水质氨氮测定中误差来源与控制方法

近年来,人们愈加重视环境污染的处理问题,尤其是水质监测相关工作。在水质氨氮测定过程中,存在诸多影响因素,导致测定结果出现误差。因此,为了保障水质检测结果的精准度,需要采取有效措施,控制检测过程中存在的各种影响因素。本文主要对水质氨氮测定中误差来源进行分析,并提出相应的控制方法,以保障水质氨氮测定方法的可靠性。     

浅谈实验室关于氨氮的相关问题

文章分别阐述了实验室检测氨氮、氨氮总氮关系和氨氮废液处理需要注意的相关问题。并提出了一些行之有效的解决方法,避免在日常工作中出现相关问题。     

地表水中氨氮监测的质量控制

对地表水中的氨氮含量进行准确的检测,是做好地表水质量监测工作的关键[1]。为此,在开展地表水监测实验等相关工作时,要对整个操作过程进行全面严谨的质量管控。要严格按照监测方案和标准等相关要求,规范做好样品采集、数据监测、数据整理等各个环节的工作,这样才能确保监测数据的准确性和可靠性,为准确判定地表水的污染、卫生情况提供有力支撑。本文对如何加强地表水中氨氮监测的质量控制进行了深入的研究分析,希望能够对该领域监测工作的优化改进提供有价值的参考和建议。     

硝化菌在含氨氮废水中的应用

取生活污水处理厂好氧池污泥,通过合理控制工艺参数,驯化和培养活性污泥中的硝化菌,在好氧系统接种该污泥,并通过控制工艺参数,可降解多种含氨氮废水,经处理的出水氨氮达到一级排放标准。     

进水氨氮浓度对电催化氧化降解垃圾渗滤液的影响研究

构建BDD-Ti电催化氧化系统处理老龄垃圾渗滤液生化出水,探讨进水氨氮浓度对电催化氧化降解污染物的影响。结果表明,经BDD-Ti电催化氧化系统处理,COD和氨氮可完全被氧化至未检出状态,去除率均可达到100%。进水氨氮浓度越高,COD降解速率越低,氨氮被完全去除的电催化氧化反应时间越长,生成的NO₃^--N浓度提高,TN去除率下降。COD降解和氨氮降解为竞争关系,当氨氮氧化速率上升时,COD氧化速率下降;当氨氮完成降解时,COD氧化速率上升。因此得出结论,高进水氨氮浓度不利于COD、氨氮和TN去除,宜加强生化段的氨氮去除效果,以降低进入电催化系统的氨氮浓度,以使电催化氧化处理后出水达到《生活垃圾填埋场污染控制标准》(GB16889-2008)表2排放标准。     

徐汇区地表水中氨氮、总氮与总磷变化趋势及相关性研究

本文根据2020年度徐汇区地表水6个断面的氨氮、总氮与总磷的监测数据,分析了不同时期氨氮、总氮与总磷的变化趋势,并研究了三者之间的相关性。结果表明,丰水期氨氮、总磷浓度较高,水体富营养化较严重,枯水期相对受到的污染较少。枯水期、平水期与丰水期,氨氮、总氮与总磷相互之间均存在显著的相关性,在日常检测分析工作中可通过对氨氮、总氮和总磷含量中某一参考值的计算,判断另外两种参考值的大致含量范围,以预测稀释倍数,从而提升检测分析的效果。     

亚铵法制浆废水低温条件下生物脱氮控制措施

我国北方地区冬季气温低时,污水处理厂生化系统普遍存在去除效率低,氨氮和总氮不能稳定达标的问题。特别是亚铵法制浆废水,具有较高的氨氮、总氮,在低温条件下,生化系统更加难以运行。文章提出了若干运行控制措施,并结合实际验证了有效性,为相关行业生物脱氮运行控制提供经验,确保在低温条件下,氨氮、总氮能够长期稳定达标。     

容器选用和储存方式对氨氮空白的影响

在使用纳氏试剂分光光度法测定氨氮的现场空白值时,常出现氨氮空白水样的数值偏高甚至高于本方法检出限的问题。因此,本实验对日常工作中容易忽视的氨氮空白影响因素进行分析,结果表明,棕色玻璃瓶和聚乙烯瓶储存的氨氮水样最好分别在5天内和7天内检测。选用一次性聚乙烯瓶作为日常氨氮样品的采集及储存容器更佳。容器清洗方式选用冲洗方式即可。加入硫酸固定剂后的氨氮水样最好保存在2～5℃冰箱中。     

