高压静电场对火电厂循环冷却水阻垢效果及机理

利用双通道工业循环冷却水分析测试台和高压静电水处理器,对火电厂的冷却水进行阻垢效果和机理研究。结果表明,施加工作电压2．0～4．0kV时,平均阻垢率随电压的升高而增大,达到61．7％,以后随着电压的升高平均阻垢率呈下降趋势,在7．5kV电压作用下平均阻垢率43．4％。对垢样晶体的SEM扫描图片表明,经高压静电场处理前的水垢晶体以方解石型硬垢为主,处理后发生了晶型转化,转化为文石型软垢,有利于垢的去除。     

推流式反应器厌氧消化浮萍和猪粪混合物

使用带隔板的推流式反应器(体积约为4 m3),对浮萍与猪粪(干重比1:1,湿重比7:1)的混合物、猪粪进行为期50 d的中温厌氧消化产气性能比较研究,结果表明,在有机负荷为3.5 g(VS)/(L·d)时,浮萍与猪粪(干重比1:1,湿重比7:1)混合物的VS产气率为0.31 L/g,COD转化率为63.2％,反应器容积产气率为1.00 m3/(m3·d);猪粪的VS产气率为0.28 L/g,COD转化率为57.1％,反应器容积产气率为0.71m3/(m3·d).进料COD和SS的平均浓度分别为19.19 g/L和14.28 g/L,推流式反应器对其平均去除率分别为59.7％和68.7％.由此说明,带隔板的推流式厌氧反应器对浮萍和猪粪的混合物有较好的厌氧消化能力,浮萍与猪粪混合物的厌氧消化性能优于猪粪.     

新型柱状核桃壳活性炭脱硫动力学

采用以农业废弃物核桃壳为原料,天然软锰矿为添加剂共混制成的新型柱状活性炭进行了不同水蒸气含量下的烟气脱硫实验,利用Bangham和Elovich 2种模型对实验结果进行模拟与比较。实验结果表明,随着水蒸气含量的增加,穿透硫容和时间逐渐增加,并在水蒸气含量为10%时达到最大点,此时硫容为243.0 mg/g。模拟结果表明,2种模型均可以较好地模拟烟气脱硫实验结果,其中Elovich模型具有更高的拟合相关度和准确性。在对Elovich模型加以改进以包含水蒸气影响后,可以更好地描述烟气在不同水蒸气含量下的新型柱状活性炭脱硫情况。     

剩余污泥中微生物絮凝剂的提取方法比较

分别采用低浓度和高浓度剩余污泥对剩余污泥中微生物絮凝剂(MBF)的多种提取方法(超声法、树脂法、超声-树脂法、树脂-超声法、超声-树脂-超声法和树脂-超声-树脂法等)进行了比较研究.结果表明,各种复合形式的提取效果均优于超声法或树脂法单独使用的提取效果.在各种复合形式中,以树脂-超声法所提取MBF的含量最高且絮凝效果最好.此外,所提取的MBF浓度与污泥浓度正相关.从剩余污泥中直接提取MBF,在降低MBF生产成本的同时实现了污泥的资源化利用.     

Production of Poly(l-Lactide)-Degrading Enzyme by Amycolatopsis orientalis ssp. orientalis and Its Catalytic Ability in Biological Recycling of Poly(l-Lactide)

The fermentation conditions for poly(l-lactide) (PLA)-degrading enzyme production by Amycolatopsis orientalis ssp. orientalis were statistically optimized by response surface methodology. The optimal value of the most important factors was 0.39 % PLA and 0.34 % gelatin for 2.81 days of cultivation. Under these conditions, the model predicted a PLA-degrading activity of 155.30 U/l. The verification showed the production amount of 154.2 U/l. The crude enzyme from A. orientalis ssp. orientalis showed potent PLA-degrading ability, which is efficient for the biological recycling of PLA. Up to 4,000 mg/l of PLA granule was completely degraded within 5 days at 45 °C by the crude enzyme. l-lactic acid (600 mg/l) was obtained as a degradation product of PLA after only 2 h of incubation. The results indicated that the crude PLA-degrading enzyme from A. orientalis ssp. orientalis has the potential to degrade PLA to lactic acid for the recycling of PLA industry and waste disposal.     

ALAD genotypes and blood lead levels of neonates and children from e-waste exposure in Guiyu,China

Extensive e-waste recycling activity in Guiyu, China, has been conducted using primitive techniques for the last 20 years, resulting in serious heavy metal environmental contamination. A polymorphic variant of the δ-aminolevulinic acid dehydratase (ALAD) gene has been found to influence lead uptake and, thus, may influence an individual’s susceptibility to lead toxicity. We therefore explored whether the ALAD gene polymorphism affects blood lead levels of newborns and children in Guiyu. A total of 273 newborns and 504 children, and a combination of 2004/2005 and 2006 independent recruitments were used for this study. Umbilical cord blood from newborns (Guiyu/exposed group 189 vs. Chaonan/reference group 84) and venous blood from children (exposed group, 319 vs. Chendian/reference group 185) were collected. Blood lead levels (BLLs) were measured via graphite furnace atomic absorption spectrometry (GFAAS) for all samples, while ALAD genotyping was performed using PCR-RFLP for 273 neonate cord blood and 246 children’s blood. The median BBLs of neonates in exposed group vs. the reference group were 10.50 (2.36–40.78) vs. 7.79 (0.8–19.51) for 2004/2005 and 9.41 (9.28–47.60) vs. 5.49 (0.35–18.68) for 2006, while child mean BLLs were 15.31?±?5.79 vs. 9.94?±?4.05 for 2004/2005 and 13.17?±?5.98 vs. 10.04?±?4.85 for 2006. The genotype frequencies in newborns were 98.90 % for the ALAD-1/ALAD-1 homozygote and 1.10 % for the ALAD-1/ALAD-2 heterozygotes, while the values were 95.93 and 4.07 %, respectively, in children. The allele frequencies of the ALAD-1 and ALAD-2 were 99.45 and 0.55 % for newborns, but 97.97 and 2.03 % for children, respectively. No significant differences in blood lead levels were found between ALAD-1/ALAD-1 and ALAD-1/ALAD-2 either in newborns or in children. The frequency distribution of the ALAD-2 allele in newborns from the exposed group was lower than that of the reference group. There were no significant differences, between the two different ALAD genotypes in the lead load of newborns and children. The frequency distribution of ALAD gene does not influence the blood lead levels of newborns and children in this case, which means that the higher lead burden in the exposed children was possibly influenced by e-waste recycling, but not ALAD genotypes.     

