It is worth mentioning
that when the BOD/COD ratio was in the range of 0.2–0.3, extremely
long HRTs of 25–45 days were required by conventional biological technologies to achieve a modest COD removal of around 63%.
Whereas when the BOD/COD ratio of LFL was above 0.4, COD removal
efficiencies of 80% or higher were generally achieved with all conventional processes with relatively short HRT in the range of 5–20 days