降雨径流时农田沟渠水体中氮、磷迁移转化规律研究

为有效阻控降雨条件下农田土壤流失氮、磷通过沟渠进入水体,通过对降雨时农田排水沟渠系统中总氮、总磷的测定和分析,研究降雨径流下沟渠系统水体中氮、磷的迁移转化规律和时空分布.结果表明,农田排水沟渠系统本身不太稳定,在外界条件(降雨)的作用下可以引起一系列的变化,同时农田排水沟渠系统又具有抗冲击可修复能力,可以使氮、磷的各项转化作用恢复.该特征使得总氮、总磷在沿程迁移过程中表现出一定的变化规律:总氮浓度沿程呈3次多项式曲线变化,总磷浓度整体呈指数递减变化;同时各断面的总氮、总磷自身转化也有其降解规律,总氮和总磷浓度随时间均呈3次多项式曲线变化.     

海南省大气污染源排放清单及环境影响研究

基于海南省2016年工业环境统计数据,通过自下而上的方法建立海南省2016年工业大气污染源排放清单,并利用中国多尺度排放清单模型(MEIC)排放清单进行背景源补充,使用CALPUFF模型进行大气污染模拟。污染物排放清单结果显示,2016年海南省SO_2、NO_x、CO、PM_(2.5)、PM(10)、黑碳(BC)、有机碳(OC)、挥发性有机物(VOCs)和NH3的排放量分别为1.50×10~4、5.10×10~4、4.56×10~5、2.34×10~4、2.10×10~4、3.50×10~3、1.20×10~4、4.96×10~4、6.50×10~4 t,其中SO_2主要排放源为化石燃料固定燃烧源(分担率66.67%),NO_x主要排放源为交通源(分担率51.18%),CO、PM_(10)、PM_(2.5)主要排放源为生活源(分担率分别59.01%、81.28%和87.62%),VOCs主要排放源为工业溶剂使用源(分担率75.91%),NH_3主要排放源为农业源(分担率93.54%)。排放量较大的区域集中在儋州市、澄迈县一带。SO_2、NO_x年均最大浓度均出现在海口市,PM_(10)、PM_(2.5)年均最大浓度均出现在定安县。交通源对全省污染物浓度贡献突出,工业源虽然对颗粒物浓度贡献率较低,但仍需加强PM_(2.5)治理。     

中国屠宰行业的总氮减排趋势分析

屠宰行业是总氮排放的重点行业,但由于缺乏监测,该行业的总氮排放量尚无法准确估算。通过对屠宰废水相关排放标准的国内外对比、行业总氮产排污状况以及水污染防治技术等的分析,预测了中国"十三五"期间屠宰行业的总氮排放量,并对屠宰行业的总氮减排机制进行了深入探讨。     

雨水收集系统结合自循环系统下的景观湖体氮磷特征

为评估采用雨水作为城市景观湖体补充水源的富营养化发生风险,以天津文化中心景观湖为研究案例,分析了其典型的2套运营系统:雨水收集系统(雨水经沉淀井、蓄水模块和垂直潜流湿地进入景观湖)和中心湖水体的循环及净化系统(湖水抽排至垂直潜流湿地再进入景观湖)中景观湖的氮磷浓度变化规律。采用2015年3—10月的长期监测,研究湖中氮磷营养盐的时间变化趋势以及形态变化规律,提取影响湖中氮磷浓度的因素。结果表明:2015年3—10月景观湖中总氮和总磷平均浓度分别为(1.551±0.491)mg·L~(-1)和(0.058±0.029)mg·L~(-1),溶解态氮和磷分别占71.7%和50%,系统运行稳定时总氮和总磷浓度主要分布在1.0~1.3 mg·L~(-1)和0.029~0.05 mg·L~(-1)之间;总体上,溶解态氮为湖水中氮存在的主要形式,而磷则主要以颗粒态形式存在,在降雨条件下,部分污染物随着降雨冲刷进入湖体,因此景观湖中溶解态磷的浓度增高;湿地是否稳定运行是影响景观湖中总氮、溶解态氮以及总磷浓度的因素,而降雨条件是影响景观湖体的总磷浓度以及溶解态磷浓度的因素;景观湖的富营养化风险较低,降雨期间进入湖体的溶解态磷是最大的风险因子。     

无砾石微孔管地下渗滤系统处理生活污水的中试研究

进行了无砾石微孔管地下渗滤系统处理生活污水的中试研究。基于不同土壤、不同管径、不同植物的协同效应,对比研究了不同系统处理污水中有机物、氮、磷和SS的去除效果及其影响因素。结果表明,不同土壤、不同管径及不同植物组成的系统,对生活污水中有机物、氮、磷和SS的去除效果差别较大。中试系统对COD、总磷、氨氮、总氮和SS的最佳去除率分别达到86.13%、90.20%、61.24%、65.49%和97.43%,对应的出水COD、总磷、氨氮、总氮和SS的平均浓度分别为64.29、0.69、22.13、26.19和5.56 mg/L。分析表明,进水SS浓度过高、外界温度下降等共同作用是导致系统对生活污水中NH4+-N和TN的去除率相对较低的主要原因。     

