Ammonia

  • 文章类型: Journal Article
    电解锰渣(EMR)是电解锰金属(EMM)行业的副产品,含有高浓度的潜在污染物,例如NH4-N和可溶性Mn2。这些成分对生态环境构成严重威胁。为了探索准确,高效,EMR的无害化处理方法,这项研究提出了一种低温热化学方法。正交试验设计考察了反应温度的影响,反应时间,生石灰(CaO),碳酸钠(Na2CO3),磷酸钠(Na3PO4)(审阅者#3),锰固化和从EMR中去除氨的耗水量。结果表明,最佳反应条件为反应温度60℃(综述#3),反应时间10min。CaO将Mn2+沉淀为氢氧化锰(Mn(OH)2)(审阅者#3),实现有效的锰固化和氨去除。Na2CO3的添加导致Mn2+形成碳酸锰(MnCO3)(审阅者#3)沉淀,而Na3PO4使Mn2+形成磷酸锰三水合物(Mn3(PO4)2·3H2O)(审阅者#3)。增加的水消耗增强了离子之间的相互作用充足性。在最佳条件下(CaO10%,Na2CO31%,Na3PO40.5%,和80%的用水量),铵离子去除率达到98.5%,可溶性Mn2+的凝固率为99.9%。影响铵离子去除的顺序为CaO>耗水量>Na3PO4>Na2CO3。因此,本研究为EMR的低成本工艺处理和高效无害化处理提供了一种新的方法(综述#3)。
    The Electrolytic Manganese Residue (EMR) is a by-product of the electrolytic manganese metal (EMM) industry, containing high concentrations of potential pollutants such as NH4+-N and soluble Mn2+. These components pose a serious threat to the ecological environment. To explore accurate, efficient, and harmless treatment methods for EMR, this study proposes a low-temperature thermochemical approach. The orthogonal experiment design investigates the effects of reaction temperature, reaction time, quicklime (CaO), sodium carbonate (Na2CO3), sodium phosphate (Na3PO4) (Reviewer #3), and water consumption on manganese solidified and ammonia removal from EMR. The results indicate that optimal conditions are a reaction temperature of 60 ℃ (Reviewer #3) and a reaction time of 10 min. CaO precipitates Mn2+ as manganese hydroxide (Mn(OH)2) (Reviewer #3), achieving effective manganese solidified and ammonia removal. The addition of Na2CO3 causes Mn2+ to form manganesecarbonate (MnCO3) (Reviewer #3)precipitate, while Na3PO4 makes Mn2+ form Manganese phosphate trihydrate (Mn3(PO4)2·3H2O) (Reviewer #3). Increased water consumption enhances the interaction adequacy between ions. Under optimal conditions (CaO 10%, Na2CO3 1%, Na3PO4 0.5%, and 80% water consumption), the removal rate of ammonium ions reaches 98.5%, and the solidification rate of soluble Mn2+ is 99.9%. The order of influence on ammonium ion removal is CaO > water consumption > Na3PO4 > Na2CO3. Therefore, this study provides a new method for low-cost process disposal and efficient harmless treatment of EMR (Reviewer #3).
