Phosphate adsorption performance of a novel filter substrate made from drinking water treatment residuals

Phosphate is one of the most predominant pollutants in natural waters. Laboratory experiments were conducted to investigate the phosphate adsorption performance of a(NFS) made from drinking water treatment residuals. The adsorption of phosphate on the NFS fitted well with the Freundlich isotherm and pseudo second-order kinetic models. At p H 7.0, the maximum adsorption capacity of 1.03 mg/g was achieved at 15°C corresponding to the wastewater temperature in cold months, and increased notably to 1.31 mg/g at 35°C.Under both acidic conditions(part of the adsorption sites was consumed) and basic conditions(negative charges formed on the surface of NFS, which led to a static repulsion of PO43-and HPO42-), the adsorption of phosphate was slightly inhibited. Further study showed that part of the adsorption sites could be recovered by 0.25 mol/L Na OH. The activation energy was calculated to be above 8.0 k J/mol, indicating that the adsorption of phosphate on NFS was probably a chemical process. Considering the strong phosphate adsorption capacity and recoverability, NFS showed great promise on enhancing phosphate removal from the secondary treated wastewater in the filtration process.     

北京城市发展对土壤微生物群落功能多样性的影响

为研究城市发展对土壤微生物功能多样性的影响,以北京市建成区为例,采用Biolog-ECO微平板技术分析不同环路内3种类型绿地(居民区内绿地、街道边绿地、公园内绿地)土壤微生物群落功能多样性的变化.结果表明:二环内各绿地类型土壤微生物群落的AWCD(average well color development,平均颜色变化率)相对较高,分别为1.107、1.192、1.007,表明其土壤微生物群落代谢活性较高,利用碳源能力较强,其他环路土壤微生物群落利用碳源能力相对较弱;其中,各绿地类型土壤微生物群落对羧酸类碳源的利用能力最弱.城市环路梯度下居民区对土壤微生物群落多样性的影响相对较大;街道对土壤微生物群落功能多样性无显著影响(或者城市环路梯度下街道边绿地土壤微生物群落功能多样性趋同);四环～五环公园内绿地土壤微生物群落功能多样性与其他环路之间存在显著差异.对土壤微生物群落碳源利用能力进行主成分分析的结果显示,居民区内绿地、街道边绿地、公园内绿地提取的与土壤微生物碳源利用相关的主成分累积贡献率分别为86.79%、87.09%、84.92%,对主成分分离起主要作用的碳源主要是氨基酸类、糖类、多聚物类和羧酸类物质.冗余分析(RDA)表明,pH、土壤含水量是影响土壤微生物群落代谢能力和功能多样性的主要因素.城市绿地类型和环路因子对土壤微生物利用碳源分异存在一定影响,但对碳源代谢能力变异的解释量(5.91%)低于土壤理化因子的解释量(16.26%).研究显示,城市环路对土壤微生物功能多样性产生一定影响,但各环路街道边绿地土壤微生物功能多样性无显著差异,并且二环内、二环～三环、三环～四环各绿地类型土壤微生物多样性也无显著差异,说明城市发展可能使土壤微生物群落功能多样性趋于同质化.      

改性聚氨酯海绵的合成及其油水分离性能

以膨胀石墨与氧化锌为原料,采用复合改性法改性聚氨酯海绵,在硅烷偶联剂的作用下,用月桂酸的醇溶液表面修饰后制备出改性聚氨酯海绵. 通过扫描电子显微镜(SEM)与接触角测定仪进行表征,对改性聚氨酯海绵的吸油、吸水及循环使用性能进行了测定,并试验获得了最佳的油水分离条件. 结果表明:改性聚氨酯海绵具有良好的疏水超亲油性,在膨胀石墨分散液与氧化锌胶体溶液体积比为1∶1时,对于质量浓度为20 g/L的机油水溶液,饱和单位吸油量最高可达17.7 g/g,对机油的选择性吸附系数为10.41,油水分离效果最佳;在选择吸附过程中,15 min以内油水分离效率就能达到78.41%;改性聚氨酯海绵每次循环利用后,单位吸油量的减幅均低于7.3%,循环使用性能良好. 研究显示,该种改性聚氨酯海绵对油水体系中的油类具有很好的选择性,吸附完成后,经过简单的挤压将油回收后即可循环利用,具有便捷、高效、循环、无二次污染的特性.      

