HYDRAULIC MODE OF NEW OUTSIDE CYCLE ANAEROBIC REACTOR BY RESIDENCE TIME DISTRIBUTION IN WASTEWATER TREATMENT

摘要

In this paper, a new type of energy saving process-the Outside Circling Anaerobic Reactor (OCAR) was use for treating municipal wastewater. In order to understand the treatment efficiency, Lithium salt (LiCl) was selected as a tracer to study the hydraulic characters of OCAR. Residence time distribution (RTD) models were used to analyze the relation between hydraulic characters and the wastewater treatment efficiency of the reactors. The result showed that hydraulic mixing degree in the OCAR is higher than that of in the traditional EGSB in the same operation conditions. With the up-flow velocity improving, the dead zone percentage of the reactors decreased, and the mixing condition between the sludge bed and wastewater was enhanced. When the up-flow rate increased, the hydraulic mixing degree in traditional EGSB increased firstly and then decreased. In OCAR, the hydraulic mixing degree in the modified reactor increased during the total reaction process. When the upflow velocity is 9.00m/h the dead area ratio in the reactor is only 0.87%. The result showed the modification is successful in improving the flow behavior in the OCAR.