TREATMENT CHARACTERISTICS AND OPERATIONAL PARAMETERS OF A NEWLY DEVELOPED REACTOR WITH SLUDGE SEPARATION FILTER AND AIRLIFT PUMP FOR CARBON AND NITROGEN REMOVAL

Abstract

Nutrient removal from sewage is one of the most urgently required issues from the viewpoint of prevention of eutrophication and preservation of water quality for water supply system. Among several nutrient removal methods, biological treatment, which is a modified activated sludge system is widely applied. However, biological nitrogen removal process, which consists of nitrification and denitrification steps, needs opposite operations at several stages such as necessity of oxygen and requirement of electron donor of organic compounds. In this study, treatment characteristics of a reactor with both sludge separation filter and airlift pump are investigated. This reactor has sludge separation filter in the middle part and airlift pump that supplies oxygen and circulate liquid from aerobic zone to anoxic zone in order to cut down the required energy. From laboratory scale experiments, design and operational parameters are investigated and it is shown that NH4-N loading rate of 35 mgN/(L-media･hr) at aerobic zone and DO loading rate of less than 0.15 kgDO/(kgMLSS･d) to anoxic zone are required for stable treatment.