MAP法处理氨氮废水最佳条件的研究

MAP法是一种比较新颖有效的处理氨氮的方法，该方法是通过化学沉淀的方式使废水中的氨氢浓度降到很低。而且沉淀反应不受温度、水中毒素的限制。由单项试验以及正交实验的方法对MAP法处理氨氮废水的工艺进行优化研究，结果表明，在pH=8.5，反应时间为3h,Mg:N:P=1:3:1.0:1.1时为较佳反应条件；氨氮的去除率随着反应时间的增加而增加，随着Mg:N比值的增加而增加。     

Ammonia large scale atmospheric dispersion experiments in industrial configurations

A programme of large-scale experiments for atmospheric dispersion was carried out by INERIS over a period extending from December 1996 to April 1997. The objectives of the test campaign were to measure anhydrous ammonia concentrations in a range of few meters to 2 km from the release, in order to generate data to be used to improve 2-phase discharge and dispersion modelling.

The discharges were released from a 6-tonne storage tank of pressurised liquid ammonia and through a discharge device with an outlet diameter of 2 in. Fifteen trials were carried out with various release configurations corresponding to industrial situations (impinging jets on the ground and on a wall at various distances, release through a flange without seal…). The quantity of ammonia discharged from the liquid phase varied according to the tests, from 1.4 to 3.5 tons for durations between 7 and 14 min and, therefore, at flow rates between 2 and 4.5 kg/s. Approximately 200 sensors were settled downwind to measure ammonia concentrations and temperature in the plume. These tests showed that for discharges with identical flow rates the distances corresponding to the same concentration vary a lot according to the configurations. These distances tend to be reduced by the presence of obstacles or retention dikes that collected liquid ammonia. In the paper, the main experimental results are presented. In order to enable the comparisons with numerical predictions, more detailed information are given in [Bouet R. (1999). Ammoniac—Essais de dispersion atmosphérique à grande échelle. INERIS rapport, ref INERIS-DRA-RBo-1999-20410 (available at http://www.ineris.fr/recherches/recherches.htm).     

Effects of free ammonia on volatile fatty acid accumulation and process performance in the anaerobic digestion of two typical bio-wastes

The effect of free ammonia on volatile fatty acid(VFA)accumulation and process instability was studied using a lab-scale anaerobic digester fed by two typical bio-wastes:fruit and vegetable waste(FVW)and food waste(FW)at 35°C with an organic loading rate(OLR)of 3.0 kg VS/(m~3·day). The inhibitory effects of free ammonia on methanogenesis were observed due to the low C/N ratio of each substrate(15.6 and 17.2,respectively). A high concentration of free ammonia inhibited methanogenesis resulting in the accumulation of VFAs and a low methane yield. In the inhibited state,acetate accumulated more quickly than propionate and was the main type of accumulated VFA. The co-accumulation of ammonia and VFAs led to an "inhibited steady state" and the ammonia was the main inhibitory substance that triggered the process perturbation. By statistical significance test and VFA fluctuation ratio analysis,the free ammonia inhibition threshold was identified as 45 mg/L. Moreover,propionate,iso-butyrate and valerate were determined to be the three most sensitive VFA parameters that were subject to ammonia inhibition.     

人造沸石负载纳米氧化镁同步脱氮除磷的研究

氮、磷是引发水体富营养化的限制性因素,控制水体中的氮、磷总量可以有效抑制水体富营养化的产生。以人造沸石为研究对象,探究不同改性方法对人造沸石同步去除水中氮、磷的影响。主要工艺为高温碱(NaOH)浸改善沸石结构,高温盐浸(MgCl)负载纳米态氧化镁。结果表明改性的最佳条件为:两阶段的烘干温度45℃;NaOH溶2+3-液浓度0.5 mol/L;MgCl溶液的浓度1 mol/L。对NH-N和PO的去除效率分别可达到83.76%和74.24%。对人造沸石2 4 4的热稳定性进行了实验,其烧失量达40.6%。最后,对吸附饱和的人造沸石进行脱附实验,脱附剂的选择为NaCl、KCl以及+3-两者的混合液。NaCl对NH4+-N和PO43-都有较为明显的脱附效果,脱附率分别可达84.54%和59.35%。     

