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1.
随着三江平原沼泽湿地的垦殖,农田排水不断进入沼泽湿地,对湿地生态系统造成不同程度的影响。当一定氮、磷浓度的农田排水进入毛果苔草沼泽湿地后,水中TN、NH4+-N、TP和PO43--P的含量均明显升高,8~9月份TN和NH4+-N含量分别为自然沼泽湿地水体的1.51~2.10倍和1.53~3.02倍;TP和PO43--P含量分别为1.30~4.08倍和4.33~11.33倍。接受农田排水的毛果苔草根、茎叶生物量明显增高,相应的植物不同部分TN、TP含量也明显增高,其毛果苔草根部TN、TP含量与水中TN、TP含量的相关关系比自然湿地毛果苔草的这一相关关系更强,表明农田排水可促进毛果苔草的生长和对氮、磷的吸收。由于农田排水中磷的含量相对较高,造成湿地水系统N/P失衡,对湿地毛果苔草生态系统的稳定性和生物生产力形成潜在的威胁,因此应控制农田排水直接排入沼泽湿地。 相似文献
2.
利用构建的东风港缓冲带现场试验基地和设计的径流流量测定装置,模拟上海地区农业面源污染物浓度和典型单次降雨历时及降雨量,对不同坡度缓冲带滞缓径流和农田氮磷污染物去除能力开展定量化试验研究。结果表明:相同植被缓冲带,坡度越小,其滞缓径流和土壤水力渗透的能力越强,19 m长的2%坡度缓冲带径流初始出水时间比5%坡度缓冲带延长了7.3 min,两者的渗流水量比值达到1.74;不同坡度缓冲带渗流氮磷污染物去除量显著高于径流,2%、3%、4%和5%坡度缓冲带对于氮磷污染物的渗流去除量与径流去除量的比值分别为2.32、2.15、1.82和1.64;坡度的变化对缓冲带净化面源氮磷污染物效果的影响显著,坡度越小,缓冲带渗流水量越大,其氮磷污染物的总去除率和单位面积去除负荷也越高,2%坡度缓冲带对氮磷污染的总去除率和单位面积污染去除负荷分别是5%坡度的1.56倍和1.66倍,2%坡度缓冲带对TN、NH3--N、TP的单位面积去除负荷均最高,分别达到0.661 g/m2、0.672 g/m2和0.044 g/m2。 相似文献
3.
由于降水较少以及地下水超采,北方地区大部分河流基流匮乏,河水主要来自未经深度处理的城市生活污水和工业废水,河水水质难以达标.在这些地区,利用河流漫滩土壤和含水层的天然净化能力,建立近自然土壤-含水层侧渗系统是净化河水的有效途径之一.在介绍侧渗系统净化机理及适用条件的基础上,通过室内试验和野外示范工程研究索须河土壤-含水层对河水中氨氮的去除效果.室内试验表明该处土壤及浅部含水层对氨氮的去除主要通过稀释、吸附和微生物等作用;通过对示范工程典型剖面上的监测井观测表明该系统对氨氮的去除效果良好,受降水补给的土壤和含水层使得河水中的氨氮硝化为亚硝酸盐和硝酸盐.硝酸盐在地下水中很难被去除,只有少部分通过反硝化作用转化成N2.土壤-含水层侧渗系统行之有效,可应用于类似索须河的北方河流. 相似文献
4.
夏季长江河口潮间带反硝化作用和N2O的排放与吸收 总被引：16，自引：1，他引：15
采用培养箱乙炔抑制和现场静态箱法,于夏季(7月)在长江河口潮滩潮间带进行了采样,研究表明,长江河口潮滩水体自身N2O产生速率很低,在潮汐淹没期沉积物是上覆水体N2O的来源,其来自沉积物中反硝化、硝化等氮素循环的多个反应过程,沉积物中N2O自然产生速率在0.10～8.50μmol/(m2·h)之间,反硝化速率在21.91～35.87μmol/(m2·h)之间。退潮出露期中潮滩是大气N2O的排放源犤交换速率在-11.03～13.17μmol/(m2·h)之间犦,5～10cm地温是影响N2O排放速率的显著性因素;低潮滩-大气界面N2O排放、吸收速率在-5.75～0.49μmol/(m2·h)之间。总体上看,中潮滩是大气N2O的排放源;而低潮滩对大气N2O有明显的吸收作用。潮滩植被(海三棱草和底栖藻类)的光合作用明显抑制了N2O的排放并可能导致吸收,而其呼吸作用则增加了N2O的排放,潮间带-大气界面N2O的排放和吸收与CO2的排放、吸收有显著的正相关关系。 相似文献
5.