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  • 文章类型: Journal Article
    自然通风的奶牛场的气体排放量的季节性和每日变化是建立有效和具体的缓解计划的重要数据。本研究旨在连续两年测量三个自然通风的奶牛谷仓中的甲烷(CH4)和氨(NH3)排放量。在每个谷仓里,通过多点采样器将来自五个室内位置的空气样本绘制到光声红外多气体监测器上,随着温度和相对湿度。还记录了牛奶生产数据。结果表明,三个谷仓中CH4和NH3排放的季节性差异在几年内没有明显的趋势。全球范围内,dielCH4的排放量在白天增加,小时内变化很高。平均每小时CH4排放量(gh-1牲畜单位1(LU))在奶牛场1中从8.1到11.2和6.2到20.3,在奶牛场2中从10.1到31.4和10.9到22.8,在奶牛场3中从1.5到8.2和13.1到22.1,在第1年和第2年。DielNH3排放量在数小时内变化很大,在白天增加。平均每小时NH3排放量(gh-1LU-1)在奶牛场1中从0.78到1.56和0.50到1.38,在奶牛场2中从1.04到3.40和从0.93到1.98,在奶牛场3中从0.66到1.32和从1.67到1.73,在第1年和第2年。此外,CH4和NH3的排放因子分别为309.5和30.6(gday-1LU-1),分别,用于自然通风的奶牛谷仓。总的来说,这项研究提供了季节性和每日气体排放量变化的详细特征,强调了未来纵向排放研究的必要性,并根据季节和白天确定了更好地适应现有减排策略的机会。
    Seasonal and daily variations of gaseous emissions from naturally ventilated dairy cattle barns are important figures for the establishment of effective and specific mitigation plans. The present study aimed to measure methane (CH4) and ammonia (NH3) emissions in three naturally ventilated dairy cattle barns covering the four seasons for two consecutive years. In each barn, air samples from five indoor locations were drawn by a multipoint sampler to a photoacoustic infrared multigas monitor, along with temperature and relative humidity. Milk production data were also recorded. Results showed seasonal differences for CH4 and NH3 emissions in the three barns with no clear trends within years. Globally, diel CH4 emissions increased in the daytime with high intra-hour variability. The average hourly CH4 emissions (g h-1 livestock unit-1 (LU)) varied from 8.1 to 11.2 and 6.2 to 20.3 in the dairy barn 1, from 10.1 to 31.4 and 10.9 to 22.8 in the dairy barn 2, and from 1.5 to 8.2 and 13.1 to 22.1 in the dairy barn 3, respectively, in years 1 and 2. Diel NH3 emissions highly varied within hours and increased in the daytime. The average hourly NH3 emissions (g h-1 LU-1) varied from 0.78 to 1.56 and 0.50 to 1.38 in the dairy barn 1, from 1.04 to 3.40 and 0.93 to 1.98 in the dairy barn 2, and from 0.66 to 1.32 and 1.67 to 1.73 in the dairy barn 3, respectively, in years 1 and 2. Moreover, the emission factors of CH4 and NH3 were 309.5 and 30.6 (g day-1 LU-1), respectively, for naturally ventilated dairy cattle barns. Overall, this study provided a detailed characterization of seasonal and daily gaseous emissions variations highlighting the need for future longitudinal emission studies and identifying an opportunity to better adequate the existing mitigation strategies according to season and daytime.
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  • 文章类型: Journal Article
    肝性脑病(HE),影响慢性肝病患者的病态考验总是坚持寻找理性,超越时间证明的标准,即乳果糖和利福昔明。在这个RCT中,我们比较了静脉内(IV)L-鸟氨酸-L-天冬氨酸(LOLA)与口服LOLA对慢性肝病(CLD)伴明显肝性脑病(OHE)患者的疗效.40名患有OHE的CLD患者以1:1的比例随机分配给IV或口服LOLA。从第1天至第5天对患者进行HE分级并监测血清氨水平。目的是比较IV与口服LOLA在HE等级改善方面的疗效及其与氨水平的相关性。这项研究在印度临床试验注册中心注册,CTRI/2020/12/029943。两组患者的基线特征相似。从第1天到第5天,静脉LOLA组的氨水平平均差异为55.4±32.58µmol/L,口服LOLA组为60.75±13.82µmol/L(p=0.511)。从第1天至第5天在每组内观察到氨水平的显著降低(p<0.001)。两组HE等级和氨呈正相关。LOLA,不管给药途径如何,在OHE中表现出疗效。
    Hepatic encephalopathy (HE), a morbid ordeal affecting chronic liver disease patients always insists for the search of a rational, superior & infallible agent beyond the time-proven standards i.e., Lactulose & Rifaximin. In this RCT, we compared the efficacy of intravenous (IV) L-ornithine-L-aspartate(LOLA) versus Oral LOLA in patients with chronic liver disease(CLD) enduring overt Hepatic Encephalopathy(OHE). 40 CLD patients with OHE were randomly assigned IV or oral LOLA in a 1:1 ratio. Patients were graded for HE and monitored for serum ammonia levels from day 1 to day 5. The aim was to compare IV versus oral LOLA efficacy in HE grades improvement and its correlation with ammonia levels. The study was registered with clinical trials registry-India, CTRI/2020/12/029943. Baseline characteristics of patients in both groups were similar. The mean difference in ammonia levels from day 1 to day 5 was 55.4 ± 32.58 µmol/L in the IV LOLA group and 60.75 ± 13.82 µmol/L in the oral LOLA group (p = 0.511). Significant reductions in ammonia levels were observed from day 1 to day 5 within each group (p < 0.001). HE grade & ammonia correlated positively in both groups. LOLA, regardless of administration route, has demonstrated efficacy in OHE.
