Arsenic and lead leaching from the waste derived fertilizer ironite

The toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP) were performed on commercially purchased samples of the waste-derived soil amendment marketed as Ironite. Ten samples of the 1-0-0 grade (the most widely available in Florida) were tested. Two samples of the 12-10-10 grade and three samples of the 6-2-1 grade (a liquid version) were tested as well. TCLP leachate concentrations from the 1-0-0 grade samples ranged from 5.0 to 8.0 mg L(-1) for lead and 2.2 to 4.8 mg L(-1) for arsenic. SPLP concentrations from the 1-0-0 samples ranged from 0.62 to 3.1 mg L(-1) for lead and 1.9 to 8.2 mg L(-1) for arsenic. All of the 1-0-0 grade samples exceeded the U.S. hazardous waste toxicity characteristic (TC) limit for lead (5 mg L(-1)), while five of the 10 SPLP samples exceeded the TC limit for arsenic (5 mg L(-1)). The greater arsenic leachability in the SPLP relative to the TCLP was determined to be a result of lower pH conditions in the SPLP. A composite sample of the 1-0-0 grade was found to leach much greater concentrations of both arsenic and lead using California's waste extraction test (WET). Lead leachate concentrations were much lower in the two 12-10-10 samples (0.03 mg L(-1) or less); arsenic concentrations in these leachates (both TCLP and SPLP) exceeded 5 mg L(-1). None of the 6-2-1 samples contained lead or arsenic above TC limits. An experiment performed on the 1-0-0 grade which examined leachability as a function of pH found that at pH values in the range of what is encountered in the human digestive system (pH 4.0 to 1.5) lead leached 2-36% of its initial content, and arsenic leached 1-6% of its initial content. A simple gastric acid leaching experiment found 83 and 37% of the lead and arsenic present to leach, respectively.     

农林废弃物生物质燃烧特性的研究

采用TGA-92型热重—差热综合分析仪,对秸秆、桉树木废料、花生壳、稻草、大豆杆及棉杆进行燃烧特性分析。结果表明,生物质的燃烧主要集中于燃烧前期;不同试样表观活化能虽然不同,但属于同一个数量级;着火温度都比较低,主要集中在150~200℃之间;生物质的发热量低,在燃烧过程中放热很集中;相对燃尽时间较短,燃尽率较高;燃烧反应服从燃烧动力学的基本方程表征的规律。     

从烟草废弃物中提取茄尼醇的工艺条件研究

简要介绍烟草废弃物的现状,在已有工艺基础上提出一个浸取茄尼醇的方案.经过浸取溶剂的筛选、浸取工艺的实验研究和正交实验优化得到以下较为适宜的浸取条件为浸取溶剂为石油醚Ⅱ、温度为60 ℃、浸取时间5 h、液固比6:1.     

Effect of remineralization on heavy-metal leaching from cement-stabilized/solidified waste

Crushed samples of stabilized/solidified (s/s) waste were leached at constant leachate pH in the pH range 4-7 with nitric acid solutions to evaluate the influence of remineralization on metal release. The s/s waste consisted of synthetic heavy-metal sludge containing 0.1 mol L(-1) copper nitrate, 0.1 mol L(-1) zinc nitrate, and 0.1 mol L(-1) lead nitrate mixed with ordinary Portland cement. Unleached and leached particles were characterized by scanning electron microscopy and energy-dispersive X-ray spectrometry. Two consecutive leaching fronts advancing from the surface of the particles toward the center were identified: the first front was associated with the dissolution of portlandite and partial reaction of the calcium silicate hydrate gel, while the second front was associated with the dissolution of calcium-aluminum hydroxy sulfates such as ettringite and monosulfate. At pH 4 and 5, a remineralization zone rich in heavy metals formed immediately behind the second leaching front. The shell extending from the remineralization zone to the surface of the particles was depleted in calcium, sulfate, and heavy metals. As a result of remineralization, heavy-metal releases to the leachate were reduced by factors ranging between 3.2 and 6.2 at pH 4 and between 74 and 193 at pH 5. At pH 6 and 7, remineralization of Pb and Zn occurred further behind the second leaching front and closer to the surface of the particles. The amount of heavy-metal release depended on both the leachate pH and the remineralization factor.     

