不同氮源对黄花鸢尾净化富营养化水体的影响

利用水生植物床系统研究了不同氮源(硝酸盐、亚硝酸盐、铵盐)对黄花鸢尾(Iris pseudoacorus)去除水体氮磷营养盐效率的影响,同时对植物的生长量、水体中叶绿素a含量、黄花鸢尾对氮磷的吸收利用以及氮循环细菌的分布和氧化亚氮的通量进行了综合研究。结果表明:黄花鸢尾对硝酸盐氮具有优先选择性,而对氨氮的去除效果较差。从植物总氮、总磷吸收量来看,3种氮源中硝酸盐氮>亚硝酸盐氮>氨氮;从氮循环菌分布和N2O释放量来看,硝酸盐氮>氨氮>亚硝酸盐氮。一定范围内,植物对营养盐的吸收随营养盐浓度增加而增加,但水体中营养盐浓度过高则会抑制植物的生长,浓度为80 mg/L的硝酸盐氮,亚硝酸盐氮和氨氮都对黄花鸢尾生长有抑制作用,尤其是高浓度氨氮溶液中,植物的湿重明显减少,因此,黄花鸢尾更适宜治理硝酸盐污染的水体。     

MBR工艺出水在粉土介质中的污染物转化规律研究

通过土柱试验模拟了MBR工艺出水在粉土介质中的下渗过程,并对下渗过程COD_(Mn)和三氮(NO_3~--N,NO_2~--N,NH_3-N)的迁移转化规律进行了分析研究.试验结果表明:MBR出水中的CODMn在粉土介质中容易得到降解,而氮素虽然在粉土介质中存在硝化和反硝化反应,经拟合总氮反应符合一级反应动力学方程,但从总体上看总氮降解速率缓慢,试验条件下总氮的衰减系数为0.105 9 m~(-1).     

MBBR工艺短程硝化影响因素研究

采用移动床生物膜反应器(MBBR)处理南方城市模拟生活污水,研究了DO、pH、进水氨氮负荷及HRT等因素对出水氨氮、亚硝酸盐氮和硝酸盐氮的影响,探索了该反应器实现短程硝化的控制条件。试验结果发现,当反应器在DO=0.5~1.0mg/L、pH=8~9、进水氨氮负荷为35mg/L及HRT=14h时,获得了稳定的亚硝酸盐氮积累,实现了短程硝化。     

陡河水库水中含氮量监测与初析

水体中的含氮化合物,大体可分为有机氮与无机氮两种,二者之和即为总氮(TN)。无机氮又包括氨氮(NH_3—N)、亚硝酸盐氮(NO_2—N)和硝酸盐氮(NO_3—N)。监测氮的含量,对于掌握水体被污染的情况及其自净作用有很大意义。总氮还是评价水库富营养化状况的重要指标。总氮可直接测定,也可用无机氮与有机氮含量相加的办法求得。     

低碳城市污水反硝化除磷若干影响因素的试验研究

广州地区城市污水碳量严重偏低、碳氮磷比例失调,其同步脱氮除磷一直是个难题,为此以SBR法进行反硝化除磷影响因素的试验研究.试验表明:缺氧段硝酸盐负荷决定反硝化吸磷效果,在硝酸盐足量情况下,缺氧除磷率达到99.4%.通过对ORP与pH的在线监测发现,ORP无法作为缺氧吸磷过程的控制参数,pH可以指示缺氧吸磷情况.以亚硝酸盐氮作为电子受体研究发现,15 mg/L以下的亚硝酸盐氮可以作为电子受体进行吸磷作用,当亚硝酸盐氮浓度达到23.8 mg/L时,反硝化吸磷受到了明显的抑制;厌氧初始pH在6～8变化时,厌氧释磷量随着pH的升高而增加,pH变化只影响厌氧释磷量,不影响释磷速率.缺氧初始pH降到6时,反硝化吸磷效果变差,缺氧段pH偏碱性条件下,反硝化除磷仍能够稳定进行.     

