The SEM observations were conducted to evaluate the appearance of encapsulated-ORBs and the immobilization of degraders in the ORICBs.
Even though no pores were observable by the naked eye, the results of SEM observations show that micropores existed in the PVA–alginate layer of encapsulated-ORBs. As mentioned, micropores may favor slow release of oxygen from capsules into groundwater (Chen et al., 1996; Idris et al., 2008). Ball-shaped microorganisms existed on the surface of the ORICs.
The micrograph shows that ORICBs had a high biomass density of degraders.