土壤中的氮素是植物生长发育的基础,由于城市湿地土壤受特殊水文条件影响,土壤全氮(TN)的分布规律和影响机制较为复杂,因此研究土壤TN的空间分布特征具有重大的生态意义。本文以再生水为主要补给水源的北京门城湖湿地公园为研究区,运用ArcGIS和地统计学对该区土壤TN的空间分布特征进行研究。结果表明:研究区土壤TN质量分数较高,差值明显,变异系数达47.35%;比较不同的植物群落区可知,香蒲群落区土壤TN质量分数最高。对影响研究区土壤TN分布的因素分析得出:土壤TN、全磷(TP)质量分数呈极显著正相关关系(r=0.81,P0.01);TN、土壤有机质(SOM)质量分数呈显著正相关关系(r=0.62,P0.05);气候因子中,湿度和温度对TN分布同样影响显著。水质参数中,再生水出水口处测得的土壤TN的指标数值更高,随出水口距离的增加,参数值总体呈下降趋势且逐步趋于稳定,说明植被对湿地土壤中氮素空间分布的调整具有重要作用。 相似文献
6.
为去除农村家庭饮用地下水中的硝酸盐,以农村自酿米酒为碳源,利用简易的沙桶装置开展了反硝化去除硝酸盐的实验,对比了不同乙醇浓度下的反硝化效果。实验结果表明,以沙桶为实验装置,自酿米酒为碳源,在家庭中异位反硝化去除抽取地下水中的硝酸盐方法是有效果,易操作的。硝酸盐的去除率和C/N质量比有直接关系,当C/N质量比大于1.99时,硝酸盐去除率达99%,亚硝酸盐零积累,但易积累乙酸盐;当C/N质量比为0.89时,硝酸盐去除率达99%,生成物亚硝酸盐浓度远高于国家饮用水限值(1 mg/L);当C/N质量比为0.43时,反硝化过程不彻底,硝酸盐去除率不高,且易生成溶度较高的亚硝酸盐。溶解氧的存在不会对反硝化产生显著影响。米酒和硝酸盐之间的C/N最佳比例,宜大于本次实验的0.89,小于1.99,利用农村自酿米酒作为碳源去除地下水中硝酸盐是可行的。 相似文献
7.
中国干旱内陆流域水体 N、P负荷特征与动态变化——以黑河流域为例 总被引：6，自引：0，他引：6
以黑河流域中游地区为研究区域，通过11年在不同河流断面的长期监测和区域内各类水体如地下水、泉水、水库和河流的空间选点取样分析，研究了干旱内陆流域水体 N、P等植物营养元素的负荷与时空分布及动态变化特征。浅层地下水与河水中NO3-N含量普遍较高，含量超过 1．1 m g／L，大部分平原水库水中NH4-N含量超过 0．3 m g／L；河水与浅层地下水TP、NH4-N与NO3-N含量均呈现沿流域从出山口至下游的显著递增变化，同时还具有明显的随时间递增趋势，其中NH4-N含量在河流出山口及下游断面平均年增加幅度分别为 0．11 m g／L和 0．114 m g／L；流域水体 N、P含量的季节变化明显，黑河流域春季及春夏之交的枯水期大部分河段NH4-N、NO3-N和TP等要素含量为全年最高并出现水质超标污染。控制干旱内陆流域水域尤其是枯水期的 N、P污染，应成为干旱内陆流域水资源保护问题中值得关注的关键内容。 相似文献
8.
