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低温污水生物反硝化脱氮效果差,投加氧化还原介体有利于反硝化过程,不同碳源对反硝化脱氮过程有不同影响。本文考察了不同碳源(丙酸钠、甲醇、乙醇及乙酸钠)对低温投加氧化还原介体1,2-萘醌-4-磺酸盐(NQS)污水生物反硝化脱氮过程的影响。以硝态氮、总氮、亚硝态氮浓度、去除率和脱氮速率、化学需氧量(COD)、氧化还原电位(ORP)的变化对不同碳源的影响进行了表征,发现丙酸钠为碳源时的反硝化速率最高,最高为7mgNOx--N/(gVSS·h),分别是甲醇[0.88mgNOx--N/(gVSS·h)]、乙醇[2.72mgNOx--N/(gVSS·h)]和乙酸钠[1.97mgNOx--N/(gVSS·h)]为碳源时的8倍、2.6倍和3.6倍;硝态氮的最大去除率为61.5%,分别是甲醇(8.9%)、乙醇(6.6%)和乙酸钠(15.3%)为碳源时的6.9倍、9.3倍和4倍;总氮的最大去除率为47.4%,分别是甲醇(9.1%)、乙醇(10.3%)和乙酸钠(10.3%)为碳源时的5.2倍、4.6倍和4.6倍。 相似文献
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投加缓释碳源是降低低碳氮比废水总氮(TN)的有效途径。使用聚己内酯(PCL)、玉米芯(CC)和二价铁盐(FeSO4、FeCl2)为电子供体,以聚乙烯醇和海藻酸钠为骨架,经过化学交联制备了PCL-CC基质(PC)、PCL-CC-FeSO4基质(PCF-S)和PCL-CC-FeCl2基质(PCF-C) 3种固体缓释碳源,构建了铁-碳协同脱氮除磷的反硝化滤池,并将其用于处理模拟废水,比较了PC、PCF-S和PCF-C在连续流反硝化滤池中的有机物释放特性与其强化脱氮除磷的性能。结果表明:PC、PCF-S和PCF-C 3种基质均可长期稳定释碳达48 d以上;在PCF-C与PCF-S缓释碳源滤池中,铁自养反硝化和异养反硝化之间存在明显的协同作用,2种反硝化作用的结合可显著增强滤池对氮磷的去除效果,3种碳源基质中PC反硝化潜能最好;相较于中低浓度阶段,高浓度进水阶段3种碳源滤池对氮素的去除率均有所下降,脱氮效果变差,这是由于高浓度进水阶段2种PCF基质出现铁壳积累现象,其积累程度由有机物释放速率和脱氮负荷共同决定... 相似文献
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人工湿地反硝化碳源补充研究进展 总被引:2,自引:0,他引:2
碳源作为反硝化过程的电子供体,是影响人工湿地反硝化过程的主要因素.人工湿地的反硝化碳源主要来自于进水,但是由于进水中的溶解性有机碳浓度很低,并且大部分为难降解有机碳,因此需要考虑使用外加碳源提供反硝化电子供体.研究中用于人工湿地反硝化碳源主要有污水、低分子碳水化合物和植物生物质等.植物生物质作为人工湿地反硝化碳源有其独特的优势,不仅价格低廉,来源充足,而且解决了湿地植物的处置问题,还不会增加系统的能耗和二氧化碳的排放量.本文结合现有人工湿地反硝化碳源补充的相关研究,描述了不同外加碳源对反硝化过程的作用,并对不同外碳源的效能进行了对比. 相似文献
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研究了好氧颗粒污泥利用外源碳源和胞内储存物质对同步硝化反硝化(SND)的影响.当序批式反应器(SBR)运行方式不同时好氧颗粒污泥对进水碳源的利用方式不同.在一定m(COD):m(N)下,以外源基质为碳源的缺氧反硝化速率为胞内储存物质的4.5~5.5倍;当m(COD):m(N)相同时,利用胞内储存物质的SND效率明显高于外源基质.外源碳源的大量存在使得硝化反应相对滞后,好氧中后期尽管硝态氮充足,但反硝化所需的碳源往往不足:而胞内储存物质的慢速降解特性使得硝化与反硝化过程能够同步进行,从而实现了较高效率的同步硝化反硝化. 相似文献
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《水处理技术》2021,(9)
为了探究葡萄糖作为补充碳源对反硝化规律的影响,建立序批式反应器(SBR),考察了不同乙酸与葡萄糖混合比对氨氮氧化及亚硝酸盐积累的影响。结果表明乙酸与葡萄糖混合比及污泥负荷均能影响反硝化规律。当碳源充足时,碳源类型对硝化过程影响不显著,而对反硝化过程具有显著影响。当ρ(乙酸)/ρ(葡萄糖)为2/1时,反硝化速率快,且ρ(NO_2~--N)的最大积累量为2.24 mg/L。在污泥负荷为1 000 mg/L时,各反应器中硝态氮均能被反硝化,但ρ(乙酸)/ρ(葡萄糖)为1/2组别中反硝化速率最慢,ρ(NO_2~--N)积累量最小。NO_3~--N的存在对NO_2~-N的还原具有一定抑制作用。 相似文献
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Effects of exogenous addition on soil mineralization and nitrification of typical wetlands in the Yellow River Basin 下载免费PDF全文
Taking Zoige Wetland (soil A) in the upper reaches of the Yellow River, Baotou Nanhai Wetland (soil B) in the middle reaches, and the Yellow River Delta Wetland (soil C) in the lower reaches as the research objects, NH4NO3 and glucose were used as external nitrogen and carbon sources, respectively, and a 28 d constant temperature cultivation method was used. The effects of exogenous addition on daily average carbon mineralization rate (Caverage), net nitrogen mineralization rate (NNmin), and net nitrification rate (NNnitri) of typical wetland soil in the Yellow River Basin were studied. The results show that wetland types have significant effects on soil carbon and nitrogen mineralization and nitrification rates, and differences in soil physical and chemical properties are the main influencing factors. Carbon addition significantly increased Caverage of different wetland soils and the most significant promotion was exerted on soil A. However, nitrogen addition had no significant effect on Caverage. Addition level had significant influence on NNmin. Low level carbon addition significantly inhibited NNmin of soil C while had no significant effect on that of soil A or soil B. High level carbon addition significantly prevented NNmin of different wetland soils. Low level nitrogen addition had no significant effect on NNmin. High level nitrogen addition significantly inhibited NNmin of soil B and soil C, while had no significant effect on soil A. Exogenous addition had no significant effect on NNnitri. 相似文献
