钻井废弃液中石油污染物及细菌生态多样性

采用GC/MS分析方法,发现平湖油田钻井废弃液中含有烃类、酸类和酯类等23种有机污染物质,含量达到49 800 mg/L。运用16S rRNA基因分析法测得的微生物生态多样性表明,废弃液中微生物种类丰富,包括γ和β变形杆菌,γ-Proteobacteria是优势菌群,占克隆总数78.6%。Oceanospirillales、Pseudomonadales和Enterobacteriales是γ-Proteobacteria纲的主要菌群。     

有机肥与化肥的生产能耗、投入成本和环境效益比较分析——以污泥堆肥生产有机肥为例

针对目前国内肥料生产和施用现状,分别从能耗、成本和污染物排放等三个方面对有机肥和化肥进行比较分析。化肥生产呈现高能耗和高污染排放,而有机肥则表现为低能耗、无污染的特点,同时还可消纳废弃物,减轻污染负荷。从投入成本上分析,化肥相对于有机肥具有一定优势,其单位面积和折纯养分投入分别是有机肥的53%和26%。有机肥相对于化肥,其污染物排放负荷很低。从节能减排和降低投入的角度,提出支持基于废弃物资源化的有机肥产业化发展。     

Nitrogen-retaining property of compost in an aerobic thermophilic composting reactor for the sanitary disposal of human feces

Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems. As the products of composting can be utilized as a fertilizer, it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost. In this study, batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces. Attention was paid to the characteristics of nitrogen transformation. Under the controlled conditions of temperature at 60°C, moisture content at 60%,anda continuous air supply, more than 70% fecal organic removal was obtained, while merely 17% fecal nitrogen loss was observed over a two-week composting period. The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content. The fecal NH₄-N which was the main component of the inorganic nitrogen ( > 90%) decreased rapidly in the first day, decreased at a slower rate over the following days, and finally disappeared entirely. The depletion of NH₄-N was accompanied by the accumulation of NH₃ gas in the ammonia absorber connected to the reactor. A mass balance between the exhausted NH₃ gas and the fecal NH₄-N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss. Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.     

Development of pretreatment protocol for DNA extraction from biofilm attached to biologic activated carbon (BAC) granules

The biologic activated carbon (BAC) process is widely used in drinking water treatments. A comprehensive molecular analysis of the microbial community structure provides very helpful data to improve the reactor performance. However, the bottleneck of deoxyribonucleic acid (DNA) extraction from BAC attached biofilm has to be solved since the conventional procedure was unsuccessful due to firm biomass attachment and adsorption capacity of the BAC granules. In this study, five pretreatments were compared, and adding skim milk followed by ultrasonic vibration was proven to be the optimal choice. This protocol was further tested using the vertical BAC samples from the full-scale biofilter of Pinghu Water Plant. The results showed the DNA yielded a range of 40 μg·g^-1 BAC (dry weight) to over 100 μg·g^-1 BAC (dry weight), which were consistent with the biomass distribution. All results suggested that the final protocol could produce qualified genomic DNA as a template from the BAC filter for downstream molecular biology researches.     

木麻黄根区土壤理化特性及酶活性与青枯病发生关联分析

为探究木麻黄(Casuarina spp.)根区土壤理化特性及酶活性与青枯病发生的关系,进而为加强生物防治提供参考.选取位于广东省潮州市饶平县大埕镇、湛江市吴川市塘尾镇和湛江市徐闻县前山镇的3个木麻黄人工林为研究对象,在每个林分下分别设置3个样地,每个样地采集木麻黄青枯病感病植株和健康植株根区土壤各3份,共54个土壤样...     

Bacterial diversity in activated sludge from a consecutively aerated submerged membrane bioreactor treating domestic wastewater

The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were a?l...     

农村黑臭水体沉积物细菌群落结构特征

沉积物微生物是农村黑臭水体物质循环和有机物降解等过程的主要驱动者,其群落结构组成常因外界环境的微小变化而变化.以菏泽市东明县29个农村黑臭水体为研究对象,测定农村黑臭水体上覆水和沉积物氮、磷及重金属等污染物指标,结合Illumina测序结果,分析农村黑臭水体沉积物细菌群落组成和多样性特征及其与环境因子的相关性.结果表明,该区域农村黑臭水体上覆水和沉积物中污染物分布范围均较广.与农业面源相比,以农村生活污水为主要污染来源的农村黑臭水体上覆水中氮、磷污染物浓度更高,分别是农业面源的3.1倍和1.5倍.此外,该区域农村黑臭水体沉积物中重金属含量处于较低水平,普遍低于菏泽市土壤元素背景值.该区域农村黑臭水体沉积物细菌群落的优势菌门为变形菌门、放线菌门、绿弯菌门、厚壁菌门和酸杆菌门,这5种优势菌门的序列总和占全部序列的70.3%～83.6%.γ-变形菌纲、α-变形菌纲、厌氧绳菌纲和放线菌纲是沉积物细菌群落的优势菌纲;硫杆菌属和假节杆菌属是其优势菌属.Spearman相关性分析结果表明,环境因子中DO、 COD、 TN、 TP和有机质对农村黑臭水体沉积物细菌菌属有显著影响(P<0.05),沉...     

