高铁铝矾土制备聚合氯化铝铁及其在污水处理中的应用研究

利用含铁的低品位铝矾土为主要原料,添加适量铝酸钙粉,制备出絮凝剂聚合氯化铝铁.制备方法为酸溶两步法.对影响聚合铝铁制备的因素,如盐酸浓度、盐酸用量、温度和铝酸钙粉用量等进行了系统研究,得到了制备聚合铝铁的优化条件,同时将该絮凝剂用于实际工业污水的处理.研究结果表明:制备的絮凝剂絮凝效果明显优于一些传统的絮凝剂;不仅具有去浊性能好、沉降快的优点,而且具有原料易得,制备成本低的优势.     

活性污泥胞外聚合物提取方法研究

考察4种方法(蒸气法、EDTA法、NaOH法和搅拌法)对3种活性污泥(可乐厌氧活性污泥、可乐好氧活性污泥和市政污水污泥)胞外聚合物的提取效率,对比分析了各提取方法对不同样品提取所得胞外聚合物的组成影响,结果表明,EDTA法提取多糖的效率最高,提取市政污水污泥、可乐好氧活性污泥和可乐厌氧活性污泥胞外聚合物糖分别在8.3、16.7和9.7 mg/g VSS左右;NaOH提取蛋白质的效率最高,提取市政污水污泥、可乐好氧活性污泥和可乐厌氧活性污泥胞外聚合物蛋白质分别为:3.15、0.55和5.57 mg/g VSS.对于3种不同种类污泥,EDTA法提取EPS总量效率最高,分别为市政污水污泥10.7 mg/g VSS、可乐好氧活性污泥16.8 mg/g VSS和可乐厌氧活性污泥9.97 mg/g VSS,分别比效率最低的搅拌法高出5倍、5倍和3倍.     

Maximum permissible and negligible concentrations for some organic substances and pesticides

The aim of the paper is to provide interested parties the methods that were used for generic hazard assessment in The Netherlands, and the resulting so-called maximum permissible concentrations (MPCs) and the negligible concentrations (NCs) for approximately 150 organic substances and pesticides. The MPCs and NCs were derived for water, sediment, and soil. The concentration in the environment above which the risk of adverse effects was considered unacceptable to ecosystems is called the MPC. The MPCs take into account that the substances are distributed among the different environmental compartments, and are harmonized accordingly. The MPCs served as a basis for the Dutch government to set generic environmental quality standards (EQS) in The Netherlands (IWINS,[15]). EQS in turn are used by the Dutch Government to assess the environmental quality and for other environmental policy purposes. Concentrations in the environment below which the occurrence of adverse effects is considered to be negligible are called NCs. Hazards must be reduced when the environmental concentration of a substance exceeds its MPC. In-between this limits reduction of hazards is preferable. The MPC is a scientifically derived hazard limit. The NC is simply defined as 1% of the MPC. In general, there is a great demand for ecotoxicological data that currently limits a more reliable estimate of many MPCs. For water, approximately half of the MPCs are derived on the basis of four or more NOECs (no observed effect concentrations). For the other half, MPCs are based on only a few chronic or acute tests. For soil and sediment, however, almost no ecotoxicological data are available, and MPCs for those compartments have, in many cases, been derived from MPCs in water applying the equilibrium partitioning method (EqP-method), resulting in MPCs with greater uncertainty. Some of the methods and underlying assumptions that have been used may need improvement. For example, the factor between MPC and NC, the statistical extrapolation method, the method that is used for secondary poisoning, the role of the background concentrations of ‘naturally’ occurring substances, and the bioavailability and the EqP-method. There is a great need for hazard limits, and the present compilation tries to provide those as well as identifying research gaps.     

Global-scale environmental transport of persistent organic pollutants

In order to realistically simulate both chemistry and transport of atmospheric organic pollutants, it is indispensable that the applied models explicitly include coupling between different components of the global environment such as atmosphere, hydrosphere, cryosphere and soil system. A model with such properties is presented.

