Identical full-scale biogas-lift reactors (BLRs) with anaerobic granular sludge and residual activated sludge for brewery wastewater treatment and kinetic modeling

Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor （R1） started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate （OLR） of 7.4 kg chemical oxygen demand （COD）/（m3.day）, COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor （R2） started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/（m^3·day）, COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics,biogas compositions, and biogas- lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients （R2 〉 0.95）, which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time.     

人工鱼群神经网络应用于城市污水处理厂进水量预测研究

城市污水处理厂进水量的预测精度对污水厂的安全运行与科学管理具有重要影响。将人工鱼群算法用于神经网络的训练过程,并根据污水厂进水量的变化特性,考虑其周期性及气温、天气和节假日等影响因素,建立人工鱼群神经网络的预测模型。将人工鱼群神经网络预测模型应用到实际中,研究结果表明人工鱼群神经网络具有预测精度高、误差小的优点,在污水管网监测预警及实现管网与水厂联动等方面具有一定的实际意义。     

珠穆朗玛峰地区新降雪的化学特征

根据1998年8、9月份在珠穆朗玛峰东侧东绒布冰川源头所采集的新降雪样的化学成分资料并与不同时期前人在该地区采集的降水样进行对比,初步探讨了该地区降水的化学特征及其气候环境意义.结果表明,珠峰地区夏末降水非常纯净,主要离子浓度可与南极和格陵兰地区相当,代表了全球偏远地区的大气环境本底值;珠峰地区不同季节降水的化学成分有明显的差异,反映了不同的水汽来源和气候状况.8～9月的水汽主要来源于南亚季风;4～5月的降水深受中亚干旱、半干旱区粉尘的影响,说明其降水的化学特征具有气候敏感性.     

天津市大气降水化学组成特征及来源分析

为了解天津市大气降水的化学组成及其来源,2013年1—12月在天津市环境监测中心、天津市塘沽区环境保护监测站、天津市蓟县环境保护监测站采集降水样品,分析了pH、EC(电导率)和主要离子的分布特征. 结果表明:天津市降水的pH、EC雨量加权平均值分别为5.58、98 μS/cm. 降水中各离子雨量加权平均当量浓度(当量浓度＝质量浓度×离子价数/分子量)为Ca2+>SO₄2->NH₄+>NO₃->Cl->Mg2+>Na+>F->K+. 其中,Ca2+、SO₄2-、NH₄+、NO₃-和Cl-是降水中的主要离子,占总离子当量浓度的91.3%. 降水中SO₄2-/NO₃-(当量浓度比)为2.1,近10年来呈逐渐降低趋势,表明天津市大气污染向复合型转变趋势明显. 总离子当量浓度季节差异大,冬季高、夏季低;SO₄2-、NH₄+、NO₃-等当量浓度在冬季最高,Ca2+当量浓度在春冬季基本相当. 从空间分布上看,降水化学组成在天津市环境监测中心、天津市塘沽区环境保护监测站、天津市蓟县环境保护监测站分别表现为受综合源、工业源和海洋源、工业源和农业源的影响特征. 富集因子计算结果表明:降水中Ca2+和K+主要来自地壳;Mg2+主要来自地壳,同时也受海洋源的影响;Cl-的海洋源和人为源的贡献基本相当;但降水中的SO₄2-、NO₃-主要来自人为活动.      

环境因子对水华暴发的影响研究

水华是当水体藻类开始大量生长和繁殖并且聚集,最终达到一定浓度的现象。综述国内大型浅水湖泊及水库中影响水华暴发的环境因素的研究现状,分析水体营养条件以及适宜的气象、水文、生物条件等有利于藻类生长或聚集的环境影响因子,同时简介中国水华污染现状。对水华暴发研究领域的未来发展具有一定参考价值。     

Characterization of volatile organic compounds in the urban area of Beijing from 2000 to 2007

Beijing is one of the most polluted cities in the world. In this study, the long-term and continuous measurements of volatile organic compounds (VOCs) in the urban area of Beijing, specifically at Beijing 325 m Meteorological Tower, were conducted from 2000 to 2007. The annual record of VOC trends exhibited in two different phases was separated in 2003. Records show that VOC concentrations increased from 2000 to 2003 due to the abrupt increase in vehicle number. Contrarily, since 2003, there had been a decrease in VOCs concentrations as the policy on gasoline and air pollution was implemented. Toluene, benzene, and i-pentane are the chemicals that abound in and are directly related to vehicle activity, such as in vehicle exhaust and gasoline evaporation. Furthermore, records indicate that there had been seasonal variation in VOCs levels in that VOCs level in summer is higher than that in winter. As such, temperature is considered to significantly contribute to VOCs in Beijing. Records also show that VOCs level was high in the morning and during rush hours in the evening. In contrast, VOCs level was low during midday due to photochemical destruction with OH radical and dilution effect. In this study, a particular benzene to toluene ratio range (0.4-1.0) was used as the indicator of air propelled by vehicular exhaust. We also applied the correlation coefficients between BTEX and i-pentane to evaluate evaporation influence to ambient BTEX in the Beijing urban area.     