岩溶湿地与稻田土壤团聚体细菌群落结构的比较

研究湿地系统中的土地利用变化对土壤团聚体中细菌群落结构的影响,可以为阐明土地利用变化对湿地土壤团聚体稳定性的影响机制提供理论依据.以会仙岩溶湿地和稻田为研究对象,利用高通量测序技术和生态网络分析对土壤团聚体（大团聚体0.25~2 mm、微团聚体0.053~0.25 mm和粉、黏粒<0.053 mm）细菌群落结构进行研究.结果表明：①微团聚体在稻田中占29.64%,显著高于其在天然湿地中的占比（22.20%）.②门水平上,绿弯菌门在稻田土壤大团聚体、微团聚体和粉、黏粒中的相对丰度分别为7.97%、8.56%和7.40%,显著高于其在天然湿地这3种粒径团聚体中的相对丰度（4.93%、4.81%和3.76%）;目水平上,厌氧绳菌目在稻田这3种粒径团聚体中的相对丰度分别为2.35%、3.03%和2.65%,显著高于其在天然湿地这3种粒径团聚体中的相对丰度（0.92%、0.91%和0.43%）.③生态网络分析显示,稻田微团聚体和粉、黏粒网络的节点数、边数和平均邻居数均高于天然湿地,并且在这两种组分中网络的平均连通度更大,特征路径长度更短;稻田大团聚体网络具有更长的特征路径长度、更高的模块性.结果表明,天然湿地改变为稻田后,土壤团聚体细菌群落结构改变,稻田微团聚体和粉、黏粒中细菌群落具有更高的物质循环和信息传递的效率,而稻田大团聚体细菌网络紧密性低,模块性高,其细菌群落结构更稳定.     

生物炭对盐碱土壤氨挥发的影响

为探明生物炭对黄河三角洲盐碱土壤氨(NH_3)挥发的影响,通过室内连续培养的方式,先测定改良的通气法对土壤NH_3挥发的回收率,再对比施加肥料颗粒与肥料水溶液对土壤NH_3挥发的影响,最后探究生物炭的种类、添加量及施肥种类对NH_3挥发速率和总量的影响.结果表明,以硫酸铵为氮源进行的NH_3挥发捕集实验,NH_3回收率平均值高达100. 30%.在相同施氮量下,施加尿素水溶液的处理比施加尿素颗粒的处理NH_3挥发减少了60. 29%,施加硫酸铵水溶液的处理比施加硫酸铵颗粒的处理NH_3挥发减少了61. 40%.相较于不添加生物炭只施用硫酸铵水溶液的空白处理,添加0. 5%生物炭且施加生物炭种类为水稻300℃(RB-300)、水稻600℃(RB-600)、棉花300℃(CB-300)和棉花600℃(CB-600)的处理,NH_3挥发总量分别减少了18. 68%、16. 16%、9. 35%和8. 26%,且施肥后2d内NH_3挥发速率最大,占总挥发量的53. 80%～64. 02%.添加生物炭后,NH_3挥发量随生物炭添加量的增加呈现出先降低后增加的趋势.因此,田间施肥前添加少量生物炭并结合水肥一体化管理技术,可以有效地减少NH_3挥发并提高氮肥利用率.     

Estimating the volatilization of ammonia from synthetic nitrogenous fertilizers used in China

Although it has long been recognized that significant amounts of nitrogen, typically in the form of ammonia (NH(3)) applied as fertilizer, are lost to the atmosphere, accurate estimates are lacking for many locations. In this study, a detailed, bottom-up method for estimating NH(3) emissions from synthetic fertilizers in China was used. The total amount emitted in 2005 in China was estimated to be 3.55 Tg NH(3)-N, with an uncertainty of ± 50%. This estimate was considerably lower than previously published values. Emissions from urea and ammonium bicarbonate accounted for 64.3% and 26.5%, respectively, of the 2005 total. The NH(3) emission inventory incorporated 2448 county-level data points, categorized on a monthly basis, and was developed with more accurate activity levels and emission factors than had been used in previous assessments. There was considerable variability in the emissions within a province. The NH(3) emissions generally peaked in the spring and summer, accounting for 30.1% and 48.8%, respectively, of total emissions in 2005. The peaks correlated with crop planting and fertilization schedules. The NH(3) regional distribution pattern showed strong correspondence with planting techniques and local arable land areas. The regions with the highest atmospheric losses are located in eastern China, especially the North China Plain and the Taihu region.