阴离子对Acidithiobacillus ferrooxidans氧化活性及次生铁矿物形成影响

酸性矿山废水（AMD）具有酸度高并含有大量可溶性Fe、硫酸根及重（类）金属的特点,采用生物矿化方法促使AMD中Fe向羟基硫酸铁次生矿物转变,对AMD后期石灰中和减少氢氧化铁和废石膏的产生,提高中和效率具有实际意义.通过模拟酸性矿山废水,考察了Cl^-、NO₃^-、PO₄^3-3种阴离子对嗜酸性氧化亚铁硫杆菌（A.ferrooxidans）体系中pH值、Fe²⁺氧化率、总Fe沉淀率、次生铁矿物矿相的影响.结果表明,高浓度阴离子对A.ferrooxidans氧化Fe²⁺能力具有抑制作用.A.ferrooxidans对阴离子的耐受性依次为PO₄^3- > NO₃^- > Cl^-.阴离子浓度在A.ferrooxidans耐受范围内时,其对Fe²⁺的生物氧化速率基本没有影响.但高浓度阴离子会通过抑制A.ferrooxidans的氧化活性,从而间接影响Fe³⁺的水解成矿过程,导致培养终点时总Fe沉淀率降低和次生铁矿物产量减少.受Fe³⁺供应速率降低的影响,次生铁矿物的合成途径易向施氏矿物转变.     

催化氧化法处理焦化污水生化出水的中试研究

采用ClO_2三相催化氧化工艺对焦化污水二沉池出水的处理进行了中试研究,考察了进水量、供气量、加药量等参数对焦化污水COD处理效果的影响,得出的最佳工艺条件为:进水量0.2 m~3/h,有效催化剂用量0.5 m~3,供气量10 m~3/h,盐酸投加量60 m L/h,氯酸钠投加量30 m L/h。最佳工艺条件下,平均出水COD为44 mg/L,平均去除率为80.3%,能达到国家一级排放标准。     

Sensitivity evaluation of the visual,tactile, and auditory detection response task method while driving

Objectives: In this article, we evaluate the sensitivity to cognitive load of 3 versions of the Detection Response Task method (DRT), proposed in ISO Draft Standard DIS-17488.

Methods: We present a user study with 30 participants in which we compared the sensitivity to cognitive load of visual, audio, and tactile DRT in a simulated driving environment. The amount of cognitive load was manipulated with secondary n-back tasks at 2 levels of difficulty (0-back and 1-back). We also explored whether the DRT method is least sensitive to cognitive load when the stimuli and secondary task are of the same modality. For this purpose, we used 3 forms to present the n-back task stimuli: visual, audio, and tactile. Responses to the task were always vocal. The experiment was based on a between-subject design (the DRT modalities) with 2 levels of within-subject design study (modalities and difficulty of the secondary n-back tasks). The participants' primary task in the study was to drive safely, and a second priority was to answer to DRT stimuli and perform secondary tasks.

Results: The results indicate that all 3 versions of the DRT tested were sensitive to detecting the difference in cognitive load between the reference driving period and driving and engaging in the secondary tasks. Only the visual DRT discriminated between the 0-back and 1-back conditions on mean response time. Contrary to expectations, no interaction was observed between DRT modality and the stimuli modality used for presentation of the secondary tasks.

Conclusions: None of the 3 methods of presenting DRT stimuli showed a consistent advantage in sensitivity in differentiating multiple levels of cognitive load if all response times, hit rates, and secondary task performance are considered. If only response time is considered, the visual presentation of the DRT stimulus used in this study showed some advantages. In interpreting these data, it should be noted that the methods of DRT stimulus presentation varied somewhat from the currently proposed draft ISO standard and it is possible that the relative salience level of the visual DRT stimulus influenced the findings. It is further suggested that more than 2 levels of difficulty of the n-back task should be considered for further investigation of the relative sensitivity of different DRT stimuli modalities. Parameters that indicate change in cognitive load (response time, hit rate, task performance) should be analyzed together in assessing the overall impact on the driver and not individually, in order to obtain a fuller insight of the assessed cognitive load.     

