Nanofiltration process of glyphosate simulated wastewater

Nanofiltration separation of glyphosate simulated wastewater was investigated using a DK membrane. The effects of operating parameters and the addition of impurities on membrane performance were studied in detail. It was found that at 20 °C, with a glyphosate concentration of 500 mg/L and pH of 2.96, the glyphosate retention rate and the membrane permeate flux increased slightly with increasing transmembrane pressure. With an increase in operating temperature, the permeate flux increased linearly while the retention rate decreased. The permeate flux and glyphosate retention rate decreased with increasing feed concentration. Within the pH range of 3-5, the glyphosate retention rate decreases with increasing pH and reaches a minimum at the isoelectric point of the membrane, while the permeate flux reaches a maximum level at this point. In the pH range of 5-11, with the increases of pH, the glyphosate retention rate increases and the permeate flux decreases. Glyphosate retention decreases slightly with increasing NaCl and phosphite concentrations. This can be explained in terms of the shielding phenomenon.     

Treatment of domestic sewage by a metal membrane bioreactor

A submerged flat metal MBR (membrane bioreactor) was used to treat synthetic domestic sewage in this study. The experiment was continued for 270 days and ran under two modes as AMBR (aerobic membrane bioreactor) and A/O-MBR (anoxic/aerobic membrane bioreactor) at a permeate flux of 0.4-1 m3/(m2 d). PVA (polyvinyl alcohol) gel beads were added to the aeration tank with a volume ratio of 10% at the end of the A/O-MBR mode. The mean COD and TN removal efficiencies achieved 96.69 and 32.12% under the AMBR mode, and those were 92.17 and 72.44% under the A/O-MBR mode, respectively. SND (simultaneous nitrification and denitrification) occurred at high MLSS (mixed liquor suspended solids) concentration. The metal membranes reduced effluent COD during filtration. The system ran stably for 115 days at a permeate flux of 0.8-1 m3/(m2 d) without changing membranes under the AMBR mode, but the membrane filterability decreased gradually under high MLSS or A/O-MBR mode, and the addition of PVA worsened the membrane filterability on the contrary. PSD (particle size distribution) and sludge fractions had evident influence on membrane fouling. The main fouling mechanism was cake formation under the AMBR mode, and that was pore blocking under the A/O-MBR mode.     

某水库大坝巨型溶蚀大厅加固处理方案及喷锚支护参数优化研究

某RCC重力坝坝基巨型溶蚀大厅规模大,坝基以下岩体厚度小,发育深度大,坝基开挖爆破导致洞顶以上岩体松动,存在坝基塌陷的安全隐患.在充分研究区域地形地质条件的基础上,采用三维非线性有限元法研究了不同施工方案下坝基巨型溶蚀大厅的应力场、位移场及破坏区分布,并在此基础上提出溶蚀大厅的加固处理方案及喷锚支护参数.     

Extended activated sludge model no. 1 (ASM1) for simulating biodegradation process using bacterial technology

Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 (ASM1), this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.     

当前的就业压力与增加就业的途径

创造有利于扩大就业的宏观经济环境,健全和完善劳动力市场体系,制定有利于扩大就业的各类政策,对失业者提供救助和必须的社会保障……     

人民币离岸货币规模的计量估计方法研究

关于人民币离岸货币规模问题,国内有关机构和学者通过调查和估算等方法进行了测算。本文在借鉴国内外研究,总结了相应的各种计量估计方法,并且有选择性地采用季节法和CR时间序列法等方法,对人民币离岸货币规模进行定量估测,并进一步对计量结果与调查结果存在的差异进行了分析。     

"品质为本应用为先"蜂窝纸板市场前景看好

“品质为本，应用为先”。蜂窝纸板制品是纸质材料中的后起之秀，并具有独自的优势和个性，作为木质材料、EPS发泡塑料等主要替代品，已成为人们关注的热点。     

抽油泵凡尔罩可靠性分析及对策

石油开采过程中，抽油泵凡尔罩故障性断脱的频繁发生．不仅加大了采油作业工作量．增加了采油成本．同时也严重影响了原油产量。河南双河油田每年都有60-80口油井的抽油泵凡尔罩发生断脱?指出凡尔罩断脱主要表现为磨损、变形、腐蚀、脱扣等4种形式．分析归纳了造成凡尔罩断脱失效的主要影响因素有6个方面：凡尔罩材质选用不合适，油井深，凡尔罩结构不理想，柱塞上下往复运动所产生的交变应力对凡尔罩造成疲劳损坏，老油井含砂量高使凡尔罩内壁形成研磨划伤，加工工艺流程不合理。针对上述原因．提出了提高凡尔罩质量可靠性的4项主要技术措施：在修复泵时更换凡尔罩材质，将凡尔罩原热处理工序流程进行调整，运用渗氮技术对凡尔罩进行表面化学热处理，对凡尔罩的结构进行优化改进。采用以上措施所产生的积极效果在现场得到了验证：双河油田2003年以来．73口油井采用了改进后的凡尔罩，在保持产液量不变的状况下，投用至今未发生一起断脱事故．效果良好     

用总成本控制理念管理设备

通过对供排水企业工程项目设备投资成本构成因素的分析和研究，提出以总成本控制理念贯穿工程项目设备管理的全过程，探讨了使企业获得最佳效益的有效途径。     

强磁防垢技术研究及其在油田的现场应用

对国内某油田注水管线的结垢现象及水质和垢物成分进行了分析，探讨了强磁防垢机理，研究了磁处理的特点。通过室内晶相显微观察法。优化选择强磁处理的最佳磁参数，根据最佳磁参数设计出适合此油田现场使用的强磁防垢器，并在油田现场安装磁化器实施强磁防垢技术．观察磁防垢前后注水管线状况和结垢对比。现场实践表明，强磁防垢技术不但操作方便，而且可取得显著的效果和经济效益。