矿化垃圾床反应器厌氧甲烷氧化协同生物脱氮的研究

垃圾卫生填埋过程中逸散的甲烷与渗滤液处理过程中反硝化段不够彻底产生的硝酸盐对周围环境具有严重的威胁,反硝化厌氧甲烷氧化技术可实现甲烷与硝酸盐的同步去除,极具应用前景.本研究通过模拟垃圾填埋过程,以矿化垃圾作为垃圾填埋的覆土层与反硝化厌氧甲烷氧化微生物的接种源,建立了矿化垃圾床系统.结果表明,反应系统在140d的运行期间...     

多级A/O工艺设计及其在应急污水处理工程中的应用

为有效缓解资阳市第二污水处理厂现状处理能力不足导致的污水溢流问题,改善周边水生态环境,新建了规模为5000 m³/d的应急污水处理工程。该工程采用“多级A/O+磁混凝沉淀”组合工艺,对其中的多级A/O工艺段进行了深化设计,并对本项目的实际运行效果进行了分析。深化设计结果表明,多级A/O反应器级数宜采用2级,流量分配比宜为7∶3,污泥回流比宜为100%。运行期间的监测数据表明,出水指标均满足《四川省岷江、沱江流域水污染物排放标准》(DB51/2311-2016),其中的COD_Cr、TP和TN的去除率分别为96.6%、97.6%和87.2%。通过设置初段硝化液回流,充分发挥初级缺氧池的脱氮能力,使多级A/O工艺的脱氮效率得到了强化。该项目采用的组合工艺简单有效,出水效果好,为城市溢流污水的高标准排放提供了一种更优选择。     

珠江口磨刀门水体中重金属分布、分配特征及其影响因素

本文利用2018年1月盐水上溯期间在磨刀门区域所获得的现场调查资料,分析该区域的重金属污染现状及空间分布特征,探究重金属的迁移转化特点以及盐度等环境因素对重金属分配结果的影响。基于水体盐度及层化水平将研究区域分为淡水区、混合区及咸水区。结果表明,颗粒态与溶解态重金属含量在淡水区与咸水区之间存在显著差异,颗粒态重金属含量均呈现出由陆向海方向随盐度增加而降低的趋势,各元素的空间变异程度依次为Cd>Cr>Zn>Pb>Cu>As>Ni>Co;溶解态Pb、Cr、As、Co浓度沿向海方向呈逐渐升高趋势,而Cd、Cu、Ni、Zn浓度则呈现“低—高—低”的变化特征,各元素的空间变异程度依次为Zn>Cr>Cd>Pb>Cu>Co>As>Ni。重金属的固液分配系数沿向海方向呈逐渐下降趋势,主成分分析结果表明,盐度和悬浮物浓度是影响磨刀门河口重金属分配的主要环境因素。     

盐度变化对崇明东部河口潮滩氮营养盐循环影响实验模拟研究

以长江口咸淡水交互作用最为典型岸段崇明东部潮滩作为研究区域,运用实验模拟方法,定量地研究了盐度变化对潮滩生态系中无机氮的迁移、转化过程的影响。结果发现,盐度升高有利于沉积物中的NH4-N向上覆水扩散,但NO2-N和NO3-N的界面扩散呈现相反的变化趋势;沉积物中可交换态无机氮含量变化特征显示,在盐度变化剧烈的潮滩生态系统内,硝化作用可能是控制沉积物(尤其是表层沉积物)中无机氮分布的重要因素。     

Ni foam/Cu电极电催化还原硝酸盐氮

采用恒流电沉积法制备了泡沫镍/铜（Ni foam/Cu）电极.以Ni foam/Cu电极为阴极、Ti/RuO₂-Ir₂O₃电极为阳极构建电解体系,对水中硝酸盐氮进行电催化还原处理.并研究了电解质对总氮和氨氮去除率的影响和电极的稳定性.在一定范围内,增大电解质NaCl的浓度可以提高总氮和氨氮去除率.当NaCl浓度为0.5 g·L^-1时,在电解电流密度为8 mA·cm^-2的条件下对100 mg·L^-1 NO₃^--N溶液进行6次重复电解实验,2.5 h后硝酸盐氮去除率均可以达到94.5%以上.当NaCl浓度为1.25 g·L^-1时,在电解电流密度为8 mA·cm^-2的条件下对100 mg·L^-1 NO₃^--N溶液电解2.5 h,出水中氨氮浓度只有2.90 mg·L^-1,总氮去除率达到79....     

聚酰胺微塑料对大肠杆菌和脱氮副球菌的毒性

微塑料对环境微生物的毒性尚不清楚.本研究通过生长曲线测试、活性氧(ROS)生成、无机氮转化效率和塑料添加剂检测,探究了聚酰胺(PA)微塑料对典型环境微生物—大肠杆菌和脱氮副球菌生长的影响.PA微塑料对大肠杆菌的毒性与其浓度呈正相关,高浓度PA(100mg·L-1)微塑料对大肠杆菌和脱氮副球菌的生长均产生了显著抑制,胞内...     