好氧颗粒污泥低温反硝化除磷的影响因素研究

以模拟城市生活污水为原水,在低温条件下研究SBAR反应器中好氧颗粒污泥反硝化除磷的效能。采用多组平行试验考察了pH、NO_3~-—N、NO_2~-—N、碳源类型对反硝化除磷的影响。结果表明:用乙酸钠作为碳源,pH控制在7±0.1,初始硝酸盐浓度为5 mg/L,或初始亚硝酸盐控制在15～30 mg/L时,有较理想的脱氮除磷效果。     

晚期垃圾渗滤液短程硝化反硝化工艺特性研究

采用间歇式反应器(Batch Reactor,BR)研究了晚期垃圾渗滤液短程硝化反硝化工艺(SND)工艺特性.试验发现:在进水氨氮负荷约为0.27 gNH3—N/(L·d),温度约为27℃,pH控制在7.5时,该工艺DO浓度控制在1 mg/L时硝化效果较好.DO浓度从0.75 mg/L增加到1 mg/L时,氨氧化速率明显增加;继续再增加溶解氧浓度,氨氧化速率增加不明显.在整个过程中,亚硝酸盐积累率变化不大,维持在91％以上.当温度控制在25℃以上时,反应器处理效果较好.随着温度的下降,亚硝酸菌和反硝化菌活性降低,当温度低于25℃时,氨氧化速率和亚硝酸盐降解速率下降较快,曝气时间和出水亚硝酸盐氮浓度明显增加.     

新型亚硝化工艺开发研究

采用长污泥龄、低氧或微氧工艺控制亚硝化反应,成功地开发出了一种全新的亚硝化工艺,连续运转245d。试验结果表明,新型亚硝化工艺氨氮转化率平均为68.1%,亚硝酸盐氮生成率为63.7%,硝酸盐氮生成率平均为1.2%,氨氮几乎全部转化为亚硝酸盐氮,未发生硝酸盐积累。出水中氨氮负荷为0.238kgN/(m3·d),亚硝酸盐氮负荷为0.526kgN/(m3·d),污泥龄为198d,污泥比增长率为0.0051d-1,污泥产率为0.0375gVSS/gNH3-N。长污泥龄、低溶解氧、游离氨、亚硝酸抑制等的共同作用,是实现稳定亚硝化的关键。     

Do和pH作为SBR硝化终点参数试验研究

为更好地实现SBR脱氮在线模糊控制,以生活污水为研究对象,通过改变曝气量、氨氮负荷等因素,研究DO和pH作为好氧硝化过程终点控制参数的特点。结果表明:曝气量过大时,DO曲线不能明显反映出好氧硝化终点;曝气量在0.16～0.8m~3/h范围内时,SBR好氧硝化阶段出现两次跃升,分别指示异氧菌降解有机底物的结束和自氧菌降解氨氮的终点。pH在7.5～8.2之间,有机物降解至难降解时pH出现极大值,随着硝化反应的进行直至硝化结束,pH不断下降并出现极小值,然后pH快速上升或维持不变。     

官厅水库水体氮污染特征分析

据官厅水库2001--2006年的水质监测资料，对官厅水库总氮、氨氮、硝酸盐氮及亚硝酸盐氮在不同断面、不同月份及不同年际的浓度变化进行分析，2004--2006年的总氮和氨氮浓度大幅度下降，硝酸盐氮和亚硝酸盐氮浓度变化不明显．但2006年四氮浓度仍然偏高，且非汛期氮污染高于汛期。通过以上分析，提出了整治建议。     

铜电极表面硝酸盐电化学还原机理研究

目前地表水受到严重氮污染,其中以离子态硝酸盐为主。实验利用线性扫描伏安法与恒电位电解法,研究了铜电极表面硝酸盐电化学还原产物与反应机理。结果表明,硝酸盐的还原产物取决于外加电位。铜电极上硝酸盐的吸附从-0.6 V(以汞/氧化汞电极为参比)开始,-0.8~-1.0 V之间硝酸盐还原为亚硝酸盐,该反应为整个硝酸盐还原过程的速控步骤;理想产物氮气主要在-1.0~-1.2 V之间生成;-1.2~-1.4 V之间主要还原产物为氨氮。随着电势降低,反应速率增大,对副产物氨氮的选择性也升高。     

