Iron and lead ion adsorption by microbial flocculants in synthetic wastewater and their related carbonate formation

Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe^3＋ and Pb^2＋, two representative metals in wastewater, through the precipitation of carbonate minerals by a microbial flocculant （MBF） produced by Bacillus mucilaginosus. MBF was added to synthetic wastewater containing different Fe^3＋ and Pb^2＋ concentrations, and the extent of flocculation was analyzed. CO2 was bubbled into the mixture of MBF and Fe^3＋/Pb^2＋ to initiate the reaction. The solid substrates were analyzed via X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. The results showed that the removal efficiency decreased and the MBF adsorption capacity for metals increased with increasing heavy metal concentration. In the system containing MBF, metals （Fe^3＋ and Pb^2＋）, and CO2, the concentrated metals adsorbed onto the MBF combined with the dissolved CO2, resulting in oversaturation of metal carbonate minerals to form iron carbonate and lead carbonates. These results may be used in designing a method in which microbes can be utilized to combine CO2 with wastewater heavy metals to form carbonates, with the aim of mitigating environmental problems.     

Numerical simulation of alga growth and control in Dalian Bay

WAHMO model was used to simulate the distribution of pollutants in Dalian Bay, China as to predict well as the growth and control of alga. The observed and predicted values of main pollutants showed a good trend at all study locations and the different between them can be ignored. Simulation results illustrated that phosphate was one of limited factors to control algal growth at the location near the sewage outfall, meanwhile, away from the sewage outfall, the synergy of ammonium nitrogen and phosphate was the limited factor.     

矿产资源开发与矿山环境保护战略研究

本文在收集大量数据资料基础上,阐述了我国矿产资源特征与开发现状,论述了我国主要矿山地质环境问题及其危害,深刻剖析了产生诸多矿山地质环境问题的根源,提出了矿产资源可持续开发利用与矿山环境保护的对策建议。为促进矿产资源开发与矿山环境保护协调发展提供参考。     

氮磷肥料对HB-5菌株降解莠去津的促进作用及去毒效应的影响

以莠去津降解细菌HB-5为研究对象,进行了氮、磷肥单一及复合施肥对HB-5细菌降解土壤中莠去津的促进作用的研究,探讨了莠去津降解率与土壤中速效氮、速效磷含量之间的关系及莠去津降解过程中生态毒性的变化情况.莠去津在土壤中的残留采用高效液相色谱法进行测定;土壤中速效氮和速效磷分别采用碱解扩散法及0.5mol/L-NaHCO3浸提-钼锑抗比色法测定;土壤的生态毒性采用蚕豆根尖微核法进行测定.结果表明,在实验的前5d,不论氮、磷肥单一或复合施肥均能够明显促进HB-5对莠去津的降解,不同施肥条件下莠去津的降解速率依次为:氮、磷肥复合单施磷肥单施氮肥不施肥料对照;实验5d后,各处理中莠去津降解率没有显著差异(p0.05),均达到了95%以上.土壤中速效氮和速效磷含量随着莠去津的降解而呈现逐渐减少的趋势.土壤的生态毒性试验结果表明,莠去津经HB-5菌株降解后,土壤的生态毒性显著降低;各施肥处理土壤中莠去津的生态毒性均低于不施肥处理的土壤;实验的前5d,各处理土壤中生态毒性的大小依次为:氮、磷肥复合单施磷肥单施氮肥不施肥料对照.实验7d时,各处理土壤中莠去津的生态毒性均恢复到空白对照水平.氮磷肥料的施用不仅能促进HB-5菌株对土壤中莠去津的降解,而且能加速降低土壤的生态毒性,为莠去津污染土壤的快速修复提供了理论依据.     

矿区可持续发展能力建设中生态环境管理研究

实现矿区的可持续发展有赖于发展模式的转变,转变传统的生态环境管理的基本观念,提出要完善和优化矿区的生态环境管理体制,建立矿区"环境-资源-经济"信息管理系统和生态环境综合分析决策模型,寓经济发展于环境管理中,寓环境管理建设于经济发展中,寓矿区发展于环境和经济的协调发展之中,推进矿区持续发展,为矿区环境保护和经济发展建立一个和谐的可持续发展模式.     

