铁炭复配修复地下水中NO_3~--N的条件研究

采用了铁炭复配修复地下水中NO3--N,探讨了实验条件对修复效果的影响。结果表明,在pH值近中性条件(初始pH 6.42)下,反应时间为1 h时NO3--N修复率达到60.85%;Fe/C=1∶1时介质最佳用量分别为4~5 g;Fe/C=1/1.5时修复率为72.80%;反应速率在高振荡强度下大于低振荡强度;氧化铜的催化效果最好,可使修复率提高7.5个百分点。铁炭复配介质修复地下水中NO3--N是有效可行的,修复率随反应时间的增加而提高,在Fe/C=1∶1时修复率与介质用量呈正相关,无限减小Fe/C比并不能无限提高修复率,振荡强度对修复具有显著影响,低振荡强度下的修复过程较高强度存在滞后现象,并非所有金属氧化物催化剂对铁炭修复NO3--N均有促进作用。     

厌氧氨氧化ASBR中亚硝氮和氨氮降解规律研究

采用生物膜ASBR反应器,研究了厌氧氨氧化反应过程中亚硝氮与氨氮降解速度的变化规律。结果表明,降解过程主要分为2个阶段:速度上升期(0~30 min)和速度下降期(30~150 min)。一阶指数衰减模型的模拟结果表明,20 min以后亚硝氮、氨氮降解速度逐渐减少,亚硝氮降解速度始终高于氨氮降解速度,但是两者差值随时间逐渐减少。     

介质阻挡放电联合催化臭氧化降解甲苯

采用介质阻挡放电区后结合MnOx/Al2O3/发泡镍去除甲苯,考察甲苯进气方式、臭氧产生方法及湿度对甲苯与O3同时去除的影响。结果表明,O3是等离子体区后催化降解甲苯的主要物种,介质阻挡放电联合催化臭氧化可实现甲苯及O3的同时高效去除。输入电压为9.0 kV时,甲苯的去除效率达92.8%,在80 min内O3的去除效率维持在99%以上。水蒸气对催化剂催化分解臭氧的活性没有直接的影响,O3浓度较高时湿度对甲苯降解效率的影响很小。GC-MS分析结果表明,甲苯降解的主要气相副产物有烷烃、酸、酮和含苯环有机物,提出了甲苯的降解途径。     

无碴轨列车运行引起的环境振动影响评价

对遂渝高速铁路无碴轨道试验段客车运行引起的环境振动进行了现场实测,根据实验数据分析得知:环境振动强度随距离增大而减小,随车速增大而增大,但车厢数量对环境振动强度影响不明显;环境振动主要频率范围为30～120 Hz,距轨道距离、车速、车厢数量对振动主要频率影响不显著;在轨道两侧31.9 m处,速度超过104.7 km/h列车环境振动强度超过GB 10070-1988要求,须采取措施隔振。     

脉冲电解法预处理酸性染料废水

研究了脉冲电解法预处理酸性偶氮类染料废水的处理效果,考察了不同工艺条件对废水COD去除率、脱色率和可生化性的影响。结果表明,脉冲电源峰值电压12 V,频率600 Hz,占空比50%的条件下电解40 min后,COD去除率可达59%,废水脱色率达91.4%,BOD5/COD由0.09提高至0.34。在相同条件下,脉冲电解法的电流效率是直流电解法的2倍左右。与现行常用的铁/碳反应床相比,脉冲电解法在成本上也具有一定的优势,应用前景较好。     

北京和上海典型复合包装废物处置环境影响比较

采用生命周期评价法研究比较了北京和上海两地纸塑铝复合包装处置阶段的环境影响。通过现场和资料调研的方式获得此阶段的能量物质的输入输出和环境外排数据。结果表明:北京和上海两地纸塑铝复合包装处置阶段的环境影响潜值分别为-0.428 Pt和9.776 Pt,其主要集中在气候变化、土地占用和无机物对健康的损害三方面;每提高10%的回收率,其环境影响潜值北京和上海可分别降低5.446 Pt和5.799 Pt;上海地区纸塑铝复合包装处置阶段对环境的影响在任何同回收率的情况都要高于北京地区,其主要原因是上海地区填埋产生的温室气体释放量过大和再生企业距离打包点较远。     

光/电Fenton牺牲阳极法降解有机污染物

采用Fe片为阳极和石墨为阴极,在可见光(λ450 nm)照射并外加电压条件下,以有机染料橙Ⅱ(orangeⅡ)及有机无色小分子2,4-二氯苯酚(2,4-dichlorophenol,DCP)为目标化合物,探讨了光/电Fenton牺牲阳极法降解有机污染物的最佳反应条件,结果表明,在电压=3 V,pH=3.0,H2O2浓度为5×10-5mol/L时,orangeⅡ的降解效果最好,反应10 h矿化率可达到78%,210 min内2,4-DCP降解率为91.4%。通过对光/电Fenton体系原位循环伏安参数测定及过氧化物酶催化反应吸光光度法和苯甲酸荧光分析法检测光/电Fenton降解orange II过程中H2O2和羟基自由基(.OH)的变化,表明orangeⅡ降解过程涉及.OH历程。     

