一株戴尔福特菌的异养硝化与好氧反硝化性能研究

通过在好氧反硝化培养基中添加氨氮和在异养硝化培养基中添加硝基氮,研究了从实验室SBR反应器中新分离的一株戴尔福特菌的异养硝化作用与好氧反硝化作用的相互影响.研究表明:加入氨氮后,24 h后的硝基氮去除率最大可提高1.47%,48 h后菌体生长较为旺盛,氨氮去除率则均在90%以上;同时发现加入硝基氮后,菌体生长推迟,但氨氮去除率最大可提高4.16%.异养硝化与好氧反硝化作用之间是相互促进的.此株戴尔福特菌可在同一条件下自身实现同步硝化反硝化,具有一定的工程应用价值.     

Treatment efficiency of integrated vertical-flow constructed wetland for saline wastewater

The integrated vertical-flow constructed wetland(IVCW) was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity(A:10‰ B:20‰,C:30‰),respectively.The removal rates of dissolved organic carbon(DOC),NH3-N and NO3--N dropped 90.4%-48.6%,80.2%-40.3% and 84.8%-60.9%,respectively,when salinity increases from 10‰ to 30‰.The removal rate of TP increased 14%-31.2%,oppositely.A 20-day inflow salinity drastic change shock affective trial was done on units D and E.Unit D was used as a control and irrigated with saline sewage(20‰).Unit E was irrigated with sewage with low salinity(5‰) as a salinity drastic change shock on the third and fourth days.DOC,NH3-N and NO3--N removal efficiency of unit E showed a three-stage process of change,"rapidly decrease,increase beyond the normal standard,and then back to the normal standard".TP removal value was negative during the 2-day shock period.     

生物滞留系统去除氮的影响因素研究

传统雨水生物滞留系统对氮的去除很不稳定,为了提高硝氮和总氮的去除效果,尝试在生物滞留系统底部增加内部淹没区,提供所需的缺氧环境并延长系统内雨水的停留时间,改善系统的除氮能力。对有淹没区运行条件下进水有机物浓度和滞留时间除氮的影响进行了试验。结果表明系统在有淹没区和无淹没区运行条件下,对NH₄₊-N的平均去除率均在90%以上。无淹没区时系统对NO_3--N的去除率为21%。有淹没区时(滞留时间2 h)系统对NO_3--N和TN的去除作用显著提高到74%和78%。淹没运行时进水中COD浓度可以显著影响NO_3--N的去除效果,当COD浓度为0-100 mg/L,NO_3--N(7-9 mg/L)去除率随COD浓度的增加而显著升高。滞留时间对NO_3--N去除效果的影响较为明显,滞留时间从1 h增加到8 h,系统的NO_3--N平均去除率从21%增加到93%。     

流动注射分析法测定水样中的NO2--N和NO3--N

采用流动注射技术测定水样中的NO-/2-N和NO-/3-N.以N-(1-萘基)乙烯二胺盐酸盐和对氨基苯磺酸为显色剂,在540nm下比色测定NO-/2-N的含量.水样中的NO-/3-N,在稀醋酸条件下用锌粉将其预还原成NO-/2-N后,也在上述相同的条件下测定其含量.NO-/2-N的检出限为0.005×10-/6,NO-/3-N的检出限为0.05×10-/6,分析速度为65次/小时.     

Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

The effects of ammonium (NH₄⁺-N ) and nitrate ( NO₃^--N ) were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0—3 cm) of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO₃^- concentration in preculture solution). The results showed that Fe(Ⅱ) concentrations in root tip apoplast of maize were only 20—40 nmol/g FW which accounted for 7%—13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH₄⁺-N or NO₃^--N for 60 min led to an increase of Fe(Ⅱ) in root tip apoplast. NH₄⁺-N led to an increased concentration of Fe(Ⅱ) and exchangeable Fe (Fe(Ⅱ) and Fe (Ⅲ)) in root tips, while NO₃^--N increased FeCN reductase activity. The relationship between pH and Fe fractions, FeCN reductase activity was also discussed.     