从氨氮的能力验证可疑结果看实验室管理

目的通过对水中氨氮的检测能力验证,提高检测人员技术水平和实验室管理水平。方法 2016年重庆市质量技术监督局组织了水质(氨氮、铅)检测能力验证活动,本实验室参加了氨氮的能力验证,测试方法分别为HJ 535-2009《水质氨氮的测定纳氏试剂分光光度法》和GB/T 5750.5-2006《生活饮用水标准检验方法无机非金属指标水杨酸盐分光光度法》。以Z比分值来评价和判定检测结果。结果氨氮理论值为0.44mg/L,本实验室上报值为0.506 mg/L,2|Z|3。氨氮数据为可疑,通过分析原因,采取相应纠正措施,最终获得满意结果。结论采用标准样品进行实验室内部质量控制,提高检测人员操作技能、数据分析能力,可获得满意结果。通过能力验证可疑结果的应用实例描述实验室管理,体现能力验证结果的应用价值。     

水质监测中氨氮测定影响因素与控制

水资源是人类生存的重要资源之一,但是随着目前城市化进程的不断推进,水体污染的问题越来越严重。这不仅会对周围的生态环境造成影响,还会对人类的生存发展产生非常严重的阻碍作用,因此必须要合理地控制目前现有水体当中的氨氮含量。本文主要研究水质监测中氨氮测定的影响因素与控制方法。     

Effect of ruminal ammonia-nitrogen concentration on protein degradation in situ

Two experiments were conducted to determine the effect of ruminal ammonia-nitrogen concentration on rate of ruminal protein degradation. In Experiment 1, four Holstein steers were fed a basal diet of corn grain and corn silage at hourly intervals. Continuous intraruminal infusions of solutions containing sodium bicarbonate and either sodium chloride or ammonium chloride resulted in ruminal ammonia-nitrogen concentrations that averaged 4.8 and 17.3 mg/dl. Ruminal fluid pH, fluid volume, and turnover rate of fluid and molar percentage of acetate, propionate, and butyrate were similar across treatments, reflecting steady state conditions. Rates of nitrogen and dry matter disappearance from polyester bags containing soybean protein supplements with 10.2 or 50.1% soluble nitrogen were not affected by increase of ruminal ammonia-nitrogen concentrations from 4.8 to 17.3 mg/dl. In Experiment 2, Holstein steers were fed twice daily a basal diet of urea-supplemented corn grain and corn silage. Polyester bags containing soybean protein supplements were placed in the rumen at -4, 0, or 4 h with reference to feeding and incubated from 1 to 12 h. Peak ruminal ammonia-nitrogen concentrations occurred during different periods of incubation for each treatment. Ruminal ammonia-nitrogen concentrations ranged from 3 mg/dl at 6 h postfeeding to 46 mg/dl at 1 h postfeeding. Nitrogen and dry matter disappearance rates during 0 to 1 and 1 to 12 h of incubation did not differ among treatments.     

制革废水中氨氮脱除方法的研究进展

综述了制革废水中氨氮处理的主要方法,阐述了物理化学法、生物法和新型生物脱氮法氨氮的去除原理和应用研究进展.分析了制革废水氨氮处理工艺中存在的主要问题,提出了相关的解决方法.     

水样中氨态氮含量的不同测定方法比较

分别采用纳氏试剂比色法、苯酚—次氯酸盐(或水杨酸—次氯酸盐)比色法和凯氏定氮仪蒸馏—滴定法对两种水样进行氨态氮含量的测定,比较了不同方法的检测精确度和准确度。结果显示,凯氏定氮仪蒸馏—滴定法的准确度和精确度最高,适用于有浊度或颜色的水样。     

减少制革污水中氨氮含量的工艺研究

本文讨论了制革生产中氨氮的产生及在各工序的分布， 并通过清洁工艺有效地降低了制革污水中的氨氮含量， 减少制革污水的污染问题。     

水样预处理对氨氮分析结果的影响

本文在国家标准规范的基础上仔细探讨了水样预处理过程中的絮凝、过滤步骤对氨氮分析结果的影响,给广大实验操作者提供了一些比较明确的数据和结论,以使操作人员在实验分析中能清晰判断要预处理与否并对水样进行合理的预处理。     

The effects of urea and artificial saliva on rumen bacterial protein synthesis in sheep receiving a high-cereal diet

Four sheep fitted with cannulas in the rumen and duodenum and given a basal diet of 18% chopped hay, 41% rolled barley and 41% flaked maize, known to be associated with low rates of bacterial protein synthesis in the rumen, were used in a 4 × 4 Latin Square experiment to study the effects of continuous intraruminal infusions of water (2 litres day^?1; control), urea solution (7.5 g urea litre^?1, 2 litres day^?1; urea), artificial saliva (4 litres day^?1; saliva) and artificial saliva with added urea (3.75 g urea litre^?1, 4 litres day^?1; saliva+urea) on rumen ammonia-nitrogen concentration, pH, liquid clearance rates and bacterial protein synthesis. Rumen ammonia-nitrogen concentrations for control, urea, saliva and saliva + urea treatments were 81, 158, 38 and 151 mg litre^?1, respectively. Corresponding mean values for rumen pH were 6.18, 6.09, 6.37 and 6.41 units and for rumen liquid clearance rates 0.082, 0.057, 0.062 and 0.051 h^?1. The mean rate of bacterial protein synthesis in the rumen, estimated from the duodenal entry of α-?-diaminopimelic acid, for the control treatment was 163 g crude protein (CP) kg^?1 organic matter (OM) apparently digested in the stomach. Corresponding rates for the saliva and saliva + urea treatments were 169 g CP kg^?1 OM apparently digested and 215 g CP kg^?1 OM apparently digested, indicating responses in protein synthesis to the urea+saliva treatment but not to the saliva alone treatment. Infusion of urea solution increased the mean rate of protein synthesis to 204 g CP kg^?1 OM apparently digested in the stomach but the responses were variable between animals and in three of the animals were small. It is concluded that with the type of diet used an enhanced entry of saliva into the rumen is necessary to ensure that supplementary urea produces a consistent improvement in ruminal protein synthesis.     

