膜电解氢自养膜生物反应器还原水中的ClO_4~-

考察了膜电解氢自养膜生物反应器在不同水力停留时间(HRT)和电流强度下对饮用水中ClO4-的去除效果。结果表明,在进水ClO4-浓度和电流强度分别为10 mg/L和300 mA的情况下,HRT从12 h降低到4 h,反应器出水ClO4-浓度随HRT的降低呈增大趋势,但运行稳定后去除率均维持在99%以上,出水pH较进水有所增大,但增加幅度随HRT的缩短而减小。当电流强度从100 mA增加到200 mA时,出水ClO4-浓度随电流强度的增大而减小,稳定运行后出水ClO4-浓度低于4μg/L,出水pH受电流强度变化的影响不大。整个运行过程未检测到中间产物ClO3-和ClO2-的存在。     

琼脂碳源生物反硝化去除水源水中硝酸盐

针对受硝酸盐污染的水源水,以琼脂为反硝化细菌的碳源和微生物载体,通过生物反硝化作用脱除水源水中的硝酸盐,并利用曝气生物滤池(BAF)去除琼脂反应器出水中残留的少量CODMn和NO2--N等污染物。实验结果表明,水源水自然接种的条件下,可以顺利启动琼脂反应器;在温度为25℃左右,琼脂反应器在进水NO3--N约25 mg/L、水力停留时间1.5 h时,能获得70%的硝酸盐氮去除率;曝气生物滤池在水力停留时间0.5 h、气水比2.8时,可控制最终出水的CODMn和NO2--N分别在5.0 mg/L和0.10 mg/L以下;琼脂反应器的脱氮效果与温度、进水NO3--N浓度及水力停留时间等有关。研究指出,琼脂反应器与曝气生物滤池构成的组合系统能较好地脱除水源水中的硝酸盐并且能控制最终出水水质,不会导致二次污染,从而获得合格的饮用水源水。     

不同水力停留时间条件下PCL为碳源去除水产养殖水体硝酸盐的效率及微生物群落分析

以可生物降解聚合为碳源的固相反硝化可以避免水产养殖用水硝酸盐处理过程中碳源反复添加、碳源不足或过量等问题。水力停留时间(hydraulic retention time,HRT)是生物反应器运行管理的主要参数之一,用固定膜反应器固相反硝化的方法研究了HRT对以聚己内酯(polycaprolactone,PCL)为碳源的反应器去除循环水养殖系统硝酸氮(浓度为170~197 mg·L~(-1))的效率的影响。研究结果表明不同水力停留时间对硝酸盐去除效率差异显著。在HRT为6 h和8 h时,硝酸盐速率分别为(0.55±0.32)g·(L·d)~(-1)和(1.05±0.33)g·(L·d)~(-1),且出水亚硝氮浓度和氨氮浓度均明显低于进水浓度;在HRT为4 h和2 h时,进出水硝酸盐浓度差异不明显。电子扫描显微镜观察显示PCL表面生物膜主要为杆状菌,应用傅里叶红外扫描观察发现使用前后PCL的化学结构没有发生明显改变。应用高通量方法测定的微生物群落结构表明,62%的细菌为Proteobacteria(62%),在鉴定出的细菌中,食酸菌属(Acidovorax),固氮螺菌属(Azospira),丛毛单胞菌属(Comamonas),代尔夫特菌属(Diaphorobacter),懒小杆属(Ignavibacterium),弗拉特氏菌属(Frateuria)可以同时降解PCL和进行反硝化。     

MBR工艺短硝化反硝化处理生活污水的研究

以模拟生活污水为对象,研究了中温(25～30℃)条件下,膜生物反应器-短硝化反硝化生物脱氮的效果,试验结果表明,在曝气量为0.15 m3/h,pH值为7～8的条件下,出水COD保持在100 mg/L以下(平均49 mg/L),出水氨氮在5.0 mg/L以下(平均3.1 mg/L),NO2-得到了富集,出水中基本监测不出NO3-,总氮去除率平均为86.2%,最高达94.0%,且系统的耐冲击负荷能力较好;曝气量和pH值是短硝化过程的重要影响因素.     

MBBR处理猪场废水厌氧消化液的研究

采用移动床生物膜反应器(MBBR)处理猪场废水厌氧消化液,考察了水力停留时间(HRT),进水COD和NH3-N浓度对反应器处理效果的影响.结果表明,在温度为20～30℃,填料填充比为50%,进水COD和NH3-N浓度分别为1016 mg/L和496 mg/L条件下,当HRT为12.5 h时,COD和NH3-N去除率可分别达到62%和77%,猪场废水厌氧消化液中可生物降解性有机物基本得到去除,当HRT增至23.8 h时,COD和NH3-N去除率分别为64%和86%,出水COD和NH3-N浓度分别为368 mg/L和70 ms/L,均达到了<畜禽养殖业污染物排放标准>(GB18596-2001)的要求.     

