酸性高浓度含氟废水处理技术

介绍了对某化工厂排放的酸性高浓度含氟废水进行处理的试验，采用石灰中和沉淀，氯化钙（或聚丙烯酰胺）二级絮凝沉淀，砂滤工艺进行处理，操作控制条件如下：pH为8－9，Ca^2 与F^-的摩尔比为3．0，聚丙烯酰胺投加量为2mg/L，沉淀时间为1h，处理工程运行后的验收监测结果表明，出水中的残氟浓度可以达到国家规定的一级排放标准，且系统运行稳定，工艺简便。     

温度对生物强化除磷工艺反硝化除磷效果的影响

以处理城市污水的中试规模生物强化除磷A2/O活性污泥工艺系统为研究对象,考察了温度对系统COD去除和脱氮除磷效果的影响,特别是温度对活性污泥反硝化除磷性能的影响.结果表明,当温度从(30.9±0.8)℃降低到(9.1±0.6)℃时,A2/O系统的脱氮除磷效果显著下降,系统对TN和TP的污泥去除负荷明显下降.通过污泥反硝化除磷活性实验发现,随着温度的降低,系统中活性污泥的最大厌氧释磷速率、最大好氧吸磷速率和最大缺氧吸磷速率都降低.活性污泥中反硝化除磷菌(DPB)占聚磷菌(PAOs)总量的比例随温度降低稍有下降,但平均值仍维持在47.5％左右.用阿伦尼乌斯公式对实验结果进行拟合,得到系统中活性污泥聚磷菌厌氧释磷反应活化能Ea1为148.0 kJ· mol-1,聚磷菌好氧吸磷反应活化能Ea2为228.8 kJ·mol-1,发生在缺氧条件下反硝化除磷菌的吸磷反应活化能Ea3为315.8 kJ·mol-1.对不同温度下污泥絮体粒径分析结果表明,随温度降低,粒径分布更加集中,系统中活性污泥絮体颗粒平均粒径减小,不利于污泥絮体内部反硝化除磷缺氧微环境的形成.     

生态系统服务约束关系界定及影响机制分析

以长江经济带为研究对象,选择InVEST模型对长江经济带代表性的5种生态系统服务进行评估,根据两两配对关系原理进行约束线提取,并构建生态系统服务约束关系与影响因素相互作用模型,对其作用机制进行探究.结果表明,2000～2015年长江经济带5种生态系统服务两两间共表现出矩形型,对数型,抛物线型和驼峰型4种约束类型;7种影...     

HCA强化混凝预处理生活污水的效能及机理

通过单因素及正交试验,以聚二甲基二烯丙基氯化铵（HCA）为混凝剂对模拟农村生活污水进行强化混凝预处理,考察了影响HCA混凝去除SS、TP及有机物的主要因素及其主次顺序,并以Zeta电位及分形维数对HCA的混凝机理进行了分析.结果表明,影响HCA处理效果的因素顺序为初始pH值值 > HCA投加量 > 絮凝搅拌时间 > 混合搅拌速度梯度 > 混合搅拌时间 > 絮凝搅拌速度梯度,在优化条件下HCA混凝对SS、TP及COD去除率最高分别达94.1%、74.9%及61.1%;当HCA投加量为15mg/L时,Zeta电位与絮体分形维数分别为-2.03mv及1.0149.试验表明HCA对生活污水具有较好的处理效果,强化混凝去除污染物的机理主要是电性中和作用.     

A review on application of flocculants in wastewater treatment

Flocculation is an essential phenomenon in industrial wastewater treatment. Inorganic coagulants (salts of multivalent metals) are being commonly used due to its low cost and ease of use. However, their application is constrained with low flocculating efficiency and the presence of residue metal concentration in the treated water. Organic polymeric flocculants are widely used nowadays due to its remarkable ability to flocculate efficiently with low dosage. However, its application is associated with lack of biodegradability and dispersion of monomers residue in water that may represent a health hazard. Therefore, biopolymers based flocculants have been attracting wide interest of researchers because they have the advantages of biodegradability and environmental friendly. But, natural flocculants are needed in large dosage due to its moderate flocculating efficiency and shorter shelf life. Thus, in order to combine the best properties of both, synthetic polymers are grafted onto the backbone of natural polymers to obtain tailor-made grafted flocculants. This paper gives an overview of the development of different types of flocculants that were being investigated for treatment of industrial wastewater. Furthermore, their flocculation performance will be reviewed and the flocculation mechanism will be discussed.     