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  • 文章类型: Journal Article
    背景:饮食可以影响肝硬化和肝性脑病(HE)的氨生成,但饮食偏好对肝硬化代谢组学的影响尚不清楚。由于大多数西方人口遵循肉类饮食,我们的目的是确定在肉类饮食的肝硬化门诊患者中,用含蛋白质的素食/素食替代品代替单一肉类膳食对氨和代谢组学的影响。
    方法:采用以西方肉类为基础的稳定饮食,患有和未患有HE的肝硬化门诊患者按1:1:1随机分为3组。给患者一个含有20克蛋白质的汉堡,素食(V)或素食(VG)。在观察患者时,在基线和餐后3小时每小时抽取用于代谢组学的血液,通过液相色谱-质谱和氨。粪便微生物组特征,氨的变化,和代谢组学在组间/组内进行比较。
    结果:基线时粪便微生物组组成相似。肉组的血清氨从基线增加,而VG或V组则没有。与非肉类组相比,肉类组中支链和酰基肉碱的代谢物减少。与V和VG组相比,在肉组中注意到脂质分布的变化(较高的鞘磷脂和较低的溶血磷脂)。
    结论:用非肉类替代品替代单一肉类膳食导致更低的氨生成和以支链氨基酸为中心的血清代谢组学改变。酰基肉碱,溶血磷脂,无论HE或粪便微生物组如何,肝硬化患者的鞘磷脂和鞘磷脂。用素食或素食替代品间歇性替代肉类可能有助于减少肝硬化中的氨生成。
    BACKGROUND: Diet can affect ammoniagenesis in cirrhosis and hepatic encephalopathy (HE), but the impact of dietary preferences on metabolomics in cirrhosis is unclear. As most Western populations follow meat-based diets, we aimed to determine the impact of substituting a single meat-based meal with an equal protein-containing vegan/vegetarian alternative on ammonia and metabolomics in outpatients with cirrhosis on a meat-based diet.
    METHODS: Outpatients with cirrhosis with and without prior HE on a stable Western meat-based diet were randomized 1:1:1 into 3 groups. Patients were given a burger with 20 g protein of meat, vegan, or vegetarian. Blood for metabolomics via liquid chromatography-mass spectrometry and ammonia was drawn at baseline and hourly for 3 hours after meal while patients under observation. Stool microbiome characteristics, changes in ammonia, and metabolomics were compared between/within groups.
    RESULTS: Stool microbiome composition was similar at baseline. Serum ammonia increased from baseline in the meat group but not the vegetarian or vegan group. Metabolites of branched chain and acylcarnitines decreased in the meat group compared with the non-meat groups. Alterations in lipid profile (higher sphingomyelins and lower lysophospholipids) were noted in the meat group when compared with the vegan and vegetarian groups.
    CONCLUSIONS: Substitution of a single meat-based meal with a non-meat alternatives results in lower ammoniagenesis and altered serum metabolomics centered on branched-chain amino acids, acylcarnitines, lysophospholipids, and sphingomyelins in patients with cirrhosis regardless of HE or stool microbiome. Intermittent meat substitution with vegan or vegetarian alternatives could be helpful in reducing ammonia generation in cirrhosis.
