Biological Fixed-Film Systems

INTRODUCTION Overview. The work reviewed here was published during 2003 and described researches that involve biofilms treating pollutants. This review explicitly excludes research in medical biofilms, dental biofilms, biofilms causing corrosion and biofilm formation in drinking water treatment and distribution systems. Anaerobic Processes is a separate section of this issue, therefore, anaerobic biofilm treatment systems research is not reviewed here. However, denitrification in biofilm treatment systems is covered when appropriate. Similarly, biofilm systems for the treatment of air pollutants are not covered in this section (subject of the Gaseous Emissions from Wastewater Facilities section). Coverage. The references catalogued here are divided on the basis of fundamental research area or reactor types. Fundamental research into biofilms is presented in two sections, characterization/measurement and growth/modeling. The reactor types that are covered are trickling filters, rotating biological contactors, fluidized bed and airlift bioreactors, submerged bed biofilm reactors, biological granular activated carbon, membrane bioreactors, and immobilized cell reactors. Thereafter, innovative reactors that are not easily classified are presented, and an additional section on biofilms on sand, soil, and sediment is given.