The AWTP Nutrient Challenge: A New Level of Nutrient Control

The Western Corridor Recycled Water Project (WCRWP) in Queensland will reclaim water from municipal effluent for reuse to reduce demand by industrial users of current sources and possibly also to replenish source water. Nutrients are a key concern for this project for two reasons: (1) very stringent effluent nitrogen and phosphorus requirements, and (2), potential operational issues with respect to the RO units. Broadly, the options to reduce phosphorus were to upgrade the WWTPs, provide chemical precipitation ahead of MF, or provide pH adjustment ahead of RO to keep the phosphorus in solution. Chemical precipitation of phosphorus ahead of the MF units was selected due to time constraints and to safeguard against spikes in the influent phosphorus concentration which could cause operational issues. An ROC treatment system was developed to reduce the overall discharge of nutrients (nitrogen and phosphorus) to the Brisbane River from that currently being discharged by the four WWTPs.