Microelectrode Studies in Biofilms and Sediments

摘要

The thesis will focus on transport phenomena and conversions in biofilms from bioreactors, with emphasis on those from waste water treatment plants, and in freshwater sediments. A general outline of the field is given in Chapter 1, including immobilization techniques and consequences of immobilization for the activity and efficiency of biocatalysts, as well as a general description of the microbial processes in aquatic sediments. In chapter 2 a new technique will be described, using ion-selective microelectrodes for direct concentration measurements inside biofilms, and two newly developed ion-selective microelectrodes will be presented. The use of aggregated microorganisms is essential for anaerobic waste water treatment. Chapter 3 is a study on the consequences of aggregation of methanogenic bacteria on the conversion rate. Chapter 4 is a microelectrode study on the nitrification process in bacterial aggregates from a fluidized bed reactor. A microelectrode study in three types of aquatic sediments is presented in Chapter 5. Ammonium, nitrate and oxygen fluxes were measured, and the location of nitrifying and denitrifying zones was determined.