利用黑土洼沟净化官厅水库入库水水质研究 总被引：4，自引：0，他引：4
对高含沙、低污染永定河河水进行初步净化处理,是解决官厅水库水体污染,恢复水库向北京市供水功能的重要途径之一.示范工程研究表明,永定河水经黑土洼沟沉淀、大气富氧、增加水体停留时间等作用,对SS、COD、BODs、总氮TN、总磷TP的平均去除率分别达到87.4%、47%、36%、72%、73%,处理系统可大幅度减少入库污染物质总量,降低河湖富营养化发生的危险. 相似文献
9.
岩溶断陷盆地生态环境脆弱,石漠化严重,植被恢复是该地区生态重建、水土保持的有效措施。文章采用空间换时间的方法,以云南省泸西县岩溶断陷盆地5种不同演替阶段（玉米地、人工林、草地、灌木林、原始林）不同土层（0～10、10～20 cm）的土壤为研究对象,对比分析不同植被类型和不同深度条件下土壤C（碳）、N（氮）、P（磷）含量及化学计量比差异,旨在探明研究区土壤养分垂向分布及化学计量学特征,为该地区植被恢复管理及土地合理利用提供科学依据。结果表明：不同演替阶段、不同土壤深度土壤养分含量存在较大差异;随着演替年限的增长,土壤SOC（土壤有机碳）、TN（总氮）含量总体呈增长趋势且主要表现在0～10 cm深度土层上,而TP（总磷）含量存在波动,未表现出明显变化规律;各演替阶段0～10 cm土层的SOC、TN含量数值上均要高于10～20 cm土层,除原始林地以外,其余演替阶段不同土层间TP含量没有显著差异;在0～10 cm土层上,C/N、C/P、N/P均与土壤SOC含量呈显著正相关,C/P、N/P与土壤TN含量呈显著正相关,土壤TP含量与C/N、C/P和N/P无显著相关性;植被类型和土壤深度显著影响研... 相似文献
10.
多层渗滤介质处理微污染水体的中试研究 总被引：3，自引：0，他引：3
对传统的渗滤系统进行改进,采用多层渗滤介质系统,以期增大人工土层对颗粒有机物的接触氧化表面积,同时设置曝气装置保证好氧过程的氧气供应,可以大大提高污水地下处理系统的水力负荷。以北京典型的细砂、中砂、粗砂和砾石为填充材料,处理北京市海淀区上庄水库的污染水体,远优于类似的系统。现场试验结果表明,改进后的系统能创造良好的好氧/厌氧环境,对污染物去除效果良好,CODCr、TN、NH+4-N和TP去除率分别达到了48.57%~94.87%、18.49%~70.21%、20.51%~87.50%和5692%~80.65%,出水达到了地表水Ⅲ-Ⅳ类水质标准。多层渗滤介质系统通过微生物的硝化、反硝化作用实现生物脱氮是去除氮的主要途径;土壤的吸附与沉淀作用是去除磷的主要途径。
相似文献
11.
Effects of plants development and pollutant loading on performance of vertical subsurface flow constructed wetlands 总被引：4，自引：4，他引：0
B. Cheng C. W. Hu Ph.D. Y. J. Zhao Ph.D. 《International Journal of Environmental Science and Technology》2011,8(1):177-186
The influent concentration has a great effect on nutrients removal efficiency in vertical subsurface flow constructed wetland systems, but treatment performance response to different C: N: P ratios in the influent are unclear at present. At the first growing seasons, the effects of the plants present or not, season, the different C: N: P ratio in influent condition and their interaction on treatment performances were studied in the planted or the unplanted wetlands in greenhouse condition. Each set of units was operated at hydraulic loading rates of 40 L/d. Low, medium and high-strength (100, 200, 400 mg/L of chemical oxygen demand or 20, 40, 80 mg/L total nitrogen) synthetic sewage were applied as influent. According to the first growing season results, the average removal efficiencies for the unplanted and the planted wetlands were as follows: chemical oxygen demand (44–58 % and 55–61 % respectively), total nitrogen (26–49% and 31–54 %) and total phosphorus (36–64 % and 70–83 %). The both wetlands system was operated as an efficient treatment system of highest average removal rates of both chemical oxygen demand and total phosphorus when medium-strength synthetic sewage were applied. When high strength synthetic sewage was applied, the planted wetlands usually had a higher nutrients removal rates than the unplanted over the study period. The plants grew well under any high loading treatment over the study period. Anyhow, it also proved that the wetland systems have a good capacity to treat different strength wastewater in greenhouse condition. 相似文献
12.