高浓度氨氮污泥脱滤液的半硝化实验研究

对高浓度氨氮污泥脱滤液进行了半硝化实验研究。运行结果表明,反应器进水氨氮浓度在402 mg/L、HRT=5.5 h、温度为22～31℃、DO〈1.0 mg/L、pH值在7.4～8.2时,半硝化反应器出水的NO 2--N/NH3-N维持在1.13～1.32,且负荷达到1.76 kg N/（m3.d）,NO2--N/NOx...     

硫自养填充床生物反应器去除水中的高氯酸盐

建立了硫自养填充床生物反应器用于水中Cl O-4的去除,考察水力停留时间(HRT)、水温的影响及副产物产生规律。结果表明,当进水Cl O-4浓度为22.40~21.07 mg/L时,逐步缩短HRT为12、8、4、2、1.5和1 h,经4~6 d的适应期,反应器对其去除率可达99%以上;低浓度的NO-3-N(2.17 mg/L)的存在对Cl O-4的降解不产生抑制,两者可同步去除;3℃以内的水温波动对其去除影响较小,较大的温度波动(-8℃)会造成去除率下降;Cl-作为惟一还原产物,其浓度增多符合化学计量比。同时,研究证实了硫歧化反应的发生,出水SO2-4浓度的增加量大于理论值,S2-离子浓度较低(0.40 mg/L);该反应主要受HRT和水温的影响,缩短HRT,降低温度均有利于抑制该反应的发生。硫自养过程消耗水中碱度,Cl O-4完全去除时,出水p H值比进水降低约1.1个单位。     

CAB-MBR复合反应器实现亚硝化-脱氮除磷的启动研究

将厌氧折流板反应器(ABR)与膜生物反应器(MBR)组合的新型CAB-MBR反应器用于处理生活污水,进行亚硝化的启动研究。研究期间,温度为20~28℃,在HRT为7.5 h、混合液回流比R1和R2分别为200%和100%,DO为1 mg/L的条件下,启动运行了50 d,系统稳定后,NO-2出水浓度在4 mg/L以上,NO-2占NO-x总量的90%,短程反硝化效果良好。对COD、NH+4-N、TN和TP的平均去除率分别为94%、90%、75%和80%,出水平均浓度分别为25、3、9.5和0.7 mg/L。     

碱度指示MBR中同步硝化反硝化的研究

在连续的操作环境下,通过改变在膜生物反应器(MBR)中的C/N和曝气量,研究碱度对同步硝化反硝化脱氮效果的指示作用。结果发现,在反硝化完全的情况下,出水碱度(330~440 mg/L)在硝化过程中较高并与出水TN表现出好的线性关系(Alk=3.22[N]+333.08,R2=0.85);在硝化完全的情况下,出水碱度(60~280 mg/L)在反硝化过程中较低并与出水TN也有很好的线性关系(Alk=-4.93[N]+317.86,R2=0.89)。实际消耗的碱度可以作为另一个指示因子(ΔAlkexper),实际消耗的碱度随出水的NH4+-N浓度升高而降低(ΔAlkexper=-3.85[N]+149.11,R2=0.88,出水NO3--N4.5 mg/L);实际消耗的碱度随出水的NO3--N浓度升高而升高(ΔAlkexper=3.68[N]+161.11,R2=0.88,出水NH4+-N5.5 mg/L)。虽然pH的变化有一定的规律,但是对SND脱氮效果指示不灵敏。     

侧沟式膜泥法一体化OCO工艺中水力停留时间对脱氮除碳的影响

在传统OCO工艺基础上设计了一体化OCO工艺，在厌氧区放置填料，将二沉池和生物反应器合建，并就水力停留时间(HRT)对生物反应器脱氮除碳的影响进行研究。在进水COD为260～360 mg/L，好氧区DO为2 mg/L左右，缺氧区<0.5 mg/L，MLSS为4 500 mg/L左右时，分别研究了不同HRT下的脱氮除碳效果。研究结果表明：随着HRT的逐渐增大，出水COD值无明显波动，COD去除率达到90%以上，出水氨氮随着HRT的增大而降低；但仅当HRT为12 h左右时，氨氮和总氮均有良好的去除效果，去除率分别可达到93%和80%。     

Relationship between ammonia stomatal compensation point and nitrogen metabolism in arable crops: current status of knowledge and potential modelling approaches

The ammonia stomatal compensation point of plants is determined by leaf temperature, ammonium concentration ([NH4+]apo) and pH of the apoplastic solution. The later two depend on the adjacent cells metabolism and on leaf inputs and outputs through the xylem and phloem. Until now only empirical models have been designed to model the ammonia stomatal compensation point, except the model of Riedo et al. (2002. Coupling soil-plant-atmosphere exchange of ammonia with ecosystem functioning in grasslands. Ecological Modelling 158, 83-110), which represents the exchanges between the plant's nitrogen pools. The first step to model the ammonia stomatal compensation point is to adequately model [NH4+]apo. This [NH4+]apo has been studied experimentally, but there are currently no process-based quantitative models describing its relation to plant metabolism and environmental conditions. This study summarizes the processes involved in determining the ammonia stomatal compensation point at the leaf scale and qualitatively evaluates the ability of existing whole plant N and C models to include a model for [NH4+]apo.     

