POST DENITRIFICATION IN A MOVING-BED BIOFILM REACTOR PROCESS

The Sjolunda wastewater treatment plant in Malmo Sweden will have to c omply with future effluent standards of less than 10 mg BOD7/l, 8 mg N /l and 0.3 mg P/l. The upgrading scheme for enhanced nutrient removal will be based on a site-specific concept where a tertiary treatment st ep for post-denitrification will be required. An interesting process i n this respect is the moving bed biofilm reactor (MBBR). The number of practical experiences with this type of process is however still limi ted. In this paper the results from a pilot plant test are presented. The primary aim of the experiment was to demonstrate the MBBR process as part of an overall concept for nutrient removal at the Sjolunda WWT P. Two different carbon sources, ethanol and methanol were tested. In addition the effect of low phosphate concentrations on the process per formance was investigated. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.