中国海峡西岸城市群冬季PM2.5和PM10中水溶性离子的污染特征

为了研究中国海峡西岸城市群冬季大气颗粒物水溶性离子的污染特征,采集该区域8个城市共14个采样点位(包含1个背景点)的PM2.5和PM2.5~10样品,采用离子色谱分析F-、Cl-、NO3-、SO42-、Na+、K+、NH4+、Ca2+和Mg2+ 9种水溶性离子的质量浓度.结果表明,海峡西岸城市群冬季大气颗粒物污染严重,PM2.5和PM10的日均值分别为89.65,135.65μg/m3,PM2.5占PM10的66.1%.城区水溶性无机离子主要集中在PM2.5上,其浓度分布存在空间差异,温州地区水溶性无机离子浓度处于较高水平;SO42-、NO3-和NH4+是水溶性无机离子的主要贡献者,其占PM2.5 中水溶性离子总量的79.6%~89.0%,占PM10的74.2%~83.4%.由于受冬季季风的影响,该区域非海盐离子对水溶性无机离子的贡献较大.NO3-/SO42-的质量浓度比显示,冬季海峡西岸城市群已处于机动车污染与燃煤污染并存的复合型污染状态.     

餐厨垃圾渗滤液强化城市污泥消化作用研究

针对城市污水厂污泥热值低、C/N比低,厌氧消化效率低的问题,结合餐厨垃圾渗滤液中有机物含量高、C/N比高的特点,研究了城市污泥、餐厨垃圾渗滤液共消化过程.结果表明:垃圾渗滤液的添加促进了污泥厌氧消化甲烷气的产生,添加生、熟垃圾渗滤液的消化污泥累计产甲烷量分别为542 mL、2102 mL,是未添加渗滤液(参照样)的污泥消化产气量的1.2倍、4.6倍,甲烷单位产量分别为261(参照样)、675.8、971.0L·kg-1(以VS计);同污泥单独厌氧消化相比,添加生、熟垃圾渗滤液能强化污泥VS/TS的去除,其去除率分别为15.3%和26.3%;通过共消化,污泥上清液的SCOD去除率均高于90%,出水COD也基本一致,并未因垃圾渗滤液的添加而发生大的波动.污泥与餐厨垃圾渗滤液的共消化能够促进有机物的去除,强化甲烷气的产生,实现了污泥与渗滤液的稳定化、无害化和资源化.     

广州城市绿地土壤特征及其对树木生长的影响

研究广州城市绿地土壤的特征,并探讨其对树木生长的影响。结果表明:广州城市绿地土壤受到不同程度的人为干扰。其中公园和大学校园树林土壤的理化性质虽有一定改变,但仍接近自然土壤的状况;行道树的土壤则过于紧实,且pH值太高,而有机质及氮、磷含量较低。这些土壤问题会对行道树的生长造成不利的影响。文中对这些存在的问题提出了一些相应的改善措施。      

农村生活垃圾管理初探——青树坪镇垃圾污染现状调查分析报告

对湖南省双峰县青树坪镇周边4个村的生活垃圾的产量、成份、特征、污染现状等进行了调查。发现农村生活垃圾得不到及时有效的处理,垃圾中的有毒有害物质进入到土壤、河流中,最终造成农产品减产和品质下降,同时也对农村居民的健康构成威胁。在村设置垃圾收集点,由乡镇负责到各点收集并运送到县垃圾处理厂统一处理的处理模式可以解决此问题。     

基于GIS的武汉城市圈常住人口空间分布研究

结合人口普查数据和GIS手段，系统分析了20世纪90年代以来武汉城市圈常住人口空间分布现状特征，揭示了基于圈层法和方向法的空间分布演变趋势，并从政策、经济、人口迁移、交通方面剖析了导致变化的驱动力因素。     

以回收利甩标准破解“垃圾围城”

生活垃圾处理已经成为各城市面临的难题。在已有研究基础上分析了城市垃圾分类收集存在的严重问题和影响居民实施垃圾分类的关键因素,概述了现有的垃圾分类收集标准和废弃产品回收利用标准内容,最后提出加强实施相关标准、促进垃圾分类收集的建议。     

