Atmospheric gaseous organic acids in winter in a rural site of the North China Plain

Organic acids are important contributors to the acidity of atmospheric precipitation,but their existence in the Chinese atmosphere is largely unclear.In this study,twelve atmospheric gaseous organic acids,including C₁-C₉ alkanoic acids,methacrylic acid,pyruvic acid,and benzoic acid,were observed in the suburb of Wangdu,Hebei Province,a typical rural site in the northern China plain from 16^th December,2018 to 22^nd January,2019,using a Vocus@Proton-Trans...     

Start-up of PN-anammox system under low inoculation quantity and its restoration after low-loading rate shock

• PN-A was start-up under low inoculation amount and a higher NRR was achieved. • PN-anammox system was successfully restored by aggressive sludge discharge. • Increase in granular sludge was the important factor to rapid recovery. • Enrichment of AOB and AnAOB in granular sludge favors the stable operation. Partial nitritation (PN)-anaerobic ammonium oxidation (anammox) is a promising pathway for the biological treatment of wastewater. However, the destruction of the system caused by excessive accumulation of nitrate in long-term operation remains a challenge. In this study, PN-anammox was initialized with low inoculation quantity in an air-lift reactor. The nitrogen removal rate of 0.71 kgN/(m³·d) was obtained, which was far higher than the seed sludge (0.3 kgN/(m³·d)). Thereafter, excess nitrate build-up was observed under low-loading conditions, and recovery strategies for the PN-anammox system were investigated. Experimental results suggest that increasing the nitrogen loading rate as well as the concentration of free ammonium failed to effectively suppress the nitrite oxidation bacteria (NOB) after the PN-anammox system was disrupted. Afterwards, effluent back-flow was added into the reactor to control the up-flow velocity. As a result, an aggressive discharge of sludge that promoted the synergetic growth of functional bacteria was achieved, leading to the successful restoration of the PN-anammox system. The partial nitritation and anammox activity were in balance, and an increase in nitrogen removal rate up to 1.07 kgN/(m³·d) was obtained with a nitrogen removal efficiency of 82.4% after recovery. Besides, the proportion of granular sludge (over 200 mm) increased from 33.67% to 82.82%. Ammonium oxidation bacteria (AOB) along with anammox bacteria were enriched in the granular sludge during the recovery period, which was crucial for the recovery and stable operation of the PN-anammox system.     

UASB-MBR组合工艺处理黄连素废水的中试

为实现黄连素废水的规模化处理,针对黄连素废水可生化性差、有机污染物浓度高等特点,采用UASB-MBR(升流式厌氧污泥床-膜生物反应器)组合工艺,利用微生物的生化反应去除废水中的高浓度有机物和黄连素,考察在不同HRT(水力停留时间)下COD_Cr和黄连素的去除效果,并采用GC-MS(气相色谱-质谱联用仪)对系统进、出水中的特征污染物进行分析. 结果表明:①在UASB与MBR的HRT分别为96、66 h,84、58 h,72、50 h,60、41 h,以及进水ρ(COD_Cr)和ρ(黄连素)分别为2 030.0~3 660.0和19.0~400.0 mg/L的条件下,COD_Cr和黄连素的平均去除率均可达到90.0%以上,出水ρ(COD_Cr)平均值低于150.0 mg/L,ρ(黄连素)平均值低于4.0 mg/L. ②UASB与MBR的HRT分别为72、50 h为最佳运行条件. ③UASB可以明显降低废水中特征污染物的种类和浓度,UASB出水经MBR处理后,废水中的11种主要特征污染物均得到有效降解.      

大气14CO2的加速器质谱分析技术研究进展

利用加速器质谱技术测定大气¹⁴CO₂以示踪大气化石源CO₂成为当前减污降碳工作的热点。该文从加速器质谱¹⁴C分析基础出发,系统介绍了加速器质谱的工作原理、大气样品的采集及纯化、石墨化样品的制备和测定,阐述了大气碳监测领域14 CO₂测试的研究进展。随着加速器质谱技术的不断发展,大气¹⁴CO₂的研究将会更加广泛和深入,有助于进一步认识大气化石源CO₂的来源,更有针对性地开展减污降碳工作。未来应统一制定¹⁴CO₂监测方法标准,规范操作流程和质控手段,完善实验仪器配套设施,加快提升监测能力和水平。     

重金属Cd污染对旱田土壤微生物群落的影响

以太原市土堂村的旱田土壤为例,研究了Cd胁迫下对土壤微生物数量的影响。实验结果表明,在Cd质量浓度逐渐增加到10 mg/kg时的单一胁迫下,细菌依然呈显著的正相关;在Cd处于较低浓度时,放线菌和真菌呈正相关,但当质量浓度达到10 mg/kg时,放线菌和真菌开始受到抑制。Cd胁迫下对土壤生物活性的抑制率由大到小为细菌放线菌真菌。从三大菌的总数上看,随着重金属污染时间的增加,细菌、放线菌、真菌三大菌总数逐渐减少。     

母体暴露环境浓度盐酸四环素对F1代斑马鱼胚胎骨骼发育的影响

抗生素被广泛应用于兽药和饲料添加剂中,尤其是四环素等广谱抗生素,长期滥用于养殖业中.四环素是目前用量最大、应用范围最广泛的一种抗生素.抗生素在体内蓄积,或者以原型随粪便排入环境中,造成环境污染.实验用斑马鱼为模式动物来评价低浓度四环素对斑马鱼下一代(F1)发育的毒性影响.选取4月龄亲代斑马鱼(F0),分别给予0.1、1...     

广西典型岩溶地区重金属在土壤-农作物系统中累积特征及其影响因素

为了揭示碳酸盐岩区土重金属高背景值区土壤-农作物系统中重金属的迁移和累积特征,选择广西典型碳酸盐岩高背景值区,系统采集了大宗农作物及其配套耕层土145组,分析了耕层土壤和农作物中As、Cd、Cr、Pb、Hg、Cu、Ni、Zn的含量,并通过统计分析、计算生物富集因子及相关分析等方法,开展重金属元素在典型岩溶区土壤-农作物...     

溶藻细菌HSY-03对赤潮异弯藻抗氧化系统的影响

为研究溶藻细菌HSY-03(Bacillus sp.)对赤潮异弯藻的溶藻机制,采用不同浓度HSY-03无菌上清液处理赤潮异弯藻藻细胞,测定藻细胞光合色素含量、叶绿素荧光效率、细胞内部活性氧(ROS)水平和抗氧化系统活性变化.结果表明,HSY-03无菌上清液作用24 h之后,赤潮异弯藻叶绿素a含量、类胡萝卜素含量和最大光...     

行政区域环境风险评估与管理--以泉州市惠安县为例

随着经济高速发展,环境问题逐步显现,突发环境事件时有发生,开展以环境风险评估为基石的主动风险管理势在必行。本文以泉州市惠安县为例,基于行政区域环境风险指数评估方法,构建评估指标体系,结合评估区域环境风险特征,计算全县环境风险指数,绘制风险等级分布图,并提出管理建议[1]。     

基于STIRPAT模型的黑龙江省碳排放影响因素研究

2005年以来,黑龙江省社会经济持续稳步发展,截至2017年,全省GDP达到15903亿元,增长近3倍,人均GDP增长2.89倍,城镇化率达到60%,第三产业占全省生产总值比重达到55.82%。与此同时,全省碳排放量从19095万吨增加到27251万吨,增长1.43倍。通过对黑龙江省13年间社会经济数据的系统分析研判,人均GDP、城镇化率、碳排放强度等因素对全省碳排放量影响显著。