潮白河是京津冀地区的重要河流。本研究以潮白河中游段为研究区,针对该区段沉积物有机质、氮磷污染程度不明的问题,通过对研究区130个采样点表层沉积物中有机质(OM)、总氮(TN)和总磷(TP)的测定,分析了表层沉积物中有机质和氮磷的分布特征及污染来源,将有机指数和有机氮污染指数评价法相结合开展污染及生态风险评价。结果表明:(1)潮白河中游表层沉积物中OM含量变化范围为0.17%~13.15%,平均含量为5.32%; TN的含量为0.005~1.028 g/kg,平均含量为0.192 g/kg;TP的含量为0.367~4.825 g/kg,平均含量为1.662 g/kg。(2)相关性分析表明,OM与TP、OM与TN均呈弱相关,而TN与TP呈强相关。这是因为TN和TP来源相近,主要来自外源,与OM来源有一定差异。根据TOC/TN特征分析,OM主要受藻类、浮游植物和非纤维束植物等影响。(3)有机指数评价结果显示,潮白河中游段表层沉积物监测点中60%为清洁,33.85%为较清洁,4.62%为尚清洁,1.54%为有机污染。有机污染点主要位于运潮减河入潮白河口和田贾庄排干渠入潮白河口。区域有机氮评价结果以清洁级别为主,整体较好。 相似文献
13.
对于总氮和总磷的测定,国家标准HJ636—2012和GB11893—89规定总氮用碱性过硫酸钾消解,紫外分光光度法测定,总磷用中性过硫酸钾消解,分光光度法测定,两种方法分别取样、消解,分析效率低。本文对国家标准方法进行改进,建立了在一份样品中用过硫酸钾作为氧化剂一次消解,分光光度法联合测定树干茎流液中总氮、总磷含量的方法。样品中的含氮化合物在碱性过硫酸钾溶液中,在高温下氧化分解转化为硝酸盐氮(NO-3-N),其吸光度与总氮浓度成正比;含磷化合物在酸性过硫酸钾溶液中,在高温下氧化分解转化成正磷酸盐(PO3-4-P),其吸光度与正磷酸盐浓度成正比。经实际样品验证,方法精密度(RSD,n=5)为总氮2%,总磷4%,加标回收率为98.0%~104.2%(总氮)和94.0%~107.0%(总磷)。本方法将国家标准方法中配制两条标准系列、两次高压消解改进为配制一条标准系列、一次消解,可以节省50%的样品使用量,且提高了分析效率。由于有机质含量较高时,在本法条件下样品不易消解清亮,影响总氮、总磷的测定,该方法适用于有机质含量较低的树干茎流样品分析。 相似文献
14.
表面流人工湿地处理糠醛生产废水的应用 总被引：2，自引：0，他引：2
根据糠醛生产废水的特点,利用生产企业所处低洼盐碱地改造成表面流人工湿地,废水在湿地内以自然消耗的方式处理,无外排,处理的废水量等于湿地内废水的自然蒸发量、植物的蒸腾量与植物的贮存量。研究表明,经湿地处理后的废水COD去除率平均为94%,TN去除率平均为65%,TOC去除率平均为94.9%。处理后的废水pH值为6.22。 相似文献
15.
