Long-term variations of water quality in a reservoir in China

To study the spatial and temporal trends of water quality in the Yuqiao Reservoir (Ji County, Tianjin) in China, water quality data for ten physical and chemical parameters from three monitoring stations (S1, S2 and S3) was collected from 1989 to 2007 and from an other three stations (S4, S5 and S6) during the period of 1999-2007. A one-way ANOVA was employed to evaluate the spatial variation of water quality for each station. The results showed that there were statistically significant spatial differences for most water quality parameters except temperature and dissolved oxygen in the entire reservoir, and the concentrations of most parameters were higher in the uppermost part of the reservoir. The temporal trend study was conducted using the Seasonal-Kendall's test. The results revealed improving trends of water quality from 1989 to 2007, including a reduction of total phosphorous, temperature and biochemical oxygen demand and an increase of dissolved oxygen. High N:P ratios, ranging from 52.61 to 78.75, indicated that the reservoir was a phosphorous-limited environment. This study suggests long-term spatial and temporal variations of water quality in the Yuqiao Reservoir, which could be informative for water quality managers and scientists.     

Enhanced removal of chemical oxygen demand, nitrogen and phosphorus using the ameliorative anoxic/anaerobic/oxic process and micro-electrolysis

Synthetic wastewater was treated using a novel system integrating the reversed anoxic/anaerobic/oxic (RAAO) process, a micro-electrolysis (ME) bed and complex biological media. The system showed superior chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal rates. Performance of the system was optimised by considering the influences of three major controlling factors, namely, hydraulic retention time (HRT), organic loading rate (OLR) and mixed liquor recirculation (MLR). TP removal efficiencies were 69, 87, 87 and 83% under the HRTs of 4, 8, 12 and 16 h. In contrast, HRT had negligible effects on the COD and TN removal efficiencies. COD, TN and TP removal efficiencies from synthetic wastewater were 95, 63 and 87%, respectively, at an OLR of 1.9 g/(L·d). The concentrations of COD, TN and TP in the effluent were less than 50, 15 and 1 mg/L, respectively, at the controlled MLR range of 75-100%. In this system, organics, TN and TP were primarily removed from anoxic tank regardless of the operational conditions.     

ADCP测流技术及使用中应注意的几个问题

传统测流方法手段落后、信息化水平低,不能很好地适应新时期水文测报快速、准确、精度高、任务多的要求。ADCP测流仪器的引进较好地解决了这一问题。作为新型测流仪器,ADCP测流方式、使用方法、适应条件等与传统仪器有很大区别,本文通过分析ADCP测流原理、使用过程中容易出现的问题,提出了ADCP测流中需要注意的一些事项。     

臭氧对生物增强活性炭系统中菌群稳定性影响研究

为提高生物增强活性炭(BEAC)工艺的生物稳定性,进行臭氧工艺对固定的优势菌群稳定性的影响研究。结果表明,臭氧投加量1.5～2.5mg/L,接触时间大于10min时,可有效杀灭进水中的杂菌,且产生的余臭氧量(小于0.25mg/L)不会影响后续工艺中优势菌群的生物活性。通过对比臭氧—BEAC和单独BEAC工艺滤料表面菌群组成随运行时间的变化规律,臭氧—BEAC工艺优势菌在活性炭表面始终占主导地位,菌种组成及生态结构未发生改变,有较好的生物稳定性。单独BEAC工艺运行至6个月时,菌群组成发生较大变化,优势菌数量减少。通过扫描电镜观察,运行6个月的臭氧—BEAC炭上形成菌体重叠的菌团结构,并有较多未被生物覆盖的滤料表面和空缺的地方。单独BEAC工艺活性炭表面粗糙结构较少,被大量污染物与菌团相互包裹的颗粒所覆盖。     

粉末活性炭—超滤组合工艺处理长江陈行原水

以长江陈行水库原水为研究对象,探讨了粉末活性炭—超滤组合工艺对水中CODMn、UV254、浊度、氨氮等去除效果,评价投加粉末活性炭后超滤膜跨膜压差(TMP)的变化情况.结果表明:超滤膜出水CODMn均值为1.10 mg/L,平均去除率为48.7％,UV254均值为0.016 cm-1,平均去除率为76.2％;组合工艺对水中氨氮具有一定的去除效果,对总铁、总锰去除效果显著,出水浊度保持在0.031 NTU以下.粉末活性炭投加于沉淀池之前,对于改善出水水质、减轻膜污染起到了较好的效果.     

对煤炭企业安全文化建设的思考——重庆煤炭集团永荣矿业公司安全文化建设调查

近年来，笔者在重庆煤炭集团永荣矿业公司范围内作了“企业安全文化建设”调研，采取随机访谈、座谈、查看资料、设置安全综合管理若干项目打分问卷调查等多种形式进行。通过调查，得出了对企业安全文化建设的基本估价。总体上看，企业安全文化建设有了新成绩，安全文化的制度层次建设有了新进展，安全物质文化的建设有了新突破。各级组织坚持了以人为本的安全管理，不断努力打造本质化安全矿井，煤矿工人的思想、感情、意志有了新的变化，党政工团各项工作安排，处处体现安全第一的方针。然而，笔者在调查中仍发现一些问题，值得认真对待和思考。     

证券风险的外部性与证券监管

证券风险具有十分明显的外部性特征，完全依靠市场的力量无法使证券风险的外部成本内部化，所以需要政府力量的介入，通过证券监管使社会成本内部化。但由于种种原因，证券监管的效果不是很理想，过多的监管会损害市场的功能，如何处理市场和监管之间的关系是证券监管者的一大难题。     

网络银行监管:国际实践与对策选择

网络银行是技术进步与金融产业相结合的产物，它的出现导致了传统银行制度一系列的变迁，尤其是其特殊的经营形式与风险特征，给传统的中央银行监管提出了新课题。结合我国网络银行发展的现实国情，构建适应于我国网络银行发展需要的监管体系。     

建立和完善环境管理体系实现企业可持续发展

针对加入WTO后石油天然气行业所面临的形势，从国际、国内、行业三个方面进行了详细分析，找出了我国石油行业之间的差距以及自身存在的问题。只有巩固与完善石油行业HSE管理体系，建立并实施加14000环境标准管理体系，正确处理好HSE管理体系与ISO 14000环境标准管理体系间的关系，才能最终实现我国环境标准与国际环境标准接轨。同时还要积极推行清洁生产，使企业从传统的由资源到产品再到污染物排放的线型经济模式中解脱出来，实现由资源到产品最终到再生资源的循环经济模式。只有这样，企业才能做到环境与经济的融合，才能提高企业市场竞争力，最终实现可持续发展。     

区域水资源开发利用的阈限分析

区域水资源总量的有限性决定了其开发阈限存在的客观性。本文提出了区域水资源开发利用的总体模式，通过阈限分析，利用模糊综合评判模型确定了当前汉中盆地平坝区水资源开发利用所处的阶段，并提出相应的开发对策。