市政污泥掺烧对生活垃圾焚烧设施烟气中污染物排放的影响

与生活垃圾协同焚烧是污泥处置中最有前景的处置方式,但其对焚烧烟气污染物排放的影响尚未明确。利用生活垃圾焚烧炉开展生活垃圾协同处置市政污泥的试验,研究掺烧5%、10%和15%的市政污泥时焚烧烟气中酸性气体、烟尘、重金属和二噁英等的排放特征。结果表明:与单独焚烧生活垃圾的对照组相比,在各掺烧比例下,烟气中SO_2、HCl、NO_x及烟尘有一定程度的增加,但均未超过GB18485—2014《生活垃圾焚烧污染控制标准》限值;Cu、Hg排放质量浓度明显下降,Cr、Cd波动下降,Pb在高掺烧比时仍远低于限值,Ni增长幅度小于15%;二噁英总量升高,但仍符合标准限值。因此,在掺烧比例不超过15%的情况下,焚烧烟气中污染物排放仍在安全可控范围。     

Sulfate-enhanced degradation of Rhodamine B in the hydrogen peroxide/hydroxylamine system

Environmental Chemistry Letters - Hydroxyl radicals are commonly produced either by metal activation or by using external energy. However, the application of these methods is limited by low working...     

Source attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta Region,China

Estimated anthropogenic Hg emission was 11.9 tons in Pearl River Delta for 2014. Quantifying contributions of emission sources helps to provide control strategies. More attentions should be paid to Hg deposition around the large point sources. Power plant, industrial source and waste incinerator were priorities for control. A coordinated regional Hg emission control was important for controlling pollution. We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PRD) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed.     

Impacts of emissions and meteorological changes on China’s ozone pollution in the warm seasons of 2013 and 2017

O₃ increment is mainly caused by changes in meteorology rather than emissions. Emission reduction is effective to reduce O₃ nationwide, especially in summer. Strengthened NO_x controls are necessary to meet the ambient O₃ standard. We have quantified the impacts of anthropogenic emissions reductions caused by the Air Pollution Control Action Plan and changes in meteorological fields between 2013 and 2017 on the warm-season O₃ concentration in China using a regional 3D chemical transport model. We found that the impact on daily maximum eight-hour (MDA8) O₃ concentration by the meteorological variation that mostly increased O₃ was greater than that from emission reduction, which decreased O₃. Specifically, the control measures implemented since 2013 in China have reduced SO₂, NO_x, PM_2.5, and VOC emissions by 33%, 25%, 30%, and 4% in 2017, while NH₃ emissions have increased by 7%. The changes in anthropogenic emissions lowered MDA8 O₃ by 0.4–3.7 ppb (0.8%–7.6%, varying by region and month), although MDA8 O₃ was increased slightly in some urban areas (i.e. North China) at the beginning/end of warm seasons. Relative to 2013, the average 2 m temperature in 2017 shows increments in North, North-east, East, and South China (0.34℃–0.83℃) and decreases in Central China (0.24℃). The average solar radiation shows increments in North, North-east, and South China (7.0–9.7 w/m²) and decreases in Central, South-west, and North-west China (4.7–10.3 w/m²). The meteorological differences significantly change MDA8 O₃ by -3.5–8.5 ppb (-8.2%–18.8%) with large temporal variations. The average MDA8 O₃ was slightly increased in North, North-east, East, and South China. The response surface model suggests that the O₃ formation regime transfers from NO_x-saturated in April to NO_x-limited in July on average in China.     

松花江水系有机污染的现状

本文介绍了GC、GC/MS、HPLC方法在分析松花江水系有机污染物中的应用。GC/MS、HPLC所用水样在现场处理,而TLC、GC样品在实验室处理。冬夏两次取样,共检出152种有机化合物,其中主要有机污染物55种,PAH_3占19％,氯化物占14％,芳烃占13％,其它占54％。     

Ozone Artifacts and Carbonyl Measurements Using Tenax GR,Tenax TA,Carbopack B,and Carbopack X Adsorbents

