Most aerobic treatment units are also flow through systems. Unlike septic tanks, aerobic treatment units perform primary (anaerobic) treatment and secondary (aerobic) treatment within the confines of the system. This arrangement provides a much higher degree of treatment within a relatively small area. As traditional aerobic treatment units are designed for a much higher removal of solids and organic compounds than anaerobic treatment units, a downstream device is frequently not required or is severely diminished in size compared to one which would be required downstream of a septic tank. In a traditional aerobic treatment unit, the first stage of the process is called pretreatment and provides for anaerobic treatment very much like that provided by a septic tank. A separate, isolated pretreatment chamber contains sufficient hydraulic capacity to slow the velocity of the flow somewhat and allows the settling of some of the solids 15 to take place. Anaerobic bacteria partially degrade the organic material in the waste. As a flow through system, the contents of the pretreatment chamber (partially treated waste) are displaced by incoming sewage, and are transferred to the aeration chamber or biological reactor.Within the aeration chamber, air is introduced in controlled amounts creating a proper environment for the development of a number of types of aerobic bacteria. The aerobic bacteria maintain a higher metabolic rate than anaerobic bacteria, which causes them to readily consume the organic material contained in the pretreated sewage. Prior to discharge of this flow through system, the aerobic bacteria (commonly called activated sludge) must be separated from the treated liquid. If the activated sludge particles are allowed to exit the system, two problems occur. First, the activated sludge would not be available to treat additional incoming sewage. As the system is operated on a continuing basis, the cultured bacteria need to be retained for future use. Secondly, if the activated sludge is allowed to be discharged from the system, the organic nature of the sludge would be 35 considered a pollutant if returned directly to the environment.
Commonly, the activated sludge is separated from the treated liquid by allowing the solids to settle out in a gravity clarifier. In a flow through system, the contents of the aeration chamber containing the activated sludge are hydraulically displaced to the clarifier by partially treated liquid entering from the pretreatment chamber. Once in the gravity clarifier, quiescent conditions allow the activated sludge to slowly settle to the bottom of the chamber while the treated liquid is discharged from the system near the top of the chamber. The clarifier relies on having sufficient hydraulic capacity to slow the velocity of the flow through the chamber and thereby allows the activated sludge solids to settle to the bottom. The settled sludge at the bottom of the clarifier is returned, by various m eans, to the aeration chamber. This return prohibits the clarifier from accumulating a large volume of solids and thereby reducing the efficiency of solids separation. However, as a flow through system, the settling efficiency of the clarifier is dependent also on the volume and frequency of the incoming sewage flow.
最有氧治疗单位也是通过系统的流量。与不同的化粪池,好氧处理单元执行初级 (厌氧) 和二级 (有氧) 处理范围内的系统。这种安排提供程度高的范围相对较小的区域内的待遇。作为传统的好氧处理单位用于固体颗粒和有机物的厌氧处理单元比更高的去除,下游的设备通常不是必需的或严重削弱的大小相比,其中将需要下游的化粪池。在一个传统的好氧处理的单位,这一进程的第一阶段称为预处理,并提供厌氧处理很多这样提供的化粪池。一个单独的、 孤立的预处理室包含足够的液压能力有所放缓的速度流,并允许一些固体 15 发生沉降。厌氧细菌部分降解废物中的有机物质。作为通过系统的流量,预处理室 (部分处理废物) 的内容由传入污水、 流离失所和转移到曝气分庭或生物反应器。在曝气会议厅内的控制量创造恰当的环境类型的好氧细菌数量的发展,介绍了空气。好氧细菌保持高代谢率比厌氧细菌,使它们很容易消耗所载的预处理的污水中的有机物质。之前这种能量流通过系统放电,好氧细菌 (通常称为活性的污泥) 必须分开处理液。如果允许活性的污泥颗粒要退出系统,会出现两个问题。第一,活性的污泥不可额外传入污水的处理。由于系统运行在持续的基础上,培养的细菌需要保留供将来使用。第二,如果允许活性的污泥排出系统,有机污泥的性质将 35 如果直接回到环境视为一种污染物。Commonly, the activated sludge is separated from the treated liquid by allowing the solids to settle out in a gravity clarifier. In a flow through system, the contents of the aeration chamber containing the activated sludge are hydraulically displaced to the clarifier by partially treated liquid entering from the pretreatment chamber. Once in the gravity clarifier, quiescent conditions allow the activated sludge to slowly settle to the bottom of the chamber while the treated liquid is discharged from the system near the top of the chamber. The clarifier relies on having sufficient hydraulic capacity to slow the velocity of the flow through the chamber and thereby allows the activated sludge solids to settle to the bottom. The settled sludge at the bottom of the clarifier is returned, by various m eans, to the aeration chamber. This return prohibits the clarifier from accumulating a large volume of solids and thereby reducing the efficiency of solids separation. However, as a flow through system, the settling efficiency of the clarifier is dependent also on the volume and frequency of the incoming sewage flow.
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