Effects of nitrogen sources and glucose on the consumption of ethylene and methane by temperate volcanic forest surface soils

There is limited knowledge with regard to the consumption of ethylene (C2H4) and methane (CH4) in volcanic forest soils containing low microbial carbon-to-organic carbon ratio, and to the responses of both consumptions to nitrogen and carbon additions. Temperate volcanic forest surface soils under three forest stands (e.g. Pinus sylvestris L., Cryptomeria japonica and Quercus serrata) were used to compare CH4 and C2H4 consumption by forest soils, and to study the effects of nitrogen sources and glucose on both consumptions. There was a good parallel between CH4 and C2H4 consumption by for- est soils, but mineralization reduced CH4 consumption rather than C2H4 consumption in forest soils, particularly in a Pinus forest soil. The stimulatory effect of glucose addition on both CH4 and C2H4 consumption by forest soils was increased by increasing the pre-incubation period after glucose addi- tion, and a largest stimulation occurred in the Pinus forest soil. The addition of KNO3-N at the rate of 100 μg·g1 significantly reduced the consumptions of both C2H4 and CH4 by forest soils (P≤0.05). In the presence of urea plus dicyandiamide, the consumption rates of C2H4 and CH4 by forest soils were higher than those in the KNO3-N and urea-N treated soils at the same N rate (P≤0.05), but were similar to those of the control. Hence, under experimental conditions, there was a strong inhibitory effect of NO3 rather than NH4 addition on the CH4 and C2H4 consumption in these forest soils. When amount of the added NO3-N increased up to more than 2―3 times the soil initial NO3-N concentrations, both C2H4 and CH4 consumption rates were reduced to 10%―20% of the rates in soils without nitrate addition. By comparing the three forest stands, it was shown that there was a smallest effective concentration of the added nitrate that could inhibit C2H4 and CH4 consumption in the Pinus forest soil, which indicated that C2H4 and CH4 consumption of the soil was more sensitive to NO3-N addition.     

生物陶粒反应器硝化细菌的分离及硝化特性

采用生物陶粒反应器,在氨氮负荷为0.77~1.33 kg.m-3.d-1的条件下,生物陶粒反应器对氨氮的平均去除率可以达到81.32%,亚硝酸氮积累率基本稳定地保持在91%~99%,试验结果证实了在生物陶粒反应器中可实现稳定的亚硝酸型硝化.从生物陶粒反应器中分离出1株新型异养硝化细菌HSY5,经过生理生化鉴定和16SDNA测序,建立了系统发育树,鉴定出这株菌属于假单胞菌属(Pseudochrobactrum).采用乙酸钠-氯化铵培养基培养细菌进行硝化特性研究,经过12 d好氧培养,总氮和氨氮最终去除率分别为63.78%和80.87%,并且具有产生NO2-N的硝化性能.     

大汶河水系主要河流BOD1-20降解规律的研究

采用实验室测定和数学模拟的方法，对大汶河水系主要河流的CBOD和NBOD降解规律进行了实验室模拟研究，分析了各主要河流的污染现状，为计算大汶河水系的环境容量以及制定相应的污染防治措施提供科学依据．     

石灰性土壤剖面氮素的矿化和硝化作用

以陕西关中灌区红油土和渭北旱塬红垆土为供试土样,研究不同土层氮素的矿化和硝化作用。结果表明,除０－２０ｃｍ土层外,红油土２０－４０ｃｍ及４０－６０ｃｍ土层,红垆土２０－４０ｃｍ土层,仍存在着相当数量的可矿化氮,６０ｃｍ或４０ｃｍ以下低而稳定。铵态氮的硝化作用也具有明显的层次性：６０ｃｍ以上土层硝化作用快,以下慢,这种变化与硝化细菌的分布一致,总体上看,红油土中氮素的矿化和硝化作用强于红垆土。铵态氮     

多孔载体存在下生物脱氮技术

为有效去除污水中的含氮物质 ,在体积为 3.5 L 的鼓泡曝气塔内使用模拟污水 ,研究了同时硝化和反硝化过程。实验过程中 ,在鼓泡曝气塔中投入占总体积 10 %的多孔聚氨酯载体 ,以实现微生物的固定化。实验表明 ,投加载体后 ,实验体系中含氮物质的去除效率明显提高 ;在 16～ 6 4L /h气体体积流量范围内可以在 3h内得到接近于 10 0 %的NH+ 4- N去除率 ;证明了采用补充碳源的方法可以有效提高NH+ 4- N去除率。     

海藻酸钠作为固定化细胞包埋剂的研究

通过正交实验和单因素实验,研究了包菌量,海藻酸钠(SA)浓度,交联时间和小球直径四个因素对海藻酸钠包埋菌株的脱氮性能的影响,并优选出最佳包埋条件.在最佳包埋条件下包埋的脱氮菌株的脱氮性能优于其游离状态下的脱氮性能.     

