A new device to select microcarriers for biomass immobilization : application to an anaerobic consortium

Abstract

A new device was designed to compare the biomass retention capacity of different microcarriers. Microcarriers were placed in as many as 28 independent, parallel minibioreactors under selected and identical flow conditions. Sepiolite pozzolana, clay, and foam glass (Poraver™) were examined for biomass retention capacity, characterized in terms of attached volatile solids and specific methanogenic activity, and examined with scanning electron microscopy. Sepiolite had the greatest biomass retention capacity and better internal porous volume for biomass immobilization. The specific methanogenic activity of the immobilized biomass in different materials was found to be inversely correlated to the amount of attached biomass. A maximum difference of 19% overall activity of the colonized material was observed between foam glass and pozzolana. Compared with the suspended biomass, a clear enhancement of syntrophic activity (up to 110%) and reduction of acetoclastic activity (up to 73%) was observed in the biofilm. This system of examination provides information useful for preselecting microcarriers for biomass colonization.