农业化学品投入状况及其对环境的影响

农业生产中,农业化学品的大量使用产生了明显的负外部性影响,尤其是农业的面源污染问题随化肥、农药投入的增加而不断加剧。通过统计分析方法,对农业化学品投入数量及区域分布特征、农业化学品投入存在的问题及其所造成的面源污染问题进行分析。结果表明:化肥和农药总投入不断增加,其中河南、山东、江苏、安徽、湖北和湖南6省投入总额接近全国的一半;农业化学品使用存在过量投入、投入结构失衡和施肥施药技术落后等问题;农业化学投入品的过量使用造成的环境污染问题正不断加剧,农业面源污染排放对污染总量的贡献率不断上升。最后提出了相关政策建议,包括加强农业面源污染控制的政策框架和配套制度建设、推广成熟的化肥农药施用技术和加强农业环保教育。     

Occurrence, distribution, and sources of six phenolic endocrine disrupting chemicals in the 22 river estuaries around Dianchi Lake in China

The objectives of this study are to track the occurrence, distribution, and sources of phenolic endocrine disrupting compounds (EDCs) in the 22 rivers around Dianchi Lake in China, to estimate the input and output amounts of phenolic EDCs in the water system, and to provide more comprehensive fundamental data for risk assessment and contamination control of phenolic EDCs in aquatic environment. Six phenolic EDCs were systematically evaluated in water and surface sediment in the estuaries of those rivers. The water and sediment samples were preconcentrated by solid-phase extraction system and microwave-assisted extraction system, respectively. Phenolic EDCs were analyzed by GC-MS (Thermo Fisher Scientific, USA) after derivatization. Phenolic EDCs were found ubiquitously in the aquatic environment. The total concentrations ranged from 248 to 4,650 ng/L in water, and 113 to 3,576 ng/g dry weight in surface sediment. The residue amount of phenolic EDCs in Dianchi Lake was 258 kg/a. Concentrations of the phenolic EDCs in the Lake decreased with increase in distance to the estuaries of those rivers which run through urban and industrial areas. The rivers seriously contaminated by phenolic EDCs were Xin River, Yunliang River, Chuanfang River, Cailian River, Jinjia River, Zhengda River, and Daqing River which run through the old area of Kunming City. Satisfying correlations were observed between the concentrations of the target compounds in water and in surface sediment. NP1EO, NP2EO, and BPA were identified as the three predominant phenolic EDCs. There were significant correlations between phenolic EDCs and many basic water quality parameters. Urban and industrial areas are the major contributors for phenolic EDCs, especially in Kunming City. Compositional profiles of phenolic EDCs in surface sediment were similar to those in river water. The concentrations of phenolic EDCs in the rivers located in the northwest part of the valley were very high, and posed a potential risk to aquatic organisms and even human. The concentrations of NP2EO, NP1EO, and BPA were at moderate levels of other areas. The basic water quality parameters (TOC, TN, DO, and pH) play important roles on the distribution, fate, and behavior of phenolic EDCs in the valley.     

Spatial and temporal trend of Chinese manure nutrient pollution and assimilation capacity of cropland and grassland

Dynamics of livestock and poultry manure nutrient was analyzed at a provincial scale from 2002 to 2008. The nutrient capacity of 18 kinds of croplands and grasslands to assimilate nutrients was assessed in the same temporal–spatial scale. Manure nitrogen (N) had increased from 5.111 to 6.228 million tons (MT), while manure phosphorus (P) increased from 1.382 to 1.607 MT. Manure N and P share similar spatial patterns of yields, but proportion of specialized livestock husbandry and contribution of leading livestock categories (swine, cattle, cow, sheep, layer chicken, broiler chicken) were different. The nutrients generated from dominant seven provinces took more than about half of total manure N in China. After subtracting the chemical fertilizers, there were some manure nutrient capacities in western part of China. Risk analysis of manure nutrient pollution overload in eastern and southern parts of China was serious, which should restrict livestock's developments. Amount of chemical fertilizers applied should be reduced to make room for manure nutrients. For the sake of greenhouse effects, the emission of methane (CH₄) and nitrous oxide (NO _x ) emissions in China is serious for the global change, thus merits further statistics and studies. The spatial and temporal pattern of Chinese manure nutrient pollution from livestock and the assimilation capacity of cropland and grassland can provide useful information for policy development on Chinese soil environment and livestock.