Abstract

Four popular thermally desorbable adsorbents used for air sampling (Tenax TA, Tenax GR, Carbopack B, and Carbopack X) are examined for the potential to form artifacts with ozone (O₃) at environmental concentrations. The performance of these adsorbents for the ketone and alde-hyde species identified as O₃-adsorbent artifacts was also characterized, including recovery, linearity, and method detection limits (MDLs). Using gas chromatography/mass spectrometry, 13 different artifacts were identified and confirmed for both Tenax TA and Tenax GR, 9 for Carbopack B, but none for Carbopack X. Several O₃ artifacts not reported previously were identified, including: pentanal, 3-hexanone, 2-hexanone, hexanal, 3-heptanone, and heptanal with Tenax TA; pentanal, 3-hexanone, 2-hexanone, hexanal, and 3-heptanone on Tenax GR; and 1-octene and 1-nonene with Carbopack B. Levels of straight-chain aldehyde artifacts rapidly diminished after a few cycles of adsorbent conditioning/O₃ exposure, and concentrations could be predicted using a first-order model. Phenyl-substituted carbonyl artifacts (benzalde-hyde and acetophenone) persisted on Tenax TA and GR even after 10 O₃ exposure-conditioning cycles. O₃ breakthrough through the adsorbent bed was most rapid in adsorbents that yielded the highest levels of artifacts. Overall, artifact composition and concentration are shown to depend on O₃ concentration and dose, conditioning method, and adsorbent type and age. Calibrations showed good linearity, and most compounds had reasonable recoveries, for example, 90 ±15% for Tenax TA, 97 ±23% for Tenax GR, 101 ±24% for Carbopack B, and 79 ±25% (91 ±9% for n-aldehydes) for Carbopack X. Benzeneacetaldehyde recovery was notably poorer (22–63% across the four adsorbents). MDLs for several compounds were relatively high, up to 5 ng. By accounting for both artifact formation and method performance, this work helps to identify which carbonyl compounds can be measured using thermally desorbable adsorbents and which may be prone to bias because of the formation of O_3- adsorbent artifacts.     

Performances of mesophilic anaerobic digestion systems treating poultry mortalities

Abstract

A closed‐loop anaerobic digestion system consisting of a leachbed (LB) and an upflow anaerobic sludge blanket (UASB) was tested as an alternative for the disposal of poultry mortalities. This paper compares the performances of three LB‐UASB treatment systems with different initial moisture contents in the LBs. Each LB was loaded with one chicken and 5, 10 or 18 liters of water. The LBs initially carried out the hydrolysis/acidification phase while the UASBs the methanogenesis phase. Due to repeated inoculation by the UASBs, the LBs with 10 and 18 liters of water started producing methane on day 5, while the one with 5 liters of water on day 19. However, methane production rates were low before day 40 for the LB with 10 liters of water and day 60 for the other LBs. Methane production gradually improved as the LBs continued to receive ungranulated sludge from the UASBs. The LBs eventually became balanced methane reactors. Continued balanced fermentation in the LBs resulted in leachates with very low substrate concentrations that could no longer support high‐rate methanogenesis in the UASBs. Consequently, methane production rates from the UASBs decreased quickly while that from the LBs reached peak levels. Cumulative methane production from each LB eventually exceeded that from its connecting UASB. After 118 days of digestion, 414, 437 and 470 liters of methane were produced from the three systems, respectively. Cumulative methane production from the LBs with 5 and 18 liters of water accounted for 63% of the total methane produced from their respective systems. The LB with 10 liters of water produced 75% of the total methane from that system. Methane yields ranged from 0.485 to 0.554 m³ (Kg TS) ¹. About 86% of the initial dry weight was biodegraded. All three systems performed very well with little operational problems. Overall, the system that started with 10 liters of water in the LB performed the best. Strategy for enhancing system performances and implementing farm applications are discussed.     

Mass transfer coefficients for volatilization of polychlorinated biphenyls from the Hudson River,New York measured using micrometeorological approaches

Air–water exchange is an important process controlling the fate of many organic chemicals in the environment. Modeling this process is hampered by the lack of direct observations. Thus, the purpose of this work was to derive direct measurements of the mass transfer coefficients for air–water exchange (v_aw) of polychlorinated biphenyls (PCBs) that may be used to check the validity of values derived from tracer gas experiments. v_aw values for PCBs were determined using previously published turbulent fluxes divided by the corresponding dissolved phase concentrations. The median v_aw values for each homolog decreased with increasing molecular weight and ranged from 0.29 for hexachlorobiphenyls to 2.2 m d^?1 for monochlorobiphenyls with a propagated uncertainty of about 70%, lower than in previous studies. Due to relatively low wind speeds and possible sorption of PCBs to colloids, these numbers may be biased low. These field measurements of v_aw differ by as much as a factor of 23 from predictions based on the widely-used Whitman two-film model. Therefore a new formulation for the calculation of v_aw based on field measurements is needed. This study demonstrates that micrometeorological approaches are a viable option for the measurement of v_aw for hydrophobic organics such as PCBs and should be used to generate enough field data on the air–water exchange of hydrophobic organics to allow the development of new predictive models.     

乌鲁木齐市降尘的浓度水平和空间分布及与城市PM_(10)的相关性分析

以2005—2009年乌鲁木齐市城市大气降尘数据为依据,对乌鲁木齐市城市自然降尘的浓度水平和变化规律进行了研究,用Arc-GIS绘出乌鲁木齐市城市自然降尘的空间分布图,并分析和探讨了城市降尘与PM10相关性及防治对策。