控制ORP实现连续流反应器部分亚硝化稳定运行

利用ORP在线监控设备,研究了控制ORP值实现连续流部分亚硝化反应器稳定运行的可行性,并使出水水质满足厌氧氨氧化需求.结果表明,在亚硝氮与氨氮比值、温度和pH值恒定的条件下,反应器内ORP值波动主要由于DO浓度波动引起.在稳定的亚硝化系统中,当ORP值大于250mV左右时,反应器出水亚硝氮与氨氮比值大于2.1;当ORP值控制在150mV左右时,反应器出水亚硝氮与氨氮比值稳定在1.2~1.3之间.ORP值控制在120mV时,反应器出水亚硝氮与氨氮浓度比值为0.9~1.06.将ORP值控制在150mV时,随着进水氨氮浓度由300mg/L提高至813mg/L,反应器出水亚硝氮与氨氮比值基本维持在1.1~1.3之间.但随之增加的游离氨浓度易导致亚硝化菌活性抑制.因此,在低氧环境下ORP作为连续流部分亚硝化反应器亚硝化程度的控制指标,其灵敏度和精度明显优于DO监测设备.     

森林经营主体的碳汇供给潜力差异及影响因素研究

增加森林碳汇已成为应对气候变化的重要举措。论文基于浙江、江西和福建三省农户和林场的调研数据,以杉木为案例树种,引用生长模型、修正的Faustmann 模型碳密度和价格数据,对单一和碳汇木材复合经营目标下的杉木最佳轮伐期和林地期望值进行了分析,并基于此比较了不同森林经营主体碳汇供给潜力的差异,同时模拟了不同营林成本和利率水平下对森林经营主体碳汇供给差异造成的影响。可以发现,在可能的碳汇林经营模式下,基于目前杉木市场价格远高于碳价格的现实,森林经营主体的经营采伐决策并不会发生明显改变,从而导致在大范围的碳价格变动下碳汇的供给也没有显著增加,这也说明木材收益和碳收益的两个不同经营目标是协调的;林场凭借着规模、技术和资金等资源禀赋优势将成为今后碳汇林的适宜经营和供给主体;从影响因素来看,目前市场利率处于低位徘徊的前提下,即碳汇林地的潜在投资价值巨大,尤其对劣等土地的投资效果明显;理论上营林成本会提升继而导致碳汇供给增加,这反而对于森林固碳有显著正面影响。     

焉耆盆地土壤重金属的污染及潜在生态风险评价

通过采集干旱区典型绿洲-焉耆盆地表层土壤样品,测试其中10种重金属的含量,采用多元统计分析、污染指数法及潜在生态风险指数法研究土壤中重金属的赋存特征、来源及其污染状况和潜在的生态风险.结果表明:焉耆盆地土壤中10种重金属的平均值和最大值均未超过土壤环境质量二级标准,但重金属Zn、Pb、Cu、Ni、As和Cr的最大值超过新疆土壤背景值,超标率分别为8%、7%、11%、9.2%、12%和8.1%. 统计分析表明焉耆盆地土壤中10种重金属的平均含量顺序为: Mn>Zn>Cr>Ni>Cu>Co>Pb>As>Cd>Hg. 研究表明焉耆盆地土壤中重金属Zn、Pb、Hg、Cu之间具有较高的相关性, 主要来源于人为污染;重金属Mn、Co、Cd、Cr、Ni、As之间具有较高的相关性,主要来源于自然地质背景;污染指数评价表明焉耆盆地土壤中10种重金属均未出现污染状况,处于较低的生态风险,但土壤中重金属Pb、Zn、Hg的含量在部分地区相对较高的现象应引起重视.     

舟山本岛大气污染输送过程的数值模拟分析

利用HYSPLIT-4后向轨迹模式和NCEP(美国国家环境预报中心)的2012年GDAS(全球资料同化系统)气象数据,结合NO₂、PM_2.5、PM₁₀和SO₂等常规大气污染物的质量浓度数据,对舟山本岛2012年4月、7月、10月和12月的大气污染输送过程进行了模拟,并通过聚类分析和潜在源区分析〔包括PSCF(潜在源贡献)和CWT(浓度权重轨迹)计算〕,确定大气污染传输路径及影响源区. 结果表明:舟山本岛气流后向轨迹呈明显的季节变化特征,4月主要受来自黄海海面气流轨迹的影响,其占总轨迹数的36.7%,ρ(PM₁₀)为(53.24±24.33)μg/m3;7月以途经琉球群岛和东海气流轨迹为主,占总轨迹数的48.4%,对ρ(NO₂)、ρ(PM_2.5)、ρ(PM₁₀)和ρ(SO₂)贡献分别为(24.63±6.33)、(28.60±4.83)、(52.89±18.76)和(8.67±3.11)μg/m3;10月气流轨迹主要来自于东海海面,占总轨迹数的49.2%;12月气流则主要来自辽宁南部和黄海,占总轨迹数的66.1%,对ρ(NO₂)、ρ(PM_2.5)、ρ(PM₁₀)和ρ(SO₂)贡献分别为(28.48±15.14)、(58.71±14.10)、(69.83±38.94)和(20.83±13.28)μg/m3. 舟山本岛PM_2.5的潜在源主要为毗邻城市间局地污染,集中于浙江沿海城市及杭州湾、上海等地.      