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  • 文章类型: Journal Article
    氮污染引起的水体富营养化是一个亟待解决的全球性问题。青衣河是我国典型的微污染河流。在这项研究中,我们以这条河流为研究对象,调查了一种草本植物的氮污染净化能力,RumexjaponicusHoutt.(RJH)。与硝酸盐氮(NO3--N)和亚硝酸盐氮(NO2--N)相比,RJH对总氮(TN)表现出更好的净化性能,总磷(TP)和氨氮(NH4+-N),最高去除率为37.22%,52.13%,100%,分别。当培养装置中氨氮的初始浓度从1mg/L增加到10mg/L或实际河流中,RJH可以完全去除氨氮,并表现出对污染物干扰的优异抵抗力。这表明RJH在天然微污染河流氨氮去除中具有巨大的应用潜力。此外,根硝化的综合效应,吸收自我生长,剥离,和其他人有助于RJH脱氮。特别是,根的硝化作用起主导作用,占73.85%±8.79%。高通量测序结果表明,硝化细菌占RJH中所有细菌物种的75%以上。此外,RJH表现出良好的生长状态和较强的适应性。其与叶绿素A的相对生长速率和吸收降解速率的相关系数分别为0.9677和0.9594。我们的研究表明,RJH是除氨的优良品种之一。这为净化微污染河流提供了一种非常有前途和可持续的方法。
    Water eutrophication caused by nitrogen pollution is an urgent global issue that requires attention. The Qingyi River is a typical micro-polluted river in China. In this study, we took this river as the research object to investigate the nitrogen pollution purification capacity of a herbaceous plant, Rumex japonicus Houtt. (RJH). Compared to nitrate nitrogen (NO3--N) and nitrite nitrogen (NO2--N), RJH showed better purification performance on total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH4+-N), with a highest removal rate of 37.22%, 52.13%, and 100%, respectively. RJH could completely remove ammonia nitrogen and exhibit excellent resistance to pollutant interference when the initial concentration of ammonia nitrogen in the cultivation devices increased from 1 mg/L to 10 mg/L or in the actual river. This indicated the great application potential of RJH in ammonia nitrogen removal from natural micro-polluted rivers. In addition, combined effects of nitrification of roots, absorption of self-growth, stripping, and others contributed to nitrogen removal by RJH. Particularly, the nitrification of roots played a dominant role, accounting for 73.85% ± 8.79%. High-throughput sequencing results indicate that nitrifying bacteria accounted for over 75% of all bacterial species in RJH. Furthermore, RJH showed good growth status and strong adaptability. The correlation coefficients of its relative growth rate with chlorophyll A and the degradation rate of absorption were 0.9677 and 0.9594, respectively. Our research demonstrates that RJH is one of the excellent varieties for ammonia removal. This provides a very promising and sustainable method for purifying micro-polluted rivers.
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  • 文章类型: Journal Article
    面对人口增长带动的作物种植对氮的需求不断增加,这项研究提出了一种可持续的解决方案,以解决需求增加和从废水中去除氮的能源密集型过程。我们的方法涉及从废水中去除氮,并随后将其作为肥料返回土壤。使用来自七叶树果壳(ATFS)的生物炭,医疗后使用的副产品,研究了热解温度对ATFS生物炭(ATFS-BC)吸附NH4-N能力的影响。值得注意的是,在300°C下热解的ATFS-BC(ATFS-BC300)表现出最高的NH4-N吸附能力,为15.61mg/g。ATFS-BC300的优异性能归因于其较高数量的氧官能团和更多带负电荷的表面,这有助于增强NH4-N的吸附。ATFS-BC300对NH4-N的去除涉及物理扩散和化学吸附,NH4-N在生物炭上形成强大的多层吸附。碱性条件有利于ATFS-BC300吸附NH4-N;然而,三价和二价离子的存在阻碍了这一过程。培育水稻植物以评估NH4-N吸附的ATFS-BC300(NH4-ATFS-BC300)作为氮肥的潜力。值得注意的是,中等剂量的NH4-ATFS-BC300(3.96g/kg)表现出与水稻幼苗中商业氮肥相似的关键农艺性状。此外,与商业肥料相比,高剂量的NH4-ATFS-BC300表现出优异的农艺性状。本研究确立了利用ATFS-BC300作为废水处理和氮肥供应的两用解决方案的可行性,为解决环境挑战提供了一个有希望的途径。