umu试验研究饮用水氯和氯胺消毒过程中遗传毒性的变化以及消毒条件的影响

采用umu遗传毒性测试方法考察了消毒剂投加量、反应时间和消毒剂氯氮比对某饮用水厂臭氧-生物活性炭出水加氯或氯胺消毒前后遗传毒性的影响.结果表明,炭后水具有一定的遗传毒性(20～70 ng/L),加氯或氯胺消毒后遗传毒性增加.反应时间为24 h,在相同投加量下氯消毒遗传毒性(40～95 ng/L)高于氯胺消毒遗传毒性(20～40 ng/L);当氯初始投加量从0 mg/L增加到10 mg/L时,炭后水的遗传毒性先迅速增加,在0.5～1 mg左右达到极大值,然后再降低,在3～5 mg左右达到极小值后缓慢上升,但是氯胺消毒后水样遗传毒性变化规律不如氯消毒的明显.当投加量为3 mg/L时,随着反应时间从0 h延长至72 h,无论是氯消毒还是氯胺消毒,炭后水遗传毒性均是先迅速增加,在2 h时达到极大值后再下降,在18 h左右达到极小值然后缓慢上升,而且任意反应时间内,氯胺消毒的遗传毒性(20～62 ng/L)均小于氯消毒(83～120 ng/L).本试验还研究了消毒剂氯氮比对炭后水氯消毒后遗传毒性的影响.在本试验条件下,从遗传毒性的角度看,对于饮用水消毒氯胺比氯更安全,而且2种消毒方式的遗传毒性的变化规律均不同于总HAAs的变化规律.     

纺织洗布废水回用新工艺研究

纺织洗布废水具有较高的COD,浊度,电导率,处理此类废水一般都采用普通的生化处理使其达标排放。采用臭氧-曝气生物滤池(BAF)组合工艺对广东某纺织品有限公司洗布废水的生化处理出水进行深度处理以达到企业确定的回用标准。经试验表明:臭氧投加量为30mg/L时,深度处理系统的COD去除率超过62.5%,出水COD控制在30mg/L以下,浊度<1NTU,完全达到企业确定的回用标准。纺织洗布废水回用新工艺具有处理成本很低,处理效果稳定,具有显著的环境效益和经济效益。     

人工湿地对化粪池出水净化效果的对比研究

对比了四种复合人工湿地系统对化粪池出水COD、TP、NH3-N和SS的净化效果,试验系统均采用间歇式进水,时间间隔为1d。为期7个月的运行结果表明,系统出水水质均达到城镇污水处理厂污染物排放标准(GB18918-2002)中的二级标准,其中潜流(水平流)+垂直流(上行流)湿地系统对COD的去除效果最好;垂直流(下行流)+垂直流(上行流)湿地系统对TP、NH3-N、SS去除效果最好;选用含钙石灰石和含铁矿粉做填料、采用间歇式的运行方式可以提高湿地系统对污染物的去除率。     

土壤含水层处理出水的回用健康风险评价

通过土壤柱实验,研究了土壤含水层处理工艺对污水处理厂二级处理出水的处理效果。初步讨论了土壤含水层处理工艺对各种污染物的去除机理,并评价了不同回用途径再生水对人体的健康风险。研究结果表明:土壤含水层处理工艺能够有效去除二级处理出水中的有机物和重金属离子,对大肠菌和粪大肠菌的去除率大于99.9%。健康风险评价结果显示:再生水的健康风险主要来自致癌物质,终生致癌风险在10-6数量级,而非致癌物质的健康危害风险在10-9数量级。     

密闭环境空调系统二次污染问题研究

密闭环境空调系统存在一系列特殊的室内空气品质问题.详细介绍了密闭空间空调系统二次污染的现状、对人员健康的影响、控制措施.提出2种解决空调系统二次污染问题的思路:终点控制和起点控制.终点控制措施和起点控制措各有其优点及缺点,适用范围也不一样.潜艇、深水工作船、宇宙飞船等密闭空间空调系统要根治二次污染问题,必须起点控制和终点控制相结合,在工程实践中逐步摸索出适用的方法.     

电池生产含铅废水处理技术研究

研究针对电池生产废水含铅、含氟、含磷、高酸性的特点,采用物化加生化的混凝气浮-化学反应-曝气生物滤池的处理工艺,去除废水中的氟、铅及部分磷酸盐,同时充分吸收、吸附污水中的污染物,达到降解有机污染物、减少污水中BOD5、COD的含量,从而达到良好的处理效果,最终达标排放。     

磷酸活化纺织固体废弃物制备活性炭及表征

以纺织固体废弃物为原料,磷酸为活化剂,采用一步活化法制备活性炭。采用正交实验研究了磷酸浓度、浸渍时间、活化温度和活化时间对活性炭吸附性能的影响,得到最佳工艺条件,借助氮吸附等温线、BET方程、BJH方程、SEM和FTIR分析了活性炭孔结构和表面化学性质。结果表明:最佳工艺条件为磷酸浓度40%(质量分数)、浸渍时间24h、活化温度500℃、活化时间30min。最佳条件下活性炭碘值为967mg/g,亚甲基蓝值为112mL/g,BET比表面积为1107.51m2/g,总孔容积为1.239cm3/g,中孔容积为1.024cm3/g,中孔占82.65%。活性炭表面具有羟基、羰基、内酯基和多种含磷官能团。