Proceedings

With the challenge of meeting new tighter ammonia consents in municipal wastewater treatment, tertiary aerated sand filters, combining the solids removal aspects and self-cleaning properties of continuously backwashed up-flow filters (CoUF’s) with the ammonia conversion capabilities of an attached growth filter are becoming increasingly popular. With specific reference to the DynaSand / DynaOxy system, this paper examines how the filters work, covering their form and operation and what mechanisms are used in their control. The optimisation of process air requirements to maximise the ammonia conversion effectiveness of biomass is considered, along with energy consumption issues and operational practices required to ensure efficient operation in the longer term. The results of a monitoring study of a full-scale installation treating a dry weather flow of over 2000 m3 /day are presented.

KEY WORDS Ammonia Removal, Aerated Sand Filter, Control, CoUF, DynaOxy, DynaSand, Nitrification, Operating Costs, Proof Testing, Tertiary Treatment