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591.
黄菖蒲和狭叶香蒲根系对氮磷的吸收动力学 总被引:3,自引:0,他引:3
采用改进的常规耗竭法,研究了黄菖蒲(Iris pseudacorus L.)和狭叶香蒲(Typha angustifolia L.)根系对NH4+、NO3-和H2PO4-的吸收特征及差异。结果表明,这2种植物根系对NH4+、NO3-和H2PO4-的吸收动力学特征均可采用Michaelis-Menten方程描述。2种植物根系对NH4+、NO3-和H2PO4-的亲和力(Km)和最大吸收速率(Vmax)有显著差异。吸收H2PO4-时,黄菖蒲根系具有较高的Vmax值和较低的Km值,说明黄菖蒲具有嗜磷特性,并能够适应广范围浓度的H2PO4-环境,适宜用于污染水体磷的去除;吸收NO3-时,狭叶香蒲根系具有较高的Vmax值和较低的Km值,表明狭叶香蒲可用于广范围浓度NO3-污染的水体修复;吸收NH4+时,黄菖蒲根系具有较低的Vmax值和Km值,而狭叶香蒲根系具有较高的Vmax值和Km值,说明黄菖蒲适宜用于NH4+污染较轻水体的修复,而在NH4+污染较重水体中宜选用狭叶香蒲作为先锋植物。 相似文献
592.
A2O工艺中雌激素的行为变化和去除机理 总被引:1,自引:0,他引:1
研究了厌氧-缺氧-好氧(A2O)活性污泥工艺对生活污水中天然雌激素雌酮(Estrone,E1)、17β-雌二醇(17β-Estradiol,E2)以及17α-乙炔基雌二醇(17α-Ethynylestradiol,EE2)的去除性能。在对COD、N和P具有良好去除效果的前提下,对E1、E2和EE2的去除率可分别达到92.7%、100%和62.7%。通过对各反应单元内3种雌激素的物料平衡分析,表明A2O工艺对雌激素的去除主要发生在厌氧段和好氧段。以失活污泥作为对照组,好氧硝化过程中雌激素去除的小试实验发现,好氧过程中E1、E2的去除主要依靠生物降解作用,而EE2的去除则主要依赖于活性污泥对其的吸附作用。 相似文献
593.
594.
Xiao Wu Jun Zhu Curtis Miller 《Journal of environmental science and health. Part. B》2013,48(6):477-485
Kinetics of H2 production from liquid swine manure supplemented with glucose by mixed anaerobic cultures was investigated using batch experiments under four different pH conditions (4.4, 5.0, 5.6, and uncontrolled). The temperature for the experiments was controlled at 37 ± 1°C and the length of experiments varied between 50 and 120 hours, depending upon the time needed for completion of each individual experiment. The modified Gompertz model was evaluated for its suitability for describing the H2 production potential, H2 production rate, and substrate consumption rate for all the experiments. The results showed that the Gompertz model could adequately fit the experimental results. The effect of pH was significant on all kinetic parameters for H2 production including yield, production rate and lag time, and the substrate utilization rate. The optimal pH was found to be 5.0, at which a maximum H2 production rate (0.64 L H2/h) was obtained, and deviation from the optimal pH could result in substantial reductions in H2 production rate (0.32 L H2/h for pH 4.0 and 0.43 L H2/h for pH 5.6). The results also showed that if pH was not controlled for the batch fermentation process, the substrate utilization efficiency could steeply decrease from 98.8% to 33.7%. 相似文献
595.
596.
Ming-Hong Wu Liang Tang Gang Xu Jing Ma Ning Liu Liang Wang Jian-Qiu Lei 《Environmental science and pollution research international》2013,20(4):2651-2660
Fourteen and 17 sediment samples were collected from three main rivers of Shanghai in July and November, respectively. Eight polybrominated diphenyl ether (PBDE) congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) were detected in these samples to clarify the pollution status in the metropolis. Instrumental analyses showed that the concentrations of ∑8PBDEs ranged from 10.97 to 64.05 ng/g dry weight (dw), with an average value of 29.71 ng/g dw. BDE-209 was the predominant congener accounting for more than 97 % of total PBDEs, followed by BDE-47 and BDE-99. Remarkable spatial and seasonal distributions of PBDE concentrations were observed, suggesting that local sources, seasonal climates, and hydrologic conditions might be the influencing factors. Moderate correlations (r 2?=?0.28–0.51, p?<?0.05) were found between total organic carbon and PBDEs, which indicated that organic carbon content influenced the distributions of PBDEs in sediment of Shanghai at some extent. Hazard quotients revealed PBDEs posed no potential risk to benthic organisms in the study area at present. 相似文献
597.
Xian-De Xie Xiao-Bo Min Li-Yuan Chai Chong-Jian Tang Yan-Jie Liang Mi Li Yong Ke Jie Chen Yan Wang 《Environmental science and pollution research international》2013,20(9):6050-6058
Floatation tailings (FT) are the main by-products of the hydrothermal sulfidation–flotation process. FT (FT1 and FT2) were obtained by treating two different neutralization sludges (NS) (NS1 and NS2). This paper quantitatively evaluated the environmental risks of heavy metals (Zn, Cd, Cu, Pb, and As) in FT versus NS. The total concentration and leaching rates (R 2) of heavy metals in FT were much lower than those in NS, demonstrating that the hydrothermal sulfidation–flotation process was able to effectively suppress the mobility and leachability of heavy metals. The BCR-three sequence leaching procedure of FT confirmed that all metals were transformed into more stable forms (residue and oxidizable forms) than were found that in NS. The potential ecological risk index indicated that the overall risks caused by heavy metals decreased significantly from 6627.59 and 7229.67 (very serious risk) in NS1 and NS2, respectively, to 80.26 and 76.27 (low risk) in FT1 and FT2, respectively. According to the risk assessment code, none of the heavy metals in FT posed significant risk to the natural environment except Zn (with low risk). In general, the risk of heavy metals in FT had been well controlled. 相似文献
598.
599.
随着我国城市化水平的提高,城市交通能源消费占总能源消费的比重逐渐增大,交通方式选择及其影响因素研究引起广泛关注。本研究通过调查南京居民出行交通方式,并通过多项logit模型(multinomial logit model),探究影响居民交通选择的关键因素,为城市交通政策的制定提供科学依据,并根据估算结果分析不同政策下交通方式改变带来的节能减排效应。结果显示:出行特性(如出行距离)、出行者的个人特征(如性别、年龄、职业)与出行者的家庭特征(如是否有私家车,是否有小孩)都对交通方式选择有显著影响。如果通过有效的交通政策引导,使私家车出行转变为轨道交通出行,南京每天大约可减少1573.5吨碳排放。 相似文献
600.