Carrousel氧化沟的流动特性研究

采用颗粒动态分析仪(PDA)对倒伞形表面曝气机曝气的Carrousel小试氧化沟进行测试,得出了氧化沟内较系统的流动特性参数.比较了固液两相在氧化沟内流动的差别,发现固液两相流动速度差别较小,由于惯性的影响,固相的沉降速度略大于液相.考察了表曝机的转速、表曝机相对于液面的位置、氧化沟的深度等因素对氧化沟内流动的影响,随着表曝机转速的增大和表曝机浸入液面深度的增加,流动速度和沉降速度均会增大,而氧化沟深度增加时,距离液面同一深度处的速度则会减小.实验结果与污水处理厂的实际情形进行比较发现,二者变化趋势一致,说明本实验结果可用于指导工程实际,为氧化沟的优化设计提供依据.     

高铁铝矾土制备聚合氯化铝铁及其在污水处理中的应用研究

利用含铁的低品位铝矾土为主要原料,添加适量铝酸钙粉,制备出絮凝剂聚合氯化铝铁.制备方法为酸溶两步法.对影响聚合铝铁制备的因素,如盐酸浓度、盐酸用量、温度和铝酸钙粉用量等进行了系统研究,得到了制备聚合铝铁的优化条件,同时将该絮凝剂用于实际工业污水的处理.研究结果表明：制备的絮凝剂絮凝效果明显优于一些传统的絮凝剂;不仅具有去浊性能好、沉降快的优点,而且具有原料易得,制备成本低的优势.     

高气泡表面积通量浮选柱气浮除藻的研究

湖泊、水库等水源的富营养化，使藻类去除成为饮用水生产的重要任务。本研究采用高气泡表面积通量浮选柱气浮除藻，考察了混凝剂、气泡表面积通量和浮选柱高度等因素的影响。试验表明，高气泡表面积通量浮选柱气浮可高效地去除绿藻、硅藻和蓝藻，叶绿素a和藻类去除率达95％以上，比传统浮选柱气浮和沉降作业有较大幅度提高。与普通气浮柱比较，高气泡表面积通量浮选柱增加了气泡与藻的碰撞几率，防止因大表观充气速率造成的紊流和扰动，使气泡／藻结合体有相对静态的浮升环境，避免了气泡／藻结合体在浮升过程中的脱落，实现对藻类的迅速捕集和转移。     

不同喷枪在CFB锅炉SNCR工程中的应用

针对不同喷枪在循环流化床锅炉(CFB)选择性非催化还原(SNCR)脱硝系统中的工程应用展开研究。利用CFD模拟,分析不同雾化粒径对还原剂穿透距离及覆盖面积的影响。计算表明,较大的雾化粒径有利于还原剂的混合。75 t/h CFB锅炉工程实验结果显示,雾化粒径D50=102 μm的喷枪比雾化粒径D50=59 μm的喷枪可提高脱硝效率8%~10%,同时可降低氨氮比(NSR)13%,与计算结果一致。     

The interaction effects of FEN1 rs174538 polymorphism and polycyclic aromatic hydrocarbon exposure on damage in exon 19 and 21 of EGFR gene in coke oven workers

Polycyclic aromatic hydrocarbon (PAH) exposure and genetic susceptibility were conductive to genotoxic effects including gene damage, which can increase mutational probability. We aimed to explore the dose-effect associations of PAH exposure with damage of exons of epidermal growth factor receptor (EGFR) and breast cancer susceptibility gene 1 (BRCA1), as well as their associations whether modified by Flap endonuclease 1 (FEN1) genotype. Two hundred eighty-eight coke oven male workers were recruited, and we detected the concentration of 1-hydroxypyrene (1-OH-pyr) as PAH exposure biomarker in urine and examined base modification in exons of EGFR and BRCA1 respectively, and genotyped FEN1 rs174538 polymorphism in plasma. We found that the damage indexes of exon 19 and 21 of EGFR (EGFR-19 and EGFR-21) were both significantly associated with increased urinary 1-OH-pyr (both P_trend < 0.001). The levels of urinary 1-OH-pyr were both significantly associated with increased EGFR-19 and EGFR-21 in both smokers and nonsmokers (both P < 0.001). Additionally, we observed that the urinary 1-OH-pyr concentrations were linearly associated with both EGFR-19 and EGFR-21 only in rs174538 GA+AA genotype carriers (both P < 0.001). Moreover, FEN1rs rs174538 showed modifying effects on the associations of urinary 1-OH-pyr with EGFR-19 and EGFR-21 (both P_interaction < 0.05). Our findings revealed the linear dose-effect association between exon damage of EGFR and PAH exposure and highlight differences in genetic contributions to exon damage and have the potential to identify at-risk subpopulations who are susceptible to adverse health effects induced by PAH exposure.

