论市政给排水工程施工管理

市政给排水工程是城市市政建设的重要组成部分,它的施工质量直接决定着一座城市能否实现正常运转。本文主要从管理现状、存在问题的角度出发,分析指出加强市政给排水工程管理的措施。     

关于小区生活污水排放的几个方案

近年来,经济的发展使城乡人民的生活水平不断提高,然而污水管网及污水处理设施发展滞后,严重影响了群众的居住环境和生活质量。为治理环境污染,各种类型的污水处理技术应运而生。     

市政道路施工的有效管理措施

本文对市政工程道路建设管理存在的弊端和遇到的问题进行了简要分析,建议市政道路建设加强监督管理措施,可以有效地提高工作效率,并对市政道路施工后的质量施工管理进行了阐述。     

复合型热泵在商住楼中的应用

针对商住楼,提出了一种复合型热泵系统。在夏季,该系统给室内供冷的同时利用热回收制备生活热水,在环境温度较高时,利用生活给水带走一部分冷凝热;在冬季,该系统既可以制备生活热水,也能给室内供热,在环境温度较低时,利用消防水池的水作为热源,实现了设备本身和建筑物内水资源的充分利用,从而保证热泵常年都有较高的能效值。     

Lead and cadmium in teeth,bone and kidneys of rats with a standard Pb‐Cd supply

Male Wistar rats received a combination of 25 ppm PbCl₂ and 5 ppm CdCl₂ in drinking water at different developmental stages. Pb and Cd levels of incisors, molars, epiphyses, diaphyses and kidney cortex were recorded by atomic absorption spectrophotometry. The results confirmed that Pb has an affinity for hard tissue and especially to teeth, but it also accumulated in soft tissues under the above conditions. In addition, the results indicated none or only a moderate placental or mammary barrier for Pb, and suggested a high absorption of lead from the intestine of sucklings. The results also confirmed that kidney cortex is a primary target for Cd, and indicated that Cd has crossed the placental and mammary barriers to some degree. The positive significant correlation between Cd levels in molars and kidney cortex suggested that rodent molars indicate a degree of Cd absorption, whereas incisors do not. It is supposed that rodent molars are comparable to human deciduous teeth. It is thus confirmed that human deciduous teeth indicate previous lead exposure. It is further inferred that they also can be used as indicators of previous Cd‐exposures.     

The impact of the petroleum sector on the output of the Nigerian construction sector

The petroleum sector plays an important role in the Nigerian economy, as it is the single largest revenue earner of the country and one of the largest contributors to the gross domestic product (GDP). This study estimated the impact of petroleum and gas revenue on the performance of the construction sector using a polynomial distributed lag model. We extracted data on the petroleum and gas sector (PGS), the GDP and construction sector output (CNS) for this study from the Central Bank of Nigeria (CBN) Statistical Bulletin. The analysis employed econometric methodology, which includes testing for stationarity and co‐integration as well as estimating the distributed lag model. The result shows that the petroleum and gas revenue significantly affected construction output for three consecutive years starting from their year of occurrence. The study concluded that the PGS has a far‐reaching impact on the growth and development of the construction sector. It therefore recommends supporting the channelling of funds from the petroleum sector into development of constructed facilities infrastructure.     

市政污泥在超临界甲醇条件下酯化制油研究

利用自行设计的反应釜研究了市政污泥在超临界甲醇条件下的油化行为。主要考察了温度、停留时间、污泥与甲醇的配比、催化剂对污泥油化过程的影响,以期找到最佳反应条件。结果表明:当控制温度在360℃、停留时间为80 min时,制得的生物油产量最高,可达44.7%。当干污泥量为20 g时,污泥与甲醇的固液比越大,其产油率越高。加入催化剂能有效促进污泥油化过程,以碱性催化剂KOH的促进效果最明显。     

垂直流人工湿地组合工艺在绿色建筑中的应用

在某房地产公司深圳总部绿色建筑工程中,采用水解酸化/垂直流人工湿地组合工艺处理优质杂排水,采用接触氧化/反硝化沉淀/垂直流人工湿地处理生活污水,对实际设计参数、水质监测数据进行分析可知,垂直流人工湿地组合工艺对污染物的总体去除率较高,出水水质完全能满足回用要求.垂直流人工湿地组合工艺完全可满足绿色建筑对节约水资源、保护环境、减少污染的要求.     

MBR微滤膜在污水处理厂的清洗维护实践

针对MBR工艺常出现的膜污染问题,在实际运行过程中通过不断摸索、分析总结,探讨了MBR工艺微滤膜清洗维护的有效方法,为MBR工艺的进一步应用、发展提供参考.     

低温下生物增效技术对去除氨氮效果的改善

在冬季水温低的情况下,为改善对氨氮的去除效果而实施了生物增效试验,连续30d向某污水处理厂的曝气池投加硝化菌,研究了投加菌剂后对氨氮的去除效果.投加菌剂10 d后,在水温为12.4 ～ 15.2℃时,二沉池出水氨氮浓度＜15 mg/L,对氨氮的去除率由68.6％提高至84.7％,处理水量由6.2×104 m3/d提升至7.5×104 m3/d.菌剂投加期结束后的30 d内,在维持高处理水量的前提下,出水氨氮＜7 mg/L,去除率＞91％,处理水量超过设计水量约25％.同时,该技术的费用较低,直接菌剂成本仅为0.067元/m3.