    In the face of increasing nitrogen demand for crop cultivation driven by population growth, this study presents a sustainable solution to address both the heightened demand and the energy-intensive process of nitrogen removal from wastewater. Our approach involves the removal of nitrogen from wastewater and its subsequent return to the soil as a fertilizer. Using biochar derived from Aesculus turbinata fruit shells (ATFS), a by-product of post-medical use, we investigated the effect of pyrolysis temperature on the NH4-N adsorption capacity of ATFS biochar (ATFS-BC). Notably, the ATFS-BC pyrolyzed at 300 °C (ATFS-BC300) exhibited the highest NH4-N adsorption capacity of 15.61 mg/g. The superior performance of ATFS-BC300 was attributed to its higher number of oxygen functional groups and more negatively charged surface, which contributed to the enhanced NH4-N adsorption. The removal of NH4-N by ATFS-BC300 involved both physical diffusion and chemisorption, with NH4-N forming a robust multilayer adsorption on the biochar. Alkaline conditions favored NH4-N adsorption by ATFS-BC300; however, the presence of trivalent and divalent ions hindered this process. Rice plants were cultivated to assess the potential of NH4-N adsorbed ATFS-BC300 (NH4-ATFS-BC300) as a nitrogen fertilizer. Remarkably, medium doses of NH4-ATFS-BC300 (594.5 kg/ha) exhibited key agronomic traits similar to those of the commercial nitrogen fertilizer in rice seedlings. Furthermore, high doses of NH4-ATFS-BC300 demonstrated superior agronomic traits compared to the commercial fertilizer. This study establishes the viability of utilizing ATFS-BC300 as a dual-purpose solution for wastewater treatment and nitrogen fertilizer supply, presenting a promising avenue for addressing environmental challenges.
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  • 文章类型: Journal Article
    无金属碳基催化剂在NH3低温选择性催化还原NOx(NH3-SCR)中备受关注。然而,碳基催化剂上的NH3-SCR反应机理仍然存在争议,这严重限制了碳基SCR催化剂的发展。在这里,我们通过硝酸氧化处理成功地重建了碳基催化剂,从而增强其在NH3-SCR中的低温活性。结合实验结果和密度泛函理论(DFT)计算,我们提出了一个以前未报道的NH3-SCR反应机理在碳基催化剂。我们证明了C-OH和C-O-C基团不仅可以有效激活NH3,而且可以显着促进中间体NH2NO的分解。这项研究增强了对碳基催化剂上NH3-SCR机理的理解,并为开发低温无金属SCR催化剂铺平了道路。
    Metal-free carbon-based catalysts are attracting much attention in the low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR). However, the mechanism of the NH3-SCR reaction on carbon-based catalysts is still controversial, which severely limits the development of carbon-based SCR catalysts. Herein, we successfully reconstructed carbon-based catalysts through oxidation treatment with nitric acid, thereby enhancing their low-temperature activity in NH3-SCR. Combining experimental results and density functional theory (DFT) calculations, we proposed a previously unreported NH3-SCR reaction mechanism over carbon-based catalysts. We demonstrated that C-OH and C-O-C groups not only effectively activate NH3 but also remarkedly promote the decomposition of intermediate NH2NO. This study enhances the understanding of the NH3-SCR mechanism on carbon-based catalysts and paves the way to develop low-temperature metal-free SCR catalysts.
