市政再生水对铸铁材料的腐蚀特性生研究

以我国北方某市政再生水厂的出水为研究对象,采用失重法和电化学测试法研究了该再生水对铸铁材料的腐蚀特性,同时考察了初始pH值和含盐量对腐蚀的影响效应.失重法和电化学测试结果均表明,该再生水对铸铁材料的腐蚀速率随时间的延长而逐渐降低,并最终趋于稳定.用失重法比较再生水和自来水对铸铁的腐蚀情况,发现在初期再生水的腐蚀速率大于自来水,但随着时间的延长,二者腐蚀速率的差异逐渐缩小.电化学测试结果表明,铸铁在再生水中能形成抑制腐蚀的保护层.当pH值为6.5-8.2时,铸铁在再生水中的腐蚀速率随pH值的升高而降低.经纯水稀释后的再生水对铸铁的腐蚀速率有增加的趋势,表明仅以含盐量和Larson指数等来评价再生水的腐蚀性是不可靠的.     

Fenton氧化去除高盐废水中有机物:过程优化控制研究

本研究采用Fenton氧化去除高盐废水中有机物,同时对氧化反应过程进行优化控制研究。实验结果表明,药剂投加方式和反应条件的控制对Fenton氧化的影响很大。在药剂投加总量一致的前提下,分批相比单次投加有机物的去除效率更好。在控制反应温度为60℃,过氧化氢投加量为10%(v/v),亚铁和过氧化氢摩尔比为0.05,TOC去除率可以达到90%以上,两级Fenton氧化后废水的TOC小于200 mg/L,达到隔膜电解的厂界进水标准。     

Morphological and physicochemical characteristics of iron corrosion scales formed under different water source histories in a drinking water distribution system

The corrosion scales on iron pipes could have great impact on the water quality in drinking water distribution systems (DWDS). Unstable and less protective corrosion scale is one of the main factors causing “discolored water” issues when quality of water entering into distribution system changed significantly. The morphological and physicochemical characteristics of corrosion scales formed under different source water histories in duration of about two decades were systematically investigated in this work. Thick corrosion scales or densely distributed corrosion tubercles were mostly found in pipes transporting surface water, but thin corrosion scales and hollow tubercles were mostly discovered in pipes transporting groundwater. Magnetite and goethite were main constituents of iron corrosion products, but the mass ratio of magnetite/goethite (M/G) was significantly different depending on the corrosion scale structure and water source conditions. Thick corrosion scales and hard shell of tubercles had much higher M/G ratio (>1.0), while the thin corrosion scales had no magnetite detected or with much lower M/G ratio. The M/G ratio could be used to identify the characteristics and evaluate the performances of corrosion scales formed under different water conditions. Compared with the pipes transporting ground water, the pipes transporting surface water were more seriously corroded and could be in a relatively more active corrosion status all the time, which was implicated by relatively higher siderite, green rust and total iron contents in their corrosion scales. Higher content of unstable ferric components such as γ-FeOOH, β-FeOOH and amorphous iron oxide existed in corrosion scales of pipes receiving groundwater which was less corroded. Corrosion scales on groundwater pipes with low magnetite content had higher surface area and thus possibly higher sorption capacity. The primary trace inorganic elements in corrosion products were Br and heavy metals. Corrosion products obtained from pipes transporting groundwater had higher levels of Br, Ti, Ba, Cu, Sr, V, Cr, La, Pb and As.     

Microbial community compositional analysis for series reactors treating high level antibiotic wastewater

A full-scale biosystem consisting of two anaerobic reactors (HA and BF1) and four aerobic ones (BF2-BF4 and OD) in succession and receiving antibiotic-bearing (mainly streptomycin) wastewater was used for studying the impacts of antibiotics on microbial community structures. Significant decreases of streptomycin (from 3955 ± 1910 to 23.1 ± 4.7 μg L(-1)) and COD(Cr) were observed along the treatment process. Cloning results show that the anaerobic reactors (HA and BF1) were dominated with Deltaproteobacteria (51%) mainly affiliated with sulfate-reducing bacteria (SRB), while the aerobic BF2 receiving streptomycin of 408.6 ± 59.7 μg L(-1) was dominated with Betaproteobacteria (34%), Deltaproteobacteria (31%) and Bacteroidetes (14%). Gammaproteobacteria (15.9-22.4%), Betaproteobacteria (10.0-20.3%), and Bacteroidetes (4.5-29.7%) became the major bacterial groups in aerobic BF3-OD receiving streptomycin of ≤83 ± 13 μg L(-1). Archaea affiliated with Methanomethylovorans hollandica-like methylotroph was abundant in HA and BF1 (archaea/bacteria, 0.54-0.40; based on specific gene copy number), suggesting the coexistence of SRB and methanogens in degrading pollutants. Fungi were abundant (fungi/bacteria, 0.15; based on specific gene copy number) with the dominance of Ascomycota (clone ratio of Ascomycota/eukarya, 25.5%) in BF2, suggesting that fungi could be an important player in pollutant removal under high levels of antibiotics. This study demonstrates that under high antibiotic levels, wastewater treatment communities may maintain system stability through adjusting bacterial, archaeal, and eukaryal compositions.     

