纳米复合脱氮剂/气动超声吹脱高浓度氨氮废水

在自制0.2 t/h气动超声吹脱实验装置中,通过自主研发的纳米复合脱氮剂(CT-601)与气动超声波的耦合作用,在不同氨氮初始浓度、吹脱时间、CT-601投加量、气液比等条件下对高浓度氨氮废水进行研究。结果发现,在常温下p H=11、气液比=900∶1、脱氮剂投加量为0.0848 g/L时,超声吹脱60 min,处理2 000 mg/L的模拟废水时,去除率可达到93%以上,处理浓度为2 156 mg/L的实际废水时,去除率达到90%以上,较普通吹脱法和超声吹脱法分别提高40%和10%。同时还发现,该装置对COD去除率为29.72%,运行成本也只有7.24元/m3。     

吹脱法预处理皮革废水的实验研究

对某皮革厂综合废水进行吹脱预处理实验,综合考察了影响氨氮去除的各个因素(pH值、汽液比、吹脱温度、氨氮初始浓度),同时对该预处理工艺去除铬、SS(悬浮固体浓度)、COD和硫化物的条件进行了优化,并进行了能耗及运行成本估算。结果表明:该厂皮革废水的最佳吹脱工况为pH=11,气液比=1 800,温度25~35℃,在此条件下,当进水ρ(NH3-N)=304.7 mg/L、ρ(Cr)=65.0 mg/L、ρ(SS)=1 700 mg/L、ρ(COD)=2 700 mg/L、ρ(S2-)=112.3 mg/L时,相应的去除率可达78.1%~83.5%、96.4%、88.2%、45.6%和85.0%,且吹脱法对氨氮具有较高的抗冲击负荷能力,吨水处理成本约为3.61元,可作为皮革废水的预处理工艺。     

吹脱法去除垃圾渗滤液中的氨氮研究

对吹脱法去除垃圾渗滤液中的氨氮进行了研究 ,控制吹脱效率高低的关键因素是温度、气液比和 pH值。在水温大于 2 5℃ ,气液比控制在 35 0 0左右 ,渗滤液 pH值控制在 1 0 5左右 ,对于氨氮浓度高达 2 0 0 0～ 4 0 0 0mg/L的垃圾渗滤液 ,去除率可达到 90 %以上     

吹脱-沸石吸附法处理荧光粉生产废水研究

研究了吹脱-沸石吸附法处理荧光粉生产废水.正交试验结果表明:氨吹脱工艺中影响NH3-N去除率因素的重要性顺序为:pH＞温度＞气液比.当pH=11、气液比(V/V)=100:1、温度T=40℃、吹脱时间t=120 min,吹脱工艺对荧光粉生产废水中NH3-N的去除率为74.46%.试验确定的沸石吸附单元较佳的工艺参数为:滤速0.04 m/min、接触时间14min、pH=7.5,吹脱-沸石吸附工艺总NH3-N去除率96.04%.试验结果表明再生沸石氨吸附性能稳定,适于高氨氮的荧光粉生产废水处理.     

吹脱法去除垃圾渗滤液中的氨氮研究

对吹脱法去除垃圾渗滤液中的氨氮进行了研究，控制吹脱效率高低的关键因素是温度、气液比和pH值。在水温大于25℃，气液比控制在3500左右，渗滤液pH值控制在10．5左右，对于氨氮浓度高达2000～4000mg／L的垃圾渗滤液，去除率可达到90％以上。     

氨吹脱-Fenton氧化预处理阿奇霉素废水的研究

采用氨吹脱-Fenton试剂氧化法对阿奇霉素废水进行预处理，考察了各种因素对处理效果的影响。实验结果表明：在pH值为11，吹脱时间160 min，温度30℃的条件下，氨氮浓度从2 458.7 mg/L降低到421.7 mg/L，去除率可达82.85%；Fenton氧化吹脱出水的适宜工艺条件：初始pH值为3、反应时间90 min、FeSO₄·7H₂O投加量为0.01 mol/L、H₂O₂/Fe²⁺的投加比16∶1，此时，COD去除率为72.6%；废水经预处理后，有效地改善了废水水质，提高了废水的可生化性，由初始的0.1增至0.37，为后续废水的生化处理提供了有利条件。     

