电解预处理-UASB-CASS工艺处理糠醛废水

对电解预处理-UASB-CASS工艺处理糠醛废水进行了研究,通过试验确定了电解预处理阶段主要影响因素为电流强度大小和电解时间,极板间距对COD去除率影响不大;电解预处理最佳工艺参数为:电流强度0.3 A,电解时间4 h,极板间距30 mm.在此条件下COD去除率为20.6%,废水可生化性提高了38.1%.加上后续的UASB-CASS工艺,出水COD浓度＜150 mg/L,满足《污水综合排放标准》(GB8978-1996)二级排放标准.     

浅析新疆平原水库的环境地质问题

文章从新疆平原水库的特点及其作用出发,阐明了平原水库较适宜新疆的自然地理和经济状况;同时也分析了平原水库存在的环境地质问题及其治理措施,并强调病险库治理的迫切性     

外喷雾水电联锁湿式煤电钻的研制及应用

分析了传统湿式打眼难以推广应用的原因,叙述了外喷雾水电联锁煤电钻湿式打眼法.     

泡沫活性炭的制备及其对丙酮的吸附性能研究

以中间相沥青和原煤为原料,在高温高压下发泡成型,经过高温炭化和水蒸气活化后制得了比表面积为672m2/g、中孔发达的泡沫状成型活性炭(MACFoam).该成型活性炭中含有大量的微米级孔道并具有良好的透气性,可以作为气流通道.由其所装填的吸附床层对丙酮的吸附行为与颗粒活性炭相似,可以使用Yoon-Nelson方程对实验穿...     

Phosphorus fluxes at the sediment–water interface in subtropical wetlands subjected to experimental warming: A microcosm study

Global warming is increasingly challenging for wetland ecological function. A temperature controlled microcosm system was developed to simulate climate change scenarios of an ambient temperature (control) and an elevated temperature (+5 °C). The effects and associated mechanisms of warming on phosphorus (P) fluxes at the sediment–water interface of six subtropical wetlands were investigated. The results indicated that P fluxes were generally enhanced under the experimental warming as measured by higher P concentrations in the porewater and overlying water as well as higher benthic P fluxes. The release of P from sediment to porewater occurred more strongly and quickly in response to experimental warming compared to the subsequent upward transfer into overlying water. The average accumulative benthic P output from the tested wetlands under the experimental warming was greater by 12.9 μg cm^?2 y^?1 (28%) for total P and 8.26 μg cm^?2 y^?1 (25%) for dissolved reactive P, compared to the ambient scenarios. Under warming the redistribution of P fractions in sediments occurred with greater NH₄Cl–P and lower BD–P (extracted by a bicarbonate buffered dithionite solution) accompanied by greater NaOH–P. The higher temperature enhanced total phospholipid fatty acids. A shift in the microbial community was also observed with a relative dominance of fungi (a 4.7% increase) and a relative decline (by 18%) in bacterial abundance, leading to the higher secretion of phosphatase. Comparing between wetlands, the potential P fluxes in the nutrient-enriched wetlands were less impacted by warming than the other wetland types investigated. Thus wetlands characterized by low or medium concentrations of P in sediments were more susceptible to warming compared to P-rich wetlands.     

Spatial variability of bacteria in the rhizosphere of Elsholtzia splendens under Cu contamination

Elsholtzia splendens is a well-known Cu-tolerant plant; yet, the impact of Cu-contaminated soil on bacterial community in its rhizosphere is not known. We studied the spatial variability of bacteria in the rhizosphere using Cu-contaminated soil with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR. In the uncontaminated soil, the content of the dissolved organic carbon (DOC) and bacterial diversity gradually increased in the rhizosphere soil along the root growth direction (from the interface zone to the meristematic zone), while for the Cu-contaminated soil, the highest DOC content and the strongest potential bioavailability of Cu were found in the interface zone, which also had the lowest bacteria diversity. Bacteria diversity was positively correlated with DOC in the uncontaminated soil (p?Firmicutes only existed in the rhizosphere of contaminated soil, while the very small amount (if any) of some species exists such as Deinococcus-Thermus, indicating that the contaminated environment altered the bacterial composition. Moreover, spatial variation of the bacterial community was found among different soil zones. Real-time PCR confirmed the spatial variation via the gene expression of flagellin (fliC) and chemotaxis gene (cheA). The spatial characteristics of cheA expression were consistent with that of DOC and bacterial diversity. In conclusion, we demonstrated that the spatial variation of the bacterial community in the rhizosphere was present, independent of Cu contamination. DOC and Cu toxicity may affect specific gene expressions such as fliC and cheA, resulting in bacterial spatial variation.     

活性焦吸附对煤化工废水膜处理工艺的影响

煤化工废水经过生化处理后一般难以达到回用标准,须采用有效的深度处理工艺才能实现废水的资源化利用。通过对比研究方式,采用“混凝-超滤-反渗透工艺”及“混凝-活性焦吸附-超滤-反渗透”2种处理工艺,考察了活性焦吸附对后续膜处理工艺的影响。结果表明,活性焦对废水中的芳香族类等主要污染物具有很好的吸附性能,混凝出水经活性焦吸附后进人膜系统可有效减缓膜污染,降低膜通量的衰减程度并提高产水水质,因此,将活性焦吸附用于煤化工废水膜系统的前处理,采用“混凝-活性焦吸附-超滤-反渗透工艺”深度处理煤化工废水是有效可行的。     

絮体性质对纳滤膜污染的影响

混凝过程产生的絮体会对后续膜过滤性能产生一定的影响。实验中利用激光粒度仪研究2种混凝剂(AlCl3和PAC)在不同投加量下的絮体性质,混凝出水(不经过沉淀)直接进入纳滤膜(NF270)装置进行过滤实验。研究表明,投加量低(<0.20 mmol/L)的情况下,混凝出水反而使纳滤通量衰减发生恶化,随着投加量的增加,纳滤膜通量衰减得到有效的减缓。直接过滤腐殖酸(HA)的膜通量衰减(J/J0)为0.65,投加量为0.50 mmol/L时,AlCl3和PAC 2种混凝剂产生的通量衰减(J/J0)分别为0.78和0.75。滤饼层阻力受到絮体尺寸的影响较大,絮体尺寸越大,形成的滤饼层透水性更好。通过污染模型分析,混凝出水的纳滤膜污染机理主要是滤饼层阻力。     

Degradation of diuron in aqueous solution by ozonation

Degradation of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] in aqueous solution and the proposed degradation mechanism of diuron by ozonation were investigated. The factors that affect the degradation efficiency of diuron were examined. The generated inorganic ions and organic acids during the ozonation process were detected. Total organic carbon removal rate and the amount of the released Cl(-) increased with increasing ozonation time, but only 80.0% of the maximum theoretical concentration of Cl(-) at total mineralization was detected when initial diuron concentration was 13.8 mg L(-1). For N species, the final concentrations of NO3(-) and NH4+ after 60 min of reaction time were 0.28 and 0.19 mg L(-1), respectively. The generated acetic acid, formic acid and oxalic acid were detected during the reaction process. The main degradation pathway of diuron by ozonation involved a series of dechlorination-hydroxylation, dealkylation and oxidative opening of the aromatic ring processes, leading to small organic species and inorganic species. The degradation efficiency of diuron increased with decreasing initial diuron concentration. Higher pH value, more ozone dosage, additive Na2CO3, additive NaHCO3 and additive H2O2 were all advantageous to improve the degradation efficiency of diuron.