H. N. McKellar D. L. Tufford M. C. Alford P. Saroprayogi B. J. Kelley J. T. Morris 《Estuaries and Coasts》2007,30(6):989-1006
Tidal freshwater sections of the Cooper River Estuary (South Carolina) include extensive wetlands, which were formerly impounded
for rice culture during the 1,700s and 1,800s. Most of these former rice fields are now open to tidal exchange and have developed
into productive wetlands that vary in bottom topography, tidal hydrography and vegetation dominants. The purpose of this project
was to quantify nitrogen (N) transport via tidal exchange between the main estuarine channel and representative wetland types
and to relate exchange patterns to the succession of vegetation dominants. We examined N concentration and mass exchange at
the main tidal inlets for the three representative wetland types (submerged aquatic vegetation [SAV], floating leaf vegetation,
and intertidal emergent marsh) over 18-21 tidal cycles (July 1998–August 2000). Nitrate + nitrite concentrations were significantly
lower during ebb flow at all study sites, suggesting potential patterns of uptake by all wetland types. The magnitude of nitrate
decline during ebb flow was negatively correlated with oxygen concentration, reflecting the potential importance of denitrification
and nitrate reduction within hypoxic wetland waters and sediments. The net tidal exchange of nitrate + nitrite was particularly
consistent for the intertidal emergent marsh, where flow-weighted ebb concentrations were usually 18–40% lower than during
flood tides. Seasonal patterns for the emergent marsh indicated higher rates of nitrate + nitrite uptake during the spring
and summer (> 400 μmol N m-2 tide-1) with an annual mean uptake of 248 ± 162 μmol m–2 tide–1. The emergent marsh also removed ammonium through most of the year (207 ± 109 μmol m–2 tide–1), and exported dissolved organic nitrogen (DON) in the fall (1,690 ± 793 μmol m–2 tide–1), suggesting an approximate annual balance between the dissolved inorganic N uptake and DON export. The other wetland types
(SAV and floating leaf vegetation) were less consistent in magnitude and direction of N exchange. Since the emergent marsh
site had the highest bottom elevation and the highest relative cover of intertidal habitat, these results suggest that the
nature of N exchange between the estuarine waters and bordering wetlands is affected by wetland morphometry, tidal hydrography,
and corresponding vegetation dominants. With the recent diversion of river discharge, water levels in the upper Cooper estuary
have dropped more than 10 cm, leading to a succession of wetland communities from subtidal habitats toward more intertidal
habitats. Results of this study suggest that current trends of wetland succession in the upper Cooper River may result in
higher rates of system-wide inorganic N removal and DON inputs by the growing distributions of intertidal emergent marshes. 相似文献
16.
Nutrient limitation of the rhizophytic macroalgaPenicillus capitatus found associated with subtropical seagrass meadows in Bermuda was determined from enrichment assays and subsequent tissue analyses. The photosynthetic response ofP. capitatus to additions of inorganic nitrogen (N) or phosphorus (P), measured as oxygen evolution in closed incubation chambers, increased significantly in both the 16 h and 6 d experiments only with nitrogen enrichment. The average photosynthetic response for all treatments was virtually identical in the two experiments, indicating that there was not a significant time lag in nutrient uptake and that the short term (16 h) assay accurately reflected the longer term (6 d) photosynthetic response to nutrient enrichment. Average tissue nitrogen levels for the nitrogen-treated algae were 29% higher than the phosphorus-treated algae and 18% greater than the controls, corroborating the results from the photosynthesis assay.P. capitatus may acquire nutrients directly from sediment sources via rhizoid holdfasts. Ratios of total dissolved nitrogen (TN) to total dissolved phosphorus (TP) in pore water at 10 and 20 cm depths (6.1 and 4.5, respectively) indicate a nitrogen-limited nutrient pool. These low pore water TN:TP ratios may be a function of a limited sorptive capacity of the calcium carbonate sediments for phosphate, anthropogenic nutrient inputs, or high rates of denitrification, all of which would induce N rather than P limitation in these carbonate-rich sediments. 相似文献
17.
