Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency. Uniform design was applied to determine the combination of target temperature (110–210°C), microwave holding time (1–51 min), and NaOH dose (0–2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization. Maximum solubilization ratio (85.1%) of VSS was observed at 210°C with 0.2 g-NaOH/g-SS and 35 min holding time. The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP). Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge. The highest CMP was a 27% improvement over the control. In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge, a semi-continuous thermophilic reactor fed with pretreated TWAS without neutralization (at 170°C with 1 min holding time and 0.05 g NaOH/g SS) was stable and functioned well, with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%, respectively, which were higher than those of the control system. Additionally, methane yields (L@STP/g-CODadded, at standard temperature and pressure (STP) conditions of 0°C and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%, respectively, compared to the control reactor.     

撒哈拉沙漠独有的气象灾害

独一无二的大沙漠撒哈拉沙漠位于非洲北部,东临红海,南部到达苏丹和尼日尔河河谷;西起大西洋海岸,北部以阿特拉斯山脉和地中海为界,处在250毫米等雨线(约北纬14。线)以北,是世界上最大的沙漠。"撒哈拉"是阿拉伯语"大荒漠"一词的音译。     

高温(70℃)玉米秸秆水解液产氢行为及群落结构

考察了高温条件下(70℃)牛粪堆肥、土壤、厌氧污泥、腐烂秸秆种接种物利用玉米秸秆水解液的产氢行为。结果表明:牛粪堆肥接种时达到最大的产气量(1355.7mL/L)和氢气产量(608.4mL/L),随后依次为腐烂秸秆、厌氧污泥和土壤。修改的Gompertz方程可以较好描述产氢量随时间变化趋势(R2>0.99)。牛粪堆肥接种时达到最大的产氢潜力(676.0mL/L),而土壤接种时的迟滞时间最小(9.8h)。DGGE图谱显示:不同接种物对应不同的微生物群落结构。Bacillus thermozeamaize,Enterobacter sp.JDM-19和Thermoanaerobacterium polysaccharolyticum strain,KMTHCJT和可能分别是牛粪堆肥,厌氧污泥和腐烂秸秆接种条件下的关键产氢微生物。     

碳钢在高温高盐矿井水中腐蚀与缓蚀性能的试验研究

为了解决高温高盐矿井水对碳钢管道和设备腐蚀问题,进行了缓蚀挂片试验,研究适应该类水质的缓蚀剂种类和最佳投加量。试验结果表明：软化剂氢氧化钙和碳酸钠对碳钢均有一定缓蚀效果．其平均缓蚀率分别为17．33％、57．46％。因此药剂软化过程同时达到防腐效果有限：单独投加缓蚀剂HEDP的缓蚀效果明显,其静态缓蚀率82．46％以上,动态缓蚀率76．45％：复合配方缓蚀剂的缓蚀效果最好,最佳配方为“有机膦酸一聚环氧琥珀酸一锌盐”或“有机膦酸一磺酸基团多元共聚物一锌盐”,在投加量80mg／L时动态缓蚀率接近90％。     

高温状态下受热时间对膨润土物性指标的影响∗

高温状态下膨润土的物性指标变化是高放核废物深地质处置库设计的重要参数之一。通过高温状态下不同受热时间MX80钠基膨润土的比重、液塑限、自由膨胀率试验,研究了受热时间对膨润土基本物性指标的影响规律;并通过热重分析(TGA)、X衍射(XDR)、电镜扫描(SEM)试验,从微观角度对上述变化规律进行了合理解释。研究结果表明:随着受热时间的增加,膨润土的比重、液塑限、自由膨胀率在受热15～30天内急剧下降,降幅分别为2.5%、3.1%和28.3%,之后各值变化量很小;高温状态下,膨润土的矿物成分转化、结合水脱附、微观形貌改变是膨润土物性指标发生变化的根本原因,三者之间相互作用和彼此影响。     

Two-step accelerated mineral carbonation and decomposition analysis for the reduction of CO2 emission in the eco-industrial parks

