The Characteristics And Kinetics Of SBBR Technology And Its Application In Wastewater Treatment

In this paper the state of the art is reviewed of Sequencing Batch Biofilm Reactor (SBBR) technology and its application in the wastewater treatment first. SBBR technology is a new type of combined biofilm reactor technology. It combines the sequencing batch operation mode with the biofilm process with both advantages.This research work focused on the study of the characteristics, kinetics and application in wastewater treatment of SBBR technology by means of a type of specific reactor systems.The first part of the research work is on the characteristics of SBBR technology. It included the make-up and operation modes of reactor system, the selection of operation phases, the feasibility of feeding and draining simultaneously and the volumetric exchange rate, the measurement of retention time distribution (RTD)in the reactor, the analysis of flow pattern in the reactor, the calculation of hydrodynamic shear force in the reactor and the analysis of its effects and the measurement of oxygen transfer coefficients and oxygenating performance parameters. The research results showed that the SBBR employed is a type of packed bed SBBR with external recirculation loop. The reactor system is capable of operating in more than ten modes by means of the automatic control box designed specially. Under the conditions of aeration and the recirculation pump operation, the cycle time for water in the reactor is only two minutes long and the water is at the state of high speed recirculation resulting in the good mass transfer and mixing effects; Under the experimental conditions, the oxygen transfer coefficients KLa are between 39-103(h-1) and the oxygenating capacity is from 8.0 10 -3 to 20.5 10 -3 kgO2/h; The filling stuff composed of ceramic grains belongs to the porous media. Under the condition of no aeration, the flow pattern in the packed bed of the reactor is infiltration, i.e., during the phase of feeding and under the limited aeration mode, the flow pattern in the packed bed of the reactor is infiltration; Under the given conditions, the infiltration rate K equals 3.0175 104 m2, Under differentaeration intensity the linear relationship between the pressure difference and flow speed in the packed bed was obvious. Under the operation conditions of the reactor there is the obvious hydrodynamic shear force which is typically equivalent to 0.962 dyn/cm2. Hydrodynamic shear force has the marked influences on the biofilm leading to the steady state structure, the equilibrium thickness and density of biofilm. During the feeding (draining) phase of the reactor the flow pattern is between ideal plug flow and completely mixing flow and is mainly characterized by plug flow. During the reaction phase, the influent, after entering the reactor, rapidly became the completely mixing flow. The volumetric exchange rate of feeding and draining simultaneously in the reactor can reach 65-74% if only the influent hydraulic loading rate is controlled properly. There are several ways to increase the volumetric exchange rate.The second part of the research work is on the feasibility of treatment of simulated municipal wastewater with SBBR technology. It included the performance and efficiency of the removal of carbonaceous organic wastes (COD) and nitrification and denitrification. It can be further divided into the followings: the start-up of the system (the immobilization and acclimation of microorganisms), the examination of principal mechanisms and influencing factors of the removal of COD and NH/-N, the examination of the degree and routes of the removal of total nitrogen (T-N) or NH4+-N, the estimation of oxygen utilization efficiency of the system and the microscopic examination and analysis of the phase of the microbial communities. The experimental results showed that there were several rapid ways to immobilize and acclimatize the microbial communities in SBBR. The immobilization of the microbial communities on the filling stuff of ceramic grains belonged to the surface adsorption immobilization process. The existence of hydrodynamic...