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Yongqiang Tian Jun Liu Xueyan Zhang Lihong Gao 《Nutrient Cycling in Agroecosystems》2010,88(3):429-446
Nitrogen nutrient management is crucially important in shallow-rooted vegetable production systems characterized by high input
and high environmental risk. To investigate the effects of summer catch crop (sweet corn, common bean, garland chrysanthemum
and edible amaranth), residue management, and soil temperature and water on the succeeding cucumber rhizosphere nitrogen mineralization
in intensive production systems, we determined the rates of net nitrogen mineralization and nitrification in a 4-year field
experiment on greenhouse cucumber double-cropping systems. Summer catch crop and its residue significantly increased the succeeding
cucumber rhizosphere mineral nitrogen contents, when compared to conventional practices. In general, summer catch crop and
its residue significantly increased the rates of both net nitrogen mineralization and net nitrogen nitrification at 4 or 40°C,
and increased the rates of net nitrogen immobilization (negative mineralization) and net nitrogen nitrification at 15 or 28°C,
in succeeding cucumber rhizosphere after four-year treatment. Soil temperature and water had more influence than catch crops
and residue management on N mineralization. The effect of carbon on nitrogen mineralization was more pronounced than that
of nitrogen, and the effect of microbial carbon on the different forms of inorganic N was more pronounced than that of organic
carbon. When the effects of soil temperature and water content were eliminated, cumulative net nitrogen mineralization and
nitrification in catch crop and residue management plots were 296–784 and 57–84% higher, respectively, than conventional practices
plots. Catch crops and residue management influenced change of ammonium-N more significantly than that of nitrate-N. Additionally,
there were complex relationships between fruit yield and soil N mineralization in catch crop- and residue management-induced
systems. 相似文献
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Soil nitrogen transformation has been the subject of growing attention in many semi-arid grassland ecosystems. In our study,
we employed an intact soil core in situ incubation technique and measured seasonal changes in soil net nitrogen mineralization
and nitrification rates. The measurements were taken from the upper 0–10 cm soil layer of a permanent grassland during a growing
season in a 8.5-year field experiment on the Loess Plateau, China that had four grazing intensities (0, 2.7, 5.3 and 8.7 sheep
ha−1). Our results demonstrate marked seasonal variations in inorganic nitrogen pools, net nitrogen mineralization and net nitrification.
The rates of mineralization and nitrification were highest in August and lowest in September. No consistent differences in
monthly net nitrogen mineralization and monthly nitrification rates were observed among the different grazing intensities.