A/A/O工艺脱氮除磷运行效果分析

为提高城市污水处理厂科学运行管理水平和出水质量,通过对某污水处理厂污水处理工艺的沿程采样分析,对比分析了A/A/O工艺脱氮除磷效果与工艺运行控制参数之间的相关关系。结果表明,A/A/O工艺对总氮去除率为83.2%,出水中氮的形态主要为硝酸盐氮;出水中总磷浓度基本达到一级A标准,总磷去除率在86.3%以上;缺氧段具有明显...     

三峡库区大宁河流域非点源污染研究

以大宁河流域巫溪水文站控制流域为研究对象,应用分布式非点源污染模型SWAT,利用实测流量、泥沙负荷及氮、磷负荷数据对模型进行了率定和验证,并模拟了大宁河流域的径流量和营养物质氮、磷的排放.结果表明,月平均流量在率定期和验证期的效率系数分别达到了0.93和0.62;泥沙负荷的效率系数分别为0.70和0.34;氨氮和总磷的效率系数分别达到了0.31和0.37.大宁河流域污染物质的排放存在着较大的空间差异,有机氮和有机磷的5年平均排放量区间分别为2.01～38.15和0.35～5.89 ks/(hm2·a),其中,流域西南部子流域的有机氮和有机磷平均排放量最大,分别为38.15和5.89 ks/(hm2·a),是大宁河流域污染物排放的最敏感区域.     

碳氮磷比例失调城市污水的同步脱氮除磷

为解决现行同步脱氮除磷工艺处理南方地区碳、氮、磷比例失调城市污水中,因C/N、C/P偏低,碳源不足而降低脱氮除磷效率的难题,试验以碳源偏低的广州市城市污水为研究对象,采用厌氧/好氧交替运行的SBR系统,通过对厌氧、好氧时段的合理调控,在无需额外添加碳源的条件下,有机物、氨氮、总氮和总磷的平均去除率分别可达90%、72%、41%和99%,不仅能使有机物和氮的出水指标达到国家排放标准,而且总磷出水浓度能达0.5 mg/L以下。通过进一步分析同步高效脱氮除磷的影响因素和控制条件,得出合理污泥龄的控制是实现同步脱氮除磷的关键,厌氧/好氧交替运行的方式不仅强化了磷的释放和吸收,而且降低了碳源偏低和硝酸盐对同步脱氮除磷影响的结论。     

纺织行业水污染物排放量的关键影响要素研究

分析了2005—2012年纺织行业单位产品的用水量、主要水污染物排放强度和排放浓度的变化趋势,并采用灰色关联度分析方法,对各要素与行业主要水污染物排放量进行了关联分析。结果显示,2005—2012年中国纺织行业主要水污染物的排放强度显著下降,2012年COD和氨氮的排放强度分别为5.93、0.41kg/t,相比2005年分别下降了51.9%和39.7%。与纺织行业COD排放量变化最为密切的指标是单位产品的废水排放量、单位产品取水量与单位产品COD排放量,说明纺织行业生产工艺的提升对行业COD排放量的降低有较为密切的关系。与氨氮排放量变化最为密切的指标是单位企业产品产量、氨氮平均排放浓度与总量类指标,说明企业规模、末端治理工艺与氨氮排放量有较为密切的关系。     

天津市工业源挥发性有机物排放清单及区域分布研究

基于典型工业企业自主申报数据,采用排放因子法,建立了天津市工业源VOCs排放清单。经计算,天津市2014年工业源VOCs排放量为16.52万t,其中VOCs生产环节、储运和运输环节、以VOCs为原料的工艺过程、含VOCs产品的使用和排放环节以及其他环节的VOCs排放量分别为12.94万、0.07万、0.63万、1.80万、1.08万t,对天津市工业源VOCs排放总量的贡献率分别为78.33%、0.42%、3.81%、10.90%、6.54%。滨海新区工业源VOCs排放量最大,对天津市工业源VOCs排放总量的贡献率达88.25%,其中大港、临港经济区和天津经济技术开发区为滨海新区工业源VOCs排放的主要功能区。     

“十三五”总氮、总磷总量控制政策建议

近几年,总量减排作为环境保护的重要抓手,以COD和氨氮等主要水污染物为控制指标,不断推进,取得了显著的成效。截至2013年,中国COD和氨氮较2010年分别下降了7.81%和7.11%,水环境质量明显改善。随着总量减排工作的持续推进,COD和氨氮的排放总量基本得到有效控制,相应的环境污染问题也得到明显缓解,但总氮、总磷等新的环境污染问题开始凸显。重点分析了中国总氮、总磷总量控制的必要性和可行性,并提出相应的总量控制政策的建议。     

Global total ozone dynamics

An overview of the ozone issues is given including the following aspects: 1. The impact of tropospheric ozone on climate as a greenhouse gas (GHG), 2. Solar activity effects on TO and ozone concentration vertical profiles in both the troposphere and stratosphere (in cases of solar radiation absorption by the stratosphere, an unexpected problem arises via a coupling between processes of increased absorption due to “bursts” of solar activity and an enhanced destruction of ozone molecules due to the same increase resulting in weakening UV radiation absorption) and 3. Surface ozone concentration variations under conditions of polluted urban atmospheres which lead to episodes of photochemical smog formation (dangerous for human health).     

