染料废水脱色混凝剂(PSDC-Ⅰ) 的制备和效果实验

研究了由固体废物 (炼铁废渣 )制取的含有多种金属离子的染料废水脱色混凝剂 (PSDC Ⅰ ) ,试验了它对染料废水的脱色效果及对印染废水的混凝效果 ,并与PAC进行了比较。考察了影响PSDC Ⅰ混凝及脱色效果的因素。结果表明 ,pH值在 6— 10范围内 ,PSDC Ⅰ具有良好的混凝效果。PSDC Ⅰ的两个最佳脱色区为 pH值 6— 8和 pH值 13左右。与PAC相比 ,PSDC Ⅰ不仅具有良好的混凝效果而且具有良好的脱色效果     

不同深度处理工艺去除污水处理厂出水中氮磷的比较研究

城市污水厂出水直接进入天然水体、或经过深度处理后回用于灌溉、补充景观水体和回灌地下水,均需要进行安全性评价.针对北京市北小河污水处理厂出水经过深度处理后回用于奥运公园的安全性,比较了不同深度处理工艺对营养盐(氮、磷)总量和不同形态的去除效果.研究表明,二级处理本身对氮磷的去除效果十分有限,回用水需经过深度处理.在所研究的生物活性炭吸附、微滤、超滤、反渗透以及上述技术的组合工艺中,使用超滤和反渗透联用的工艺路线对脱氮除磷的效果较为理想,其他工艺对去除氮磷的效果十分有限.     

不同深度处理工艺去除污水处理厂出水中氮磷的比较研究

城市污水厂出水直接进入天然水体、或经过深度处理后回用于灌溉、补充景观水体和回灌地下水,均需要进行安全性评价.针对北京市北小河污水处理厂出水经过深度处理后回用于奥运公园的安全性,比较了不同深度处理工艺对营养盐（氮、磷）总量和不同形态的去除效果.研究表明,二级处理本身对氮磷的去除效果十分有限,回用水需经过深度处理.在所研究的生物活性炭吸附、微滤、超滤、反渗透以及上述技术的组合工艺中,使用超滤和反渗透联用的工艺路线对脱氮除磷的效果较为理想,其他工艺对去除氮磷的效果十分有限.     

高气泡表面积通量浮选柱气浮除藻的研究

湖泊、水库等水源的富营养化，使藻类去除成为饮用水生产的重要任务。本研究采用高气泡表面积通量浮选柱气浮除藻，考察了混凝剂、气泡表面积通量和浮选柱高度等因素的影响。试验表明，高气泡表面积通量浮选柱气浮可高效地去除绿藻、硅藻和蓝藻，叶绿素a和藻类去除率达95％以上，比传统浮选柱气浮和沉降作业有较大幅度提高。与普通气浮柱比较，高气泡表面积通量浮选柱增加了气泡与藻的碰撞几率，防止因大表观充气速率造成的紊流和扰动，使气泡／藻结合体有相对静态的浮升环境，避免了气泡／藻结合体在浮升过程中的脱落，实现对藻类的迅速捕集和转移。     

焦炉装煤烟尘治理方案的探讨

焦炉装煤烟尘含有害物质，污染环境，危害人体健康。袋式除尘器的使用，消除了烟尘的污染，但因投资大、运行费用高、操作复杂，难以得到快速、广泛的推广。根据实验结果和已有应用情况，本文推荐了三相流化床除尘装置和颗粒层除尘器，它们可用于焦炉装煤烟尘治理，其投资和运行费用会大大降低。     

染色残液电化学处理碳素阴极材料性能比较

为实现染色残液的高效处理及废水回用,鉴于染色残液良好的导电性,选用电化学处理技术,以模拟活性红X-3B染色残液为研究对象,在钌铱形稳电极为阳极和合适的电解条件下,比较石墨板、石墨毡、炭毡、ACF（活性炭纤维毡）、碳纤维电极〔CFF（碳纤维布）、CFB（碳纤维刷）〕等碳素阴极材料的电化学处理效能.结果表明:碳素阴极材料可实现染色残液的完全脱色,活性红X-3B的降解过程符合一级反应动力学特征,其中CFF为阴极时COD_Cr去除率达到86.37%,一级动力学反应常数为0.010 3 min-1,是石墨毡（0.007 3 min-1）的1.4倍.相比于石墨板电极,CFB显示出优异的二电子氧还原和产H₂O₂能力,单位面积产H₂O₂的浓度为10.40 μmol/L,是石墨板（1.08 μmol/L）的9.7倍,产生的H₂O₂导致活性红X-3B的降解,30 min内实现完全脱色.循环伏安曲线表明,碳纤维电极（包括CFF和CFB）的析氧电位明显高于其他电极,可有效抑制析氧副反应,提高有机污染物降解过程中的电催化效率,有利于降低能耗.研究显示,碳纤维可作为阴极材料应用于电化学处理染色残液,具有良好的稳定性.      

