.0mg/g 3个加标水平的土霉素平均回收率范围是80.85%~109.59%,相对标准偏差(RSD)为2.45%~6.38%。土霉素菌渣中土霉素残留量平均为4.741 mg/g。实验表明,该方法具有简单、方便、快速、准确性强、灵敏度高的特点,可以应用于土霉素的分析检测。