Thermophilic two-stage dry anaerobic digestion of model garbage with ammonia stripping

To avoid the inhibition of methane production by ammonia that occurs during the degradation of garbage, anaerobic digestion with prior ammonia production and subsequent stripping was investigated. In the ammonia production phase, the maximum ammonia concentration was approximately 2800 mg N/kg of total wet sludge in the range of 4 days of sludge retention time, indicating that only 43% of total nitrogen in the model garbage was converted to ammonia. The model garbage from which ammonia was produced and stripped was subjected to semi-continuous thermophilic dry anaerobic digestion over 180 days. The gas yield was in the range of 0.68 to 0.75 Nm(3)/kg volatile solid, and it decreased with the decrease of the sludge retention time. The ammonia-nitrogen concentration in the sludge was kept below 3000 mg N/kg total wet sludge. Microbial community structure analysis revealed that the phylum Firmicutes dominated in the ammonia production, but the community structure changed at different sludge retention times. In dry anaerobic digestion, the dominant bacteria shifted from the phylum Thermotogae to Firmicutes. The dominant archaeon was the genus Methanothermobacter, but the ratio of Methanosarcina increased during the process of dry anaerobic digestion.     

Comparisons of methods used for estimating the growth of Tetrahymena pyriformis W

Growth of Tetrahymena pyriformis W was used to assess the relative nutritive value (RNV) of 40 foodstuffs. Growth of the organism was estimated by ammonia-nitrogen (NH₃-N) accumulation, media optical density (OD) and the reduction of triphenyl-tetrazolium chloride (TTC) for triphenyl-formazan. The latter approach was evaluated both on a linear and on a logarithmic scale. All methods used to determine RNC were compared to the microscope cell-counting procedure before and after adjustment by linear regression equations. When compared to cell counts, the measurement of NH₃-N accumulation resulted in the lowest mean difference, followed by the measurements of TTC reduction on a logarithmic scale, OD and then TTC reduction on a linear scale. Mean deviations from cell count values were reduced for all methods after regression equations were used to fit experimental values to the same range as the cell count values. It was concluded that cell counts should be used to calculate RNV and that NH₃-N or OD determinations could increase the efficiency of the RNV procedure for preliminary sample screening.     

少/无氨氮助剂在活性染料深色印花中的应用

为研制具有高得色性能的活性染料深色印花专用少/无氨氮助剂,比较了不同印花助剂的吸湿性、对棉纤维的溶胀性和对活性染料的促溶性,并探讨了助剂结构与上述性能之间的内在关联。优选具有优良性能的助剂进行复配,用于棉织物活性深色印花。结果表明:各种助剂中,丙三醇具有最佳的吸湿性,1,4-丁二醇对棉纤维的膨化最强,酰胺类助剂对活性翠蓝K-GL的促溶最好;当丙三醇和1,4-丁二醇的质量比为2∶8时,无氨氮复配助剂在棉织物活性翠蓝深色印花上的得色性能远高于市售尿素替代剂391-H,略高于尿素水平,且在活性红、橙、蓝和黑染料印花中均具有良好的印制性能,能够有效降低印花废水中的氨氮含量。     

Incorporating test and control product variability in degree of difference tests

Detecting overall differences in inherently variable products presents a unique set of challenges. The degree of difference-control lot variation (DOD-CV) test was developed to include control lot variability within the test [Pecore, S., Stoer, N., Hooge, S., Holschuh, N., Hulting, F., & Case, F. (2006). Degree of difference testing: A new approach incorporating control lot variability. Food Quality and Preference, 17(8–9), 552–555] by comparing products from two control lots and one test lot. This test has been successfully used to detect differences between products with variability induced by production, preparation or heterogeneous composition. Because products with variable control product will also have variable test product, there is a need for representation of test product variability as well as control product variability. The degree of difference-control and test lot variation (DOD-CTV) test represents product variation in both control and test lots by comparing products from two control lots and two test lots. By using an incomplete block design, this can be accomplished without increasing the number of samples required per lot, the pairs evaluated per panelist, or the time spent by each panelist in their evaluation.