磁絮凝预处理景观湖泊的补水试验研究

为了快速净化景观湖泊的补水,采用磁絮凝法对Ⅴ类甚至劣Ⅴ类河道水体进行预处理,设计正交试验,分析了絮凝剂(PAC)、助凝剂(PAM)以及磁铁粉的投加量对预处理效果的影响,并利用正交试验法和多指标综合评分法进一步优化磁絮凝预处理工艺参数,结果表明最佳工艺参数为:磁铁粉加入量100 mg/L,PAC投加量150 mg/L,PAM投加量2 mg/L。在此最佳工艺参数下,进行验证试验,COD去除率达到50.39%,TP去除率为96.65%,浊度去除率为91.59%,氨氮去除率为6.31%,除氨氮外,其他各指标基本均能达到地表水环境Ⅲ类水体标准,达到了预处理目的,为后续深度净化减轻负荷压力。     

强化混凝组合工艺处理微污染水源水研究

采用静态烧杯实验考察了强化混凝组合工艺解决某水厂出水COD_(Mn)、色度及铝含量超标的问题。结果表明,高锰酸盐与次氯酸钠联合预氧化,配合使用少量黏土、粉末活性炭混合物强化混凝,可以在氯化物不超标的情况下,使出水COD_(Mn)、色度及铝含量得到有效控制。     

Imazaquin degradation and metabolism in a sandy loam soil amended with farm litters

Irnazaquin applied in legume crops has a long residual time in soil, which often impacts safety of the susceptible crops. To increase safety of imazaquin application, two composted litters, bovine manure （BM） and chicken manure （CM）, were used to determine their effects on imazaquin environmental behavior by incorporating each kind of manure into the tested sandy loam soil at 10% （w/w）. The degradation of imazaquin in BM- and CM-amended soil was about 2.4 and 1.5 times, respectively, faster than that in unamended soil. The half-lives of imazaquin in BM-amended soil varied between 6.7 and 15.4 d over the temperature range of 20 to 40℃, and the degradation rate constant （k） increased by a factor of about 1.5 for every 10℃ change. Higher mix ratio did not significantly increase the degradation, and the optimal active degradation of imazaquin was observed approximately at the mix ratio of 10：1 of soil to BM. The different moisture levels had negligible effect on imazaquin degradation. In both unamended and BM-amended treatments, two metabolites were observed at 5, 10 and 30 d after treatment. One metabolite at retention time （RT） of 8.4 rain was identified as 2-（4- hydroxyl-5-oxo-2-imidazolin-2-yl） quinoline acid, originating from the loss of isopropyl group and hydroxylation at the 4-position of imidazolinone ring. The other at RT of 12.9 rain was identified as quinoline-2,3-dicarboxylic anhydride, resulting from detachment of imidazolinone ring and the forming of dicarboxylic anhydride. This finding suggested that the addition of farm litters into soil might be a good management option since it can not only increase soil fertility but also contribute to increase safety of imazaquin application to the following susceptible crops.     

低强度超声波强化污水生物处理机制

研究发现低强度的超声辐照可以有效促进微生物的活性,可将其用于强化污水的生物处理,通过增强反应器内微生物的活性来提高污水的处理效率.本文综述了超声波在生物工程和生物学上的国内外研究成果,对低强度超声波的生物效应以及在促进生物活性中的主要作用机制进行了探讨,并分析了其在强化污水生物处理中的应用前景.     

钒钛磁铁矿制备絮凝剂用于有机污水处理的研究

以钒钛磁铁矿为原料,利用盐酸浸出工艺制备铁、钛、钒三元絮凝剂,对工艺条件进行优化后用于处理模拟有机污水,并与聚合氯化铁(PFC)的絮凝效果进行对比.结果表明:在浸出时间为4 h、浸出温度为80℃、液固质量比为5、盐酸初始质量分数为20％时,浸出效果最佳,钒、铁、钛的浸出率分别为99.98％、97.77％、10.41％;...