饮用水处理工艺中消毒副产物的变化特征研究

为阐明饮用水厂运行中主要消毒副产物的形成特征及转化规律,提出有效的控制措施,以北方某饮用水厂为研究对象,对采用预加氯的不同处理单元出水中3类消毒副产物,即8种卤乙酸(HAAs)、亚硝基二甲胺(NDMA)和4种三卤甲烷(THMs)的变化特征进行了研究。结果表明,经预氯化后3类副产物显著增加,HAAs、NDMA和THMs和质量浓度合计分别为33.1μg/L、9.0 ng/L和55.1μg/L;经双层滤料过滤后得到不同程度去除,5种可去除HAAs的去除率为15.7%～60.8%,NDMA去除率为48.1%,4种THMs的去除率为26.1%～49.2%。氯胺消毒下总出水中3类副产物含量也未明显增加,表明预氯化及氯胺消毒是进一步削减消毒副产物产生、降低饮用水健康安全风险的重要控制措施。     

微波预处理剩余污泥的研究进展

介绍了微波预处理污泥的作用机理及作用过程,包括污泥絮体破解、污泥细胞破碎及有机物的释放、有机物水解、美拉德反应等,总结了微波预处理污泥的作用效果（物理特性、化学特性、生物特性）、影响微波预处理效果的因素（污泥特性、处理条件）和微波预处理污泥对其后续厌氧消化的影响。指出了目前研究中存在的主要问题是试验规模偏小,预处理方式为间歇处理,在对污泥中有毒有害有机物和病原微生物的去除研究方面还需加强。提出今后应重点开展微波组合工艺对污泥中有毒有害有机物和病原微生物去除的基础研究,同时积极开发相关设备,开展微波预处理污泥的连续和中试研究,推动微波技术在污泥资源化、减量化和无害化处理中的应用。     

A numerical study of the unsteady heat/mass transfer inside a circulating sphere

Numerical methods are used to investigate the transient, forced convection heat/mass transfer inside circulating spheres at low to moderate Reynolds numbers. The heat/mass balance equations were solved numerically in spherical coordinates system by a finite difference method. The values considered for the sphere interior Reynolds number are Re_int ? 1000. The computations were focused on the influence of the sphere Peclet number, Pe, and Re_int on heat/mass transfer rate for Pe/(1 + μ) ? 10⁴.     

Historical distribution and partitioning of phosphorus in sediments in an agricultural watershed in the Yangtze-Huaihe region, China

Agricultural intensification developed rapidly in East China since the 1980s, which caused most of the lakes in these areas to become eutrophic at almost the same time. Less is known about the relationship between agricultural intensification and watershed water quality, as well as historical nutrients dynamics and lake eutrophication processes. The study area, a typical agricultural watershed with high-yield grain production characterized by multipond systems in China's Yangtze-Huaihe region, was selected to evaluate the effects of agricultural intensification on P sediment retention using 137Cs dated sediment cores. Experimental results showed that P kept increasing in the multipond sediments during the past decades, which could be attributed almost entirely to agricultural intensification. An inflection point appeared in the 1980s, before which TP showed no or only a slight increase (200 mg x kg(-1)). Thereafter, it increased dramatically (about 400 mg x kg(-1) by the year 2004) due to the extensive application of phosphate fertilizers. The chemical reactive fraction, KCl-extracted phosphorus (KCI-P), accounted for only 0.3% or less of TP. However, NaOH-extracted inorganic P (NaOH-Pi), accounting for 13-46%, was the main factor causing TP to increase due to long-term P fertilization, whereas CaCO3-bound phosphorus (Ca-P), together with residual phosphorus (Res-P) stayed at a relatively stable level. The increasing TP contents indicated that there was a potential to overwhelm the sorption capacity of multipond systems causing continuous water quality deterioration in the watershed and downstream waters. It is implied that P export resulting from agricultural intensification and water deterioration should be taken into account during the formation of watershed management strategies for the water environment.     

Characterization and reactivity of MnO(x) supported on mesoporous zirconia for herbicide 2,4-D mineralization with ozone

Manganese oxide was supported on mesoporous zirconia (MnO(x)/ MZIW) by wet impregnation, drying, water washing, and calcinations with manganese acetate tetrahydrate as the metal precursor for the first time and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectra (FTIR), temperature-programmed reduction (TPR), temperature-programmed oxygen desorption (O2-TPD), and UV-vis diffuse reflectance spectra (UV-vis DRS) measurements. The catalyst was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) aqueous solution with ozone. The characterization studies showed that nonstoichiometrically MnO(x) was highly dispersed on mesoporous zirconia by the strong interaction of the [Mn(H2O)6]2+ complex with surface hydroxyls of the support. Moreover, the multivalence oxidation states of MnO(x) enhanced the electron transfer, causing the higher catalytic reactivity. On the basis of all information obtained under different experimental conditions, MnO(x)/MZIW enhanced the mineralization of 2,4-D by the formation of *OH radicals resulting from the catalytic decomposition of ozone.     

γ-Al2O3/TiO2混合纳米粒子改性PVDF超滤膜

为提高聚偏氟乙烯（PVDF）膜的亲水性和强度,将纳米二氧化钛（TiO2）溶胶和纳米氧化铝（γ-Al2O3）按不同比例与聚偏氟乙烯共混,采用相转化法制得共混超滤膜。考察了不同比例的混合纳米粒子对PVDF超滤膜的纯水通量、截留率、力学性能等的影响。并利用扫描电子显微镜（SEM）观察了膜的表面和内部微观结构,红外光谱分析（FTIR）和X射线衍射仪（XRD）考察纳米粒子在PVDF基体中的存在状态,通过对复合膜进行拉力测试研究混合纳米粒子对膜力学性能的影响,并使用接触角测量仪测定膜表面和水之间的接触角来定量分析比较膜表面的亲水性。结果表明,γ-Al2O3/TiO2混合比为1∶2时,膜的性能达到最优,孔隙率为74%,水通量为120 L/（m2.h）,截留率为93%,拉力最大负荷为35 N,拉伸应变为22%。