Leachate characteristics,dry matter yield of Urochloa decumbens and properties of two contrasting soils irrigated with sludgewater in columns

Increasing demands on freshwater and challenges in disposal of wastewaters encourage their use for irrigation. The study evaluated the effects of irrigation of signal grass (Urochloa decumbens) with sludgewater on leaching, uptake and retention of a range of elements in two contrasting soils in columns. The grass was grown on a sandy loam and a clay soil packed in plastic columns and irrigated for 119 days with either undiluted, diluted sludgewater or tap water. The sludgewater had a pH of 6.9 and high aluminum (Al), manganese (Mn), iron (Fe), and boron (B). Analyses were conducted on leachates, above-ground plant biomass (two harvests), and soils at the end of the experiment. Sludgewater treatments increased grass biomass yield and uptake of nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) in both soils with a greater nutrient uptake from the clay than the sandy loam. The application of sludgewater increased Mn and reduced P (sandy loam only) in the leachate with no effects on Al, Fe, or B. Uptake of Al, Fe, and B was increased by sludgewater application. Even when diluted, the sludgewater increased extractable Mn, particularly in the clay soil. The findings showed that irrigation of the soils with sludgewater increased Mn and B concentrations and uptake by signal grass, with no negative effects on biomass production. Leaching and accumulation in the soils of toxic elements were minimal in the short term. Sludgewater can therefore be used to grow signal grass in both soils although these effects need to be evaluated under field conditions.     

某铝厂熔铸项目职业病危害控制效果评价

采用职业卫生调查、职业卫生检测、检查表分析法等方法对某铝厂熔铸项目存在的职业病危害进行了识别、分析,提出了职业病危害防护措施方面的建议。     

CHANGE IN LAKE TROPHIC STATE AND INTERNAL PHOSPHORUS RELEASE AFTER ALUMINUM SULFATE APPLICATION1

ABSTRACT: Recovery of eutrophic lakes after nutrient diversion may be delayed if the lake experiences significant internal phosphorus (p) loading to the water column. A maximum dose of aluminum sulfate, defined herein, was applied to the anaerobic sediments of the hypolimnia of two dimictic Ohio lakes following septic tank diversion, with the objective of attaining long term control of the release of phosphorus to the water column from these sediments. The results were compared to a similar, downstream, untreated lake. Total phosphorus concentration declined sharply after treatment and has remained so through 1980 for both lakes, a period of 5 and 6 years of control, respectively. Internal P loading from anaerobic, hypolimnetic sediments was partially controlled by the treatment but there are other important sources, perhaps in the littoral zone, in these lakes. Algal biomass is Smaller and water transparency has increased. Both lakes became mesotrophic after treatment, as described by the Carlson (1977) trophic state index, and remain in that improved condition to date. No deleterious side effects were observed, although one lake experienced a significant decrease in diversity of planktonic microcrustacea and a lakeward extension of the macrophyte community. This method appears to be an effective and lasting means of accelerating the recovery of a eutrophic lake following nutrient diversion.     

化学污泥中铝盐混凝剂的回用

在自来水厂和污水处理厂中 ,铝盐作为混凝剂已得到了广泛的应用。在絮凝过程中所产生的化学污泥不仅体积大 ,而且还含有大量的铝盐 ,若不加以回用处理 ,会对环境产生不良影响。对几种铝盐污泥的回用方法进行了阐述 ,以便进一步探索综合利用含铝盐化学污泥的有效途径。     

电容器阳极铝箔工艺研究现状与发展

论述了影响中高压铝电解电容器用高纯铝阳极箔立方织构比例及力学性能的各种因素,分析了阳极箔生产过程中均匀化退火、热轧、预备退火、成品退火等工艺过程对立方织构及综合性能的影响,提出了提高阳极箔性能的工艺发展方向。     

浅谈混凝剂在气田水处理中的应用

在重庆气矿气田水处理中加入了聚合氯化铝和聚丙烯酰胺,其应结果表明,这两种絮凝剂配合使用的效果较好,能达到石油企业废水回注指标(pH值为6～9,SS小于30mg/L,石油类物质少于10mg/L)。分析了两者单独使用的处理结果,针对目前使用中存在的问题,指出应注意的事项,并对今后重庆气矿气田水处理运行中混凝剂的使用提出了建议。     

用煤矸石和鼓风炉淤泥制备聚硅酸铁铝混凝剂

研究了以煤矸石和鼓风炉淤泥为原料，在常压条件下制备高效混凝剂凝剂聚硅酸铁铝的方法，确定了合理的生产工艺和操作条件，用该混凝剂处理实际废水，并与聚合硫酸铁的处理效果进行比较，结果表明，出水COD和色度去除率均提高约30%，SS去除率提高约10%，同时探讨了该混凝剂处理废水的反应机理。     

改性环氧树脂灌封提高铝电解电容器的三防性能

针对铝电解电容器出现的三防问题，通过对环氧树脂进行改性，提高环氧树脂的防护能力，并以此对铝电解电容器进行灌封，经过三防试验检验，结果表明采用改性环氧树脂灌封能效提高铝电解电容器的三防性能。     

锰渣脱硫制硫酸锰技术在电解锰行业的应用

介绍了某电解锰企业锰渣煅烧含高浓度SO₂烟气的资源化处理路线,阐述了氧化锰矿浆烟气脱硫制MnSO₄技术的工艺设计。该烟气脱硫制MnSO₄装置运行稳定,尾气中SO₂质量浓度为32.1~51.9 mg/m³,达到排放设计要求,脱硫装置产生的MnSO₄浆液中Mn²⁺质量浓度为(40±1)g/L,连二硫酸锰质量浓度小于5 g/L,满足电解锰生产要求。     

Adsorption removal of thiocyanate from aqueous solution by calcined hydrotalcite

A hydrotalcite with Mg/AI molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite （HTC-500） was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.