In summary, the increased methane production in the biocharamended
digesters compared to the control digester could be
attributed to the enhanced process stability provided by high alkalinity
(buffering capacity), improved sludge digestibility provided
by alkaline pH, alleviated NH3 inhibition, improved CO2 reduction
by hydrogenotrophic methanogens and higher electrical conductivity
(Fig. 5D, as discussed in Section 3.2.2) which probably
promoted interspecies electron transfer efficiency.