3.5. Waste treatment process selection: overall performance versus
energy efficiency
Neither anaerobic nor aerobic processes alone were capable of
efficiently treating simulated shampoo wastes under the operating
conditions tested here. It is probable that relative performance
might be improved by process optimisation (e.g., increasing reactor
sizes), but the goal was to reduce energy consumption for the
whole system, which data indicate is better served by combining
treatment options. Both anaerobic–aerobic and aerobic–anaerobic
reactor sequences were considered, but it was concluded to place
the anaerobic unit first because anaerobic processes are better suited
to high strength wastes and aeration requirements then would
be lower in second-stage aerobic units. However, the best reactor
type was not clear for the anaerobic step, which is governed by
overall operational performance and net energy demand of the
whole system