滇池流域磷循环系统的物质流分析

研究营养元素在社会经济系统中的物质代谢结构及特征,是有效预防和控制地表水体富营养化的关键性分析技术之一.以滇池流域磷循环为研究案例,运用物质流分析方法建立了2000年流域静态物质流模型(PHOSFAD),并在此基础上识别出流域磷循环系统的总体结构特征,以及资源开采、化工生产、农业种植、畜禽养殖、居民生活等生产和消费部门的物质利用效率特征,为科学防治滇池水体富营养化提供了重要决策依据和参考.     

Selection of appropriate organic additives for enhancing Zn and Cd phytoextraction by hyperaccumulators

Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid （EDTA）, citric acid, acetic acid, oxalic acid, glutamine and monosodium glutamate waste liquid （MGWL） from food industry. Experiments in pots were carried out to study the effects of the additives on Zn and Cd phytoextraction. Furthermore, a leaching experiment with lysimeter was performed to evaluate the environmental risks of additive-induced leaching to underground water. The results showed that EDTA had a strong mobilizing ability for Zn and Cd, followed by mixed reagent （MR） and MGWL. MGWL and acetic acid at 5 mmol equivalent per liter resulted in seed germination index less than 2%. Experiments in pots verified the phytotoxicity of acetic acid and MGWL. Addition of the mixed reagent at 6--10 mmol/kg significantly increased Zn phytoextraction by Thlaspi caerulescens. The same for EDTA and the mixed reagent at 10 mmol/kg by Sedum dfredii. But only mixed reagents could significantly increase Cd phytoextraction by the studied hyperaccumulators. This suggested that the strong chelant was not always the good agent to enhance phytoextraction. S. alfredii combined with 2--10 mmol/kg soil MR was preferred for phytoremediation of Cd/Zn contaminated soils in southern China, this could result in high phytoextraction of Cd/Zn and reduce the leaching risk to underground water than EDTA assisted phytoextration.     

Impact of anions on the heavy metals release from marine sediments

Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions CL^-, SO4^2- and HCO3^- on the release ofCd, Pb, Cu and Zn from the sediments. The results showed that the sequences about the impact of the three anions were Cl^-〉HCO3^-〉SO4^2＋. The release potential of heavy metals in the presence of each anions was in the following order： Cd≥Cu 〉Zn≈Pb. The correlations were positive between CI content and the quantity of Cd released from the marine sediment, whereas there was no significant relationship between CI content and amount of Cu and Zn released. For SO4^2- and HCO3^-, the release of the heavy metals from marine sediments was not obvious.     

Selective extraction and separation of Fe, Mn oxides and organic materials in river surficial sediments

In order to investigate the adsorption mechanism of trace metals to surficial sediments （SSs）, a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials （OMs） in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils and sediments, NH2OH .HCl （0.1 mol/L） ＋ HNO3 （0.1 mol/L）, （NH4）2C2O4 （0.2 mol/L） ＋ H2C2O4 （pH 3.0）, and 30% of H2O2 were respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09%--3.36% for the hydroxylamine hydrochloride treatment, 80.63%- 101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation ofFe, Mn oxides and OMs in the SSs, and important for further mechanism study of trace metal adsorption onto SSs.     

Effect of humic substances on the precipitation of calcium phosphate

For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate （as P） and 20 mg/L HS （as dissolved organic carbon, DOC） at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium （Ca） and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction （XRD） and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite （HAP） by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.     

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China

Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals （Fe, Mn, Zn, Cu, Pb, and Cd） using the modified sequential extraction procedure （MSEP）. The results show that the differences between NSCSs and SSs in Fe fi＇actions were insignificant and Fe was dominantly present as residual phase （76.22% for NSCSs and 80.88% for SSs） and Fe-oxides phase （20.33% for NSCSs and 16.15% for SSs）. Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase （48.27%） and that in SSs present as residual phase （45.44%）. Zn, Cu, Pb and Cd were found dominantly in residual fractions （〉48%）, and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter （OM）, and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.     

Degradation of 2,4-dichlorophenoxyacetic acid in water by ozone-hydrogen peroxide process

IntroductionAt present, several types of organic pollutantsreferred to as environmental endocrine disruptors(ED) have been suggested to be associated withabnormal sexual development (Hu, 2000). It wasreported that the ED led to the decline of reproductive…     

消防行政审批机构受理审核时限所需报送的材料

1.建筑工程消防设计审核 建筑工程消防设计审核,是指公安消防监督机构对新建、改建、扩建、建筑内部装修和用途变更的建筑工程项目.(其中包含下列内容:利用新、改、扩建地下工程开办旅馆、商店等消防安全审查;新、改、扩建生产、储存化学易燃物品设施的消防设计审批;新、改、扩建摄制场所防火设计审批;新、改、扩建室内娱乐场所消防设计审批;新、改、扩建化学危险物品储存设施消防设计审批;消防设计图纸报送审核.)     

亚硝酸盐对聚磷菌吸磷效果的影响

以厌氧/好氧生化反应器中的聚磷菌为实验对象,探讨了亚硝酸盐对聚磷菌吸磷效果的影响.结果表明:低浓度NO₂^--N可以作为聚磷菌的电子受体,实现NO₂^--N型反硝化除磷,但吸磷总量和吸磷速率明显低于NO₃^--N型反硝化除磷的效果;当NO₂^--N和NO₃^--N共存于缺氧环境时,NO₂^--N对NO₃^--N型反硝化除磷的除磷总量和速率没有影响,但会降低NO₃^--N的消耗量;NO₂^--N型反硝化除磷污泥的好氧吸磷量和速率均低于传统A/O厌氧放磷污泥的效果,但由于它经历了缺氧吸磷和好氧吸磷2个阶段,因此,从吸磷总量或出水水质看,二者相差不大.     

基于微生物相互作用机理的完全耦合活性污泥模型研究

根据微生物生长机理,推导出微生物的耦合作用机理并在该机理的基础上改进了ASM3 Bio-P模型.假设活性污泥系统中有机物氧化过程、生物硝化过程、生物反硝化过程、生物除磷过程可同时存在,在ASM3 Bio-P模型上添加相关的开关函数,推导出完全耦合活性污泥模型(FCASM).基于计算机程序进行数值模拟,并将FCASM模拟结果与实测值以及ASM3 Bio-P模型模拟值进行对比.结果表明,完全耦合活性污泥模型对氨氮模拟的稳态出水值为1.90 g·m-3,ASM3 Bio-P模型模拟的氨氮稳态出水值为0 g·m-3,而实测的氨氮稳态出水值为1.50 g·m-3,完全耦合活性污泥模型的结果更接近真实值.