Temporal variations of benthic diatom community and its main influencing factors in a subtropical river, China

Benthic diatoms are the main component in many aquatic ecosystems such as streams, creeks and rivers, and they function as important primary producers and chemical modulators for other organisms in the ecosystems. In this study, the composition of benthic diatoms was investigated and further explored the primary physicals and chemicals affecting their temporal variations in the upper Han River, China. There were seasonal variations in physical and chemical variables in waters over the sampling period of 2007–2010. Water temperature (t), chemical oxygen demand, total nitrogen, dissolved organic carbon (DOC), silica and fluoride were much higher in the high flow season (i.e., July or August) than these in the base flow season. Three species Achnanthidium minutissimum (composed of 10.7 % of the total diatom abundance), Achnanthidium pyrenaicum (11.9 %), and Achnanthidium subatomus (12.7 %) accounting for more than 5 % of the total diatom abundance were persistently dominant in all seasons, while the other two prostrate and motile species including Eolimna minima and Nitzschia dissipata also dominant in the base flow season. The species richness always peaked in autumn with significant difference with summer (p?<?0.01), and density of benthic diatom varied and peaked in April. Analyses indicated that the temporal variation in benthic diatom communities was strongly related to t, nitrogen, organic pollutants (indicated by COD and DOC), and hydrological regime. The research will expand the understanding of water chemistry monitoring, and improve watershed- scale management and conservation efforts in the upper Han River, China.     

The distribution of 4-nonylphenol in marine organisms of North American Pacific Coast estuaries

One of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-NP), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. We measured 4-NP levels in the seawater, sediment, and twelve organisms within the California estuary, Morro Bay, and examined biomagnification of 4-NP using stable isotope abundances (δ¹⁵N and δ¹³C) to quantify trophic position. 4-NP concentrations in organisms from Morro Bay included 25000 ± 8600 ng g⁻¹ lw in liver of California sea lion, 14000 ± 5600 ng g⁻¹ lw in liver of harbor porpoise, 138000 ± 55000 ng g⁻¹ lw in liver of sea otters, 15700 ± 3600 ng g⁻¹ lw in liver of seabirds, 36100 ± 6100 ng g⁻¹ lw in arrow goby fish, 62800 ± 28400 ng g⁻¹ lw in oysters, and 12700 ± 1300 ng g⁻¹ lw in mussels. 4-NP levels generally showed a pattern of trophic dilution among organisms in Morro Bay, with exceptions of biomagnification observed between three trophic links: mussel to sea otter (BMF 10.9), oyster to sea otter (BMF 2.2), and arrow goby to staghorn sculpin (BMF 2.7). Our examination of other west coast estuaries of USA and Canada revealed that mean 4-NP concentrations in gobies and mussels from Morro Bay were significantly higher than those from a more urbanized estuary, San Francisco Bay (goby: 11100 ± 3800 ng g⁻¹ lw) and from a remote estuary, Bamfield Inlet, Canada (goby: 9000 ± 900 ng g⁻¹ lw, mussel: 6100 ± 700 ng g⁻¹ lw). Relative to other estuaries worldwide, 4-NP levels in seawater (0.42 ± 0.16 μg L⁻¹) and sediment (53 ± 14 ng g⁻¹ dw) of Morro Bay are low, but gobies and oysters have higher 4-NP levels than comparable fauna.     

铁氧体强化低温低浊水的处理效果

在低温低浊水(T<10℃,浊度<40 NTU)处理中,采用常规处理流程难以达到理想效果。实验采用铁氧体(Fe3O4)配合聚合氯化铝(PAC)进行低温低浊水的实验研究。通过混凝沉淀烧杯实验,比较两者投加量对其处理效果的影响,实验结果表明PAC为30 mg/L,Fe3O4为0.004 mg时为最佳投药量。采用混凝沉淀过滤的常规处理工艺,并保证适当的混凝搅拌强度。     

不同混合比牛粪玉米秸中温干发酵产沼性能

设置5组牛粪和玉米秸的混合物(干物质比为0∶1、1∶0、1∶1、1∶2、2∶1),研究其在中温35℃下干发酵产沼性能,以产沼性能最好实验组的实验数据为基础,对比研究了两类产气模型。研究结果显示:玉米秸与牛粪的混合干发酵运行效果较好;其中,牛粪和玉米秸干物质比为2∶1时产沼效果最好,产气量最高为81 209 mL,干物质产气率为0.312 m3/kg,整个发酵过程中产气量和甲烷的含量比较稳定,CH4含量最高达56.59%,总固体、挥发性固体的去除率相对较高,分别为26.11%和34.27%。一级动力学模型与多项式函数方程2个产气模型拟合检验结果显示,应用简单的多项式函数即可对产气情况进行相对准确的预测。