Biogenic substrate benefits activated sludge in acclimation to a xenobiotic

► Biogenic substrates enhance performance of activated sludge in acclimation and degradation of a xenobiotic. ► Biogenic substrates' positive effect is enrichment of sludge's energy that shortens acclimation lag time. ► Biogenic substrates can cause diauxic growth which lengthens lag time. ► The positive effect often wins over the negative effect to result in a net benefit.