苦土处理氮磷废水的研究

采用苦土为沉淀剂对模拟氮磷废水和实际氮磷废水进行了脱氮除磷实验研究,探讨了苦土投加量、pH及反应时间对废水中氮磷去除率的影响。此外,对苦土处理氮磷废水的动力学进行了研究,并对苦土及反应沉淀物进行了XRD分析。结果表明,以苦土为沉淀剂,处理氨氮浓度为200 mg/L的模拟废水的最佳条件为:苦土与氨氮(NH4+-N)的质量比为25∶1,平衡时间10 min,氨氮去除率可达到93%,磷去除率达到99%。用苦土为沉淀剂处理南京某厂的实际氮磷废水(氨氮浓度为590 mg/L,磷浓度为1 630 mg/L),氨氮的去除率达到92%,磷的去除率达到99%。苦土处理氮磷废水的动力学数据符合二级动力学模型,主要以化学反应为主。处理后废水中沉淀物的XRD分析表明其主要成分为磷酸铵镁,进一步证明苦土处理氮磷废水主要以化学反应为主。     

二氧化氯泡沫分离法处理水合肼类废液

采用二氧化氯泡沫分离装置,研究了二氧化氯泡沫分离法对水合肼类废液的处理效果.通过实验重点考察了废水pH值、二氧化氯投加量和反应时间等参数对废水处理效果的影响.在最佳反应条件(即pH值为10,每升废水中二氧化氯的投加量为5 mg/1 000 COD、反应时间为3 h)下进行反应,原废液(COD值为30 000～35 000 mg/L,氨氮总量为2 500～2 700 mg/L)经处理后COD去除率达到99%,氨氮去除率达到96%以上.     

反渗透处理稀土氨氮废水试验研究

根据稀土冶炼厂排放的碳铵沉淀洗涤废水的水质情况，采用NH4Cl和 NaCl模拟废水进行了反渗透可行性对比实验。模拟实验发现，在相同条件下反渗透对NaCl 较NH₄Cl 有着更高的去除率，而NH₄Cl 相对NaCl则有着更高的产水速率。实际废水试验结果表明，在恒定操作压力范围内回收率为65%的条件下，NH₄Cl浓度为2.85 g/L的碳铵沉淀洗涤废水经反渗透处理其NH₄Cl去除率为77.3%，可作为氨氮废水的预处理。对该废水处理成本进行了分析，得出其约为2.7元/m³，比相近浓度氨氮废水的氨吹脱处理成本节省约26%。     

低C/N比水产养殖废水生物脱氮实验研究

随着短程硝化-反硝化理论研究的发展,在低C/N比条件下,实现污水的生物脱氮处理已成为可能。为此,设计了水产养殖用水的三级生物膜短程硝化-反硝化处理工艺,并对该工艺在去除模拟水产养殖废水主要污染物的作用进行了初步研究。研究结果表明,在进水pH值7.5~8.5,温度为28~32℃,溶解氧为0.5~1 mg/L,游离氨浓度为5~10 mg/L的条件下,模拟废水的COD、NH4+-N和TN的平均去除率分别达到94.4%、91.6%和70.1%;并且低C/N比对出水氨氮NH4+-N的去除率影响不大,NO2--N的平均浓度控制在5.2 mg/L以下,低于鱼类的耐受浓度。表明该短程硝化-反硝化工艺设计,可用于低C/N比水产养殖废水主要污染物的生物处理,尤其是可消除NO2--N对水产养殖的潜在威胁,基本达到养鱼回用标准。     

好氧氨氧化菌混培物的氨氧化动力学研究

采用批式呼吸法求得好氧氨氧化菌产率系数为0.2119 mg COD/mg NH4 -NOD(或者0.7268 mg COD/mg NH4 -N)和氨氧化菌最大氨氮降解速率为0.1 mg NOD/(mg COD·h)(或者0.0292 mg N/(mg COD·h)).用间歇式批试验法,加入24 μmol/L NaN3抑制NO2--N氧化,建立氨氧化反应动力学方程,得到氨氮半饱和系数为18.38 mg NOD/L(或者5.36 mg NH4 -N/L),DO半饱和系数为0.494 mg/L.对比参数值表明,用一步硝化动力学来描述氨氧化反应动力学模型是错误的.     

