己内酰胺生产废水的铁碳微电解深度处理与机理研究

采用铁碳微电解方法对己内酰胺生产废水进行深度处理,探讨了pH值、停留时间、铁碳质量比对处理效果的影响。在pH为4、停留时间为120 min、铁碳质量比为4的最佳处理条件下,COD去除率可达57.8%,色度去除率可达68.4%。微电解对己内酰胺废水的作用主要通过铁的絮凝作用,处理过程中的酸性条件、微电解的氧化还原和电场作用,从而提高其去除效率。     

A~2/O工艺厌氧池有机物降解动力学模型对比研究

试验考察了东阿县污水处理厂一期A2/O工艺厌氧池去除有机污染物效能,当进水ρ(COD)为548.3 mg/L时,厌氧池平均去除率达78.7%。同时探讨了几种常见数学模型模拟厌氧池去除有机物规律情况,根据实际工程监测数据确定有机底物降解动力学常数,得出Grau模型、Stover-kincannon模型和改进的Monod模型较适合模拟厌氧池去除有机物的规律,并对模型进行了检验。     

硫酸系统水平衡分析计算和生产实践

在硫酸系统中,通过水平衡分析计算烟气带入净化工序的SO2体积分数和含水量,确定净化工序的能力,控制干燥塔进口烟气温度,使干吸工序生产出合格产品;通过计算,烟气带入净化工序的水量小于产品带出的水量,制酸净化污水经过污水处理工序处理后返回到净化工序重复使用,实现净化污水零排放,消除对环境的污染.     

220kV变压器噪声及其传播特性浅析

变压器噪声呈中低频特性,距离衰减率低,传播影响范围大。通过对上海某220kV露天变电站变压器噪声的实测数据进行简要分析,论述了220kV变压器噪声的强度及其频率特性,并探讨了变压器噪声在不同距离范围内的传播衰减特性。     

印钞废水处理工艺的改进实验

印钞废水属高浓度难降解有机废水,对环境污染严重。鉴于现有处理工艺出水普遍不达标的情况,通过对比实验确定了改进方案:超滤浓缩液离心出水在进入接触氧化池前,增加新的处理单元(Fenton氧化-混凝)。Fenton氧化最佳条件:FeSO4.7H2O投加量14 g/L,H2O2的投加量34 mL/L,初始pH值6.0,氧化反应时间1.5h,温度18.8℃;混凝过程最佳条件:PAC投加量4 g/L,PAM(5‰)投加量10 mg/L,pH值7。新增单元对废水中COD去除率接近80%,可生化性提高1.6倍,色度降低36%。     

Removal of copper ions from aqueous solution by calcium alginate immobilized kaolin

Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The e ects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.     

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

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.     

Transport and fate of mercury under different hydrologic regimes in polluted stream in mining area

Seepage from Hg mine wastes and calcines contains high concentrations of mercury (Hg). Hg pollution is a major environmental problem in areas with abandoned mercury mines and retorting units. This study evaluates factors, especially the hydrological and sedimentary variables, governing temporal and spatial variation in levels and state of mercury in streams impacted by Hg contaminated runo . Samples were taken during di erent flow regimes in theWanshan Hg mining area in Guizhou Province, China. In its headwaters the sampled streams/rivers pass by several mine wastes and calcines with high concentration of Hg. Seepage causes serious Hg contamination to the downstream area. Concentrations of Hg in water samples showed significant seasonal variations. Periods of higher flow showed high concentrations of total Hg (THg) in water due to more particles being re-suspended and transported. The concentrations of major anions (e.g., Cl??, F??, NO3?? and SO4 2??) were lower during higher flow due to dilution. Due to both sedimentation of particles and dilution from tributaries the concentration of THg decreased from 2100 ng/L to background levels (< 50 ng/L) within 10 km distance downstream. Sedimentation is the main reason for the fast decrease of the concentration, it accounts for 69% and 60% for higher flow and lower flow regimes respectively in the upper part of the stream. Speciation calculation of the dissolved Hg fraction (DHg) (using Visual MINTEQ) showed that Hg(OH)2 associated with dissolved organic matter is the main form of Hg in dissolved phase in surface waters in Wanshan (over 95%).     

Remediation of copper polluted red soils with clay materials

Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The e ects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment, the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An 8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the control red soil. Acid exchangeable Cu decreased with increasing amounts of attapulgite and montmorillonite, with best remediation e ect reached at a dose of 8%. Results also showed that the Cu poisoning e ect on earthworms was reduced with the addition of attapulgite and montmorillonite. Montmorillonite showed the best e ect, with the addition of a 2% dose the mortality of earthworms decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more e ectively with the application of montmorillonite than attapulgite.