微絮凝强化过滤工艺处理低温低浊水的实验研究

以北京市某水厂冬季沉后水为研究对象,分别采用常规过滤工艺和强化过滤工艺对其进行处理.通过改变聚合氯化铝(PACl)投加量、滤料粒径d和微絮凝时间,并结合水头损失、颗粒数、总有机碳(TOC)、化学需氧量(COD)等实验数据,对低温低浊水体强化过滤工艺条件进行了研究.结果表明,强化过滤工艺与常规过滤工艺相比具有较强的除浊、去除有机物和颗粒物的能力,当微絮凝时间为2min时可以得到较好的过滤效果;PACl投药量为1.5mg·L-1时,浊度可降到0.04NTU,而常规过滤工艺最多只能将浊度降到0.2NTU.在滤料选用方面,当滤料粒径d=0.6～1.2mm时滤后水中颗粒数(2～5μm)、浊度、COD等指标均达到最优值.同时,电感耦合等离子体光谱(ICP-OES)检测结果表明,滤后水中Al3+含量小于0.2mg·L-1,并未因二次投加PACl而升高,因此,不会对水的饮用产生任何健康和安全风险.     

阳离子聚电解质聚二甲基二烯丙基氯化铵的絮凝机理初探

以聚二甲基二烯丙基氯化铵PDADMAC(特性粘度分别为2.7,1.4,0.7)为絮凝剂,对比PAC和PFC,通过残余浊度、Zeta电位、FI絮凝指数的测定,研究了PDADMAC对高岭土悬浊体系(浊度分别为6000,1000,200和10 NTU)的絮凝特性,并对其絮凝作用机理进行了探讨.结果表明,PDADMAC的吸附构型决定其絮凝机理在较低初始悬浊物浓度下(200 NTU)为单个颗粒物表面吸附覆盖及其"吸附电中和"絮凝模型;在高浊条件下(＞1000 NTU)为单颗粒表面(Monomer)部分吸附覆盖及其"吸附架桥"絮凝模型.     

Hydrolysis of polyaluminum chloride prior to coagulation: Effects on coagulation behavior and implications for improving coagulation performance

The effects of polyaluminum chloride (PACl) hydrolysis prior to coagulation on both the coagulation zone and coagulation performance of a kaolin suspension were investigated by a novel jar test named the “reversed coagulation test”. The tests showed that PACl hydrolysis prior to coagulation decreased the performance of charge neutralization coagulation in the case of short-time slow mixing (10 min; G = 15 sec ?1 ) and increased the optimal dosage for charge neutralization and sweep coagulation. Moreover, the hydrolysis time had insignificant effects on the size and zeta potential of PACl precipitates and the residual turbidity of the raw water. However, PACl hydrolysis prior to coagulation and the size of PACl precipitates had a negligible effect on the performance of sweep coagulation.The results imply that, in practice, preparing a PACl solution with deionized water, rather than tap water or the outlet water from a wastewater treatment unit, can significantly save PACl consumption and improve the performance of charge neutralization coagulation,while preparing the PACl solution with tap or outlet water would not affect the performance of sweep coagulation. In addition, the optimal rapid mixing intensity appears to be deter-mined by a balance between the degree of coagulant hydrolysis before contacting the primary particles and the average size of flocs in the rapid mixing period. These results provide new insights into the role of PACl hydrolysis and will be useful for improving coagulation efficiency.     

聚氯乙烯生产过程生命周期评价

文章运用生命周期评价方法,对我国东南某大型石化集团聚氯乙烯生产过程的资源消耗及环境影响进行量化与估算。结果表明:生产1t聚氯乙烯的总能量消耗为6102.24MJ,环境影响负荷为0.49标准人当量。聚氯乙烯生产的主要环境影响为大气颗粒物污染、光化学臭氧合成、酸化和全球变暖。     

聚氯化铝及其在工业废水处理中的应用与展望

目前,传统无机凝聚剂正逐渐被无机高分子絮凝剂所取代。系统阐述了聚氯化铝的基本性质、絮凝形态、混凝行为和混凝机理。介绍了聚氯化铝在9种工业废水处理中的应用。对聚氯化铝的研究发展方向作了展望。     

有机高分子絮凝剂PDMDAAC对活性染料印染废水混凝脱色研究

用聚合氯化铝（PAC）、硫酸亚铁、PAC和聚丙烯酰胺（PAM）、PAC和聚二甲基二烯丙基氯化铵（PDMDAAC）对以活性染料为主要成分的印染废水进行混凝脱色试验，PAC＋聚二甲基二烯丙基氯化铵（PDMDAAC）对印染废水的处理效果略低于PAC＋聚丙烯酰胺（PAM），但PDMDAAC无毒。对脱色影响因素和控制条件等进行了试验研究。     

生活垃圾焚烧飞灰水洗液中氯离子的去除研究

开展了生活垃圾焚烧飞灰水洗液处理的实验研究,先通过加入氢氧化钙(Ca(OH)_2)、偏铝酸钠(NaAlO_2)初步去除水洗液中的Cl~-,再利用反渗透膜分离技术,探究了浓淡比、操作压力、pH、Cl~-浓度对Cl~-去除效果的影响.结果表明,化学沉淀法初步处理能去除水洗液中约50%的Cl~-,膜分离对经初步处理水洗液中Cl~-的去除率高达93.5%.经过两级处理后,飞灰水洗液中Cl~-的去除率高达96.74%,Cl~-的含量满足排放标准的要求.     

氯化甲基汞对大鼠脑c-fos和c-jun基因表达的影响

为了研究即刻早期基因c-fos、c-jun在氯化甲基汞(MMC)神经毒性机制中的作用,本研究应用免疫组织化学方法对皮下注射甲基汞5.0mg/kg及0.1mg/kg的大鼠脑区FOS、JUN表达水平进行观察,对照组注射生理盐水.结果表明,急性暴露3h后,暴露组大鼠脑FOS、JUN蛋白表达均高于对照组,从而表明即刻早期基因(IEG)参与了氯化甲基汞对中枢神经系统损害的毒性过程.     

Transformation of mercury speciation through the SCR system in power plants

Coal-fired utility boilers are now identified as the largest source of mercury in the United States. There is speculation that the installation of selective catalytic reduction （SCR） system for reduction of NOx can also prompt the oxidation and removal of mercury. In this paper, tests at six full-scale power plants with similar type of the SCR systems are conducted to investigate the effect of the SCR on the transformation of mercury speciation. The results show that the SCR system can achieve more than 70%-80% oxidation of elemental mercury and enhance the mercury removal ability in these units. The oxidation of elemental mercury in the SCR system strongly depends on the coal properties and the operation conditions of the SCR systems. The content of chloride in the coal is the key factor for the oxidization process and the maximum oxidation of elemental mercury is found when chloride content changes from 400 to 600 ppm. The sulfur content is no significant impact on oxidation of elemental mercury.     

COD催化快速法中氯离子干扰问题及去除方法探讨

COD催化快速法中对测定结果干扰最大的因素是水样中的氯离子浓度。通过对不同氯离子含量的水样进行对照分析 ,讨论其干扰问题 ,从而制定出理想的去除方法 ,使得催化快速法能够快速准确的应用于实际监测中