Sorption of apolar and polar organic contaminants by waste tire rubber and its chars in single- and bi-solute systems

Single- and bi-solute sorption of organic compounds [1,3-dichlorbenzene (DCB), 1,3-dinitrobenzene (DNB) and 2,4-dichlorophenol (DCP)] on ground tire rubber and its chars was studied. The chars were prepared by pyrolyzing tire rubber at different temperatures (200-800 °C). Their surface area, aromaticity and hydrophobicity increase greatly with pyrolytic temperature, and the polymeric phase is partly converted into a condensed phase. The sorption of DNB and DCP increases with pyrolytic temperature and is characterized by a transition from a partition dominant to an adsorption dominant process. However, the sorption of DCB linearly decreases with the pyrolytic temperature. The enhanced adsorption of DNB and DCP on carbonized phase is primarily attributed to nonhydrophobic interactions such as π-π electron-donor-acceptor interactions and/or H bonding. The higher partition of DCB to polymeric phase is attributed to its high hydrophobicity. Competitive sorption between DCB and DCP on the tire chars is highly dependent on dissociation of the latter.     

Wastewater treatment plants and landfills emit volatile methyl siloxanes (VMSs) to the atmosphere: investigations using a new passive air sampler

Volatile methyl siloxanes (VMSs) are a class of chemicals with an increasing range of applications and widespread distribution in the environment. Passive air samplers (PAS) comprising sorbent-impregnated polyurethane-foam (SIP) disks were first calibrated and then deployed around two wastewater treatment plants (WWTPs) and at two landfill sites to investigate inputs of VMSs to air. SIP-derived air concentrations for ΣVMSs (ng/m³) at background sites on the perimeter of the WWTP were 479 ± 82.3 and comparable to results for the upwind samples at the landfills (333 ± 194). Order of magnitude higher concentrations of ΣVMSs (ng/m³) were found for on-site samples at the WWTPs (3980 ± 2620) and landfills (4670 ± 3360). Yearly emissions (kg/yr) to air were estimated and ranged from 60-2100 and 80-250, respectively, for the cyclic VMSs. These findings demonstrate and quantify for the first time, waste sector emissions of VMSs to the atmosphere.     

代森锰锌和ND－901中代森锰锌在大棚黄瓜上残留动态的研究

采用顶空气相色谱（GLC-HS）分析技术测定了代森锰锌、ND－901中代森锰锌在大棚黄瓜上的残留动态。喷施70％代森锰锌可湿性粉剂的500倍、250倍药液,测出黄瓜上原始沉积量分别为0.88～2.70mg/kg、1.11～3.79mg/kg;半衰期为1.6～9.5天、2.3～10.9天。黄瓜叶片上原始沉积量分别为148.01～164.08mg/kg、246.26～254.51mg/k;半衰期为15.8～16.2、18.4天。ND－901中代森锰锌的残留量均低于单剂。另外,自来水去污处理可有效地减少瓜上代森锰锌的残留量,平均去污率87％。     

微波技术在废水处理中的应用

文章简述了微波直接辐射和微波再生技术在废水处理中的应用.指出了微波技术在废水处理中存在的问题,并对其发展前景进行了展望.     

废水废气污染源在线监测系统日常维护及故障处理

伴随着我国社会现代化程度和城市化进程的不断加深,社会得到了非常好的发展,但同时也产生了大量的废气和废水,对生态环境造成了严重破坏。因此,为了将这个问题良好的解决,应建立一套具有较高科学性和合理性的废水废气污染源在线监测系统,并加大日常维护及故障处理的力度,从根源减少人们在工作生活中对生态环境造成的影响。因此,本文针对废水废气污染源在线监测系统日常维护及故障处理的有效措施,展开详细的分析,以期能够为我国生态环境可持续发展目标的实现贡献应有的力量。     

固相微萃取-便携式GC/MS快速测定水中痕量有机磷农药

采用固相微萃取-便携式气相色谱/质谱联用法（In situ SPME/GC-MS）分析地表水和废水中6种有机磷农药,通过优化测定条件,使6种有机磷农药在200 μg/L~500 μg/L范围内线性良好。方法检出限为033 μg/L～122 μg/L,低、高质量浓度标准溶液6次测定结果的RSD为68%~175%,加标回收率为849%~109%,与实验室方法的测定结果基本一致。     