不同氮、磷肥用量下双季稻田的CH4和N2O排放

以红壤双季稻田为研究对象,采用静态暗箱-气相色谱法对2009年水稻生长期内不施肥（CK）,平衡施肥（BF）、减氮磷一（DNP1）、减氮磷二（DNP2）和增氮磷（INP）等5个处理的CH4和N2O排放通量以及环境因素进行观测.结果表明,早稻生长期间BF、DNP1、DNP2和INP的CH4平均排放通量为4.57、5.42、...     

一株嗜盐聚磷菌的筛选及除磷性能初探

从运行稳定的以生活污水为碳源的污泥中富集分离,并筛选出一株嗜盐聚磷菌qdp05,通过对菌株的形态、生理生化特征及16SrDNA序列进行分析后,鉴定该菌株qdp05为肠杆菌属.当碳源为乙酸钠,盐度为2%的条件下,好氧条件下培养48h后,qdp05对磷的最终去除率为87.8%.在厌氧好氧连续培养过程,qdp05表现出明显的...     

三峡库区悬移质泥沙对磷污染物的吸附解吸特性

就三峡库区悬移质泥沙对磷污染物的吸附解吸特性从野外同步监测和室内试验研究两个方面展开研究。选取长江干流、嘉陵江和乌江共7个监测断面于2002年和2003进行野外同步监测,测试结果表明：水中的悬移质泥沙对水中各种覆存形态的磷污染物浓度具有显著影响,单位重量泥沙对磷的吸附量与水体总泥沙含量、泥沙粒径有密切关系。采集寸滩断面泥沙对磷酸盐吸附解吸特性进行室内试验研究,并根据Langmuir吸附动力学方程对吸附解吸过程进行了拟合,发现吸附速率常数k随着泥沙粒径的增加而呈递增变化,而磷酸盐初始浓度对k值的影响并不明显,同时,磷酸盐解吸量随着泥沙浓度的增加和粒径的增加呈递减变化,k值随着泥沙粒径的增加而呈递增变化,泥沙浓度对k值的影响不明显。     

Competition of bloom-forming marine phytoplankton at low nutrient concentrations

Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with di erent nitrate (NaNO3) and phosphate (NaH2PO4) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 mol/L Na2SiO3. Under nitrate limited (8.82 mol/L NaNO3) conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 mol/L. Cell density of the two dinoflagellates only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO3 concentrations between 88.2 and 882 mol/L with limited phosphate (0.36 mol/L NaH2PO4) levels. In addition, P. minimum grew well with a maximal cell density of 1690–2100 cells/mL (0.5–0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits.     

Removal of phosphate by Fe-coordinated amino-functionalized 3D mesoporous silicates hybrid materials

Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water. A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was synthesized by a post-grafting and metal cation incorporation process. The surface structure of the adsorbent was characterized by X-ray di raction, N2 adsoropion/desoprotion technique, and Fourier transform infrared spectroscopy. The experimental results showed that the adsorption equilibrium data were well fitted to the Langmuir equation. The maximum adsorption capacity of the modified silicate material was 51.8 mg/g. The kinetic data from the adsorption of phosphate were fitted to pseudo second-order model. The phosphate adsorption was highly pH dependent and the relatively high removal of phosphate fell within the pH range 3.0–6.0. The coexistence of other anions in solutions has an adverse e ect on phosphate adsorption; a decrease in adsorption capacity followed the order of exogenous anions: F?? > SO2?? 4 > NO??3 > Cl??. In addition, the adsorbed phosphate could be desorbed by NaOH solutions. This silicate adsorbent with a large adsorption capacity and relatively high selectivity could be utilized for the removal of phosphate from aqueous waste streams or in aquatic environment.