Recovery of uranium from mine waste by leaching with carbonate-based reagents

Waste materials, stored in inappropriate places, are one of the most significant environmental issues concerning mining activities. In Brazil, one closed uranium mine has faced such a problem. The waste, produced during the neutralization of acid drainage and containing several metals including uranium, has been disposed into the mine opening as a temporary alternative for over 20 years. The present work aimed at the recovery of the uranium present in the aforementioned waste. The effect of the following parameters on the leaching procedure was investigated: solid/liquid ratio, time, temperature, extracting agents, concentration of reagents, and the use of oxidants. The chemical characterization showed that the main constituents of the sample are Ca, S, Mn, and Al. Uranium is around 0.25%. The crystallized phases are ettringite (Ca(6)Al(2)(SO(4))(3)·(OH)(12)·26H(2)O) as the major phase followed by gypsum (CaSO(4)·2H(2)O), calcite (CaCO(3)), and bassanite (CaSO(4)·0.5H(2)O). Carbonate and bicarbonate were observed to be effective extractants for the uranium. However, a combination of both reagents proved to be a better option than their individual use, and extractions around 100% were achieved. The optimum experimental condition for attaining the maximum dissolution is 0.11 solid/liquid ratio, 0.50 mol L(-1) Na(2)CO(3), 1.00 mol L(-1) NaHCO(3), 20 h, and room temperature.     

新型热处理电镀黄铜连续线开发

为生产供应国外市场的高端胶管钢丝产品,在参考吸收钢帘线生产用热处理镀黄铜连续线设计的情况下,对加热炉、镀铜、镀锌、热扩散等工序作了适应性设计。用电加热管式炉加热代替卡电式加热;电解碱洗采用上下槽结构;电解酸洗电极采用耐酸的铅锑合金;水洗为反向逆流三级冲洗;镀铜采用焦磷酸盐五级电镀铜,电极采用304不锈钢板焊接而成;电镀锌电极采用纯铅铸造,保证精度和尺寸;热扩散增加2个辅助辊以减少电火花。生产线投产后,产品质量上乘,约70%供应国际高端市场。     

Investigation of pyrochlore-based U-bearing ceramic nuclear waste: uranium leaching test and TEM observation

A durable titanate ceramic waste form (Synroc) with pyrochlore (Ca(U,Pu)Ti2O7) and zirconolite (CaZrTi2O7) as major crystalline phases has been considered to be a candidate for immobilizing various high-level wastes containing fissile elements (239Pu and 235U). Transmission electron microscopy study of a sintered ceramic with stoichiometry of Ca(U(0.5)Ce(0.25)Hf(0.25))Ti2O7 shows the material contains both pyrochlore and zirconolite phases and structural intergrowth of zirconolite lamellae within pyrochlore. The (001) plane of zirconolite is parallel to the (111) plane of pyrochlore because of their structural similarities. The pyrochlore is relatively rich in U, Ce, and Ca with respect to the coexisting zirconolite. Average compositions for the coexisting pyrochlore and zirconolite at 1350 degrees C are Ca(1.01)(Ce3+(0.13)Ce4+(0.19)U(0.52)Hf(0.18))(Ti(1.95)Hf(0.05))O7 (with U/(U + Hf) = 0.72) and (Ca(0.91)Ce(0.09))(Ce3+(0.08)U(0.26)Hf(0.66)Ti(0.01))Ti(2.00)O7 (with U/(U + Hf) = 0.28), respectively. A single pyrochlore (Ca(U,Hf)Ti2O7) phase may be synthesized at 1350 degrees C if the ratio of U/(U + Hf) is greater than 0.72, and a single zirconolite (Ca(Hf,U)Ti2O7) phase may be synthesized at 1350 degrees C if the ratio of U/(U + Hf) is less than 0.28. The synthesized products were used for dissolution tests. The single-pass flow-through dissolution tests show that the dissolution of the U-bearing pyrochlore is incongruent. All the elements are released at differing rates. The dissolution data also show a decrease in rate with run time. The results indicate that a diffusion-controlled process may play a key role during the release of U. TEM observation of the leached pyrochlore directly proves that an amorphous leached layer that is rich in Ti and Hf formed on the surface after the ceramic was leached in pH 4 buffered solution for 835 days. The thickness of the layer ranges from 6 to 10 nm. A nanocrystalline TiO2 phase also forms in the leached layer. The U leaching rate (g/(m2 day)) in acidic solutions can be expressed as log(NR) = -5.36-0.20 pH, where NR is the normalized rate. Conservative leaching rates of uranium [log(NR)] for the U-bearing ceramic at pH 2 and pH 4 solutions are -5.76 and -6.16 g/(m2 day), respectively. The results show that the U release rate of the ceramic waste is 10 times slower than that of defense high-level waste glass and about 1000 times slower than that of spent fuel. The pyrochlore-based ceramic is an ideal waste form for immobilizing long-lived radionuclides of 239Pu and 235U due to the Ti- and Hf-rich leached layer that forms on the ceramic surface. The leached layer functions as a protective layer and therefore reduces the leaching rate as thickness of the leached layer increases.     