垃圾焚烧厂对环境空气中二噁英影响研究

本文通过对垃圾焚烧炉废气和周边环境空气采样,采用同位素稀释-高分辨气相色谱/高分辨质谱(HRGC-HRMS)法分析样品中二噁英浓度。废气样品中二噁英总浓度为0.919~1.152 ng TEQ/m^3,总毒性当量为0.071~0.100 ng TEQ/m^3,环境空气样品中二噁英总浓度为1.194~2.268 pg TEQ/m^3,总毒性当量为0.100~0.200 pg TEQ /m^3。比较废气与环境空气中各PCDD/Fs单体浓度的占比,得出该农村区域范围内环境空气中二噁英污染物主要来源于该垃圾焚烧炉。     

Estimation and field measurement of methane emission from waste landfills in Hanoi, Vietnam

A methodology for estimating the methane emissions from waste landfills in Hanoi, Vietnam, as part of a case study on Asian cities, was derived based on a survey of documents and statistics related to waste management, interviews with persons in charge, and field investigations at landfill sites. The waste management system in Hanoi was analyzed to evaluate the methane emissions from waste landfill sites. The quantity of waste deposited into the landfill was evaluated from an investigation of the waste stream. The composition of municipal waste was surveyed in several districts in the Hanoi city area, and the quantities of degradable organic waste that had been deposited into landfill for the past 15 years were estimated. Field surveys on methane emissions from landfills of different ages (0.5, 2, and 8 years) were conducted and their methane emissions were estimated to be 120, 22.5, and 4.38 ml/min/m², respectively. The first-order reaction rate of methane generation was obtained as 0.51/year. Methane emissions from waste landfills were calculated by a first-order decay model using this emission factor and the amount of landfilled degradable waste. The estimates of methane emissions using the model accorded well with the estimates of the field survey. These results revealed that methane emissions from waste landfills estimated by regional-specific and precise information on the waste stream are essential for accurately determining the behavior of methane emissions from waste landfills in the past, present, and future.     

危险废物焚烧中污染防治的过程控制

危险废物焚烧污染防治的重点在烟气的处理上,一般情况下烟气处理的能力是固定不变的,但焚烧系统焚烧的危险废物是千差万别的,产生的烟气中污染物浓度也是变化很大的,如果不优化废料配给等系统,很难保证烟气经处理后能达标排放。因此危险废物焚烧中污染防治是一个系统工程,需要焚烧过程中各个环节优化控制。本文以一德国企业的危险废物焚烧设备为例,详细论述在编写焚烧日计划、焚烧系统、热能利用系统和烟气处理系统等各环节的污染防治的过程控制。     

Verification results of jet resonance-enhanced multiphoton ionization as a real-time PCDD/F emission monitor

A jet resonance-enhanced multiphoton ionization (REMPI) monitor was tested on a hazardous-waste-fired boiler for its ability to determine concentrations of polychlorinated dibenzodioxins and dibenzofurans (PCDDs/Fs). Jet REMPI is a real-time instrument capable of highly selective and sensitive (from parts per billion to parts per trillion) detection of a broad range of aromatic compounds, including a number of air toxic compounds. The PCDD/F toxic equivalency (TEQ) value was derived from a predetermined correlation (R ² = 0.74) with monochlorobenzene (MClBz). This relationship was applied to nine subsequent jet REMPI on-line measurements of MClBz and parallel, standard extractive sampling for PCDD/F TEQ. For high waste-firing rates, with a range of PCDD/F TEQ values between 3.9 and 6.0 ng TEQ/m³, the TEQ values predicted by jet REMPI had a relative difference of 26% with the standard EPA Method 23 results. At low waste-firing rates (0.9–1.6 ng TEQ/m³), the relative difference increased to 219%. This limited testing shows that jet REMPI has promise as an on-line diagnostic monitor, providing feedback on the effects on PCDD/F emissions of operating parameter changes such as fuel feed interruptions or air pollution control failures.