Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance

A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K₂FeO₄ oxidation and KMnO₄ oxidation. The degree of disintegration (DD_COD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K₂FeO₄ oxidation was more efficient than KMnO₄ oxidation. The content of free water increased obviously with K₂FeO₄ and KMnO₄ oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K₂FeO₄ oxidation, and increased slightly with KMnO₄ oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K₂FeO₄ oxidation, and did not changed with KMnO₄ oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K₂FeO₄ and KMnO₄ oxidation improved the sludge dewaterability.     

废旧金属回收熔炼辐射安全管理研究

介绍了一起废旧金属熔炼导致的放射性污染事件,以及环保部门在事件中采取的措施.反思了废旧金属回收熔炼辐射安全监管存在的问题,指出相关的法律法规不够明确,对熔炼企业辐射监测的监管力度不足,废金属进出口的放射性管理存在漏洞,熔炼企业缺乏辐射安全意识和手段,提出了完善标准体系,强化口岸监测,实施分级管理,加强企业辐射安全管理等对策措施.     

Experimental study of NO2 reduction in N2/Ar and O2/Ar mixtures by pulsed corona discharge

Non-thermal plasma technology has been regarded as a promising alternative technology for NOx removal. The understanding of NO2 reduction characteristics is extremely important since NO2 reduction could lower the total NO oxidation rate in the plasma atmosphere. In this study, NO2 reduction was experimentally investigated using a non-thermal plasma reactor driven by a pulsed power supply for different simulated gas compositions and operating parameters. The NO2 reduction was promoted by increasing the specific energy density （SED）, and the highest conversion rates were 33.7%, 42.1% and 25.7% for Ar, N2/Ar and O2/Ar, respectively. For a given SED, the NO2 conversion rate had the order N2/Ar 〉 Ar 〉 02/Ar. The highest energy yield of 3.31 g/kWh was obtained in N2/Ar plasma and decreased with increasing SED; the same trends were also found in the other two gas compositions. The conversion rate decreased with increasing initial NO2 concentration. Furthermore, the presence of N2 or O2 led to different reaction pathways for NO2 conversion due to the formation of different dominating reactive radicals.     

集中供热项目环境效益分析——以某市集中供热项目为例

介绍了某市新区供热现状,并对预测模型AERMOD的运行参数及数据来源进行了简要说明,根据区内供热现状及采取集中供热方式后新区冬季采暖集中供热锅炉烟气污染物排放源强的变化情况,采用AERMOD模型分别进行了预测。在此基础上,通过对比分析,得出了大型集中供热工程具有明显环境效益的结论。     

不同载荷下轮式车辆运输振动数据预测模型研究

目的为便于执行GJB 150A进行车辆运输振动试验,研究了不同载荷下运输振动数据预测模型。方法对模型的特点和适用范围进行了分析;运用该模型分析了不同载荷下运输振动试验的试验数据规律。结果随着载荷的增加,运输振动逐渐减小,能够反映轮式车辆不同载荷下的运输振动规律,给出了运用该模型对不同载荷下车辆运输振动数据的预测方法。结论该模型简单实用,在执行GJB 150A进行运输振动试验过程中,若直接引用标准中的数据,可以采用该模型对不同载荷下的运输振动试验数据进行预测。     

高原环境对车辆动力性的影响及动力提升措施

在总结我国高原气候和地理环境特点的基础上,从反映车辆动力性能的指标出发,以加速时间、最大爬坡度和最高车速入手,理论分析了对整车高原动力性影响较大的因素,主要包括有效热效率、循环喷油量、滚动阻力系数、空气密度对空气阻力的影响等。通过分析高原环境对这些因素的影响,总结出了高原环境对车辆动力性的影响机理,并进一步提出了整车高原动力性改进的技术措施,认为先进增压、燃烧优化、高压共轨燃油喷射、高原环境标定、热平衡控制和富氧进气燃烧等技术措施成为提高车辆动力性的有效技术措施。     

基于“全碳排核算”的碳绩效评价方法研究

文章运用了能值分析方法进行了碳排放核算,核算帐户不仅包括能源消耗产生的二氧化碳,也包括生物质资源消费和废弃物排放所产生的二氧化碳。并在此基础上,将人口、经济和二氧化碳排放量综合起来考虑,引入对污染敏感的收入指数衡量一个地区碳排放绩效。并通过对天津市、上海市、北京市及重庆市2001年-2011年数据,分析和衡量四市将人口、经济和二氧化碳排放量综合考虑碳的排放绩效,通过案例区研究表明将全碳排核算的计算结果与经济、社会因素统一在同一个指标中,更加有利于区域对环境、经济和社会做全面考虑。     

某消失模铸造厂污染防治措施要点分析研究

根据某消失模铸造企业依托相邻的炼铁厂合作建厂的实际条件,对采用宝珠砂造型后消失模铸造车间的废气和废水污染产生环节进行了分析,确定主要污染为废气污染。环评根据企业的具体情况,有针对性地对中频炉熔炼、落砂及砂处理、真空浇铸、抛丸清理等各污染环节提出了合理可行的污染防治措施,并在此基础上重点对真空浇注产生的有机废气的几种处理方法进行了分析,确定该厂将有机废气经真空泵直接引入到炼铁厂煤气电站锅炉进行燃烧处理合理可行,并能满足相应的环保要求。     

北京平原区夏垫活动断裂滑动速率及古地震复发间隔

搜集了有关夏垫断裂钻孔测年数据,采用最小二乘法对数据进行拟合分析,拟合结果显示夏垫断裂滑动速率在地段和时段上均存在差异,且在时段上的差异更加明显。前20 ka以来滑动速率相对较小(0.13~0.30 mm/a);前26 ka~20 ka,滑动速率较大(1.38~2.56mm/a),约为前20 ka以来滑动速率的9~11倍。利用潘各庄探槽、东柳河屯探槽、齐心庄探槽、大胡庄探槽、地震联合钻孔剖面及钻孔资料判定除1679年三河-平谷8级地震外,前20 ka以来夏垫断裂还存在6次古地震事件,古地震平均复发间隔约为3 000 a。     

转Cry1Ac基因抗虫棉与其亲本棉花根际真菌多样性的比较

在温室条件下,利用PCR-DGGE技术和Q-PCR技术分析了两种转Cry1Ac基因抗虫棉及其亲本棉花在不同取样时期的根际真菌多样性和生物量的动态变化情况,以评价其生态安全.结果表明,转Bt基因棉与对照棉根际真菌优势条带组成在不同的取样时期极为相似,三者间差异条带多为不清晰的条带.转Bt棉SGK321根际真菌的生物量在苗期明显低于亲本对照,转Bt棉XP188根际真菌的生物量在花铃期较对照有轻微降低,其它时期两种转Bt棉根际真菌生物量没有显著降低,甚至还有增加的趋势.不过根际真菌群落结构的改变和生物量的差异不仅存在于转基因棉和其亲本对照棉之间,它同样存在于对照棉SHIYUAN321和JM20之间以及转基因棉SGK321和XP188之间.可见Bt并不是造成转基因棉和非转基因棉根际真菌群落结构差异、多样性改变和生物量减少的唯一诱因,品种的不同也对它们也有影响.