The atmospheric part of the model is based on the equations in a general contravariant form which permits easy changes of the coordinate system by redefining the metric tensor of a specifically employed coordinate system. Considering a need to include explicitly the terrain effects, the terrain following spherical coordinate system is chosen from among many possible coordinate systems. This particular system is a combination of the Gal-Chen coordinates, commonly employed in mesoscale meteorological models, and the spherical coordinates, typical for global atmospheric models.

In addition to atmospheric transport, the model also simulates the exchange between air and different types of underlying surfaces such as water, soil, snow, and ice. This approach permits a realistic representation of absorption and delayed re-emission of pollutants from the surface to the atmosphere and, consequently, allows to capture hysteresis-like effects of the exchange between the atmosphere and the other components of the system. In this model, the most comprehensive numerical representation of the exchange is that for soil. In particular, the model includes a realistic soil module which simulates both diffusion and convection of a tracer driven by evaporation from the soil, precipitation, and gravity.

The model is applied to a long-term simulation of the transport of pesticides (hexachlorocyclohexanes in particular). Emission fluxes from the soil are rigorously computed on the basis of the realistic data of the agricultural application. All four modelled systems, i.e. atmosphere, soil, hydrosphere and cryosphere, are driven by objectively analysed meteorological data supplemented, when necessary, by climatological information. Therefore, the verification against the observed data is possible. The comparison of the model results and the observations taken at remote stations in the Arctic indicates that the presented global modelling system is able to capture both trends and short-term components in the observed time series of the concentrations, and therefore, provides a useful tool for the evaluation of the source–receptor relationships.     

甲萘酚和甲萘胺在超高交联吸附树脂上的协同吸附行为

研究了水溶液中甲萘酚和甲萘胺在超高交联吸附树脂NDA103、NDA100上的协同吸附行为.实验结果表明,在较高平衡浓度范围内该吸附树脂对双组分水溶液中甲萘酚和甲萘胺双组分(摩尔比分别为3∶1、1∶1、1∶3)的吸附总量大于相同平衡浓度下对单组分水溶液中甲萘酚和甲萘胺的吸附量,呈现协同吸附现象,其主导机制是2种吸附质分子之间的氢键作用.单组分甲萘酚或甲萘胺水溶液和双组分共存水溶液中吸附质分子在吸附树脂上的吸附等温线均符合Langmuir模型.吸附温度由293K升至313K时,甲萘酚和甲萘胺在NDA103上的协同吸附效应的变化明显大于NDA100.NDA103树脂结构上的胺基既加强了对甲萘酚的吸附亲和力又增加了甲萘酚的协同吸附系数.     

水中低残留有机物萃取过程的盐析作用及色谱分析1)

用自制的高浓缩比液液萃取装置,对氯化钠作为盐析剂在萃取过程中的作用进行色谱分析,三种非挥发性有机物六六六、DDT和苯并(α)芘的最低检测限均可达到1ng*l-1以下,用本方法检测自来水有ng*l-1级六六六和DDT存在.     

Qualitatively and quantitatively assessing the aggregation ability of sludge during aerobic granulation process combined XDLVO theory with physicochemical properties

Inexact mechanism of aerobic granulation still impedes optimization and application of aerobic granules. In this study, the extended Derjaguin, Landau, Verwey, and Overbeek(XDLVO) theory and physicochemical properties were combined to assess the aggregation ability of sludge during aerobic granulation process qualitatively and quantitatively. Results show that relative hydrophobicity of sludge and polysaccharide content of extracellular polymeric substances(EPS) increased, while electronegativity of sludge decreased during acclimation phase. After 20 days' acclimation, small granules began to form due to high aggregation ability of sludge. Since then, coexisted flocs and granules possessed distinct physicochemical properties during granulation and maturation phase. The relative hydrophobicity decreased while electronegativity increased for flocs, whereas that for granules presented reverse trend. Through analyzing the interaction energy using the XDLVO theory, small granules tended to self-grow rather than self-aggregate or attach of flocs due to poor aggregation ability between flocs and granules during the granulation phase. Besides, remaining flocs were unlikely to self-aggregate owing to poor aggregation ability, low hydrophobicity and high electronegativity.     

