亚硝化/反硝化除磷同步发生的控制策略

针对碳源偏低城市污水,采用厌氧/限氧的序批式活性污泥反应器（A/LOSBR）,在连续（CA）和间歇曝气（IA）模式下,研究了亚硝化/反硝化除磷同步发生所需的最适控制策略。实验结果表明,在CA模式下,恒定30 L·h-1的气量,进行同步亚硝化/反硝化除磷的TN和PO43--P去除率分别为88.5%和95.9%;在IA模式下,恒定30 L·h-1的气量,且曝气百分数（AF）和曝气频率（fIA）值为0.5和24时,曝气量比CA模式节省了23%,该工艺的TN和PO43--P去除率分别为91.1%和92.9%。由此可知,同一气量下,IA模式比CA模式的更经济节能,且IA模式在低AF和高fIA工况下进行的同步亚硝化/反硝化除磷过程更稳定持续。     

焚烧飞灰中Pb的浸出特征及预处理效果

着重研究飞灰中重金属铅的浸出行为,探讨焚烧飞灰在不同添加剂预处理下的稳定化效果。结果显示,飞灰主要重金属为铅,在液固比0.4 L·kg-1、养护7 d条件下,分别将水泥添加量从0增至40%、磷酸钠添加量从2%增至5%、绿矾从2%增至5%,铅的稳定效果均与以上添加剂的质量百分比呈正相关性。硫化钠添加量在0至0.4%内时,铅的稳定效果与其添加量呈负相关性,超过0.4%后呈正相关性。当在飞灰中添加4%绿矾、3%磷酸钠、0.5%硫化钠、15%水泥的复合添加剂时,符合卫生填埋场入场标准,且增容比最小,经济上最省。     

Hexabromocyclododecanes in soils and plants from a plastic waste treatment area in North China: occurrence,diastereomer- and enantiomer-specific profiles,and metabolization

Plastic waste is a source of organic contaminants such as hexabromocyclododecanes (HBCDs). HBCDs have been found to cause developmental and reproductive toxicity; it is important to investigate the occurrence and metabolization of HBCDs in the soil environments with plastic waste contamination. This work analyzed HBCDs and their metabolites in soil and plant samples collected from Xinle and Dingzhou—the major plastic waste recycling centers in North China. Results showed that total HBCD concentrations in soils followed the order: plastic waste treatment site (11.0–624 ng/g) > roadside (2.96–85.4 ng/g) ≥ farmland (8.69–55.5 ng/g). HBCDs were detected in all the plant samples with total concentrations ranging from 3.47 to 23.4 ng/g. γ-HBCD was the dominant congener in soils, while α-HBCD was preferentially accumulated in plants. Compositions of HBCD isomers in soils and plants were significantly different (P < 0.05) among sampling sites and among plant species. HBCDs in farmland soil and all plant samples exhibited high enantio-selectivity based on the enantiomeric fractions (EFs). Furthermore, metabolites of pentabromocyclododecenes (PBCDEs) were frequently identified in soils, and mono-OH-HBCDs were the most common ones in plants. This study for the first time provides evidences of HBCD contamination in the soil-plant system caused by plastic waste, their stereo-selectivity, and metabolization behavior, improving our understanding of the environmental behavior and fate of HBCDs.     

东洞庭湖湿地生态系统健康状态与水位关系研究

基于CBERS卫星遥感影像数据,以东洞庭湖国家级自然保护区为研究区,通过光谱特征分析建立决策树分类模型,提取东洞庭湖湿地的地物类型。以生态系统健康理论为基础,依据东洞庭湖湿地的特点,综合湿地生产力、组织结构、弹性和功能4个方面,建立湿地生态系统健康状态评价指标体系和评价模型,利用GIS技术,分析东洞庭湖湿地在2000～2006年10个时相的生态系统健康状态。结合城陵矶水文站的水位数据,探讨了东洞庭湖湿地健康状态与城陵矶水位之间的相关性,并利用2007年两个时相的数据进行检验。研究结果表明：东洞庭湖湿地健康状态与城陵矶水位之间存在着较大的相关性,当城陵矶水位达到30 m左右时,东洞庭湖湿地健康状态达到最佳值     

Diversity and biogenesis contribution of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits

Environmental Science and Pollution Research - Microbial sulfate reduction, a vital mechanism for microorganisms living in anaerobic, sulfate-rich environments, is an essential aspect of the sulfur...     

The effects of air pollution on the lung cancer mortality in rural areas of eastern China: a multi-region study

Environmental Science and Pollution Research - Recently, the burden of lung cancer (LC) has attracted global attention. Meanwhile, LC has become the leading cause of death in China. Many studies...     

Renewable energy demand,financial reforms,and environmental quality in West Africa

Environmental Science and Pollution Research - Sustainable Development Goal (SDG-7) stipulates the need for clean energy, reduced carbon&nbsp;dioxide emissions, prevention of environmental...     

大型溞投放密度对湖库水体水质改善及底泥污染物影响

向北京市沙河水库投放大型溞(Daphnia magna),利用其摄食藻类、促进悬浮颗粒态污染物沉降的特性,以提升水体的透明度,为后续沉水植物群落的恢复创造条件,并探索大型溞的投放密度,以及投放后对水质及底泥主要污染物的影响。结果表明：向沙河水库投加大型溞的最佳密度为5~15 ind·L⁻¹;在该条件下,水体透明度可在3~5 d由40 cm提升至100 cm,浊度由19.7 NTU降至3 NTU,藻密度由2.4×10⁶ cell·mL⁻¹降至(4~6)×10⁴ cell·mL⁻¹;大型溞可在沙河水库长期存活,并可长期抑制藻类、维持水体的透明度;水体COD并未发生明显改变;大型溞的分泌物促进了悬浮颗粒态氮、磷的沉降,使TN和TP的去除率分别达到70.2%和54.9%;由于投溞后藻类浓度迅速下降,藻对NH₃-N的吸收量降低,使水体NH₃-N升高了32.2%;底泥中有机质、TN、TP均出现了一定程度的升高。针对于湖库水体透明度低的问题,应投放适宜密度的大型溞,调整水质状态,并结合水中藻类、底泥污染物等条件,综合考虑有效改善水质的方法。     

超声和无机酸浸提猪粪中的重金属

对比研究了无机酸及超声对猪粪中重金属Cu、Zn和Mn的去除效果,并对处理前后猪粪中重金属形态变化进行分析。结果表明:无机酸浸提优化条件下Cu、Zn和Mn的浸出率分别为43.24%、76.28%和78.91%;超声协同无机酸浸提优化条件下Cu、Zn和Mn的浸出率分别为39.6%、76.3%和79.9%;2种浸提方式均能显著降低猪粪中重金属有机结合态含量。     

一株铅镉抗性菌株的分离鉴定及其生物学特性

鉴定了从黑龙江扎龙湿地土壤中筛选出的一株抗铅镉的菌株,研究了其生物学特性和部分生理生化指标。利用16SrDNA序列分析鉴定其菌属,并且研究Pb2+、Cd2+、Pb2+/Cd2+、温度、pH、盐以及抗生素对菌株生长的影响。经鉴定,该菌株为阴沟肠杆菌属(Enterobacter cloacae)。该菌株对Pb2+的去除率和吸附率分别达到了70.34%和44.39%,对Cd2+的去除率和吸附率分别达到了40.54%和25.14%。该菌株最适生长温度为25℃,最适生长pH为7.0左右。此菌株对抗生素亚胺培南最敏感。随着盐、Pb2+、Cd2+、Pb2+/Cd2+混合浓度的升高,该菌株生长受到抑制。