Carbon dioxide（CO2） emissions are a leading contributor to the negative effects of global warming. Globally, research has focused on effective means of reducing and mitigating CO2 emissions. In this study, we examined the efficacy of eco-industrial parks（EIPs） and accelerated mineral carbonation techniques in reducing CO2 emissions in South Korea.First, we used Logarithmic Mean Divisia Index（LMDI） analysis to determine the trends in carbon production and mitigation at the existing EIPs. We found that, although CO2 was generated as byproducts and wastes of production at these EIPs, improved energy intensity effects occurred at all EIPs, and we strongly believe that EIPs are a strong alternative to traditional industrial complexes for reducing net carbon emissions. We also examined the optimal conditions for using accelerated mineral carbonation to dispose of hazardous fly ash produced through the incineration of municipal solid wastes at these EIPs. We determined that this technique most efficiently sequestered CO2 when micro-bubbling, low flow rate inlet gas, and ammonia additives were employed.     

中国产业能源消费氮氧化物排放影响因素分析

中国快速增长的能源消费导致大量的氮氧化物排放,研究能源消费的氮氧化物排放的影响因素对于减排政策制定具有重要意义。文章基于扩展的经济-能源-氮氧化物排放的投入产出模型,首次尝试将结构分解方法(structural decomposition analysis,SDA)运用于氮氧化物排放的影响因素分析。研究实例分析了1990-2010年中国生产部门能源消费的氮氧化物排放的变化趋势和影响因素,研究结果表明:1990-2010年中国生产部门能源消费氮氧化物共增排1 522万t,其中国内生产总值因素变动对增排贡献最大(贡献率为107.2%),氮氧化物排放系数因素变动对减排贡献最大(贡献率为-27.3%)。进一步分析表明,经济规模扩大是带动氮氧化物增排的主要原因,而技术水平提高是抑制氮氧化物增排最有效的措施,未来经济结构优化、能源强度降低和技术进步具有较大潜力,交通部门应受到特别关注。     

低温柴油吸收工艺在高温油品储罐罐顶废气净化中的应用

采用罐区减排措施和低温馏分油吸收-脱硫工艺处理高温油品罐罐顶废气,在处理气量43.0~384.5 m3/h,柴油流量10~20 m3/h,吸收柴油温度10~15℃条件下,废气经过净化后,硫化氢和有机硫化物去除率大于97.2%,净化气体非甲烷总烃浓度小于8.35 g/m3,均低于GB20950-2007《储油库大气污染物排放标准》和GB 16297-1996《大气污染物综合排放标准》中相关污染物的限值。     

中亚热带马尾松林凋落物分解过程中的微生物与酶活性动态

采用凋落物原位分解法,研究了中亚热带马尾松林中马尾松、槲栎凋落叶单独及混合(自然质量比8∶2)分解过程中的微生物数量与酶活性动态.结果表明:①3类凋落物的年分解常数K的大小为:混合凋落物(0.94)>槲栎凋落物(0.86)>马尾松凋落物(0.67);②3类凋落物真菌数量和微生物数量均在夏季(135 d时)达到最大值,而此时细菌和放线菌数量最低;③3类凋落物纤维素酶活性、酸性磷酸酶活性均与凋落物干重剩余率呈显著正相关(P<0.05),而马尾松与混合型凋落物中的多酚氧化酶活性同凋落物干重剩余率呈极显著负相关(P<0.01);④微生物数量和多酚氧化酶活性均总体表现为槲栎凋落物>混合凋落物>马尾松凋落物,酸性磷酸酶活性多表现为槲栎凋落物最低,与分解常数K排列有一定的差异,说明凋落物分解是微生物和多种酶共同作用的结果.整体研究表明,凋落物质量和季节气候的差异显著影响微生物群落及其调控的生态过程,与纯马尾松凋落叶相比,针阔混合使微生物数量和多酚氧化酶活性显著提高,这可能是导致分解加快的重要原因.     

碳排放现状及驱动因素分解实证分析研究——以东莞市为例

根据IPCC碳排放计算指南核算东莞市2005年-2011年期间能源消费的碳排放量,并进行现状分析和采用对数平均权重分解法（LMDI）因素分解分析.研究结果表明：碳排放总量以5.8％速度增长,而碳排放强度以5.8％速度递减;煤是碳排放主源,但所占比重逐年下降;工业碳排放量比重最大,但是增速减慢;交通业、服务业和居民生活碳排放量及所占比重逐年增加;经济规模的扩大是拉动东莞市人均碳排放的决定因素,累计效应远高于能源效率和能源结构对碳减排影响.