Mechanism And Experimental Study On Suspended Media Clarifier (SMC) For Activated Sludge Process

Secondary clarifier, as a solid-liquid separation unit in activated sludge processes for biological wastewater treatment, has been widely adopted. However, the overflow rate of secondary clarifier was design as 0.6～0.8m~3/(m~2.h) to satisfy the more and more strict regulation for wastewater treatment plants(WWTP). On the airscape, the area occupied by secondary clarifier is almost as large as biochemical reaction tank. What is more, another shortcoming of secondary clarifier, such as higher energy consumption, floating sludge problem, and so on, all go against further development of activated sludge process to some extent. So, the dissertation proposed for the first time 'Suspended Media Clarifier, SMC, to substitute traditional secondary clarifier, which is a new solid-liquid technology which can be combined with biochemical reaction tank. The SMC mentioned above was expected to overcome the shortcomings of secondary clarifier and push forward the development of biological wastewater treatment processes.The experimental/pilot-scale research on SMC were carried out in Anting WWTP, Shanghai. Experimental study contents: Analyse SMC's process and mechanics, which was made up by mechanics of various function zone, formation and characteristics of suspended sludge and attached sludge, as well as running mechanics of suspened carrier's zone; study on the influences of overflow rate and SVI on SMC's performance and working span; compare five different aerated washing method about the related parameters and the influence of washing effect on SMC's working span as well, propose for the suitable technology for washing; discuss the problem of the widely adopted design theory of verticle clarifier, propose a new SMC and its design method, oa which the influence of overflow rate and solid flux in sludge overflow zone on running performance.The main function regions consist of clarifying region, attached sludge region, high-concentration suspended sludge region, inlet mixing region, sludge settling region, as well as sludge thickening region. The influences of overflow rate on inlet mixing region, high-concentration suspended sludge region and attached sludge region were discussed in the dissertation, as well as the forming process and characteristics. The experimental and theoric analysis demonstrated that the main function of suspended carrier region is rectification, decreation of turbidty and...