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  • 文章类型: Journal Article
    氨溶液(氢氧化铵)用于将盐酸可卡因转化为游离碱可卡因。由于其腐蚀性,在物质使用环境中无意接触氨可能会导致伤害。这项研究的目的是描述在物质使用背景下无意的口服和口腔氨溶液暴露的特征。
    使用法国毒物中心数据库进行了10年(2009-2018年)的回顾性研究。
    总共提取了1,546个文件,包括263名药物使用者。2009年至2018年,这些风险敞口的数量大幅增加。在89%的情况下,无意中摄入氨溶液与产品倾析有关。在曝光和节日背景之前使用物质,如自由派对或teknivals,在25%和21%的案件中被确认,分别。87%的患者接受了医院检查。使用中毒严重程度评分将药物使用者的中毒严重程度分为中度(33%)或重度(15%)。
    报告的氨溶液病例数量增加与同期欧洲裂纹用户数量增加相一致。氨溶液暴露可能提示物质使用障碍的可能性。在这种情况下,患者可以被转介接受适当的治疗和支持。这项研究有一些局限性,例如由于研究的回顾性性质而缺乏可用信息,以及毒物中心在医疗电话访谈中提出的非标准问题。
    2009年至2018年期间,法国已知物质使用者的口服和口腔氨溶液暴露量增加。这些用户大多是年轻人。节日的背景和倾析经常发生。患者主要转诊至急诊科接受临床检查和护理。药物使用者口服或口腔氨溶液暴露的潜在严重程度需要所有参与这些中毒病例管理的医疗保健专业人员提高警惕。
    UNASSIGNED: Ammonia solution (ammonium hydroxide) is used to convert cocaine hydrochloride to freebase cocaine. Due to its causticity, unintentional exposure to ammonia in a substance use context can result in injury. The objective of this study was to describe the characteristics of unintentional oral and buccal ammonia solution exposure in a substance use context.
    UNASSIGNED: A retrospective study was conducted using the French poison centres database over a 10-year period (2009-2018).
    UNASSIGNED: A total of 1,546 files were extracted, and 263 substance users were included. There was a significant increase in the number of these exposures between 2009 and 2018. Unintentional ingestion of ammonia solution was linked to product decanting in 89 per cent of cases. Substance use prior to the exposure and a festive context, such as free parties or teknivals, were identified in 25 per cent and 21 per cent of cases, respectively. Patients received a hospital examination in 87 per cent of cases. The severity of intoxication in substance users was graded as moderate (33 per cent) or severe (15 per cent) using the Poisoning Severity Score.
    UNASSIGNED: The increased number of ammonia solution cases reported was consistent with an increase in the number of crack users in Europe in the same period. Ammonia solution exposure can suggest the possibility of substance use disorders. In such cases, patients can be referred to receive appropriate treatment and support. This study had some limitations, such as the lack of available information due to the retrospective nature of the study and the non-standardized questions asked by the poison centre during the medical phone interviews.
    UNASSIGNED: Oral and buccal ammonia solution exposure in known substance users in France increased between 2009 and 2018. These users were mostly young men. A festive context and decanting were frequent. Patients were mainly referred to emergency departments to receive clinical examination and care. The potential severity of oral or buccal ammonia solution exposure in substance users requires increased vigilance among all healthcare professionals involved in the management of these intoxication cases.
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  • 文章类型: Case Reports
    在BluePlains废水处理厂(WWTP)进行了全面的案例研究,以探索在两年的运营时间内将硝化污泥引入非硝化阶段的生物强化技术。这种创新方法涉及从生物养分去除(BNR)系统中回收废活性污泥(WAS),以增强高碳去除率系统中的硝化作用。完全的氨氧化剂(comammox)NitrospiraNitrosa被确定为系统中的主要硝化剂。生物强化被证明是成功的,因为从BNR返回的硝化剂能够提高高碳去除率系统的硝化活性。BNR阶段的回流污泥与A阶段特定的凯氏定氮(TKN)去除率呈正相关。生物强化过程使A阶段的TKN比去除率显着提高了三倍。结果表明,WAS的回收是一种简单的技术,可以通过硝化器生物增强低SRT系统,并将氨氧化添加到先前的非硝化阶段。TheresultsfromthiscasestudyholdthepotentialforapplicableimplicationsforotherWWTPthathaveasimilaroperationalschemetoBluePlains,允许他们从B阶段重用WAS,以前被认为是废物,以增强硝化能力,从而提高整体脱氮性能。实践要点:Comammox识别为B阶段的主要硝化剂。来自B阶段的Comammox富集污泥成功地将A阶段的东侧生物增强了三倍。A阶段西侧的Comammox的生物增强可能被重力增稠的溢流所抑制。从B阶段返回到A阶段的污泥可以通过非常小的改造和短的启动时间来改善硝化。