进水CODCr负荷对MBR去除雌激素的影响

为了探究MBR进水COD_Cr负荷对雌激素去除的影响,设置了不同进水ρ(COD_Cr)下的3组MBR,检测其对E1(雌酮)和EE2(17α-乙炔基雌二醇)的去除效果,并通过污泥浓度、污泥粒径以及微生物数量分析,揭示MBR污泥特性对E1和EE2去除效果的影响. 结果表明,尽管进水ρ(COD_Cr)差异较大,但3组MBR均取得了较好的COD_Cr及NH₃-N去除效果. 出水ρ(SEs)(SEs为类固醇雌激素)随进水ρ(COD_Cr)的增加而降低,当初始ρ(SEs)均为50 μg/L时,进水ρ(COD_Cr)为93.00、295.27、504.40 mg/L的MBR出水中ρ(E1)、ρ(EE2)平均分别为3.26、3.02、1.17 μg/L和4.76、4.46、2.64 μg/L. 随着初始ρ(SEs)的提高,出水中ρ(E1)、ρ(EE2)均有不同程度提高,当初始ρ(SEs)升至200 μg/L时,MBR出水中ρ(E1)、ρ(EE2)平均值分别为5.61、5.64、3.82 μg/L和8.14、7.87、6.57 μg/L. 相同条件下,MBR对E1的去除效果显著优于EE2.相关性分析表明,E1、EE2去除负荷均与COD_Cr去除负荷显著负相关,与NH₃-N去除负荷显著正相关(P<0.05),MBR中E1、EE2的去除是由有机物共代谢和硝化共代谢共同作用的结果,硝化过程与雌激素降解过程呈相似的环境条件要求.      

有机碳源对一体化厌氧氨氧化反应器脱氮性能的影响

试验通过在进水中投加有机碳源(白糖),研究有机碳源对一体化厌氧氨氧化反应器脱氮性能的影响。试验结果表明:进水COD浓度对一体化厌氧氨氧化反应器脱氮性能产生明显的影响。当进水中COD浓度约为50mg/L时,即可导致系统总氮去除率大幅度下降,出水总氮去除率由不添加COD的87.8%降至76%,氨氮去除率由不添加COD的98.8%降至85%;当进水COD浓度上升至约100mg/L时,出水总氮的去除率由不添加COD的87.8%降至69%,氨氮去除率由不添加COD的98.8%降至77%;当进水COD浓度约为100mg/L时,并将调节槽曝气量由原来的0.4L/min增至0.6L/min,系统出水水质明显得到优化,总氮去除率恢复到未投加COD时的水平。有效地控制一体化厌氧氨氧化反应器内有机碳源的量,能明显地提高系统的脱氮效果。     

Deposition behavior of residual aluminum in drinking water distribution system: Effect of aluminum speciation

Finished drinking water usually contains some residual aluminum.The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water quality at consumer taps.A preliminary analysis of aluminum content in cast iron pipe corrosion scales and loose deposits demonstrated that aluminum deposition on distribution pipe surfaces could be excessive for water treated by aluminum coagulants including polyaluminum chloride（PACl）.In this work,the deposition features of different aluminum species in PACl were investigated by simulated coil-pipe test,batch reactor test and quartz crystal microbalance with dissipation monitoring.The deposition amount of non-polymeric aluminum species was the least,and its deposition layer was soft and hydrated,which indicated the possible formation of amorphous Al（OH）₃.Al₁₃ had the highest deposition tendency,and the deposition layer was rigid and much less hydrated,which indicated that the deposited aluminum might possess regular structure and self-aggregation of Al₁₃could be the main deposition mechanism.While for Al₃₀,its deposition was relatively slower and deposited aluminum amount was relatively less compared with Al₁₃.However,the total deposited mass of Al₃₀ was much higher than that of Al₁₃,which was attributed to the deposition of particulate aluminum matters with much higher hydration state.Compared with stationary condition,stirring could significantly enhance the deposition process,while the effect of pH on deposition was relatively weak in the near neutral range of 6.7 to 8.7.     

