3.1. Activated carbon

 

Ross reported that the presence of spent powdered active carbon enhanced the settleability of a sludge treating maize-processing effluent. The carbon provides an additional surface area for attached-growth bacteria, which increases the density of the resultant biomass, with concomitant improved settling.

Also according to Morgan et al., the addition of supplements to a non-granular inoculum during the start-up of UASB reactors appears to be beneficial. A granular activated carbon (GAC) supplement offers two advantages: sheltered ecological niches that enhance biological attachment and thus initiate granule formation and, possibly, a capacity for the adsorption of pollutants, that can then be degraded in the immobilized state. However, this latter feature does result in what can only be described as a lag phase. The activated carbon particles enhance the development of an attached biofilm and, as such, act as a nucleus for granule formation.