Sheep grazing stimulated nitrogen transformation, and the most stimulation occurred at a heavy grazing intensity of 8.7 sheep
ha−1. The mean soil net nitrification rate was positively correlated with the soil C/N ratio and pH. The mean N mineralization
rate was negatively correlated with soil organic carbon, but was positively correlated with the soil C/N ratio. Our study
demonstrated net nitrogen mineralization and nitrification rates were strongly linked to grazing intensity, soil temperature
and moisture content. 相似文献
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I Campino 《Nutrient Cycling in Agroecosystems》1982,3(4):325-336
Three experiments were carried out to study the effect of superphosphate, potassium fertilizer salts on the extent of N mineralization and on the nitrification rate with increasing time of incubation of soil samples from a meadow.
Experiment 1: Increasing amounts of superphosphate, up to 96 mg per 30 g soil (equivalent to 174 kg P per ha) had only a small effect on the N mineralization. The samples treated with potassic fertilizer, up to 126 mg per 30 g soil (equivalent to 996 kg K per ha), reached values up to 65% higher than the control without any fertilizer. There was a positive and significant P × K interaction. The nitrification decreased with applications of any fertilizer.
Experiment 2: The addition of potassium as chloride, sulfate and carbonate increased the amount of mineralized N to the same extent. Chloride and sulfate reduced the nitrification rate, whereas carbonate promoted it.
Experiment 3: The addition of potassium chloride to soil sterilized with thimerosal had no effect on the amount of N released. With increasing time of incubation the content of mineral N in the samples increased. The abiotical release of N without K addition amounted to nearly 1.9 mg N per 100 g soil after 3 days of incubation and 15 days later to 6.0 mg N per 100 g soil. 相似文献
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以搭建垂直流人工湿地系统并种植湿地植物(灯芯草)为研究对象,研究人工湿地基质以及湿地植物对重金属Cd、Pb的富集特性,分析了重金属在植物体和土壤中的动态分布,以评价灯芯草对重金属Cd、Pb的综合富集能力以及人工湿地系统对复合重金属污水的净化效果,为利用植物修复金属污染土壤提供理论依据和技术支持。结果显示,湿地植物(灯芯草)对复合重金属Cd、Pb的富集特性高于湿地基质的富集特性。此外湿地植物(灯芯草)的根、茎、叶对重金属Cd、Pb的富集能力也各有不同,其中灯芯草根部对重金属Cd、Pb的富集效果明显大于茎、叶。对于湿地基质,其表层、中层、下层对重金属Cd、Pb的富集效果也有所差异,其表层基质对重金属Cd、Pb的富集效果明显大于中层、下层。湿地土壤基质及湿地植物(灯芯草)对复合重金属Cd、Pb污染的净化有一定作用,其中以湿地植物(灯芯草)根部及湿地表层基质净化效果较为最佳,对污水中Cd、Pb的去除率分别达到69.5%及72.3%,净化效果较好。 相似文献
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Drivers of soil net nitrogen mineralization in the temperate grasslands in Inner Mongolia,China 总被引:3,自引:0,他引:3
Xing-Ren Liu Yun-She Dong Jian-Qiang Ren Sheng-Gong Li 《Nutrient Cycling in Agroecosystems》2010,87(1):59-69
Soil net nitrogen mineralization (NNM) of four grasslands across the elevation and precipitation gradients was studied in
situ in the upper 0–10 cm soil layer using the resin-core technique in Xilin River basin, Inner Mongolia, China during the
growing season of 2006. The primary objectives were to examine variations of NNM among grassland types and the main influencing
factors. These grasslands included Stipa baicalensis (SB), Aneulolepidum Chinense (AC), Stipa grandis (SG), and Stipa krylovii (SK) grassland. The results showed that the seasonal variation patterns of NNM were similar among the four grasslands, the rates
of NNM and nitrification were highest from June to August, and lowest in September and October during the growing season.
