Optimising and trouble shooting Biological Aerated Filters

Legislation requiring the first time treatment of coastal wastewater discharges and the uprating of existing treatment plant to meet tighter quality standards has led to the introduction of the Biological Aerated Filter (BAF) as an alternative to conventional treatment options. Correct process design will ensure the required effluent quality standards are met, however, with the rationalisation of operating practises currently under way in most UK water service companies it is equally important to understand the operating limits of the process and agree an appropriate hardware specification that suits the needs and competencies of the operator. The generic Biological Aerated Filter comprise an aerated reactor containing submerged inert media supporting the growth of an attached biomass, through which the wastewater flows. No secondary clarification is required and excess biomass is removed by washing the media bed. Similar submerged, attached growth reactors which are not washed and do require secondary solids removal are known as Submerged Aerated Filters (SAF).