封闭循环养殖系统氨氮和亚硝酸盐去除效果研究

工厂化封闭循环养殖系统中,人为控制的高度介入,使得水体中氮的各种形态转化和循环过程发生了改变。其中氨氮和亚硝酸盐对系统水体环境的影响尤为突出。本文通过持续监测长春市海水养殖示范基地封闭循环养殖系统中氨氮和亚硝酸含量的变化规律及其他水化因素对氨氮和亚硝酸含量的影响。测得到其封闭循环养殖系统对氨氮的去除效率为70%左右,对亚硝酸盐的去除效率为10%左右,对封闭的循环水养殖系统对氨氮和亚硝酸盐的去除效果研究和探讨,为海水养殖示范基地优化工厂化养殖和保护水环境提供科学依据。     

Nitrogen removal from pharmaceutical manufacturing wastewater with high concentration of ammonia and free ammonia via partial nitrification and denitrification.

In this study, laboratory-scale experiments were conducted applying a Sequencing Batch Reactor (SBR) activated sludge process to a wastewater stream from a pharmaceutical factory. Nitrogen removal can be achieved via partial nitrification and denitrification and the efficiency was above 99% at 23 degrees C+/-1. The experimental results indicated that the nitrite oxidizers were more sensitive than ammonia oxidizers to the free ammonia in the wastewater. The average accumulation rate of nitrite was much higher than that of nitrate. During nitrogen removal via the nitrite pathway, the end of nitrification and denitrification can be exactly decided by monitoring the variation of pH. Consequently, on-line control for nitrogen removal from the pharmaceutical manufacturing wastewater can be achieved and the cost of operation can be reduced.     

Nitrite accumulation followed by denitrification using sequencing batch reactor.

Biological ammonia-nitrogen removal utilizes two distinct processes, nitrification and denitrification. In nitrification, ammonia oxidizes to nitrite then to nitrate. In this study, elimination of nitrite oxidation to nitrate step was attempted in order to directly remove nitrite to nitrogen gas by denitrification. For this study the supernatant from an anaerobic digester was used as an ammonia source and a sequencing batch reactor (SBR) was employed. Emphasis was given to the evaluation of the operational factors affecting nitrite accumulation and the elucidation of kinetics for biological nitrification and denitrification. Accumulation of nitrite in the nitrification process was achieved by suppressing the growth of Nitrobacter, a nitrite oxidizer, by loading high concentration ammonia supernatant immediately after all ammonia in the previous loading was oxidized to nitrite. Nitrite oxidation was taking place as the solid retention time (SRT) was increased from 2.5 days to 3.0 days in a continuously aerated SBR mode with daily feeding. However, nitrite accumulation was achieved even at longer SRT of 5 days when the aeration and non-aeration periods were appropriately combined and the non-aeration period can be used for denitrification of the accumulated nitrite with a carbon source supplied.     

大黑汀水库水质时空变化特征及下游引水策略

为探究大黑汀水库2017年养鱼网箱拆除后水质特征,于2018年分季节采集水库表层和分层水样分析水库水质时空变化特征。结果表明:大黑汀水库表层水体总氮在冬季最高,总磷在夏季最高,硝态氮是溶解性无机氮中的主要成分;大黑汀水库总氮、硝态氮、总磷和磷酸盐质量浓度总体上都表现出上游最高、中游次之、下游最低的空间分布特征,氨氮和亚硝态氮则相反;垂向上主要表现为夏季总磷质量浓度底层大于表层,与温跃层及溶解氧水平有关;养鱼网箱拆除后显著降低了水库总磷和磷酸盐质量浓度,氨氮质量浓度也显著降低,总氮和硝态氮质量浓度无显著变化;氮磷比表明磷是该水库水体富营养化的限制因子,因此养鱼网箱拆除能有效控制该水库富营养化进程;根据水质时空分布特征,下游引水应避免在冬季取水,引水高度上应选择从坝前中层水柱取水。     