环境浓度抗生素选择性压力改变活性污泥微生物群落结构

为探究环境浓度抗生素(5μg·L~(-1)和50μg·L~(-1))选择性压力下活性污泥微生物的性能变化,选择四环素及磺胺甲噁唑2种高频检出的抗生素作为研究对象,分别考察2种抗生素单一和复合作用下对序批式活性污泥反应器(SBR)中废水处理效能、微生物活性及群落结构的影响。结果表明,与不添加抗生素的空白对照组相比,2种抗生素在50μg·L~(-1)和5μg·L~(-1)暴露浓度下,经过60 d运行,COD和NH+4-N去除效果未受明显影响(P0.05),微生物的活菌比变化不显著(P0.05),ATP含量显著降低(P0.05)。在微生物群落结构方面,革兰氏阳性菌增加,革兰氏阴性菌减少,原生动物含量减少,香农-威尔生物多样性指数下降。添加抗生素的样品中微生物优势菌群由变形菌门变为放线菌门,放线菌含量(均高于45%),高于空白对照组(30.72%);放线菌门的Micropruina属所占比例最高(24%),且高于空白对照组(18.77%)。抗生素选择性压力可改变活性污泥微生物的活性及群落结构,但长期作用下对污水处理效能及抗生素抗性基因传播的影响还需要进一步研究。     

华南退化草坡自然恢复中物种多度分布的动态与模拟

华南地区退化草坡自然恢复过程中物种多度格局的动态及其模拟,尚缺乏较为系统的研究.文章探讨是否不同演替阶段群落适合不同的种多度模型,是否存在一个最佳模型以揭示演替过程中群落结构的某些内在数量特征;还要推导多个模型的尺度转换形式.为此,在地处南亚热带的鹤山退化草坡选取处于不同演替阶段的2个典型群落样地,分木本层和草本层调查每个维管植物种的多度;且选择7个具有不同函数形式和广泛代表性的种多度模型,均在倍程(即log2)尺度下拟合数据,运用卡方检验和调整决定系数评估各个模型的适合性.结果表明:(1)7个模型的适合性顺序为:对数柯西＞对数双曲正割＞对数正态＞对数级数＞生态位优先占领＞断棒＞重叠生态位,其中对数柯西适合全部数据,重叠生态位则全部不适合;(2)各模型适合与否和演替阶段无关;(3)左截断对数柯西模型预测的种多度分布显示,随着群落演替,上层(木本层)罕见种比例减少、常见种比例增多,下层(草本层)则相反,这与实际相符.对数柯西分布具有普适性,能最好地反映退化草坡自然恢复中种多度分布的格局与动态.     

大气颗粒物上多环芳烃的识别和源解析的进展

本文对当前大气颗粒物上ＰＡＨｓ的识别和源解析的定量及定性和半定量的方法进行了综述，定性及半定量方法简便易行，但误差大；化学质量平衡法结果较准确具体，但ＰＡＨｓ会发生化学反应而降解，并且没有各种燃烧源较完整的ＰＡＨｓ成份谱，这已成为ＣＭＢ广泛推行的障碍；多元统计方法不考虑ＰＡＨｓ的降解，但要求数据量大，国内外的科学工作者用不同的方法和手段，使ＰＡＨｓ来源的识别和源解析工作有了一定进展。     

铁屑协同玉米芯/花生壳处理玛瑙染色废水

针对农村玛瑙染色工业废水中存在高浓度Cr(Ⅵ)、SO42-和H+等污染严重、难处理的问题,基于玉米芯、花生壳和铁屑,分别构造了1#(玉米芯)、2#(花生壳)、3#(铁屑+玉米芯)、4#(铁屑+花生壳)动态柱实验模型,研究了生物质材料及其与铁屑协同处理玛瑙染色废水中Cr(Ⅵ)、SO42-、H+的效果和机理.结果表明,铁屑+玉米芯、铁屑+花生壳动态柱对Cr(Ⅵ)、SO42-的平均去除率分别为95.97%、96.42%和72.17%和59.55%,高于玉米芯、花生壳动态柱的89.67%、90.74%和39.00%、28.73%的平均去除率,且具有较强的抗污染负荷变化和一定的pH值提升的能力.对比分析可见,经过铁屑强化的生物质动态柱对Cr(Ⅵ)、SO42-、H+有更好、更稳定的去除效果.