Reduced nitrogen has a greater effect than oxidised nitrogen on dry heathland vegetation

We investigated the effects of different ratios of reduced (NH4+) versus oxidised (NO3(-)) nitrogen in deposition on heathland and species-rich grassland vegetation at high nitrogen deposition levels in large mesocosms filled with nutrient-poor soils to which different NH4+/NO3(-) ratios were applied. The response of the forbs, Antennaria dioica, Arnica montana, Gentiana pneumonanthe, Thymus serpyllum, the grasses Danthonia decumbens, Deschampsia flexuosa, Nardus stricta and the shrub Calluna vulgaris was recorded. The forb A. dioica and the grass D.decumbens preferred low NH4+/NO3(-) ratios and were characterised by a negative correlation between NH4+/NO3(-) ratios and biomass and survival, whereas the grasses N. stricta and D. flexuosa showed no correlation with NH4+/NO3(-) ratios. Lime addition eliminated the negative effects of high NH4+ concentrations in deposition for A. dioica and the grass D. decumbens. The implications of these findings for heathland vegetations are discussed.     

Effects of nickel chloride and oxygen depletion on behaviour and vitality of zebrafish (Danio rerio, Hamilton, 1822) (Pisces, Cypriniformes) embryos and larvae

We examined acute (2 h exposure of 5-day-old larvae) and subchronic (exposure from fertilization up to an age of 11 days) effects of NiCl(2).6H2O on embryos and larvae of zebrafish (Danio rerio), both alone and in combination with oxygen depletion. The following endpoints were recorded: acute exposure: locomotory activity and survival; subchronic exposure: hatching rate, deformations, locomotory activity (at 5, 8 and 11 days) and mortality. In acute exposures nickel chloride (7.5-15 mg Ni/L) caused decreasing locomotory activity. Oxygen depletion (or=10 mg Ni/L resulted in delayed hatching at an age of 96 h, in decreased locomotory activity at an age of 5 days, and increased mortality at an age of 11 days (LC20=9.5 mg Ni/L). The observed LOEC for locomotory activity (7.5 mg Ni/L) is in the range of environmentally relevant concentrations. Since locomotory activity was already affected by acute exposure, this parameter is recommended to supplement commonly recorded endpoints of toxicity.     

负载纳米TiO_2凹凸棒黏土的制备表征及对Mn~(2+)的吸附性能

以溶胶-凝胶法制备了负载纳米TiO2凹凸棒黏土吸附剂,采用SEM、XRD等分析方法对负载纳米TiO2凹凸棒黏土前后的结构进行了表征,并对Mn2+进行了吸附性能的研究。结果表明:经过高温焙烧后的负载纳米TiO2凹凸棒黏土吸附剂较负载前的凹凸棒黏土,因其结构中的结晶水和沸石水脱失,内部孔道面积和表面积增加,活性吸附位点的数量增大,吸附能力有了明显提高。在室温条件下(20~25℃),pH为5~6,吸附平衡时间为120 min时,负载纳米TiO2凹凸棒黏土吸附剂对Mn2+有较好的吸附效果。     

掺Al-TiO2改性膨润土去除微污染水中COD和NH4-N

采用掺Al-TiO2作为改性剂制备改性膨润土,考察了微波辐射功率、辐射时间、TiO2改性剂用量、铝盐掺杂量、pH值对微污染水中COD和NH4-N去除效果的影响。实验表明,微波辐射功率为460 W,辐射时间为8 min,TiO2改性剂用量为1.3 mmol/g,铝盐掺杂量为0.2 mmol/g为最佳制备条件。pH值为6.0,改性膨润土投加量为40 mg/L,沉淀时间为30min时,对微污染水中初始浓度15 mg/L的COD和5 mg/L的NH4-N去除率分别达到92%和59%以上。     

Fe3O4/Ag磁性纳米颗粒去除水中的铅离子

采用水相共沉淀法制备小尺寸磁性Fe₃O₄纳米颗粒,以没食子酸作为还原剂和表面修饰剂,还原Ag[(NH₃)₂]⁺制备出Fe₃O₄/Ag磁性纳米颗粒。研究该磁性纳米颗粒对水溶液中铅离子的吸附行为,研究结果表明,pH为7.0,吸附温度30℃时可得到最好的处理效果,铅的去除率可达99.7%以上,Fe₃O₄/Ag颗粒吸附行为符合二级动力学模型(R² > 0.99)。该磁性纳米颗粒经过多次再生处理后,仍具有很好的吸附效果,表明Fe₃O₄/Ag在水处理方面拥有良好的应用前景。     