厌氧氨氧化工艺脱氮及其污泥形态的研究

为研究厌氧氨氧化工艺对高浓度含氮废水的脱氮性能,在以聚乙烯海绵作为填料的上流式厌氧固定床反应器中利用人工配置高浓度含氮废水进行了实验研究.实验中通过添加充足无机碳源,实现了厌氧氨氧化反应器在总氮浓度900～1 210 mg/L长期稳定的运行,脱氮效率在80％以上,最高氮负荷为5.9 kg/m3·d.结果表明:充足的无机碳源在一定程度上可有效地降低高浓度亚硝氮对厌氧氨氧化菌的抑制作用.通过对污泥性状的研究,明确寻找出污泥上浮的原因所在.通过Stover-Kincannon模型确定系统动力学参数KB和Umax分别为30.2 g/L·d和2L2g/L·d,这将有助于对该厌氧氨氧化系统各控制条件的有效调节和准确设定,也为日后应用于实际工程中提供重要的理论依据.     

浅析黑龙江省松花江入境水质指标的变化规律

在黑龙江省松花江入境断面(肇源断面)内选择监测点,对不同月份的水体中化学需氧量、总磷、氨氮和粪大肠菌群数量的动态监测。结果表明,不同时期河流中的化学需氧量、总磷、氨氮和粪大肠菌群数量变化趋势不同,在夏季时化学需氧量和总磷的浓度较高,而氨氮的浓度在1月份较高,粪大肠菌群数量在8月份最大。     

两类微生物燃料电池治理硝酸盐废水的实验研究

采用二氧化铅阴极单室微生物燃料电池(MFC)和双室MFC,以葡萄糖为唯一电子供体,系统研究了两类微生物燃料电池的产电性能和去除硝酸盐的情况.结果表明,双室MFC闭合后,阳极室降解葡萄糖产生的电子可通过外电路传递到阴极,在生物的作用下,NO3--N得到电子被还原,平均反硝化速率达3.77 mg·L-1·d-1.双室MFC...     

V2O5/TiO2催化剂脱除NO的研究

采用了等体积浸渍法制备二氧化钛负载钒氧化物催化剂（V2O5/TiO2）,研究了V2O5负载量、反应温度、烟气流量、氨氮比以及运行时间各因素对NH3选择性催化还原NO反应（SCR）效率的影响.研究结果表明：经过500℃温度下煅烧,烟气流量为200ml/min,负载量为7wt％的V2O5/TiO2催化剂,在400℃温度下反应,NO脱除率可达70.5％.     

Sulphur transformation and deposition in the rhizosphere of Juncus effusus in a laboratory-scale constructed wetland

Sulphur cycling and its correlation to removal processes under dynamic redox conditions in the rhizosphere of helophytes in treatment wetlands are poorly understood. Therefore, long-term experiments were performed in laboratory-scale constructed wetlands treating artificial domestic wastewater in order to investigate the dynamics of sulphur compounds, the responses of plants and nitrifying microorganisms under carbon surplus conditions, and the generation of methane. For carbon surplus conditions (carbon:sulphate of 2.8:1) sulphate reduction happened but was repressed, in contrast to unplanted filters mentioned in literature. Doubling the carbon load caused stable and efficient sulphate reduction, rising of pH, increasing enrichment of S(2-) and S(0) in pore water, and finally plant death and inhibition of nitrification by sulphide toxicity. The data show a clear correlation of the occurrence of reduced S-species with decreasing C and N removal performance and plant viability in the experimental constructed wetlands.     

氨气敏电极法和纳氏试剂分光光度法对地表水中氨氮的比对测试

采用不同质量浓度的氨氮标准样品和实际样品,用氨气敏电极法和纳氏试剂分光光度法进行同步测试。结果表明,2种分析方法在水样氨氮质量浓度在0. 159～2. 81 mg/L范围内具有良好的可比性、精密性和准确性。氨气敏电极法的检出限为0. 03 mg/L,平行6次测定样品的相对标准偏差为0. 4%～4. 2%,加标回收率为85. 0%～110%;纳氏试剂分光光度法的检出限为0. 025 mg/L,平行6次测定样品的相对标准偏差为0. 5%～6. 4%,加标回收率为93. 0%～99. 8%。同时氨气敏电极法在样品预处理、试剂配制和分析时间上要优于纳氏试剂分光光度法。氨气敏电极法能够满足地表水自动监测在线比对实际工作的需求,该方法具有良好的适用性。