Phytotoxicity and groundwater impacts of leaching from thermal treatment residues in roadways

The use of coal fly ash (CFA), municipal solid waste incinerator bottom ash (MSWIBA) and flue gas desulfurization residue (FGDR) in road construction has become very common owing to its economical advantages. However, these residues may contain toxic constituents that pose an environmental risk if they leach out and flow through the soil, surface water and groundwater. Therefore, it is necessary to assess the ecotoxicity and groundwater impact of these residues before decisions can be made regarding their utilization for road construction. In this study, the physico-chemical characteristics, leaching and phytotoxicity of these residues were investigated. Specifically, multivariate analyses were used to evaluate the contributions of the leaching constituents of the CFA, MSWIBA and FGDR leachates to the germination index of wheat seeds. B, Ba, Cr, Cu, Fe and Pb were found to be more toxic to the wheat seeds than the other heavy metals. Furthermore, the leached concentrations of the constituents from the CFA, MSWIBA and FGDR were below the regulatory threshold limits of the Chinese identification standard for hazardous wastes. Analyses conducted using a numerical groundwater model (WiscLEACH) indicated that the predicted field concentrations of metals from the CFA, MSWIBA and FGDR increased with time up to about 30 years at the point of compliance, then decreased with time and distance. Overall, this study demonstrated that the risks resulting from MSWIBA, CFA and FGDR leaching could be assessed before its utilization for road construction, providing crucial information for the adoption of these alternative materials.     

Investigation on mechanism of phosphate removal on carbonized sludge adsorbent

For the removal of phosphate (PO₄^3 -) from water, an adsorbent was prepared via carbonization of sewage sludge from a wastewater treatment plant: carbonized sludge adsorbent (CSA). The mechanism of phosphate removal was determined after studying the structure and chemical properties of the CSA and its influence on phosphate removal. The results demonstrate that phosphate adsorption by the CSA can be fitted with the pseudo second-order kinetics and Langmuir isotherm models, indicating that the adsorption is single molecular layer adsorption dominated by chemical reaction. The active sites binding phosphate on the surface are composed of mineral particles containing Si/Ca/Al/Fe. The mineral containing Ca, calcite, is the main factor responsible for phosphate removal. The phosphate removal mechanism is a complex process including crystallization via the interaction between Ca^2 + and PO₄^3 -; formation of precipitates of Ca^2 +, Al^3 +, and PO₄^3 -; and adsorption of PO₄^3 - on some recalcitrant oxides composed of Si/Al/Fe.     

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products(DBPs) may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine(NDMA), may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes.The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon(PAC) sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than67% ammonia and 70%–100% N-nitrosamine precursors were removed by Mordenite zeolite(except 3-(dimethylaminomethyl)indole(DMAI) and 4-dimethylaminoantipyrine(DMAP)). PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors(dimethylamine(DMA), ethylmethylamine(EMA), diethylamine(DEA), dipropylamine(DPA), trimethylamine(TMA), DMAP, and DMAI) during the alum coagulation process.     

Characteristics of molecular weight distribution of dissolved organic matter in bromide-containing water and disinfection by-product formation properties during treatment processes

The characteristics of dissolved organic matter (DOM) and bromide ion concentration have a significant influence on the formation of disinfection by-products (DBPs). In order to identify the main DBP precursors, DOM was divided into five fractions based on molecular weight (MW), trihalomethane formation potential and haloacetic acid formation potential were determined for fractions, and the change in contents of different fractions and total DBPs during treatment processes (pre-chlorination, coagulation, sand filtration, disinfection) were studied. Moreover, the relationship between bromide concentration and DBP generation characteristics in processes was also analyzed. The results showed that the main DBP precursors were the fraction with MW < 1 kDa and fraction with MW 3−10 kDa, and the DBP''s generation ability of lower molecular weight DOM (< 10 kDa) was higher than that of higher molecular weight DOM. During different processes, pre-chlorination and disinfection had limited effect on removing organics but could alter the MW distribution, and coagulation and filtration could effectively remove organics with higher MW. For DBPs, trihalomethanes (THMs) were mainly generated in pre-chlorination and disinfection, while haloacetic acids (HAAs) were mostly generated during pre-chlorination; coagulation and sand filtration had little effect on THMs but resulted in a slight removal of HAAs. In addition, the results of ANOVA tests suggested that molecular sizes and treatment processes have significant influence on DBP formation. With increasing bromide concentration, the brominated DBPs significantly increased, but the bromine incorporation factor in the processes was basically consistent at each concentration.