On the use of a powder rheometer to characterize the powder flowability at low consolidation with torque resistances

The Anton Paar Powder Cell was used to measure the torque necessary to rotate an impeller in beds of glass beads, sand and alumina powders aerated between no aeration to the minimum for fluidization. Measured torque values depend on the material tested, on the air flow rate applied, on the impeller depth and on the height of the impeller blade. The effect of the impeller depth is linear for low impeller depth and is less than linear at high depth values. A model was developed for the interpretation of the experimental results based on the idea that the material is shearing on the surface described by the impeller rotation. The model allows to estimate an effectiveness of the impeller in the torque determination and also to predict the torque for the impeller at the at deepest positions at which the wall effects have to be considered. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

沸石-核桃壳曝气生物滤池去除废水中氨氮的研究

采用核桃壳和沸石组合作为曝气生物滤池填料,处理废水中的NH_4~+-N。试验期间,每天定时监测曝气生物滤池进水和出水的pH、溶解氧、COD、NH_4~+-N、亚硝酸盐氮和硝酸盐氮等水质指标。考察了核桃壳-沸石曝气生物滤池的脱氮性能,研究了水力负荷和气水比对曝气生物滤池去除NH_4~+-N效率的影响。此外,研究了曝气生物滤池的沿程特性。试验结果表明,核桃壳和沸石是可取的曝气生物滤池填料,具有较好的硝化能力,能有效地去除污染物。最佳水力负荷为0.04 m/h,最佳气水比为6∶1,在此条件下,NH_4~+-N去除率保持在80%以上。填料层底部向上25~55 cm段为NH_4~+-N去除高效段。     

Attached growth systems for wastewater treatment in small and rural communities: a review

This paper reviews the application of attached growth processes for municipal wastewater treatment. Attached growth processes are classified as aerobic (either aerated or non‐aerated), anaerobic and hybrid (anaerobic/anoxic and aerobic). The main advantage of attached growth systems is that they maintain a high concentration of microorganisms resulting in high removal rates at relatively small hydraulic retention times. The basic design and operational characteristics of various systems are presented in terms of packing materials, organic loading rates, treatment temperature, as well as achieved removal rates. © 2012 Society of Chemical Industry     

Impact of conditioning regimens and time on adhesion of a fiber post to root dentin using two resin cements

The aim of this study was to evaluate the influence of irrigation protocols on the bond strength of a glass fiber post bonded to dentin using two resin cements. In 200 root-filled teeth, post space was prepared and divided into five groups (n?=?40) based on the irrigation protocol: group 1 (3% sodium hypochlorite), group 2 (3% sodium hypochlorite – 17% Ethylene diamine tetraacetic acid), group 3 (a mixture of sodium hypochlorite and etidronic acid), group 4 (sodium hypochlorite – QMix), and group 5 (distilled water). Samples were subdivided into two subgroups (n?= 10) and fiber posts were cemented using subgroup A (Self-adhesive dual-cure resin cement; SEA) or B (dual-cure resin cement following an etch-and-rinse protocol, ER). Push-out bond strength was performed after 24 h and four months (n?= 10) and failure modes were categorized. Statistical analysis of data was carried out by appropriate analyses (p < 0.05). The irrigation protocol and the resin cement had a significant impact on push-out bond strength. Subgroup A group showed lower bond strength than B at both time periods when 3% NaOCl–17% EDTA and 1:1 mixture of 6% NaOCl + 18%EA protocols were used. Three percent NaOCl used in combination with 17% EDTA or QMix significantly decreased the push-out bond strength of ER at the end of four months (p < 0.05). In conclusion, dual-cure resin cements bonded with etch-and-rinse protocol showed highest bond strength when a mixture of NaOCl and etidronic acid was used as root canal irrigant. These values were differentially influenced by time.     

一体化O3-BAF—BAF组合工艺深度处理港口洗舱废水

采用一体化臭氧曝气生物滤池(O3-BAF)—曝气生物滤池(BAF)组合工艺对二级生化处理后的港口码头洗舱化学品废水进行深度处理,进水COD约为200～240 mg/L,色度为16～32倍时,经该工艺处理后出水COD<30mg/L,去除率>91%,色度降到4倍以下,出水水质达到《生活杂用水水质标准》(CJ/T 48—1999)要求。工程运行实践表明,该深度处理系统运行稳定,处理效率高,具有良好的经济效益与环境效益。     

中药综合废水处理站技术改造中试研究

在分析研究现有处理工艺的基础上,利用试验模型进行了水解酸化-两级曝气生物滤池（BAF）处理中药综合废水的中试研究,试验结果表明,当进水CODcr、SS、色度平均值分别为970mg／L、145mg／L、130倍时,出水CODcr、SS、色度平均值分别为80mg／L、43mg／L、35倍,达到了《污水综合排放标准》（GB8978--1996）中的一级排放标准。     

臭氧组合工艺深度处理混合印染废水技术经济比较

针对某纺织印染工业园污水处理厂二级生物处理出水(ρ(CODCr)=100~150 mg/L),比较研究了臭氧氧化与活性炭曝气生物滤池、絮凝沉淀、粉末活性炭吸附的组合工艺对CODCr的去除效果,探讨了臭氧组合工艺用于该污水处理厂提标改造达到GB 18918—2012《城镇污水处理厂污染物排放标准》一级B排放标准的可行性。结果表明:在臭氧投加量为40 mg/L,臭氧氧化时间为1 h的条件下,臭氧-活性炭曝气生物滤池组合工艺出水CODCr的质量浓度为61 mg/L;臭氧-粉末活性炭吸附组合工艺出水CODCr的质量浓度为57 mg/L。2种组合工艺的出水CODCr质量浓度基本达到GB 18918—2002一级B标准的排放要求,但两者在工程投资、运行成本方面表现出较大的差异。臭氧-絮凝沉淀组合工艺仅降低CODCr的质量浓度10~15 mg/L,不满足要求。     

聚氯乙烯滴灌带的研究及应用

探讨了PVC滴灌带复合材料的配方、工艺及制备方法;获得了PVC滴灌带加工的最佳工艺配方。     

二级曝气生物滤池处理高COD木薯加工废水

试验采用二级曝气生物滤池(BAF)工艺处理广西省南宁市的木薯加工废水,通过分析反应系统对COD、总氮(TN)的去除率,优化水力停留时间(HRT)、气水比,从而考察二级BAF对高COD木薯加工废水的处理效果.试验结果表明:采用二级BAF工艺处理高COD木薯加工废水可行.当HRT=8h,气水比为10∶1时,处理效果最佳,二级BAF的出水平均COD、TN分别为114.56、2.71 mg/L,平均去除率分别为92.40%、94.01%.     

曝气生物滤池后置反硝化效能研究

以甲醇为外碳源,对生活污水进行两级串联O-A曝气生物滤池脱氮及去除COD的试验研究。采用陶粒为填料,向二级滤柱中投加甲醇,确定甲醇的最佳投量,考查该种形式的曝气生物滤池脱氮效果及出水COD浓度是否达标。试验表明,甲醇投量为20mg/L时,曝气生物滤池二级出水COD﹑NH3-N﹑NO3--N﹑TN平均质量浓度分别为49.3﹑3.3﹑1.6﹑5.5mg/L,其去除率分别为85.3%﹑85.7%﹑77.1%﹑82.0%。达到很好的脱氮及去除COD效果。出水水质达到了《城镇污水处理厂污染物排放标准》一级标准中的B级标准。