再生水滴灌作物生育期内土壤中氮素 动态变化规律研究

采用大田试验方法，以地下水滴灌为对照，分析研究了再生水滴灌条件下土壤中氮素随作物生育期的动态变化规律。结果表明：再生水滴灌条件下，表层土壤中NH+4-N浓度的峰值变化情况为：再生水滴灌>50%再生水滴灌>地下水滴灌。NH+4-N在0~40 cm处浓度较高，40 cm以下深度处，NH+4-N积累量极少。在整个生育期内，NO-3-N在土壤中呈逐渐增加的趋势，但增加幅度不明显。     

Nitrogen removal via ammonia volatilization in maturation ponds.

A simple apparatus was designed to collect ammonia gas coming out from waste stabilization ponds (WSP). The apparatus has a capture chamber and an absorption system, which were optimized under laboratory conditions prior to being used to assess ammonia volatilization rates in a pilot-scale maturation pond during summer 2005. Under laboratory conditions (water temperature = 17.1 degrees C and pH = 10.1), the average ammonia volatilization rate was 2,517 g NH3-N/ha d and the apparatus absorbed 79% of volatilized ammonia. On site, the mean ammonia volatilization rate was 15 g N/ha d, which corresponds to 3% of the total nitrogen removed (531 g N/ha d) in the maturation pond studied. A net nitrogen mass balance showed that ammonia volatilization was not the most important mechanism involved in either total nitrogen or ammonia removal. Nitrogen fractions (suspended organic nitrogen, soluble organic nitrogen, ammonia, nitrite and nitrate) from the M1 influent and effluent showed that ammonia is removed by biological (mainly algal) uptake and total nitrogen removal by sedimentation of dead algal biomass.     

测定地表水中氨氮影响因素的探讨

纳氏试剂分光光度法是测定地表水、饮用水和生活污水中氨氮含量的常用方法,在测定过程中条件变化对检测结果会有一定的影响。本文从地表水测定过程中的实验用水、酒石酸钾钠纯度、采集样品的保存、显色反应时间、酸化样品的pH值、不同属性样品7个方面分析了影响氨氮测定结果的因素。该研究将有助于提高检测精密度和结果准确度。     

Impact of damming the Mogi-Guaçu River (São Paulo State, Brazil) on reservoir limnological variables

This study examined the effects of the damming of the Mogi‐Guaçu River (São Paulo State, Brazil) on the surface current velocity, water temperature, Secchi disc transparency, turbidity, colour, conductivity, pH and concentrations of nutrients and pigments. Surface‐water samples were taken before, during and after the reservoir was filled. Three sampling sites were established, one in the upper reach of the reservoir, one in the central area of the reservoir and one downstream from the dam. An additional sampling site was established on the Peixe River, the major tributary of the Mogi‐Guaçu in the study area. After filling of the reservoir, the surface current velocity tended to decrease, excepting downstream of the dam. The pH, and the Kjeldahl nitrogen, ammonia and chlorophyll‐a concentrations, tended to increase. The nitrite concentrations increased mainly in the upper reach and central area of the reservoir. The Secchi disc transparency and colour tended to decrease. A decreasing trend in dissolved oxygen concentration was observed mainly at the central area of reservoir. The conductivity tended to decrease, later returning to levels observed prior to reservoir filling. The nitrate, total phosphorus and orthophosphate concentrations exhibited an increasing trend after reservoir filling, followed by a decreasing concentration, reaching lower levels than those found prior to reservoir filling. High phaeophytin concentrations were measured for the filling phase. The observed water quality changes for Mogi‐Guaçu Reservoir generally were not as extreme as those observed for other tropical reservoirs. This trend was related to the operation of the reservoir. As Mogi‐Guaçu Reservoir is a run‐of‐the‐river reservoir with a short water retention time, the flooded area is not extensive and the retention of material and sedimentation upstream from the dam is not remarkable. These facts explain the small water quality changes observed for most of the variables after reservoir filling. The water quality decreased at the in‐lake site in the central part of the reservoir, attaining a hypereutrophic condition. This fact was related to the ageing of the reservoir and to cultural eutrophication.