泡沫分离法去除废水中微量钴离子

采用泡沫分离法对水中微量钻离子的去除进行了研究,考察了表面活性剂种类及浓度、pH、气流量等因素对钴离子去除率的影响。实验结果表明：当水中钴离子初始质量浓度为10mg／L、采用十二烷基硫酸钠（SLS）做表面活性剂且质量浓度为10mg／L、pH为11．0、气流量为300L／h时,钴离子去除率达97．61％。根据泡沫分离过程与化学反应过程在物理行为上的类似性,引入等效的化学反应常数,对泡沫分离法去除水中钴离子进行了宏观动力学研究。结果表明,该泡沫分离过程可等效为一级反应。     

人工湿地中植物的修复作用原理与应用实例

植物修复在水污染防治中具有重要作用,有着广泛的应用前景。本文阐述了水生植物在湿地污水净化过程中的物理、化学、生物等方面的作用及原理,例举了植物修复在不同水质条件下的应用实例,提出应针对植物复氧能力、植物种类选择和收割植物后续处理等方面进行深入研究。     

浅谈资源型城市可持续发展 ──以大庆为例阐述战略规划和环境政策制定的依据和原则

文章分析了资源型城市制定可持续发展战略和环境政策的依据和原则,以大庆开发建设多年来的成功经验和失败教训为例,阐释了资源型城市充分利用资源、资金、文化、人才的重要性和必要性,及对生态环境和人文环境充分保护的紧迫性。进而说明:充分利用好城市的各种资源,充分保护好城市的生态环境和人文环境,及早发展替代产业完成城市转型是资源型城市可持续发展的必由之路。     

新型除磷混凝剂的研制与应用＊

实验以处理金属表面所产生的磷化废水为研究对象,系统地分析了在新型混凝剂的使用过程中,pH值、温度、石灰投入量、沉降时间、助剂A等因素对脱磷效果的影响。结果表明,含磷量为18mg/L、COD为300mg/L、SS为150mg/L、pH值为5.7～6.5的废水,石灰投入量为300mg/L、沉降时间为10min左右、温度为25℃、pH值调节至9.0、加入5mL助剂A处理后,废水中磷含量为0.25～0.35mg/L、COD为80mg/L、SS为60mg/L,满足《污水综合排放标准》(GB8978—1996)中的一级标准。     

深圳市公路建设对生态环境的影响、治理及对策

公路建设曾经给深圳的生态环境造成了较为严重的危害 ,主要有 :严重的水土流失及其派生影响 ,对一些具有观赏价值的自然景观产生破坏 ,影响了部分区域动植物生存环境等。主要对这些环境影响及已进行的治理及其成效进行综述 ,对治理工作的不足及未来对策也进行了探讨。     

泥沙灾害和泥沙环境快速评估方法研究

泥沙灾害可以看作是泥沙环境突变或渐变积累到一定条件下发生变异时的表现形式,各类泥沙灾害和泥沙环境都具有不同的内涵和表现方面, 因此泥沙灾害和泥沙环境的评估应具有不同的对象。一旦研究的对象被确定,泥沙灾害的表现因子组合便可明确。类似地泥沙环境的环境变量和总体状况的指示怀变量也可确定。为了便于了解泥沙灾害和泥沙环境的关系,并提高评估效率,可将泥沙灾害和泥沙环境快速评估的参照组建立在能够包括影响二者表现特征的诸环境变量的最小图斑上,通过选取适当参照点,分类确定不同参照组,利用待评估地点孕灾环境因子（或环境变量）与不同参照组的相似分析。预测评估点的泥沙灾害和泥沙环境表现因子特征和动态过程.     

Environmental impact of aquaculture and countermeasures to aquaculture pollution in China