不同菠菜基因型硝酸盐积累与氮吸收、利用效率的比较

采用不同硝态氮(NO_3~--N)浓度水培试验,比较4个菠菜基因型(菠10号、菠13号、菠18号及菠57号)硝酸盐积累和氮素利用效率的差异.结果表明,0.5和15 mmol·L-1NO_3~--N浓度水平下,菠13号硝酸盐含量均最高,菠10号硝酸盐含量最低,菠18号硝酸盐含量在低硝态氮处理下与菠13号差异不显著,高硝态氮处理下与菠57号差异不显著,介于菠13号与菠10号之间.菠13号15NO_3~--N吸收速率在高、低硝态氮浓度水平下均显著高于其他基因型,而其氮素生理利用效率(Nut E)、氮素利用效率指数(NUR)显著低于菠18和菠57号;菠18和菠57号地上部分干重(SDW)、硝酸还原酶活性、Nut E、NUR显著高于菠13号和菠10号,而15NO_3~--N吸收速率低于菠13号;菠10号地上部分干重、硝酸还原酶活性、Nut E、NUR显著低于菠18和菠57号,15NO_3~--N吸收速率及氮素吸收效率(Nup E)显著低于菠13号.综上,不同菠菜基因型的硝酸盐积累和氮素利用效率存在差异,供试材料中菠57号在高、低硝态氮浓度下均具有较高的Nut E和较低的硝酸盐含量,可用于菠菜高产优质品种选育.     

Application of Constructed Wetlands on Wastewater Treatment for Aquaculture Ponds

A group of constructed wetlands （CWs） were applied to the recirculating aquaculture system. This study assessed the performance of CWs in treating the aquaculture wastewater, examined the water quality condition of aquaculture ponds and the growth and the survival rate of ＂target＂ species （Ictalurus punctatus and Megalobrama amblycephala）. The results showed that CWs were effective on reducing the concentrations of 5-day biochemical oxygen demand （BOD5, at 70.5%）, total suspended solids （TSS, at 81.9%）, chlorophyll a （Chl-a, at 91.9%）, ammonium （NH4^＋, at 61.5%） and nitrate nitrogen （NOa-N, at 68.0%）. Effect of CWs on phosphate （PO43 -P） removal was relatively lower （at 20.0%）. The concentrations of BODs, TSS, Chl-a, NH4^＋ and TN, TP in the recirculating culture pond were significantly lower than that in the control pond（ p〈0.05 ）. CWs could help to increase total yield, survival rate of the ＂target＂ species and significantly decrease feed conversion ratio （ p〈0.05 ）.     

流型、植物种类和基质厚度对人工湿地去除废水中氨氮的影响

实验模拟人工湿地,以沙、土混合物为基质,比较了水平潜流和垂直流、不同植物、不同基质厚度对氨氮(NH_4~+-N)处理效果的影响,并分别进行了分析。实验表明,水平潜流和垂直流NH_4~+-N去除率分别达到59%和68%,垂直流人工湿地处理效果较好的原因是垂直流为硝化创造了有利的条件。金边吊兰、金钱草、绿萝对NH_4~+-N的平均去除率依次为46%、60%和70%,分析认为根系是影响NH_4~+-N去除效果的主要因素。以金钱草做湿地植物,基质厚度为6 cm时去除效果最好,最大去除率达到74%,表明基质厚度与植物根系长度相适应时,NH_4~+-N的去除效果最佳。研究结果为深化湿地去除NH_4~+-N的理论研究和应用推广提供了支撑。     

The seasonal variations of δ~(18)O , Cl~- , Na~+ , NO_3~- and Ca~(2+) in the snow and firn recovered from Princess Elizabeth Land, Antarctica

Snow and firn samples recovered from two snow pits (2.5 and 4.5m deep) and one 50-m firn core along the route of the 1996/1997 Chinese First Antarctic Inland Traverse Expedition in Princess Elizabeth Land, East Antarctica, have been measured for chemical composition and oxygen isotope ratio. In the two snow pits, the variations of NO3- are partly in phase with that of δ18O, while the variations of Cl~ and Na+ are in inverse phase with that of δ18O. The variations of CI- , Na+ , NO3- and δ18O show obvious seasonal variations and annual stratag-raphy. However, with the depth increasing, the seasonal variations of δ18O are gradually smoothed below 3 m (corresponding to about 10-year mass accumulation) in depth while the seasonal variations of Cl- , Na+ and NO3- are kept fairly well in the whole profile of the 50-m firn core (corresponding to about 250-year mass accumulation). The results provide a useful tool for dating the snow stratum in this region. On the contrary, no obvious seasonal variations of Ca2 + are found in the profiles.     