水泥厂氨排放标准存在的问题及氨排放控制

为控制水泥脱硝工程产生的氨排放问题,中国发布《水泥工业大气污染物排放标准》(GB 4915—2013)对水泥企业氨排放限值提出明确要求。但水泥脱硝设施同步配套的氨在线检测仪记录数据表明,多数水泥厂脱硝后的氨排放浓度远超过标准限值。为此,对照火电厂相关标准和技术规范,指出了水泥工业氨排放标准和技术规范文件中存在的问题。结合实际检测数据和国外相关文献,确认水泥工业存在"本底氨"排放,水泥原料、协同处理废弃物、生产工况变化是导致本底氨排放的主要原因。选择性非催化还原(SNCR)脱硝设施产生的氨逃逸将增加氨排放浓度,反应温度窗口、停留时间、氨/氮摩尔比(NSR)、喷射方案等均会影响氨逃逸浓度。优化水泥生产工艺、SNCR脱硝工艺或配套选择性催化还原(SCR)脱硝系统等方式可有效控制水泥厂本底氨及氨逃逸。     

Measuring ammonia concentration over a grassland near livestock facilities using a semiconductor ammonia sensor

We demonstrated the effectiveness of a semiconductor ammonia sensor capable of performing diachronic measurements; its characteristics were checked in the laboratory by means including comparison with standard gases. We found as a result that the ammonia sensor's readings increased with increasing water vapor pressure. We compared sensor readings with values obtained by chemical analysis of samples collected in situ and checked sensor reading accuracy. Ammonia concentration was determined by combining ammonia sensor readings with measured values for water vapor pressure. In situ conditions were ammonia concentration of under 100 ppbv and water vapor pressure of 4–16 hPa. There was a good correlation with the concentration of samples trapped with boric acid and analyzed by indophenol colorimetry. We discerned a relationship between ammonia concentration and local meteorological conditions such as wind direction and speed. The estimated error of the ammonia sensor's measurements was ±9.7 ppbv when ammonia concentration as measured by acid sampling and colorimetry was regarded as correct. This demonstrated that it is possible to detect in situ fluctuations in low ammonia concentrations of about 10 ppbv, which was the background concentration in farming areas. We have shown a monitoring method for ammonia in situ that is both easy to operate and low-cost.     

Deposition of atmospheric ammonia to moorlands

Micrometeorological methods were applied to measure fluxes of atmospheric ammonia (NH3) to moorlands. Measurements were made in a wide variety of surface conditions and included both Calluna vulgaris (L.) Hull and Eriophorum vaginatum L. dominated sites. NH3 was found to deposit rapidly to all the sites investigated, providing large deposition velocities (Vd, typically 10-40 mm s(-1)) and usually minimal surface resistances (rc). A small number of measurements were made in frozen conditions and suggest a possible exception to this pattern with mean rc of 50-200 s m(-1). The effect of vegetation drying was also investigated and a possible increase in rc observed, though this was small (< 10 s m(-1)). The results are interpreted in terms of the processes controlling exchange; it is shown that NH3 deposition is predominantly to the leaf surfaces and that the net NH3 compensation point approaches zero. Annual estimates show that dry deposition of NH3 is a major source of atmospheric nitrogen to moorland ecosystems. For two typical UK sites subject to background air concentrations, NH3 dry deposition is of similar magnitude to equivalent NH4+ inputs in wet deposition. In the vicinity of emission sources, NH3 dry deposition is expected to dominate inputs of atmospheric nitrogen.     

