Wastewater treatment facilities are subject to many different drivers for completing upgrades. Among the most prevalent drivers is a need to keep current with ever-changing and increasingly stringent environmental regulations. These regulations frequently require upgrading a primary treatment facility (i.e., only screening and primary clarification) or secondary treatment facility (biological treatment for removal of BOD and TSS) to tertiary treatment and the removal of BOD, TSS and total nitrogen.

This paper discusses approaches to these typical plant upgrades via two different variants of submerged biologically active filter technologies, both using the BIOSTYR system by Veolia. The first describes an approach to secondary treatment facility upgrades in which two stages of BAF technology are added to an existing activated sludge treatment system. This is a well-established approach with traditional BAF technology. The second describes an approach to upgrade primary treatment facilities via an innovative new advancement in BAF technology whereby moving bed biofilm reactor technology is integrated into the BIOSTYR system.