J. Jaafari M. Seyedsalehi G. H. Safari M. Ebrahimi Arjestan H. Barzanouni S. Ghadimi H. Kamani P. Haratipour 《International Journal of Environmental Science and Technology》2017,14(2):291-304
In the present study, the performance of three moving bed biofilm reactors (MBBRs) has been evaluated in series with anaerobic/anoxic/oxic (A2O) units for simultaneous removal of organic matter and nutrients (nitrogen and phosphorous) from a synthetic wastewater with characteristics similar to those of a typical municipal wastewater. Response surface methodology based on central composite design was used to investigate the effects of nitrate recycle ratio, hydraulic retention time (HRT), and influent chemical oxygen demand (COD) on the organic and nutrient removal and optimization process. The optimized values of influent COD, HRT, and R were 462 mg/L, 10 h, and 3.52, respectively. The predicted and observed values at optimized conditions were 92.8% and 93 ± 1.3%, 84.3% and 84 ± 1.3%, 71.7% and 68 ± 1.6% for COD, TN, and TP removals and 100 and 97 ± 1.2 mL/g for sludge volume index, respectively. After that, the influent COD, TN, and TP were increased to 550, 48, and 12 mg/L, respectively, to partly simulate the organics and nutrient variations of real wastewater treatment plants. The COD, TN, and TP removals were 91 ± 1.3, 82 ± 1.1, and 71 ± 0.8%, respectively. The influent COD, TN, and TP were increased again to 650, 56, and 14 mg/L, respectively. After this phase, the COD, TN, and TP removals were 90 ± 0.8, 80 ± 1.2, and 70 ± 1.0%, respectively. Obtained results indicated the good stability of the optimized system and the ability of MBBRs to remain stable at influent organics and nutrient variations. The ratio of attached volatile solids to mixed liquor volatile suspended solids was 1.90 ± 0.10, 2.07 ± 0.09, and 2.25 ± 0.14 in phases 1, 2, and 3, respectively. These high ratios indicate that the microorganisms had favored the attached growth to the suspended growth within the whole operation time. 相似文献
18.
D. F. Juang Ph.D. P. C. Chen M.Sc. 《International Journal of Environmental Science and Technology》2007,4(4):481-488
A new constructed wetland was built to purify one polluted river in Taiwan, and this study was conducted to evaluate the treatment efficiency of the wetland. Due to the very limitation of available budget, several water quality items, which were stipulated by Taiwan’s Environmental Protection Administration for rivers, in the influent and effluent of wetland were analyzed and evaluated. These items included water temperature, pH, DO, BOD5, TSS, and NH4 +-N. The results showed that the average removal rates of total (unfiltered) BOD5, TSS and NH4 +-N were 36.9 %, 71.8 % and 47.1%, respectively. With the HRT more than 3.4 days, the wetland could treat the polluted river water effectively. Longer HRT in this wetland appeared no obvious improvement on the removal rate of TSS or NH4 +-N. However, BOD removal rate increased while the HRT (Hydraulic Retention Time) increased to about 5 days. In this wetland, the calculated mean first-order reaction rate constant (kT) for BOD5 was 0.15/day with a standard deviation of 0.13/day and for NH4 +-N was 0.24/ day with a standard deviation of 0.18/day. It is also concluded that there is a linear proportional relationship between BOD concentrations in the effluent of wetland and its influent mass loading rates, with the coefficient of determination (R2) of 0.6511. Similar result was seen for NH4 +-N as well, with the coefficient of determination (R2) of 0.5965. TSS removal rate was found to be linearly proportional to its influent mass loading rate, with the coefficient of determination (R2) of 0.4875. 相似文献
19.
通过试验和模拟,研究生态滤沟对城市路面径流的净化效果及适宜工况。设计了半渗透型和防渗型两套生态滤沟试验系统,每套系统由5种典型填料滤沟组成。不同影响因素的多水平正交试验和单因素试验结果表明:填料组合方式是对整体处理效果影响最重要的因素,且以粉煤灰+沙（FS）为人工填料层的生态滤沟净化效果最好,防渗与半渗透型沟槽综合去除率分别为83.12%和73.18%,最佳淹没区高度为150 mm。建立了污染物（TN、TP）去除率、出水率与各影响因素的多元回归模型,经Nash-Suttcliffe系数和决定系数检验,拟合效果良好。采用Hydrus-1D模型对3种入流浓度下TP在生态滤沟系统中的迁移进行了模拟,TP出水浓度模拟值与实测值平均相对误差分别为14.11%、17.33%和26.57%,模拟结果可靠。 相似文献