多层纤维球生物滤池净化工厂化养殖循环水处理

针对传统工厂化循环水养殖系统能耗偏高、工艺复杂等缺点,研发了一种新型多层纤维球生物滤池反应器。该反应器实现了在零换水条件下去除SS和含氮污染物,同时达到高DO出水的效果。结果表明,实验室条件下,自然挂膜的方式使纤维球形成外部好氧、内部缺氧的环境,反应器可以同时完成硝化和反硝化过程。此外,分析了不同水循环率对反应器的影响。在水循环率为3次/d时:NH~+_4-N质量浓度降低到0.2 mg/L,去除率可达到96.15%;NO~-_3-N去除率稳定在70%左右;NO~-_2-N质量浓度低至0.1 mg/L,去除率高达95.82%;出水COD质量浓度降至4.0 mg/L,去除率达到60%以上;SS去除率高达100%。该反应器较好地实现了养殖废水的同步硝化和反硝化过程。     

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.     

Effects of anions on the biosorption of microelement cations by macroalga <Emphasis Type="Italic">Enteromorpha prolifera</Emphasis> in single- and multi-metal systems

The results of research on the effects of anions on the biosorption of microelement cations by the edible marine macroalga Enteromorpha prolifera in singleand multi-metal systems are discussed in this paper. It was shown that the maximum biosorption capacity (qmax) in a single-metal system of Co(II) ions decreased in the following sequence: Cl- (46.0 mg g-1) > SO42- (42.8 mg g-1) > NO3- (41.9 mg g-1). In multi-metal systems, in which the ratios of Cl-, NO3-, and SO42- were 0:0:4, 1:1:2, 3:0:1, and 4:0:0, there were clear differences among the biosorption capacities. In all the examined systems (other than the 0:0:4 system), inhibition of the binding of microelement cations by the macroalga was observed. In all the systems, the highest value of qmax was obtained for Cu(II) cations; the value ranged from 31.9 mg g-1 in 0:0:4 (SO42- only) to 18.2 mg g-1 in 4:0:0 (Cl-only).     

不同种源条件下厌氧氨氧化反应器的启动研究

采用3组平行的sBR系统,分别接种厌氧颗粒污泥与好氧活性污泥的混合污泥、河道底泥与好氧活性污泥的混合污泥以及厌氧消化污泥与好氧活性污泥的混合污泥,以典型城市污水为进水,在相同运行环境下同时运行150～180 d,成功启动厌氧氨氧化装置,氨氮去除率分别达到88%,80%和85%,亚硝氮去除率均达到96%以上.但厌氧消化污泥与好氧活性污泥的混合污泥的启动周期更短,是相对优化的接种污泥.     

Photodegradation of <Emphasis Type="Italic">N</Emphasis>-nitrosodiethylamine in water with UV irradiation

The direct photolysis of N-nitrosodiethylamine （NDEA） in water with ultraviolet （UV） irradiation was investigated. Results showed that NDEA could be completely degraded under the direct UV irradiation. The effects of the experimental conditions, including the initial concentration of NDEA, humic acid and solution pH, were studied. The degradation products of NDEA were identified and quantified with gas chromatography-mass spectrometry （GC-MS） and high performance liquid chromatography （HPLC）. It was confirmed that methylamine （MA）, dimethylamine （DMA）, ethylamine （EA）, diethylamine （DEA）, NO2^- and NO3^- were the main degradation products. The photolysis degradation mechanism of NDEA was also discussed. As a result of N-N bond fission, NDEA was degraded by direct UV irradiation.     

Experimental investigation of incremental reactivity of di-tert-butyl peroxide

Large quantities of di-tert-butyl peroxide (DTBP) have been emitted into the troposphere due to human activities. Its role in the atmospheric photochemical reaction has not been understood. This study presents the results of the photochemical reactions of DTBP and NOx, which have been simulated in a self-made smog chamber under the temperature of (29±1)℃. Both the wall decays of ozone and NO2 could be neglected, compared to the results in simulative experiments. The effective intensity of UV light used in the experiments was 1.28×10-3 s-1, which was expressed by the rate constant of NO2 photolysis in purified air. The reaction mechanism was proposed according to our results and reports of other researchers. The maximum values of incremental reactivity (IR) in the three simulative ex- periments were 9.53×10-2, 5.23×10-2 and 3.78×10-2, respectively. The incremental reactivity decreased with the increase of initial concentrations of DTBP. The IR value of DTBP obtained in this study was comparable to that of acetylene reported in our previous research.     

化肥厂高浓度氨氮废水的处理和回用

在实验室规模研究了通过生成鸟粪石（磷酸铵镁, MAP）去除氨氮工艺条件的影响. 加入磷酸和MgO产生MAP沉淀, pH值对其影响很大, pH值为9.0时氨氮去除效果最好. PO₄^3-, Mg²⁺, NH₄⁺的摩尔比为1 ∶1.5 ∶1时, 氨氮去除率较大并且可较好地回收氨生成鸟粪石. 此外, 物料的加入次序严重影响氨氮的去除. 两步沉淀工艺氨氮去除率达99.1%, 氨回收率为80.1%.     