Conservative heavy metal total discharge schemes

Currently, according to Taiwan’s Water Pollution Control Act, the environmental control of waterbodies and water quality depends on the effluent standards and the standard of water quality in the rivers. The Act demands that each stationary pollution source comply with the effluent standard before being discharged into the rivers, and that the overall water quality in the river shall not exceed the declared standard of water quality. To improve the condition of the waterbodies and water quality of the rivers, the Environmental Protection Administration (EPA) in Taiwan has made stricter regulations concerning the discharge standard. Such regulations will help to reduce the weight of individual pollutants discharged; the discharged wastewater, however, will still gradually worsen the water quality of the rivers even after complying with the effluent standard since some of the pollutant dischargers may decrease the concentration of pollutants by diluting the water before discharging; thus, the total weight of metals discharged in the rivers will not be reduced, and the water quality in the areas where the pollutant sources are concentrated will not thereby be significantly improved. To protect the irrigation water and farmlands from being polluted by discharged heavy metals in industrial wastewater, the EPA started controlling the sources in accordance with the total quantity control (TQC) as defined in the Water Pollution Control Act, in the hope of perfecting the environmental protection of waterbodies and water quality, as well as ensuring clean water sources without any pollution for the rivers, land, and people.     

Comparison of measured total suspended particulate matter concentrations using tapered element oscillating microbalance and a total suspended particulate sampler

A comparison of the concentration of the total suspended particulate (TSP) matter measured by the tapered element oscillating microbalance (TEOM) monitor and the isokinetic TSP samplers developed at the University of Illinois was carried out in several types of confinement livestock buildings. In a majority of the measurements done, the dust concentration measured by the TEOM monitor was lower than the University of Illinois at Urbana-Champaign (UIUC) isokinetic TSP sampler; the TEOM monitor tended to underestimate the total dust concentration by as much as 54%. The difference in measurements can be attributed to the sampling efficiency of the TEOM monitor sampling head and the loss of some semivolatile compounds and particle-bound water because of heating of the TEOM monitor sampling stream to 50 degrees C. Although several articles in the literature supported the latter argument, this study did not investigate the effect of heating the sampling stream or the effect of moisture on the relative difference in dust concentration measurements. The model that best describes the relationship between the two methods was site specific, that is, the linear regression model was applicable only to four of the sites monitored. The measured total dust concentration in livestock buildings range from approximately 300 to 4000 microg/m3; a higher correlation coefficient between TEOM-TSP and UIUC-TSP monitors was obtained in swine facilities than those obtained in a laying facility.     

Prediction of mixture toxicity with its total hydrophobicity

Based on the C18 Empore disk/water partition coefficient of a mixture, quantitative structure-activity relationships (QSARs) are presented, which are used to predict the toxicity of mixed halogenated benzenes to P. phosphoreum. The predicted toxicity of 10 other related mixtures based on the QSAR model, agree well with the observed data with r2 = 0.973, SE = 0.113 and F = 287.785 at a level of significance P < 0.0001. The joint effect of these chemicals is simple similar action and the toxicity of the mixtures can be predicted from total hydrophobicity and is independent of hydrophobicity of the components or the ratio of the individual chemicals.     

Charge density of total organic carbon in Finnish lakes

Ion balance calculations were used to estimate the charge density of total organic carbon (TOC) and for calibrating the model of Oliver et al. (1983) for Finnish lakes. The database consisted of samples collected in the autumn of 1987 from 955 randomly selected lakes covering the whole country. Organic anion concentrations were estimated as the difference between Sigma cations and Sigma inorganic anions. The charge density of TOC was estimated by dividing the organic anion concentration by TOC. The median charge density was 7.5 microeq (mg TOC)(-1). In lakes with pH values lower than 4.5 the average charge density was 5.2 microeq (mg TOC)(-1) and it increased to 10.3 microeq (mg TOC)(-1) in lakes with pH higher than or equal to 7.0. The calibrated model explained 79% of the observed variability in organic anion concentration. The value for the total amount of acidic functional groups per mol organic carbon in the model of Oliver et al. (1983) was slightly higher compared to the Finnish calibration. At pH values higher than 4.4 the Finnish calibration gives lower organic anion concentrations compared to the model of Oliver et al. (1983).