Dynamics of household energy consumption in a traditional African city, Ibadan

In the last three decades the Nigerian environment has experienced rapid degradation. A major contributory factor of this phenomenon is the pattern of socioeconomic development in the country that gives little or no consideration to environmental outcomes. An aspect of this development is the economic policy of removal of subsidies on petroleum products initiated in 1986 as a result of the worsening economic situation in the country which begun in the early 1980s. The result of this is that prices of commercial fuels inclusive of kerosene and LPG (cooking gas) have continued to rise beyond the reach of majority of the Nigerian population. The paper examines the effect of increasing prices of petroleum-derived energy sources on the pattern of energy use for cooking in low and middle-income households and the environmental implication in Ibadan, the largest truly indigenous urban centre in sub-Saharan Africa. Results show that prior to the further subsidy removal of 1993, majority of households sampled used kerosene for cooking. Thereafter, a complete or partial switch in the pattern of domestic energy consumption ensued with more households using fuel wood and other more polluting and less efficient energy sources for cooking. The paper recommends a transition towards more environmental friendly energy sources for household use.     

Applicability of a Septic Tank/Engineered Wetland Coupled System in the Treatment and Recycling of Wastewater from a Small Community

A septic tank (ST)/engineered wetland coupled system used to treat and recycle wastewater from a small community in Dar es Salaam, Tanzania was monitored to assess its performance. The engineered wetland system (EWS) had two parallel units each with two serial beds packed with different sizes of media and vegetated differently. The larger-sized medium bed was upstream and was planted with Phragmites (reeds) and the smaller-sized medium bed was downstream and was planted with Typha (cattails). The ST/EWS coupled system was able to remove ammonia by an average of 60%, nitrate by 71%, sulfate by 55%, chemical oxygen demand by 91%, and fecal coliform as well as total coliform by almost 100%. The effluent from the ST/EWS coupled system is used for irrigation. Notably, users of the recycled irrigation water do not harbor any negative feelings about it. This study demonstrates that it is possible to treat and recycle domestic wastewater using ST/EWS coupled systems. The study also brings attention to the fact that an ST/EWS coupled system has operation and maintenance (O&M) needs that must be fulfilled for its effectiveness and acceptability. These include removal of unwanted weeds, harvesting of wetland plants when the EWS becomes unappealingly bushy, and routine repair.     

Odour-guided social behaviour in newborn and young cats: an analytical survey

Summary. This article surveys early chemosensory mechanisms regulating behaviour in neonatal and juvenile domestic cats (Felis sylvestris catus). It aims to retrieve material from the available literature which may promote a better understanding of the semiochemical system that supports female-to-kitten exchanges. Studies dealing with the development of olfaction from birth through weaning are presented in three sections. The first aims at locating developmental periods suitable for applying analytical procedures combining behaviour and chemistry. The second section offers a survey of observational and experimental work related to the role of olfaction in the social and feeding behaviour of kittens before weaning. The final section traces the current knowledge on the odour sources and substrates that may be involved in early mother-kitten transactions.     

城市生活垃圾堆肥—紫色土蔬菜种植试验研究

盆栽试验结果表明城市生活垃圾堆肥施入紫色土中,可增加土壤的氮肥潜能,降低作物中Ｈｇ、Ｃｒ、Ｐｂ的含量;但施量过大会影响作物生长,造成作物减产,品质下降。本次土培试验初步提供了紫色土和垃圾的较适比为１∶１。     

湖南省城镇生活垃圾总量预测研究

结合在社会系统中有一定应用的耗散结构理论的有关思想、方法和研究成果，对湖南省城镇生活垃圾总量进行建模预测，实际应用结果表明该模型具有结构简单、适用性强的特点，且预测值与实际值吻合较好。     

我国城市垃圾分类收集的经济效益分析

通过对阜新市城市生活垃圾现状的分析,以北京市2002￣2004年的垃圾成分为例,运用经济数学方法建立垃圾分类收运效益模型,对混合收集和分类收集模式进行经济效益分析与评价,从而得出对垃圾进行分类收集是可行的,是从源头治理垃圾,实现“减量化、资源化、无害化”的有效方法。     

化学絮凝法处理PVC生产废水

用９种无机絮凝剂（包括无机高分子）对ＰＶＣ生产废水的絮凝效果进行了比较和选择：选用聚合硫酸铝（ＰＡＳ）为絮凝剂，用以取代进口药剂对ＰＶＣ废水的絮凝沉淀处理，进行了实验室工艺条件试验，确定其使用的最佳工艺条件。结果表明，当废水进水ＰＨ值为６．０－７．０时，ＰＡＳ的投加量最小，而ＣＯＤｃｒ去除率＞９０％，这表明用国产ＰＡＳ取代进口药剂处理ＰＶＣ废水是完全可行的。     

膜技术在废水处理中的应用

着重介绍了膜技术在生活污水、油田采出水、造纸废水、纺织印染废水、高浓度有机废水和重金属废水中的应用。膜技术处理废水与传统的废水处理方法相比具有处理效果好，可实现废水回用和有用物质回收的优点。并展望将膜技术应用于废水处理，特别是近年来新发展起来的纳滤膜分离技术应用于含低分子量污染物的分离，与传统的废水处理过程相结合等技术均将产生较大的社会效益与经济效益。     

住宅小区垃圾压缩站环境污染及防治对策

阐述了住宅小区内设置垃圾压缩站的现实意义。论述了垃圾压缩站的污水．臭气和噪声污染问题．并对压缩站产生的臭气和噪声影响作了预测分析。对压缩站的选址及其污染防治措施提出了建议。     

膜生物反应器处理生活污水的工艺及膜材料的选择

介绍了膜生物反应器处理生活污水的工艺 ,结果表明 :膜生物反应器对生活污水中 CODCr、BOD5、NH3 -N、SS、E-coli、浊度的去除率分别为 87%～ 98%、88%～ 99%、89%～ 98%、1 0 0 %、1 0 0 %、98%～1 0 0 % ,实验出水水质稳定 ,宜于回用。聚丙烯膜比聚砜膜具有更好的出水量和抗污染性。