    A comprehensive case study was undertaken at the Blue Plains wastewater treatment plant (WWTP) to explore the bioaugmentation technique of introducing nitrifying sludge into the non-nitrifying stage over the course of two operational years. This innovative approach involved the return of waste activated sludge (WAS) from the biological nutrient removal (BNR) system to enhance the nitrification in the high carbon removal rate system. The complete ammonia oxidizer (comammox) Nitrospira Nitrosa was identified as the main nitrifier in the system. Bioaugmentation was shown to be successful as nitrifiers returned from BNR were able to increase the nitrifying activity of the high carbon removal rate system. There was a positive correlation between returned sludge from the BNR stage and the specific total kjeldahl nitrogen (TKN) removal rate in A stage. The bioaugmentation process resulted in a remarkable threefold increase in the specific TKN removal rate within the A stage. Result suggested that recycling of WAS is a simple technique to bio-augment a low SRT system with nitrifiers and add ammonia oxidation to a previously non-nitrifying stage. The results from this case study hold the potential for applicable implications for other WWTPs that have a similar operational scheme to Blue Plains, allowing them to reuse WAS from the B stage, previously considered waste, to enhance nitrification and thus improving overall nitrogen removal performance. PRACTITIONER POINTS: Comammox identifying as main nitrifier in the B stage. Comammox enriched sludge from B stage successfully bio-augmented the East side of A stage up to threefold. Bioaugmentation of comammox in the West side of A stage was potentially inhibited by the gravity thickened overflow. Sludge returned from B stage to A stage can improve nitrification with a very minor retrofits and short startup times.
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  • 文章类型: Journal Article
    氮肥支持农业集约化,但是它的制造导致了大量的污染场所。氨氮是退役氮肥场所的主要特定污染物,具有潜在的人体健康和气味风险。然而,很少有研究关注污染场地的氨氮风险评估,特别是考虑其在土壤中的固液分配过程(Kd)和铵/氨平衡过程(R)。本研究以某封闭式氮肥厂厂址为例,创新性地引入Kd和R对氨氮人体健康和气味风险进行科学评估。还得出了基于人体健康和气味风险的氨氮风险控制值(RCV)。非饱和土壤中氨氮的最高浓度为3380mg/kg,这是人类健康可以接受的,因为在各种情况下,健康RCV为5589~137,471毫克/千克。然而,在挖掘情况下,RCV的气味风险是不可接受的,在挖掘情况下为296~1111mg/kg,在非挖掘情况下为1118~35,979mg/kg。特别令人关注的是,在计算中引入Kd和R使人体健康和气味RCV增加了27.92倍。尽管由于Kd和R的引入,氨风险评估取得了进步,挖掘过程中的气味风险仍然是一个至关重要的问题。这些发现为更科学地评估受污染地点的土壤氨风险提供了依据,并为废弃氮肥厂的管理和重建提供了宝贵的见解。
    Nitrogen fertilizer supports agricultural intensification, but its manufacturing results in substantial contaminated sites. Ammonia nitrogen is the main specific pollutant in retired nitrogen fertilizer sites with potential human health and odor risks. However, few studies focus on ammonia nitrogen risk assessment at contaminated sites, particularly considering its solid-liquid partitioning process (Kd) and ammonium/ammonia equilibrium process (R) in the soil. This study took a closed nitrogen fertilizer factory site as an example and innovatively introduced Kd and R to scientifically assess the human health and odor risk of ammonia nitrogen. The risk control values (RCVs) of ammonia nitrogen based on human health and odor risk were also derived. The maximum concentration of ammonia nitrogen was 3380 mg/kg in the unsaturated soil, which was acceptable for human health because the health RCVs were 5589 ∼ 137,471 mg/kg in various scenarios. However, odor risk was unacceptable for RCVs were 296 ∼ 1111 mg/kg under excavation scenarios and 1118 ∼ 35,979 mg/kg under non-excavation scenarios. Of particular concern, introducing Kd and R in calculation increased the human health and odor RCVs by up to 27.92 times. Despite the advancements in ammonia risk assessment due to the introduction of Kd and R, odor risk during excavation remains a vital issue. These findings inform a more scientific assessment of soil ammonia risk at contaminated sites and provide valuable insights for the management and redevelopment of abandoned nitrogen fertilizer plant sites.
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