Determination of thiocyanate in the vacuum carbonate desulfurization wastewater

In acidic solution, thiocyanate molecules reacted with ferric ions to produce red complexes. The concentration of thiocyanate could be determined by spectrophotometer. The effects of wavelength, volume of color reagent, acidity and color time on absorbance were investigated. The interferences of co-existing ion were discussed as well. Results showed that the relation between absorbance and the concentration of thiocyanate was in accord with Beer's law when the concentration of thiocyanate was 2-20 mg/L. The linear regression equation was Absorbance = 0.0523 Concentration-0.0156, with a linear correlation coefficient of 0.9997. The average recovery rates of two kinds of vacuum carbonate desulfurization wastewater were 100.95% and 99.62%, and relative standard deviations were 0.79% and 0.14% respectively. It shows that the method was quick, high precision, accurate and easy to handle.     

Copula-Based Bivariate Return Period Analysis and Its Implication to Hydrological Design Event

In univariate frequency analysis, the return period of an event has a one-to-one correspondence with its characteristic value, and the response of the hydraulic structure to hydrological load expressed by the hydrological event is monotonic. Thus, the design criteria of the hydraulic structure can be equivalently represented by the return period of the hydrological event, and consequently, design event-based design parameters evaluated have been widely used in practical engineering. However, the monotonic correspondence between the return period of the hydrological event and the response of the hydraulic structure does not exist in the multivariate context, and hydrological load with a larger joint return period does not always produce a more unsafe response. Misunderstandings of concepts of return periods of hydrological event, and estimation of hydrological design events usually take place in multivariate frequency analysis. This study theoretically derives the relations between different types of joint return periods, joint return period and its marginal return periods, the occurrence of bivariate extreme events and their return periods, and then the theoretical framework is tested. Results from the case contribute to the understanding of bivariate return periods of hydrological event, and the results demonstrate that design criteria cannot be equivalently represented by joint return periods of hydrological load, and design parameters of the hydraulic structure should not be determined by multivariate hydrological design events.     

基于云模型的水体富营养化程度评价方法

水体富营养化程度评价对生态环境保护具有重要意义.针对水体富营养化程度评价不可避免的模糊性和随机性的特点,本文引入云模型的方法,对我国14个代表性湖库的富营养化程度进行评价.根据确定的评价标准,生成各评价因子隶属于各级别的综合云模型,并针对湖库实测资料,得到各评价物的确定度,由最大确定度决定湖库营养化级别.将该法所得结果与湖库实际水质状况、国内外应用较为广泛且简便的营养状态指数、评分公式法及模糊综合评价法所得结果进行对比,发现评价结果真实可靠,计算过程简洁明了,验证了该方法的可行性和有效性.     

Formation control of bromate and trihalomethanes during ozonation of bromide-containing water with chemical addition: Hydrogen peroxide or ammonia?

To ensure the safety of drinking water, ozone (O₃) has been extensively applied in drinking water treatment plants to further remove natural organic matter (NOM). However, the surface water and groundwater near the coastal areas often contain high concentrations of bromide ion (Br^?). Considering the risk of bromate (BrO₃^?) formation in ozonation of the sand-filtered water, the inhibitory efficiencies of hydrogen peroxide (H₂O₂) and ammonia (NH₃) on BrO₃^? formation during ozonation process were compared. The addition of H₂O₂ effectively inhibited BrO₃^? formation at an initial Br^? concentration amended to 350 µg/L. The inhibition efficiencies reached 59.6 and 100% when the mass ratio of H₂O₂/O₃ was 0.25 and > 0.5, respectively. The UV₂₅₄ and total organic carbon (TOC) also decreased after adding H₂O₂, while the formation potential of trihalomethanes (THMsFP) increased especially in subsequent chlorination process at a low dose of H₂O₂. To control the formation of both BrO₃^? and THMs, a relatively large dose of O₃ and a high ratio of H₂O₂/O₃were generally needed. NH₃ addition inhibited BrO₃^? formation when the background ammonia nitrogen (NH₃N) concentration was low. There was no significant correlation between BrO₃^? inhibition efficiency and NH₃ dose, and a small amount of NH₃N (0.2 mg/L) could obviously inhibit BrO₃^? formation. The oxidation of NOM seemed unaffected by NH₃ addition, and the structure of NOM reflected by synchronous fluorescence (SF) scanning remained almost unchanged before and after adding NH₃. Considering the formation of BrO₃^? and THMs, the optimal dose of NH₃ was suggested to be 0.5 mg/L.     

秦岭输水隧洞施工期废水水质评价及工艺研究

依据前期对施工废水水质的连续监测和分析检测结果,针对秦岭输水隧洞施工期废水水量较大、高SS等特点,基于水质矩阵分析原理,以废水处理后安全外排为约束,对各污染物进行权重分析,得出污染物对环境影响由高到低依次是SS、COD、Fe、NH3-N、TN、石油类。结果表明SS是制约隧洞施工废水安全外排的控制因子。根据废水污染物的构成,提出了以"混凝+沉淀+锰砂过滤+吸附"为核心的处理工艺,并用施工现场采集的废水以及人工模拟废水进行了实验室静态实验。结果表明,该处理工艺对悬浮物去除率达90%以上,对COD去除率约85%,对氨氮去除率约60%。处理后水质均能满足《地表水环境质量标准》(GB 3838-2002)中Ⅱ类水体指标。     

Transport and humification of dissolved organic matter within a semi-arid floodplain

In order to understand the transport and humification processes of dissolved organic matter(DOM) within sediments of a semi-arid floodplain at Rifle,Colorado,fluorescence excitation–emission matrix(EEM) spectroscopy,humification index(HIX) and specific UV absorbance(SUVA) at 254 nm were applied for characterizing depth and seasonal variations of DOM composition.Results revealed that late spring snowmelt leached relatively fresh DOM from plant residue and soil organic matter down into the deeper vadose zone(VZ).More humified DOM is preferentially adsorbed by upper VZ sediments,while non-or lesshumified DOM was transported into the deeper VZ.Interestingly,DOM at all depths undergoes rapid biological humification process evidenced by the products of microbial by-product-like(i.e.,tyrosine-like and tryptophan-like) matter in late spring and early summer,particularly in the deeper VZ,resulting in more humified DOM(e.g.,fulvic-acid-like and humic-acid-like substances) at the end of year.This indicates that DOM transport is dominated by spring snowmelt,and DOM humification is controlled by microbial degradation,with seasonal variations.It is expected that these relatively simple spectroscopic measurements(e.g.,EEM spectroscopy,HIX and SUVA) applied to depth-and temporally-distributed pore-water samples can provide useful insights into transport and humification of DOM in other subsurface environments as well.     

昆明城市污水处理现状及对治理滇池的影响分析

分析并评价了昆明市污水处理厂处理能力及处理效果,分析了昆明城市污水处理现状与滇池治理目标问存在的问题,并提出了建议.     

锅炉房边界噪声污染及其防治

本文引用统计数据对锅炉房边界噪声污染现状进行了叙述，分析了边界噪声超标的原因，最后对超标问题提出了几点建议，即对减轻和控制噪声污染提出了治理措施。目的是希望引起各级领导及专业人士对噪声污染的重视，切实把噪声污染的治理提到日程上，加大治理力度，为一些深受噪声污染之害的居民创造一个比较安静的环境，以解除他们的困扰。     

谷氨酸生产废水污染治理的综合分析

通过对河南省味源生物发酵工程有限公司高浓度有机废水处理工程的综合分析,结果表明所采用的废水处理工艺处理效果较好,具有明显的经济效益和环境效益.