餐厨废弃油脂生物柴油对船舶柴油机性能、排放特性以及燃烧特性的影响北大核心CSCD

为探讨生物柴油应用于船舶柴油机的可行性,将餐厨废弃油脂生物柴油与柴油混合,在船舶柴油机上进行试验,测试其对船舶柴油机性能、排放特性和燃烧特性的影响。结果表明:生物柴油混合物的高黏度以及低热值会降低有效热效率,并导致燃油消耗率略有升高;由于生物柴油的高含氧量促进完全燃烧,相比于柴油,燃烧生物柴油混合物后,一氧化碳排放量最高下降17%,二氧化碳排放量最高下降5.1%,二氧化硫排放量最高下降41%,碳烟排放量最高下降36%;生物柴油过快的燃烧速率提高了气缸内的燃烧温度,以及高含氧量促进了氮氧化物的排放;生物柴油混合物燃烧时的缸内压力与柴油非常接近。餐厨废弃油脂生物柴油对船舶柴油机的性能、燃烧特性和排放特性均具有较好的表现,可以作为柴油的替代燃料用于船舶柴油机。     

Solid waste removes toxic liquid waste: adsorption of chromium(VI) by iron complexed protein waste

The leather processing industry generates huge amounts of wastes, both in solid and liquid form. Fleshing from animal hides/skins is one such waste that is high in protein content. In this study, raw fleshing has been complexed with iron and is used for removal of chromium(VI). The effect of pH and the initial concentration of chromium(VI) on the removal of Cr(IV) by iron treated fleshing is presented. Iron treatment is shown to greatly improve adsorption of the fleshing for hexavalent chromium. The ultimate adsorption capacity of iron treated fleshing is 51 mg of chromium(VI) per gram of fleshing. That of untreated fleshing is 9 mg/g such that iron treatment increases the adsorption capacity of fleshing by 10-fold. The measured adsorption kinetics is well described by a pseudo-second-order kinetic model. The uptake of chromium(VI) by fleshing is best described by the Langmuir adsorption isotherm model. X-ray photoelectron spectroscopic (XPS) studies show that the iron is incorporated into the protein matrix. Shifts in XPS spectra suggest that dichromate binding occurs with iron at active adsorption sites and that iron treated fleshing removes chromium(VI) without reducing it to chromium(III).     

Meat waste treatment methods and potential uses

Meat waste management has been and continues to be one of the most important issues related to pollution management. This was due to the high concentration of meat waste materials like blood, hair, tail, horns and bones, among others that have to be thoroughly and effectively treated prior to their disposal. Methods like aerobic and anaerobic digestion [mesophilic or thermophilic temperatures, composting (windrows, aerated static piles and bins or aerated chambers)] are currently extensively used. Nowadays, the emphasis is on reusing the so‐called waste materials for production processes, i.e. meat and bone meal. The latter was widely recommended and used in animal nutrition as a protein source in place of proteinaceous feeds. However, this approach greatly suffered from Small Bowel Enteroclysis (SBE) occurrence and micro‐organism presence. Heavy metal absorption by means of charred bones appears to be one of the most promising applications of bones apart from other use for production of edible materials. The aim of this review was to summarise most updated references in the field of meat waste treatment and potential uses of treated waste by means of nine informative tables and six figures.     

Volatile organic compounds and metal leaching from composite products made from fiberglass-resin portion of printed circuit board waste

This study focused on the volatile organic compounds (VOCs) and metal leaching from three kinds of composite products made from fiberglass-resin portion (FRP) of crushed printed circuit board (PCB) waste, including phenolic molding compound (PMC), wood plastic composite (WPC), and nonmetallic plate (NMP). Released VOCs from the composite products were quantified by air sampling on adsorbent followed by thermal desorption and GC-MS analysis. The results showed that VOCs emitted from composite products originated from the added organic components during manufacturing process. Phenol in PMC panels came primarily from phenolic resin, and the airborne concentration of phenol emitted from PMC product was 59.4 ± 6.1 μg/m(3), which was lower than odor threshold of 100% response for phenol (180 μg/m(3)). VOCs from WPC product mainly originated from wood flour, e.g., benzaldehyde, octanal, and d-limonene were emitted in relatively low concentrations. For VOCs emitted from NMP product, the airborne concentration of styrene was the highest (633 ± 67 μg/m(3)). Leaching characteristics of metal ions from composite products were tested using acetic acid buffer solution and sulphuric acid and nitric acid solution. Then the metal concentrations in the leachates were tested by ICP-AES. The results showed that only the concentration of Cu (average = 893 mg/L; limit = 100 mg/L) in the leachate solution of the FRP using acetic acid buffer solution exceeded the standard limit. However, concentrations of other metal ions (Pb, Cd, Cr, Ba, and Ni) were within the standard limit. All the results indicated that the FRP in composite products was not a major concern in terms of environmental assessment based upon VOCs tests and leaching characteristics.     