     

我国水环境管理的现状与展望

水环境管理在国家的环境保护中具有极为重要的地位,国外在水环境管理方面有成熟的经验和新的发展趋势。通过分析国外在水环境管理方面的先进经验和发展趋势及我国水环境管理现状,提出以流域管理为中心、加强立法保证等建议。并强调,借鉴国外水环境管理的先进经验,以流域管理为基础,以水资源管理和水污染控制—体化为目标的管理模式是解决我国水环境管理存在问题的必然途径。     

沟渠式生物接触氧化法对有机物和氨氮的去除研究

生物接触氧化工艺是目前较为成熟的水质净化技术,国内外在河流水质净化、水体修复中都有较多的研究和应用.在实验室采用沟渠式生物接触氧化组合系统处理模拟村庄面源污水,较好地去除了有机物并实现氨氮转化.结果表明,当进水COD为130～290mg/L、氨氮为30～40mg/L、水力负荷为0.19～0.24m3/(m2·d)的条件下,该系统稳定运行11周,COD和氨氮的平均去除率分别达85%和79%.     

SBR法处理麻生物脱胶废水

利用 SBR工艺处理麻生物脱胶废水 ,对 CODcr、NH3-N的降解、SBR厌氧段和处理后水是否可回用进行了研究。实验结果证明 ,当进水 CODcr 15 0 0 mg/ L左右 ,MLSS的 CODcr负荷≤ 0 .74kg/ kg· d时 ,废水各项指标均可以达到 GB8978-1996苎麻脱胶废水综合排放二级标准 ,且可回用脱胶     

Effect of cadmium on nodulation and N2-fixation of soybean in contaminated soils

The effects of cadmium stress on nodulation, N2-fixation capabilities of the root nodule, the change in ultrastructure of the root nodule, soybean growth, and the distribution of cadmium in plants were studied. The results obtained show that the nodulation of soybean roots was greatly inhibited by the addition of Cd, especially at the addition level of 10 and 20 mg kg(-1) soil. The inhibition of plant growth, especially the root growth, increased as the cadmium concentration increased, with deleterious effects observed for the roots. The weight ratio of soybean root/leaf decreased as the Cd concentration increased, which might explain the reason for nodulation decreases. The results also indicate that N2-fixation of root nodule was stimulated to some extent at the low levels of Cd addition, but decreased sharply with further increase of the Cd concentration. High Cd levels were also associated with changes in the ultrastructure of root nodule, in which the effective N2-fixing area was reduced and the N2-fixing cells in the area also reduced. In addition, the results also reveal that the content of Cd in different parts of the plants was as follows: roots > stems > seeds, indicating that the accumulation of Cd by roots is much larger than that by any other part of the soybean plant, and might cause deleterious effects to root systems.     

Biofiltration of trimethylamine-containing waste gas by entrapped mixed microbial cells

The study provides novel attempt to use an aerobic biofiltration system containing entrapped mixed microbial cells (EMMC) for removal of (CH3)3N-dominant waste gases. In the study, heterotrophic microflora-immobilized cellulose was packed into an EMMC reactor to degrade (CH3)3N. Effects of (CH3)3N inlet concentrations in continuous mode of operation at various flow rates are indicated. The result indicated that the (CH3)3N removal efficiency is higher than 90% at inlet loading below 27.2 mgNh(-1) and retention time 5.3 min. In addition, the maximal mass loading to reach approximately 99% efficiency was 95.5 mgNh(-1) for trimethylamine treatment. This EMMC biofiltration system also showed higher tolerance to endure fluctuations in concentrations and flow rates and still maintained in stable performance for removal. Adaptability test in response to gradual shift up and down of inlet TMA loading indicated that lack of steady-state multiplicity and hysteresis guarantees the microbial communities more precisely adapted to continuous treatment for maintaining stability.