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221.
通过对大理地区多年来地磁场、重力场、地壳形变和地下水等地震前兆因素变化趋势的分析,指出大理地区是云南省未来10年内发生强震危险性最大的区域之一。 相似文献
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结合金川二矿区安全管理新体制的运行实践 ,介绍了二矿区构建新体制的历史背景 ;概括了推行新型运行体制的成功经验 ;回顾了新体制建设的基本做法 ;论述了安全管理新体制的基本框架和运作模式。从二矿区管理体系建设的角度 ,对安全执法体系和守法体系建设进行了探讨 ,并对如何抓好新体制的推行提出了四点启示 ,这些成功的经验、基本做法、建设性思考 ,对做好企业安全管理都具有重要的借鉴和指导意义 相似文献
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Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid 总被引:1,自引:0,他引:1
Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120 days was reduced by 100% when soils were amended with APR, HAP and HAP + OA, and the TCLP-Pb was < 5 mg/L for the red soil at P:Pb molar ratio 4.0.Water-soluble Pb could not be detected and the TCLP-Pb was < 5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APRwasmost effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pbmolar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability. 相似文献
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A combined nitritation–anammox reactor was developed to treat the digestion supernatant under various C/N ratios. Due to the difficulties for heterotroph to utilize the refractory organics, the reactor presented relatively stable performance with increasing supernatant addition. Nevertheless, the adverse effects of supernatant would accumulate during the long-term operation and thus weakened the activity and shock resistance of microbes,which further led to the gradual decrease of reactor performance after 92 days' operation.Under this circumstance, supernatant with volatile fatty acids(VFAs) residuals was further introduced into the reactor to investigate the performance of combined nitritation–anammox process with VFA addition. With the appearance of VFAs, the nitrogen removal performance gradually restored and the reactor finally achieved stable and efficient performance with C/N ratio of 0.35. The VFA residuals within 150 mg/L in the supernatant served as the extra electron donors and stimulated the heterotrophic denitrification process, which was vital for the enhancement of reactor. The nitrogen removal rate and total nitrogen removal efficiency reached 0.49 kg N/(m3·day) and 88.8% after 140 days' operation, respectively. The combined nitritation–anammox reactor was proved suitable to treat digestion supernatant. 相似文献
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介绍了大冶有色金属公司饮料厂汽水车间地基土发生胀害原因的调查及试验分析。揭示了该地基土因受化学污染发生膨胀的机理,为治理已有裂缝和防止裂缝进一步发展,确保该建筑物安全使用提供了依据。 相似文献