污水处理与中水回用项目的技术创新

主要介绍了上海幸福纺织印染有限公司在节能减排和污水处理方面进行的技术改造和所采取的措施,由此实现了3 000 t/d废水排放完全达标,COD控制在50～60 mg/L,并分3步实施了中水回用,大幅度降低了生产运行成本.     

Green rust and iron oxide formation influences metolachlor dechlorination during zerovalent iron treatment

Electron transfer from zerovalent iron (Fe0) to targeted contaminants is affected by initial Fe0 composition, the oxides formed during corrosion, and surrounding electrolytes. We previously observed enhanced metolachlor destruction by Fe0 when iron or aluminum salts were present in the aqueous matrix and Eh/pH conditions favored formation of green rusts. To understand these enhanced destruction rates, we characterized changes in Fe0 composition during treatment of metolachlor with and without iron and aluminum salts. Raman microspectroscopy and X-ray diffraction (XRD) indicated that the iron source was initially coated with a thin layer of magnetite (Fe3O4), maghemite (gamma-Fe2O3), and wüstite (FeO). Time-resolved analysis indicated that akaganeite (beta-FeOOH) was the dominant oxide formed during Fe0 treatment of metolachlor. Goethite (alpha-FeOOH) and some lepidocrocite (gamma-FeOOH) formed when Al2(SO4)3 was present, while goethite and magnetite (Fe3O4) were identified in Fe0 treatments containing FeSO4. Although conditions favoring formation of sulfate green rust (GR(II); Fe6(OH)12SO4) facilitated Fe0-mediated dechlorination of metolachlor, only adsorption was observed when GR(II) was synthesized (without Fe0) in the presence of metolachlor and Eh/pH changed to favor Fe(III)oxyhydroxide or magnetite formation. In contrast, dechlorination occurred when magnetite or natural goethite was amended with Fe(II) (as FeSO4) at pH 8 and continued as long as additional Fe(II) was provided. While metolachlor was not dechlorinated by GR(II) itself during a 48-h incubation, the GR(II) provided a source of Fe(II) and produced magnetite (and other oxide surfaces) that coordinated Fe(II), which then facilitated dechlorination.     

日本最新的用水及废水处理装置

使用在各种饮料制造出的纯水,当要维持饮料产品味道及香味等品质要求时,需使用杀菌消毒装置所制造出无味无臭的安全纯水。现在的一般纯水制造装置,会有从阴离子交换树脂而来的溶出物及高温下造成交换基的脱落及分解等缺点,因此无法从高温杀菌     

Vegetable waste treatment: comparison and critical presentation of methodologies

Vegetable industries have been considered responsible for a great amount of pollution; hence, there has been a strong need for the optimization of vegetable waste treatment systems. The currently employed systems are numerous and fall in the following large categories; thermal processes, evaporation, membrance processes, anaerobic digestion, anaerobic co-digestion, biodiesel spraying, combustion, transesterification, coagulation, and composting. Respective methodologies in conjunction with waste treatment methods were presented per waste treatment method. The comparative presentation of the various vegetable waste treatment methodologies showed that though anaerobic digestion stands for the most enviromentally friendly technique, its required longer treatment time in conjuction with its weakness to deal with elemental contaminants makes imperative the employment of a second alternative technique which could either be a membrance process (low energy cost, reliability, reduced capital cost) or a coagulation/flocculation method because of its low cost and high effectiveness. Biogas production appears to be another promising and energy effective waste treatment method. On the other hand, methods like distillation and ozonation (high cost) and electrolysis (experimental level) have not been employed in the field. Finally, new waste management technologies have been described.     

家具生产中木质废料的来源、控制与处理

分析了家具制造企业原料输入和废料产生情况,针对家具生产过程木质废料的产生情况和废料形式进行了剖析,结合生产实际提出了家具生产木质废料的控制与处理措施。     

生活垃圾填埋场地下水污染及治理研究

本文首先分析生活垃圾填埋场地下水污染及治理的必要性,其次阐述了当前我国地下水的污染情况,最后提出了地下水污染中的治理技术并做出总结.     

环境检测实验室危险废物的产生及处理分析

近年来,随着我国生态环境的不断恶化,环境检测实验室对危险废物进行科学有效地处理已经刻不容缓.为了从根本上解决现存的环境问题,实现生态环境的可持续发展,我国环境质量检测实验室的工作任务也不断加重.但不能忽视的是,环境检测实验室在对危险废物进行分类及专门处理时,由于需要使用一系列复杂的检测手段,也不可避免地会排放出许多可能...