SBBR反应器SND脱氮的影响因素分析及响应曲面优化

采用活性炭涂层改性悬浮填料,在连续曝气的条件下,考察了SBBR 反应器脱氮性能。结果表明,SBBR反应器表现出良好的同步硝化反硝化（SND）脱氮性能,对NH3-N 和TN 的去除率分别为80．7％和63．1％。典型周期内反应器同步硝化反硝化率可达82．7％。单因素试验发现,脱氮率随着曝气时间狋的增加而增加,随着溶解氧质量浓度ρDO和填料投加量δ增大而先增大后减小。同时,以溶解氧质量浓度、填料投加量和曝气时间为考察因素,脱氮率为评价指标,采用响应曲面法建立了二次多元回归模型。通过模型求解得出最佳工况：溶解氧浓度为2．37 mg／L,填料投加量为40．10％,曝气时间为5．17 h,此时,脱氮率得到最大值为69．28％。验证试验表明,回归模型的预测值与实测值偏差率为1．57％。     

Cu2+对好氧颗粒污泥理化特性的影响分析

以普通活性污泥为接种污泥,葡萄糖和乙酸钠为碳源,在SBR反应器中培养好氧颗粒污泥,考察不同质量浓度Cu2+(0 mg/L、1 mg/L、3 mg/L、5 mg/L和10 mg/L)冲击作用对好氧颗粒污泥理化特性的影响。结果表明,随着Cu2+质量浓度从0 mg/L上升至10 mg/L,好氧颗粒污泥的理化特性均受到不同程度的影响。质量浓度为1 mg/L和3 mg/L的Cu2+对COD和NH+4-N的去除率影响较小,而质量浓度为5 mg/L和10 mg/L的Cu2+对COD和NH+4-N的去除率影响较大。随着Cu2+质量浓度的增加,好氧颗粒污泥的丝状菌逐渐增多,污泥浓度不断下降,沉降性能急剧恶化;密实度降低,结构越来越松散,粒径出现两极分化的现象,而且在质量浓度为10 mg/L的Cu2+作用下颗粒污泥解体。     

城市污水条件下厌氧氨氧化反应器接种污泥筛选

采用2组平行的厌氧序批式反应器（ASBR）,分别以厌氧颗粒污泥、黑臭河道底泥与好氧活性污泥的混合污泥（R1）和厌氧消化污泥、黑臭河道底泥与好氧活性污泥的混合污泥（R2）为污泥源,以实际城市污水为进水,在相同的运行环境下同时运行180~210 d,实验结束取出各自培养的内部污泥进行扫描电镜观察其表面形态.结果表明：2组反应器均成功启动了厌氧氨氧化反应,其中R1反应器在第135天开始表现出厌氧氨氧化活性,在稳定运行阶段所达到的NH₄⁺-N去除率可达到97.35%,NO^-₂-N去除率达到99%以上,并培养出了颗粒污泥,启动时间较长;R2反应器在第102天开始表现出厌氧氨氧化活性并开始稳定运行,稳定阶段NH₄⁺-N平均去除率可达到93.17%,NO^-₂-N去除率也达到99%以上,没有形成颗粒污泥,启动时间更短.电镜结果表明2组ASBR中都可能存在厌氧氨氧化菌.     

Smog chamber studies of ozone formation potentials for isopentane

The incremental reactivity and ozone formation potential of isopentane have been studied with chamber experiments and computer simulations. The chemical mechanism used in the computer simulations is an isopentane sub-mechanism from the Master Chemical Mechanism （MCM）. The results from the chamber experiments suggest that the MCM can well simulate i-C5H12-NOx chamber experiments. The heterogeneous reaction of NO2 and water is an important source for OH radicals in the chamber experiments. The photolysis of HONO is responsible for the initiation of isopentane in photochemical reactions. The reaction rate constant for NO2 → HONO was determined to be 3.9×10-4―5.9×10-3 min-1 by conducting 3 sets of CO-NOx-air irradiations. 5 sets of isopentane-NOx irradiations under different conditions were performed in our chamber. Compared with the experiment with a low relative humidity （RH）, an increase in RH can increase the reaction rate of NO2 with H2O, so that the peak ozone occurs earlier. When isopentane is predominant over NOx, the peak ozone concentration is largely dependent on NOx concentrations.