The rates of NNM and nitrification were affected significantly by the incubation time, and they were positively correlated
with soil organic carbon content, total soil nitrogen (TN) content, soil temperature, and soil water content, but the rates
of NNM and nitrification were negatively correlated with available N, and weakly correlated with soil pH and C:N ratio. The
sequences of the daily mean rates of NNM and nitrification in the four grasslands during the growing season were AC > SG > SB > SK, and TN content maybe the main affecting factors which can be attributed to the land use type. 相似文献
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Wenxu Dong Chunsheng Hu Yuming Zhang Dianming Wu 《Nutrient Cycling in Agroecosystems》2012,94(2-3):237-247
No-tillage cropping can increase soil carbon (C) stocks and aggregation, and subsequently impact the internal nitrogen (N) cycle and gas loss. The 15N pool dilution method was used to study gross N transformations, and relative proportions of nitrous oxide (N2O) emissions derived from denitrification versus nitrification-related processes under long-term tillage systems (no-tillage, rotary tillage and conventional tillage) in the North China Plain. In-field incubation experiments were repeated in successive growing seasons during April?CNovember in 2007. Gross mineralization rates for rotary and mouldboard plough tillage (3.6?±?0.3?C10.6?±?1.5?mg?N?kg?1?days?1) were significantly higher than for no-tillage (1.7?±?0.8?C6.8?±?1.1?mg?N?kg?1?days?1). Gross mineralization was positively correlated with soil moisture and temperature, as well as with microbial biomass N and C. However, there was no consistent tillage effect on gross nitrification, and gross nitrification was positively correlated with soil moisture, but not with gross mineralization and microbial biomass. N2O emissions were higher in no-tillage (NT) than for conventional tillage (CT) during May?CAugust. The 15N labelling indicated that 26?C92?% of the N2O was directly derived from the soil ammonium (NH4 +) pool. Emission rates of N2O from both nitrification and denitrification were positively correlated with NH4 + supply as expressed by gross mineralization, but not correlated with supply of nitrate as expressed by gross nitrification. The fraction of nitrified N emitted as N2O was positively correlated with changes in soil moisture and varied within 0.01?C2.51???. Our results showed that the tillage management impact on gross N transformation was not consistent with N2O emission, and more detailed information on the controls over N2O formation needs to be sought. 相似文献
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针对生物法处理低C/N比废水存在碳源不足、脱氮效率不高问题,从石化废水处理厂活性污泥中分离得到一株低C/N比异养硝化-好氧反硝化菌株WUST-7。通过形态学观察、生理生化试验和16S rDNA序列分析,鉴定其为假单胞菌属(Pseudomonas sp.)。通过单因素实验,考察碳源种类、培养温度、初始pH和摇床转速对菌株硝化性能的影响,确定最优异养硝化培养条件为:丁二酸钠为碳源、培养温度30~35℃、初始pH8.0~9.0、摇床转速150~200r/min。在最优异养硝化条件下培养9h,可将初始浓度为107.52mg/L的氨氮去除90.64%,并且在整个培养过程中没有亚硝酸盐氮的积累,硝酸盐氮含量也始终低于3.5mg/L,总氮的去除率达88.63%。实验结果表明,菌株WUST-7在利用氨氮进行硝化反应的同时,还可以利用硝酸盐氮进行反硝化,具有良好的同步硝化反硝化潜能。 相似文献
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对有钙源条件下Sporosarcina pasteurii诱导碳酸盐-铀共沉淀修复低浓度铀废水的性能开展了试验研究。试验结果表明,该细菌能分泌脲酶水解尿素诱导产生方解石并促使其与铀发生共沉淀,使废水中铀的去除率达到95.38%;该细菌能够耐受的铀浓度高达500 mg/L;铀的去除率随Ca2+浓度的升高而增加;温度在30℃左右和碱性环境有利于方解石与铀的共沉淀。对沉淀产物进行XRD、SEM-EDS表征分析表明,其主要成分为方解石,且包含铀元素;消解分析表明,在方解石形成过程中铀以共沉淀的方式被固定到了沉淀产物中。本研究表明,Sporosarcina pasteurii诱导碳酸盐-铀共沉淀对修复低浓度铀废水有潜在应用前景。 相似文献
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以自养硝化颗粒污泥作为吸附剂,研究了其对铜离子的吸附效果及最佳吸附工艺条件,并探索了其吸附等温线。通过单因素实验研究铜离子浓度、吸附时间、污泥浓度、搅拌速度和温度对吸附效果的影响,最终得出搅拌速度、吸附时间以及污泥浓度对吸附效果有明显影响。在此基础上,通过响应曲面法耦合出吸附的最佳工况点:时间(A)=2.50h,转速(B)=125r/min,污泥量(C)=5250mg/L。在此条件下研究了颗粒污泥的吸附特性及稳定性。结果表明,硝化颗粒污泥在重金属废水中表现出极强的耐受性与稳定性,不同浓度下颗粒化率均维持在93%以上。Langmuir与Freundlich方程动力学拟合结果显示:Langmuir等温方程的拟合度R2Cu=0.999,表明硝化颗粒污泥对于Cu2+属于典型的单分子层吸附,且能描述最大吸附量为Qmax=15.02mg/g。Freundlich等温方程的拟合过程中,相关系数R2Cu=0.969,1/n=0.1305,表明硝化颗粒污泥对Cu2+吸附能力较强;较高的拟合度也在一定程度上表明硝化颗粒污泥对Cu2+的吸附是一个复杂的物理化学过程。 相似文献