镉对蓖麻耐性生理及营养元素吸收转运的影响

通过营养液栽培实验,研究了不同浓度Cd(0、25、50、100、200μmol·L-1)处理对能源植物蓖麻生长、生理特性、Cd积累以及营养元素吸收的影响.结果表明,200μmol·L-1的Cd处理使叶片、茎部鲜重和植株总鲜重分别下降了63.68%、55.21%和52.69%,根系鲜重则无显著变化;叶片过氧化氢和丙二醛含量分别提高了3.81和2.22倍,产生了明显的氧化胁迫作用;酸溶性巯基、还原型谷胱甘肽和植物络合素含量分别提高了1.73、12.63和1.62倍,GSH对于蓖麻Cd胁迫具有显著的缓解作用.根系Cd积累量和植株总积累量分别增加了3.15和2.41倍,蓖麻主要将Cd富集在其根系,有助于减轻Cd对地上部的毒害.Cd抑制蓖麻植株K和Ca的吸收,促进根系和茎部P吸收,高浓度Cd抑制P向叶片的转运;植株Zn和Cu含量、根系和茎部Mg含量表现为低促高抑,植株Mn含量及根系Fe含量表现为低抑高促.可见,Cd处理对不同营养元素的吸收有着不同的影响,应根据Cd胁迫条件下不同营养元素吸收特性来合理调控其供应.     

Occurrence and impact of polychlorinated dibenzo-p-dioxins/dibenzofurans in the air and soil around a municipal solid waste incinerator

To assess the influence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans(PCDD/Fs) on the environment in the vicinity of municipal solid waste incinerators(MSWIs), we determined the levels of PCDD/Fs in air and soil samples collected around a MSWI, which is the largest in China. The International Toxicity Equivalency Quantity(I-TEQ) concentrations of PCDD/Fs in air samples were from 0.0300 to 1.03 pg I-TEQ/m~3(0.445–13.6 pg/m~3), with an average of 0.237 pg I-TEQ/m~3, while in soil samples they ranged from 0.520 to 3.40 pg I-TEQ/g(2.41–88.7 pg/g) with an average of1.49 pg I-TEQ/g. The concentrations of PCDD/Fs in air and soil samples were comparable to other areas, and Pe CDFs were the dominant contributors, which was different from stack gas homologue patterns. Multivariate statistical analysis showed that PCDD/Fs emission from the MSWI did not directly affect the profiles of PCDD/Fs in air and soils, so that vehicles and unidentified emission sources should be considered. The daily inhalation levels of PCDD/Fs for children(0.0110 to 0.392 pg I-TEQ/(kg·day) and adults(0.00600 to 0.221 pg I-TEQ/(kg·day) near the MSWI were lower than the tolerable daily intake of 1.00 to 4.00 pg WHO-TEQ/(kg·day), but in winter the values were higher than in summer. These results can be used as basic data for assessing the risk of PCDD/Fs exposure in residents living around this MSWI, and more monitoring programs and studies should be carried out around MSWIs.     

工业源挥发性有机物动态更新平台的建立与研究

挥发性有机物(VOCs)是一类重要的大气污染物质,通过工业源VOCs动态更新平台对其进行管控是十分必要的.对比分析国内外VOCs动态更新机制的发展状况,结合天津市建立的工业源VOCs排放申报平台,提出了包括建立涵盖全行业的统一申报系统、建立规范的申报和审核流程、确定统一的总量核算办法、形成工业源VOCs排放清单、建立VOCs动态更新机制在内的动态更新平台建立思路,用于指导工业源VOCs的污染防治工作.     

Polybrominated diphenyl ethers in e-waste: Level and transfer in a typical e-waste recycling site in Shanghai,Eastern China

Very few data for polybrominated diphenyl ethers (PBDEs) were available in the electronic waste (e-waste) as one of the most PBDEs emission source. This study reported concentrations of PBDEs in e-waste including printer, rice cooker, computer monitor, TV, electric iron and water dispenser, as well as dust from e-waste, e-waste dismantling workshop and surface soil from inside and outside of an e-waste recycling plant in Shanghai, Eastern China. The results showed that PBDEs were detected in the majority of e-waste, and the concentrations of ΣPBDEs ranged from not detected to 175 g/kg, with a mean value of 10.8 g/kg. PBDEs were found in TVs made in China after 1990. The mean concentrations of ΣPBDEs in e-waste made in Korea, Japan, Singapore and China were 1.84 g/kg, 20.5 g/kg, 0.91 g/kg, 4.48 g/kg, respectively. The levels of ΣPBDEs in e-waste made in Japan far exceed the threshold limit of RoHS (1.00 g/kg). BDE-209 dominated in e-waste, accounting for over 93%. The compositional patterns of PBDEs congeners resembled the profile of Saytex 102E, indicating the source of deca-BDE. Among the samples of dust and surface soil from a typical e-waste recycling site, the highest concentrations of Σ₁₈PBDEs and BDE-209 were found in dust in e-waste, ranging from 1960 to 340,710 ng/g and from 910 to 320,400 ng/g, which were 1–2 orders of magnitude higher than other samples. It suggested that PBDEs released from e-waste via dust, and then transferred to surrounding environment.