同步硝化反硝化研究进展

同步硝化反硝化工艺同传统的生物脱氮工艺相比,可以节省碳源,减少曝气量,降低设备运行费用等优点,具有很大的发展前途。文章结合国内外研究,从微环境理论、微生物学理论和中间产物理论方面对同步硝化反硝化的产生机理进行了综述,并分析了同步硝化反硝化的实现条件和影响因素。     

Effects of acetylene at low concentrations on nitrification, mineralization and microbial biomass nitrogen concentrations in forest soils

Temperate forest surface soils at the varying distances from main trunks (e.g., Pinus koraiensis and Quercus mongolica) were used to study the effects of acetylene (C₂H₂) at low concentrations on nitrification, mineralization and microbial biomass N concentrations of the soils, and to assess the contribution of heterotrophic nitrification to nitrous oxide (N₂O) emissions from soils. The use of acetylene at partial pressures within a range from 10 to 100 Pa C₂H₂ in headspace gas gave a significant decrease in N₂O emission at soil moisture of c. 45% water-filled porosity space, and the decrease was almost the same in each soil after exposure of C₂H₂ at low concentrations. Heterotrophic nitrification could account for 21%―48% of total N₂O emission from each soil; the contribution would increase with increasing distances from the Pinus koraiensis trunks rather than from the Quercus mongolica trunks. Under the experimental conditions, the use of C₂H₂ at low concentrations showed no significant influence on soil microbial biomass N, net N mineralization and microbial respiration. However, 100 Pa C₂H₂ in headspace gas could reduce carbon dioxide (CO₂) emissions from soils. According to the rapid consumption of 10 Pa C₂H₂ by forest soils and convenience for laboratory incubations, 50 Pa C₂H₂ in headspace gas can be used to study the origin of N₂O emissions from forest soils under aerobic conditions and the key associated driving mechanisms. The N₂O and CO₂ emissions from the soils at the same distances from the Quercus mongolica trunks were larger than those from the Pinus koraiensis trunks, and both emissions decreased as the distances from trunks increased. The stepwise regression analysis showed that 95% of the variability in soil CO₂ emissions could be accounted for by the concentrations of soil total C and water soluble organic C and soil pH, and that 72% of the variability in soil N₂O emissions could be accounted for by the concentrations of soil total N, exchangeable NH⁺₄-N and microbial biomass N and 25% of the variability in heterotrophic nitrification by the soil microbial biomass N concentration. The emissions of N₂O and CO₂ from forest soils after exposure of C₂H₂ at low concentrations were positively related to the net nitrification of the soils.     

垃圾渗滤液水质特性和处理技术研究

阐述了垃圾渗滤液的来源和水质特点,因为垃圾渗滤液独特的水质特点决定了垃圾渗滤液处理的难度和复杂性。其次,阐述了垃圾渗滤液的处理技术,其中,生物法是主要的处理工艺。重点阐述了厌氧-好氧组合工艺处理垃圾渗滤液的国内外最新研究进展。最后,对垃圾渗滤液的处理技术发展进行展望,提出强化原有的厌氧-好氧处理技术,开发经济、高效的新型治理新技术如短程硝化-厌氧氨氧化耦合工艺。     

包埋活性污泥和反硝化污泥短程硝化反硝化脱氮

以模拟废水为对象,在传统的流化床反应器内,将活性污泥和经驯化的反硝化污泥按适当比例混合后,用聚乙烯醇(PVA)加适当添加剂将其包埋,并对短程硝化反硝化脱氮进行了研究.结果表明,在进水NH4+-N平均为53.60mg/L,COD为281.19mg/L,HRT12h,调控温度、溶解氧、pH等,出水亚硝化率和TN去除率分别可达95%和85%以上,短程硝化反硝化脱氮较理想.当进水COD含量从150mg/L增加到750mg/L,TN去除率从73.66%提高到96.79%.适合包埋颗粒短程硝化反硝化脱氮的最佳溶解氧浓度约为4.0mg/L.当pH一直维持在8.0左右,温度从30℃降到25℃过程中,短程硝化反硝化并未遭破坏.当温度维持在25℃,pH从8.0降到7.5,连续运行约5个周期后,短程硝化反硝转变为全程的硝化反硝化.