跌水曝气系统在污水处理工艺上的运用前景探讨

就重庆市某污水工程BT项目设计实例展开分析,结合国内外跌水曝气系统在实际工程上的运用,探讨在目前国情下,引入跌水曝气系统的可行性,并从生态环境保护和污水处理厂修建投资的经济性两个方面介绍跌水曝气系统特点,以及在氧化沟和其他污水处理工艺上的运用等。最后得出,跌水曝气系统可以作为一种独立的曝气方式设计使用,是适合中国中小型城镇水环境控制的污水处理改进技术;采用跌水曝气系统,可以使污水处理厂的运行费用得到降低,减少运行成本;可以很好的适应丘陵、山区的地形特点,进行因地制宜的设计,减少工程造价和人为对生态环境的破坏。     

分层水库曝气诱导内波特性及消减分层效果

水温分层是深水型水库水质内源污染的主要诱因。针对现有消减水温分层技术的高能耗问题,尝试利用扬水曝气器的周期性出流作为扰动源,在气水两相流条件下诱导产生内波。基于模型水库水温垂向密度剖面的历时信息,计算水库内波的特征参数,分析内波的特性及其消减水温分层的效果。当曝气量为50~200 L/h、跃温层温度梯度为0.34~0.49℃/cm时,在特定条件下能产生内波,内波的波幅在跃温层浮力频率最小处最大。随曝气时间推移,内波的能量逐渐耗散,波幅逐渐减小,内波有破碎趋势。随曝气量减小,内波的特征参数值的总趋势是先逐渐增大到极值,再逐渐减小。随温度梯度增大,内波周期有减小趋势,波速、波长、波幅则相反。内波特性受温度梯度影响较大。在本中试条件下,相对传统的循环水流混合,内波混合可使消减分层的效率提高25%~60%。     

河口村水库泄洪洞水力学关键问题研究

通过单体水工模型试验,研究河口村水库高流速泄洪洞的掺气减蚀措施,优化泄洪洞体型。结果表明:1#泄洪洞弧门后突扩突跌掺气体型合理,能形成稳定空腔,达到掺气减蚀目的;2#泄洪洞龙抬头末端突扩突跌掺气效果好,从洞身水面以上取气能满足掺气需求;2#泄洪洞鼻坎顶高程决定了其运行范围及方式,可低于下游最高洪水位。     

The effect of bubble plume on oxygen transfer for moving bed biofilm reactor

The movement of the bubble plume plays an important role in the operation of a moving bed biofilm reactor （MBBR）, and it directly affects the contact and the mixture of the gas-liquid-solid phases in the aeration tank and also the oxygen transfer from the gas phase to the liquid phase. In this study, the velocity field is determined by a 4-frame PTV as well as the time-averaged and timedependent velocity distributions. The velocity distribution of the bubble plume is analyzed to evaluate the operating efficiency of the MBBR. The results show that the aeration rate is one of the main factors that sway the velocity distribution of the bubble plumes and affect the operating efficiency of the reactor.     

给水中的氨氮问题

文中介绍了水中氨氮是水质黑臭的导因，富营养化的重要因素，在水处理上造成除锰困难，消毒水时产生氯化氰副产物，影响水中有机物的生物氧化效率，并对曝气法，折点加氯法，沸石过滤法和生物氧化法4种除氨方法做了比较和讨论。     

连续流间歇曝气工艺研究

为原有污水厂改建时增加脱氧功能，文中讨论了连续流间歇暴气工艺。研究表明：缩短曝气时段有利于提高处理能力及出水稳定性；停气期加搅拌与与运行条件和运行方式有关。由小试验结果可看出，连续流间歇 工艺简便易行，去除有机物及氮氨的效果，在一定条件下具有良好的脱氮能力。     

清水充氧实验中饱和溶解氧值确定方法的探讨

结合具体实验情况,对目前国内外5种确定饱和溶解氧值的方法进行了研究和探讨。在同一实验条件下对这5种方法的计算结果进行了对比,根据对比结果提出了一种确定饱和溶解氧值的新方法,并进一步论证了所提出方法的合理性和准确性,以期对清水充氧实验起到改进作用,从而获得较为准确的计算结果。     

人工曝气与生态湿地相结合改善清河口水环境

针对清河入河口现状水污染的特点,利用现状低洼坑塘,采用人工曝气和生态湿地相结合的组合工艺,对河道水体进行处理,可有效地去除水中的有机物污染和黑臭,减少水体中营养物质含量,改善水色及透明度,使清河口水环境得到明显改善.     

Odour generation potential of wastewaters

The odour generation potential (OGP) of a wastewater sample is defined to be the flux of odorous substances that can be volatilized from a unit volume of wastewater. Based on a simple first order decay of the odour concentration of a wastewater sample when subjected to volatilization, a procedure is presented to determine the OGP of different wastewater streams at a municipal wastewater treatment plant. The undigested sludge samples were identified to have significantly higher OGPs than other wastewater samples and therefore have greater propensities to emit odour. The aeration of activated sludge and the anaerobic digestion processes were found to reduce the OGPs of their respective waste streams considerably, thus confirming the effective removal of odorous volatile compounds by these two treatment processes.     

Long-term experience with an automatic process control for nitrogen removal in membrane bioreactors

The alternating processes applied in membrane bioreactors for municipal wastewater treatment may be an attractive option to reduce the energy consumptions and optimize carbon and nitrogen removal. However, the knowledge of these systems is often based on empirical results so to discourage the plant operators for its adoption. This paper discusses and compares the empirical evidence coming from two different alternating membrane bioreactors, a demonstration and a full-scale one. The two plants treat two real municipal wastewaters, rather different for both C:N ratio and degree of biodegradability of the influent organics. Nine steady-state runs have been carried out in the demonstration plant, while a one whole year operation has been considered for the full-scale system. Combining the results of the two MBRs, it was found that the alternating process was able to adjust automatically and adequately the aeration of the biological reactor with a nitrogen loading rate in the range 0.05–0.18 kgN m⁻³ d⁻¹ and C:N mass ratios greater than 5–6. As a result, the use of the available carbon source, with concern to the total nitrogen removal, was as low as 0.1 kg of total nitrogen removed per kg of total influent COD. Effluent total nitrogen met the standard for reuse with specific energy consumptions in the range 85–109 gTN_removed per kWh_consumed. Considering the usual loading conditions of the municipal wastewater treatment plants in Italy, membrane bioreactors operating alternating processes may be implemented to increase the nitrogen treatment capacity of existing plants and achieve the standards for reuse.