中国农田肥料N2O直接和间接排放重新评估

农田肥料(氮肥、复合肥、有机肥)是我国N₂O最大的排放源,其估计直接决定了排放总量的可靠性.为此,重新评估了中国农田肥料N₂O的直接和间接排放,选择2008年县域尺度活动数据、具有空间分异性的本土排放因子和参数来重新评估其排放规模、结构、空间格局及不确定性;通过与IPCC、EDGAR等国内外研究结果的对比分析,阐述该排放清单的可靠性和全面性.结果表明,2008年我国农田肥料N₂O排放总量为617.1 Gg(处于213.7~1149.2 Gg之间),其中,氮肥直接排放为458.8 Gg(74.5%),有机肥直接排放为121.0 Gg(19.6%),挥发沉降和淋溶径流造成的间接排放分别为28.0 Gg(4.5%)和9.3 Gg(仅占1.5%左右).排放集中在华北平原、东北的松辽平原、华中的淮河流域和四川盆地,以及华南的珠三角、雷州半岛和台湾地区的县(区、市、旗),主要分布在江苏(52.4 Gg)、四川(48.0 Gg)、湖北(43.2 Gg)、广东(40.8 Gg)、河南(39.6 Gg)、安徽(38.4 Gg)、湖南(31.6 Gg)、山东(28.9 Gg),其累积规模为全国总量的52%,其中,近50%的贡献源于164个县(区、市、旗).本排放清单具有更高的准确度和空间分辨率,而基于IPCC (2006)排放因子及参数的估计排放总量高估了约8.3%,对直接排放和间接排放则分别低估了12.5%和高估了330%.此外,在空间格局上还表现出高值区低估和低值区高估的特点,在491和1225个县(区、市、旗)的相对偏差超过了100%和50%,特别指出的是,间接排放在大部分县(区、市、旗)的相对偏差达到135%左右.     

Responses of chlorophyll fluorescence and nitrogen level of Leymus chinensis seedling to changes of soil moisture and temperature

Controlled experiment of Leymus chinensis seedlings grown in the environmental growth chambers at 3 soil moisture levels and 3 temperature levels was conducted in order to improve the understanding how leaf photosynthetic parameters will respond to climatic change. The results indicated that soil drought and high temperature decreased the photochemical efficiency of photosystem ( Fw/Fm ), the overall photochemical quantum yield of PSIl(yield), the coefficient of photochemical fluorescence quenching(qp), but increased the coefficient of non-photochemical fluorescence quenching( q, ). Severe soil drought would decrease Fv/Fm and yield by 3.12% and 37.04% under 26% condition, respectively, and 6.60% and 73.33% under 32% condition, respectively,suggesting that higher temperature may enhance the negative effects of soil drought. All the soil drought treatments resulted in the decline in leaf nitrogen content. There was no significant effect of temperature on leaf nitrogen level,but higher temperature significantly reduced the root nitrogen content and the ratio of root nitrogen to leaf nitrogen,indicating the different strategies of adaptation to soil drought and temperature. It was also implied that higher temperature would enhance the effect of soil drought on leaf photosynthetic capacity, decrease the adaptability of Leymus chinensis to drought.     

Assessment on the pollution of nitrogen and phosphorus of Beijing surface water based on GIS system and multivariate statistical approaches

This paper presented the characteristics of nitrogen and phosphorus pollution in Beijing surface water during the survey. A significant difference was found out in concentration distribution of various parameters of nitrogen and phosphorus. Most water bodies in five water systems were polluted by total nitrogen with the content even up to 120 mg/L which was higher than exceeded the fifth class standard of national surface water quality standard GB3838-2002 except for several segments of Chaobaihe and Yongdinghe. Ammonia and phosphorus showed a similar tendency of distribution with higher content in Daqinghe, Beiyunhe and Jiyunhe water systems, but with relatively low concentrations in Chaobaihe and Yongdinghe water systems. Meanwhile, nitrate was found at comparatively low content (mostly less than 10 mg/L) and could fit for corresponding water quality requirements. Totally, the water quality of Daqinghe, Jiyunhe and Beiyunhe river systems as well as the lower reaches of Yongdinghe and Chaobaihe was contaminated seriously with high content of total nitrogen and phosphorus. Through multivariate statistical approaches, it can be concluded that total nitrogen, ammonia and total phosphorus was highly correlated to chemical oxygen demand, biochemical oxygen demand, dissolved oxygen and electrical conductivity,which explained the same pollution source from anthropogenic activities.     

Using a zeolite medium biofilter to remove organic pollutant and ammonia simultaneously

IntroductionWatershortageproblemisquiteseriousinmanycitiesofChina .Thereuseofmunicipalwastewaterisoneofthekeymethodstoreleasethisproblem .Makeupwaterforrecirculatingcoolingsystemisthelargestwaterusageinmanyfactories .Thewaterqualitystandardsforreclaimedwa…