用H2O2/Fe3+处理高浓度含甲醛废水的研究

研究采用H₂O₂/Fe³⁺催化氧化处理高浓度含甲醛废水，探讨了双氧水和催化剂投加量、反应pH及反应温度等操作条件对处理效果的影响，并通过酸溶解回用失活催化剂。结果表明，较优的操作条件为：H₂O₂/COD（质量比）=2.2～2.6，Fe³⁺/H₂O₂（摩尔比）=0.048～0.058，反应pH 1.80～2.68，反应温度50℃，反应时间40 min；在上述操作条件下，甲醛去除率达到99%以上，COD去除率达到85%以上。失活的催化剂可通过稀酸溶解后循环使用，其效果与三价铁盐作催化剂的基本相同。采用H₂O₂/Fe³⁺处理含甲醛废水具有比采用H₂O₂/Fe³⁺较优的效果。     

Relationship between (210)Pb(ex) activity and sedimentary organic carbon in sediments of 3 Chinese lakes

This report demonstrates that organic matter was an important factor in lake sediment ²¹⁰Pb_ex dating. Sediment cores from lakes in central and western China with different-trophic levels were collected, and the ²¹⁰Pb_ex activity and total organic carbon (TOC) were measured. The Rock-Eval pyrolysis technique was used to deconvolute TOC into free hydrocarbons (S1), thermally less-stable macromolecular organic matter (S2a), kerogen (S2b), and residual carbon (RC). The results show significant correlations between TOC and ²¹⁰Pb_ex, particularly between S2a and ²¹⁰Pb_ex, in all the sediment cores. This indicated that the algal-derived organic component S2a may play the most important role in controlling the distribution of ²¹⁰Pb_ex. Scavenging by algal-derived organic matter may be the main mechanism. As chronology is the key to the understanding of pollution reconstruction and early diagenesis in sediments, more attention should be paid to the influence of organic matter on ²¹⁰Pb_ex.     

Distribution coefficients (Kd) and desorption rates of Cs and Am in Black Sea sediments

The distribution coefficients (K_d) and desorption rates of ¹³⁷Cs and ²⁴¹Am radionuclides in bottom sediments at different locations in the Black Sea were studied under laboratory conditions. The K_d values were found to be 500 for ¹³⁷Cs and 3800 for ²⁴¹Am at the steady state and described exponential curves. Rapid uptake of the radionuclides occurred during the initial period and little accumulation happened after four days. The desorption rates for ¹³⁷Cs in different bottom sediments were best described by a three-component exponential model. The desorption half-times of ¹³⁷Cs ranged from 26 to 50 d at the slow components. However, the desorption rate of ²⁴¹Am described one component for all sediment samples and desorption half-time was found to be 75 d. In general, the results showed that the ²⁴¹Am radionuclide is more effectively transferred to bottom sediment and has longer turnover time than ¹³⁷Cs under Black Sea conditions.     

负载V2O5-WO3/TiO2掺炭纤维脱除烟气中Hg0

通过固定床实验系统研究烟气脱除零价汞的实验，首先研究了滤袋常用的聚苯硫醚（polyphenylene sulfide，PPS）以及活性炭纤维（activated carbon fiber，ACF）在不同温度、不同气体组分下负载V₂O₅-WO₃/TiO₂催化剂，对模拟燃煤烟气中零价汞（Hg⁰）的脱除效果。然后对比研究了活性炭纤维协同滤袋常用纤维负载催化剂后，对模拟燃煤烟气中Hg⁰的脱除性能。结果表明，在汞蒸气入口浓度为50 μg/m³，纯N₂气氛下，当温度为25℃时，两者脱除率均能达到99%，当温度为200℃，负载催化剂的活性炭纤维脱除率在30%左右，PPS纤维仅为10%左右。在200℃情况下，模拟烟气的组分为N₂+O₂时，2种纤维的Hg⁰脱除率提高了10%~20%，当在混合气体中添加0.01‰后，负载催化剂的PPS纤维Hg⁰脱除率能达到80%，活性炭纤维Hg⁰脱除率能达到98%。当温度为200℃，模拟烟气的组分为N₂+O₂+HCl时，不同性能掺炭纤维负载催化剂后Hg⁰脱除率在69%~95%范围之间变化，其中PPS掺炭纤维对Hg⁰脱除效率最高达到95%，因此，负载V₂O₅-WO₃/TiO₂催化剂的PPS掺炭纤维能在高温烟气中保持较高的Hg⁰脱除率。