氨基酸修饰的高交联吸附树脂对Cu(Ⅱ)和磺胺嘧啶的吸附机制研究

采用络氨酸修饰氯球树脂（PS-DVB）并进行后交联反应制备了氨基酸修饰的高交联吸附树脂（PSTY）.研究了PSTY树脂对Cu（Ⅱ）和磺胺嘧啶（SDZ）的协同吸附性能及交互影响机制.单组分体系中,树脂对Cu（Ⅱ）的吸附随pH值的增加而增加,对SDZ的吸附随着pH值的增加先增后减;共存体系中,SDZ的共存微弱促进了树脂对Cu（Ⅱ）吸附,Cu（Ⅱ）的共存抑制了树脂对SDZ的吸附,且pH大于6后抑制更为明显.PSTY对Cu（Ⅱ）和SDZ的吸附等温线可采用Langmuir和Freundlich方程进行拟合,共存低浓度的SDZ使Cu（Ⅱ）的饱和吸附量略有增加,而高浓度的SDZ使其下降.Cu（Ⅱ）的增强去除主要是阴离子SDZ^-与树脂的质子化基团的静电作用减弱了对Cu（Ⅱ）的静电斥力,Cu（Ⅱ）与SDZ分别与PSTY中的极性基团发生配位作用和氢键作用进行竞争吸附,但Cu（Ⅱ）的配位结合力更强,虽然吸附到树脂上的Cu（Ⅱ）还可以通过桥连作用吸附SDZ,但作用较弱,因此,共存的Cu（Ⅱ）抑制了PSTY树脂对SDZ的吸附,Cu（Ⅱ）浓度越大抑制程度越高.     

Magnetic micro-particle conditioning–pressurized vertical electro-osmotic dewatering (MPEOD) of activated sludge: Role and behavior of moisture and organics

In this study, a magnetic micro-particle conditioning–pressurized vertical electro-osmotic dewatering (MPEOD) process with magnetic micro-particle conditioning–drainage under gravity–mechanical compression–electrical compression (MMPC–DG–MC–EC) stages was established to study the distribution and migration of water, extracellular polymeric substances (EPS), and other organic matter in the activated sludge (AS) matrix at each stage. Results showed that the MPEOD process could attain 53.52% water content (WC) in dewatered AS with bound water (BW) and free water (FW) reduction rates of 82.97% and 99.67%, respectively. The coagulation and time-delayed magnetic field effects of magnetic micro-particles (MMPs) along the MMPC–DG–MC stages initiated the transformation of partial BW to FW in AS. EC had a coupling driving effect of electro-osmosis and pressure on BW, and the changes in pH and temperature at EC stage induced the aggregation of AS flocs and the release of partial BW. Additionally, MMPs dosing further improved the dewatering performance of AS by acting as skeleton builders to provide water passages. Meanwhile, MMPs could disintegrate sludge cells and EPS fractions, thereby reducing tryptophan-like protein and byproduct-like material concentrations in LB-EPS as well as protein/polysaccharide ratio in AS matrix, which could improve AS filterability. At EC stage, the former four Ex/Em regions of fluorescence regional integration analysis for EPS were obviously reduced, especially the protein-like substances in LB- and TB-EPS, which contributed to improvement of AS dewaterability.     

给水管网中余氯浓度对颗粒物表面细菌附着的影响

为解析余氯浓度对颗粒物表面细菌附着的影响,以给水管网细菌为研究对象,开展其在不同余氯浓度条件下的附着实验.结果表明,低浓度氯(0~0.5 mg·L~(-1))会促进细菌在针铁矿表面的附着,而高浓度氯(0.5~3.0 mg·L~(-1))抑制了细菌的表面附着.通过定量测定及激光共聚焦显微镜的观测发现,当氯浓度为0.5 mg·L~(-1)时,聚集体总细菌数、胞外聚合物(EPS)含量均达到最大.研究结果揭示了余氯浓度调控着细菌EPS的分泌,进而影响细菌在给水管网中颗粒物表面的附着.