GOAL, SCOPE AND BACKGROUND: Aquaculture activities are well known to be the major contributor to the increasing level of organic waste and toxic compound in the aquaculture industry. Along with the development of intensive aquaculture in China, concerns are evoked about the possible effects of ever-increasing aquaculture waste both on productivity inside the aquaculture system and on the ambient aquatic ecosystem. Therefore, it is apparent that appropriate waste treatment processes are needed for sustaining aquaculture development. This review aims at identifying the current status of aquaculture and aquaculture waste production in China. MAIN FEATURES: China is the world's largest fishery nation in terms of total seafood production volume, a position it has maintained continuously since 1990. Freshwater aquaculture is a major part of the Chinese fishery industry. Marine aquaculture in China consists of both land-based and offshore aquaculture, with the latter mostly operated in shallow seas, mud flats and protected bays. The environmental impacts of aquaculture are also striking. RESULTS: Case studies on pollution hot spots caused by aquaculture have been introduced. The quality and quantity of waste from aquaculture depends mainly on culture system characteristics and the choice of species, but also on feed quality and management. Wastewater without treatment, if continuously discharged into the aquatic environment, could result in remarkable elevation of the total organic matter contents and cause considerable economy lost. Waste treatments can be mainly classified into three categories: physical, chemical and biological methods. DISCUSSION: The environmental impacts of different aquaculture species are not the same. New waste treatments are introduced as references for the potential development of the waste treatment system in China. The most appropriate waste treatment system for each site should be selected according to the sites' conditions and financial status as well as by weighing the advantages and disadvantages of each system. Strategies and perspectives for sustainable aquaculture development are proposed, with the emphasis on environmental protection. CONCLUSIONS: Negative effects of waste from aquaculture to aquatic environment are increasingly recognized, though they were just a small proportion to land-based pollutants. Properly planned use of aquaculture waste alleviates water pollution problems and not only conserves valuable water resources but also takes advantage of the nutrients contained in effluent. It is highly demanding to develop sustainable aquaculture which keeps stocking density and pollution loadings under environmental capacity. RECOMMENDATIONS AND PERSPECTIVES: The traditional procedures for aquaculture waste treatment, mainly based on physical and chemical means, should be overcome by more site-specific approaches, taking into account the characteristics and resistibility of the aquatic environment. Further research needs to improve or optimize the current methods of wastewater treatment and reuse. Proposed new treatment technology should evaluate their feasibility at a larger scale for practical application.     

Desorption of copper and cadmium from soils enhanced by organic acids

The adsorption/desorption behavior of copper and cadmium on soils was investigated in this study. The adsorption isotherm of copper and cadmium conformed to Langmuir equation better than Freundlich equation. The effect of ionic strength, pH, and organic acid, including ethylenediamine tetraacetic disodium acid salt (EDTA), citric acid, oxalic acid and tartaric acid, on the desorption of copper and cadmium was studied. The desorption of copper and cadmium increased with the increase of ionic strength, while the desorption decreased with the rise of pH. The desorption of copper and cadmium enhanced by organic acids was influenced by pH. EDTA showed excellent enhancement on the desorption of both copper and cadmium; citric acid demonstrated great enhancement on the desorption of copper but negligible enhancement on the desorption of cadmium; oxalic acid enhanced the desorption of copper only at pH around 6.4 and enhanced the desorption of cadmium in the pH range from 6.4 to 10.7; tartaric acid slightly enhanced the desorption of copper but negligibly enhanced the desorption of cadmium. The desorption mechanism in the presence of organic acids were explained as the competition of complexation, adsorption and precipitation. The net effect determined the desorption efficiency. This study provided guidance for the selection of organic acids to enhance the electrokinetic (EK) remediation of copper and cadmium from contaminated soils.     

钢铁厂冷轧废水污泥中铬回收实验研究

钢铁厂冷轧废水污泥中含有10%以上的铬、20%以上的铁和1.5%以上的锌(均以质量分数计).为了从污泥中回收铬,首先研究了污泥中铬的形态,确定为Cr(Ⅲ);然后以碳酸钠为氧化助剂,将污泥与碳酸钠按一定比例混合后焙烧,再用水浸取.研究了碳酸钠的添加量、焙烧温度和时间、浸取时间和浸取方式对铬回收率的影响.研究表明,每克干污泥中添加0.6 g或以上碳酸钠,在固定床上700 ℃焙烧4 h以上,可实现60%以上的总铬浸出率,残渣为Fe2O3基脱硫剂原料.     

金属离子对有机垃圾两相厌氧系统中UASB处理效果的促进作用

在"水解溶出 UASB反应器"处理城镇有机垃圾的两相厌氧系统中,向UASB反应器进水中添加K、Mg、Fe、Co、Ni 5种金属离子的组合促进剂,通过对UASB反应器容积负荷、产气量、产甲烷量在添加组合促进剂前后的比较,研究了组合促进剂(K、Mg、Fe、Co、Ni)对有机垃圾浸出液厌氧消化过程的促进作用.试验结果表明,添加组合促进剂后,反应器的平均容积负荷从12.89 kg COD/m3·d提高到17.79 kg COD/m3·d;平均污泥负荷从0.82 kg COD/kg VSS·d提高到1.07 kg COD/kg VSS·d.此外,平均每千克COD产气量为392.5 L,比添加组合促进剂之前增大了6.4%;而平均每千克COD产甲烷量为297.5 L,比添加组合促进剂之前增大了10.5%.对于氨氮、挥发性脂肪酸(VFA)、pH及碱度来说,在添加组合促进剂之后则无大的变化.