Does the EU ETS cause carbon leakage in European manufacturing?

Carbon leakage is of interest in both academic and policy debates about the effectiveness of unilateral climate policy, especially in Europe, where the EU Emissions Trading System (EU ETS) affects many traded sectors. We review how the literature identifies leakage and the pollution haven effect. We then evaluate whether EU ETS emission costs caused carbon leakage in European manufacturing, using trade flows in embodied carbon and value from the Global Trade Analysis Project (GTAP). We find no evidence that the EU ETS caused carbon leakage.     

Environmental disaster,pollution and infant health: Evidence from the Deepwater Horizon oil spill

In 2010 the Gulf Coast experienced the largest oil spill affecting U.S. waters in history. Evaporating crude oil and dispersant chemicals can cause major health problems. This paper examines the impact of the Deepwater Horizon oil spill on air quality and infant health outcomes. Using U.S. Environmental Protection Agency (EPA) AirData, vital statistics data from National Center for Health Statistics (NCHS), and a difference-in-difference methodology, we find that the oil spill of 2010 increased concentrations of PM2.5, NO2, SO2, and CO in affected coastal counties, increased incidence of low birth weight (<2500 g) and premature born infants (<37 weeks of gestation). Heterogeneity effects reveal more pronounced adverse infant health outcomes for black, Hispanic, less educated, unmarried, and younger mothers. Results are robust to a wide range of controls and robustness checks.     

Trophic mode and organics metabolic characteristic of fungal community in swine manure composting

Fungal trophic modes and substrates utilization ability was observed in composting. Fungi had the higher diversity and more trophic types in thermophilic phase. Fungi had the higher metabolic potential in fresh swine manure and mature production. Redox potential, organics and moisture are main factors impacting fungal community. Composting reduced pathogenic fungi and enrich dung saprotroph fungi in swine manure. The succession of fungal community, trophic mode and metabolic characteristics were evaluated in 60 days composting of swine manure by high-throughput sequencing, FUNGuild and Biolog method, respectively. The result showed that the fungal community diversity reached to the highest level (76 OTUs) in the thermophilic phase of composting, then sustained decline to 15 OTUs after incubation. There were 10 fungal function groups in the raw swine manure. Pathotroph-saprotroph fungi reached to 15.91% on Day-10 but disappeared on Day-60. Dung saprotroph-undefined saprotroph fungi grown from 0.19% to 52.39% during the treatment. The fungal community had more functional groups but the lower substrate degradation rates in the thermophilic phase. The fungal communities on Day-0 and Day-60 had the highest degradation rates of amino acids and polymers, respectively. Redundancy analysis showed that ORP (49.6%), VS/Ash (45.3%) and moisture (39.2%) were the main influence factors on the succession of fungal community in the swine manure composting process.     

古泊善后河水质污染特征及污染来源调查

以2016—2020年古泊善后河国家和省级地表水监测网水质例行监测数据为依据,采用水质指数法(WQI)对古泊善后河水质污染状况进行综合评价;基于水质评价结果,选取影响最大的两项指标COD_Mn和TP,于2020年10月对古泊善后河开展加密监测,调查分析污染来源。结果表明,2016—2020年古泊善后河水质波动变化较大,汛期降雨对水质下降影响明显,COD_Mn、TP、COD_Cr、氟化物和BOD₅是影响古泊善后河水质的主要指标;加密监测期间,古泊善后河干流水质COD_Mn和TP指标浓度分别升高28.9%、38.3%,其中宿迁段升幅显著高于连云港段;支流水质超Ⅲ类比例为22.9%,劣Ⅴ比例为6.3%;部分乡镇生活污水直排和持续降雨将农田中高浓度污染物冲刷进河流支浜,是导致水质下降的主要原因。     

镇江市挥发性有机物污染特征及来源分析

利用镇江市2019年4—10月市区4个空气质量国控站点VOCs监测数据,对大气中70种VOCs的组分特征、时间与区域变化进行分析,并用比值法研究VOCs来源特征。结果表明,4个站点PAMS组分的测定值为17.7 μg/m3~27.5μg/m3,醛酮类组分为15.4 μg/m3~165 μg/m3。各站点VOCs来源侧重点略有不同,主要来源是工业源、交通源、溶剂涂料的使用等。     

湘江大源渡枢纽底泥中镉、铅的污染特征及其潜在生态风险评价

为研究湘江大源渡枢纽底泥中Cd、Pb的污染特征及其生态风险,采集6个断面的18个底泥样品,测定了沉积物中Cd、Pb的总量、化学形态及其生物有效性,并利用地积累指数法和单因子指数法评价其污染程度与等级.结果表明,湘江大源渡枢纽底泥中Cd、Pb存在很强的积累现象,尤其是Cd污染特别严重.各采样点底泥中Cd主要以碳酸盐结合态...