Impact of Urban Sprawl on Water Quality in Eastern Massachusetts,USA

A study of water quality, land use, and population variations over the past three decades was conducted in eastern Massachusetts to examine the impact of urban sprawl on water quality using geographic information system and statistical analyses. Since 1970, eastern Massachusetts has experienced pronounced urban sprawl, which has a substantial impact on water quality. High spatial correlations are found between water quality indicators (especially specific conductance, dissolved ions, including Ca, Mg, Na, and Cl, and dissolved solid) and urban sprawl indicators. Urbanized watersheds with high population density, high percentage of developed land use, and low per capita developed land use tended to have high concentrations of water pollutants. The impact of urban sprawl also shows clear spatial difference between suburban areas and central cities: The central cities experienced lower increases over time in specific conductance concentration, compared to suburban and rural areas. The impact of urban sprawl on water quality is attributed to the combined effects of population and land-use change. Per capita developed land use is a very important indicator for studying the impact of urban sprawl and improving land use and watershed management, because inclusion of this indicator can better explain the temporal and spatial variations of more water quality parameters than using individual land use or/and population density.     

初始环境温度对餐厨垃圾好氧堆肥过程的影响

为了探索不同初始环境温度对餐厨垃圾堆肥过程和堆肥效率的影响,利用3组卧式可控温堆肥反应器进行了小规模模拟试验.通过测定堆料中水溶性碳氮比、pH值、温度和总有机碳下降率来推断反应进行的程度.试验表明,在堆料初始含水率约55%,水溶性C/N约38∶1,粗灰分质量分数为4%的反应条件下,初始环境温度控制在30℃时,堆料高温期持续时间较短,不能满足堆肥无害化要求;初试环境温度控制在40℃时,能最有效地加快堆料分解时间,缩短堆腐时间,并满足堆肥产品无害化要求;初始环境温度超过50℃,将导致堆肥pH值过低不利于好氧堆肥反应的进行.     

Evaluation and impact factors of indoor and outdoor gas-phase nitrous acid under different environmental conditions

As an important indoor pollutant, nitrous acid (HONO) can contribute to the concentration of indoor OH radicals by photolysis via sunlight penetrating into indoor environments, thus affecting the indoor oxidizing capability. In order to investigate the concentration of indoor HONO and its impact factors, three different indoor environments and two different locations in urban and suburban areas were selected to monitor indoor and outdoor pollutants simultaneously, including HONO, NO, NO₂, nitrogen oxides (NO_x), O₃, and particle mass concentration. In general, the concentration of indoor HONO was higher than that outdoors. In the urban area, indoor HONO with high average concentration (7.10 ppbV) was well-correlated with the temperature. In the suburban area, the concentration of indoor HONO was only about 1-2 ppbV, and had a good correlation with indoor relative humidity. It was mainly attributed to the heterogeneous reaction of NO₂ on indoor surfaces. The sunlight penetrating into indoor environments from outside had a great influence on the concentration of indoor HONO, leading to a concentration of indoor HONO close to that outdoors.     

我国村镇生活垃圾可燃组分基本特征及其时空差异

为了解我国村镇生活垃圾组成特征及采取焚烧处置的可行性,本研究在2015年的春夏秋冬4个季节,对我国12个省份共72个村镇生活垃圾产生源进行采样调查,分析了垃圾全组分和可燃组分的质量分数、含水率以及垃圾热值等参数,进行了地域、季节以及村与镇之间差异分析.结果表明,我国村镇生活垃圾可燃组分质量分数(湿基)由高到低的顺序为:厨余类(13%~53%)橡塑类(10%~18%)纸类(10%~15%)木竹类(0~10%)织物类(0~8%).相同行政区域内村与镇之间生活垃圾组分差异较小,南方村镇生活垃圾全组分的平均含水率大于北方,全国村镇生活垃圾平均含水率为40.1%左右.我国北方生活垃圾热值在4个季节均有81%的村镇超过3 500 k J·kg~(-1),而南方村镇生活垃圾在春、夏、秋、冬这4个季节满足这一条件的村镇分别占44%、50%、61%、72%.垃圾经分选后热值得到提高,但南方村镇春季生活垃圾可燃组分热值仍然偏低,南方其它季节56%以上的村镇和北方全年所有村镇的生活垃圾均能满足焚烧处置的热值要求,故对我国北方农村生活垃圾进行焚烧处置是可行的,而南方村镇生活垃圾需加强前处理工艺.