Time-resolved ammonia measurement in vehicle exhaust

The objective of this study was to identify the influence of sampling and analytical approach on the quality of NH3 emission data of a gasoline-fuelled three-way catalyst vehicle. NH₃ concentration measurements have been performed in the tailpipe and in the diluted exhaust after a constant volume sampling (CVS) system during five different test cycles. Chemical ionisation mass spectrometry (CI-MS) and Fourier transform infrared spectroscopy (FTIR) were used to acquire ammonia concentrations in real-time. Independently, NH₃ emission rates were determined by continuous absorption of a flow-proportional sample of exhaust gas in diluted sulphuric acid and subsequent ion chromatography (IC). Ammonia emission rates ranged from 22–94 mg km^-1. The results of the three compared techniques are in good agreement. Furthermore, time-resolved ammonia emission profiles recorded by CI-MS and FTIR coincided with respect to emission levels as well as emission dynamics. However, in the dilution tunnel, severe ammonia adsorption was observed leading to long lasting memory effects or even analyte loss. Therefore, neither ammonia real-time emission data nor NH₃ emission rates should be acquired after a CVS system.     

Effects of ammonia on periphytic communities

Laboratory tests were conducted to evaluate the chronic effects of ammonia on periphytic communities. Species richness of the protozoan component of these communities was affected at un-ionized ammonia concentrations of 相似文献   

Footprints on ammonia concentrations from environmental regulations

Releases of ammonia (NH3) to the atmosphere contribute significantly to the deposition of nitrogen to both terrestrial and aquatic ecosystems. This is the background for the national NH3 emission ceilings in Europe. However, in some countries the national legislation aims not only to meet these ceilings but also to reduce the atmospheric nitrogen deposition to local ecosystems. Such measures to reduce the load of nitrogen to local ecosystems were introduced in Denmark in 1994. In this paper we demonstrate that this regulation is reflected in the NH3 concentrations in Denmark. The Danish legislation forces farmers to applying manure to the fields during the crop-growing season. We have analyzed the seasonal variation in local NH3 concentrations over the time period of 1989-2003. During this period the seasonal variation has changed from having moderate spring and autumn concentration peaks to having a single and much more pronounced spring peak. In the analysis we apply an NH3 emission model to demonstrate that these changes in the seasonal variation are a result of the changes in the Danish legislation. The analysis demonstrates the strength of using a high-resolution emission model in the analysis of routine monitoring data.     

Effects of atmospheric ammonia on vegetation--a review

Atmospheric ammonia does not only cause acute injuries at vegetation close to the source, but significantly contributes to large scale nitrogen eutrophication and acidification of ecosystems because the amount of sources is high and after conversion to ammonium it can reach remote areas by long-range atmospheric transport. Besides having acute toxic potential, NH(3) and NH(4)(+) (= NH(y)) may disturb vegetation by secondary metabolic changes due to increased NH(y) uptake and assimilation leading to higher susceptibility to abiotic (drought, frost) and biotic (pests) stress. Prevention of damage to natural and semi-natural ecosystems will only be achieved if NH(3) emissions are drastically reduced. In this paper, the current knowledge on NH(y) emission, deposition, and its effects on vegetation and ecosystems are reviewed. Critical levels and critical loads for nitrogen deposition are discussed.     

A detailed ammonia emission inventory for Denmark

This paper describes the method used to create an ammonia inventory for Denmark and presents the emission factors used and their justification. The total Danish emission for 1996 was 92,700 t NH₄⁺–N, with agriculture accounting for nearly 99%. Emissions from animal manure accounted for 76% of agricultural emissions. We conclude that there will be a continued demand for inventories based on emission factors, despite their lack of physical and chemical realism, but that they will become more complex. This will place increased demands on the statistical information available and on the knowledge of the underlying science.     

氨法脱硫洗涤液pH的计算模型

应用酸碱质子理论,根据质子平衡方程建立了氨法脱硫洗涤液相关离子浓度与pH的相关性模型,并对其影响因素进行了讨论。研究表明:脱硫洗涤液理论计算pH与实测的pH基本吻合。结合实验验证了影响洗涤液pH的硫元素存在形态与脱硫洗涤液pH之间的相图关系,并提出模型修正方法。模型可作为氨法脱硫洗涤液pH的合理计算方法。