Resumo:
UASB reactors treating swine wastewater were operated with influent
total suspended solids concentrations (TSS) of 500, 1000, 1500 and 2000 mg.l-1,
hydraulic detention time (HDT) of 30, 20, 12 and 8 hours and consequently increasing
organic loading rates (OLR). Total alkalinity, bicarbonate alkalinity (PA - partial
alkalinity) and volatile acids alkalinity (IA - intermediate alkalinity) were measured with
the objective of to verify relations between reactor performance and alkalinity
proportions (IA:PA). IA:PA requires only one simple analytical procedure. The IA:PA
increased to value above 0.30 whenever instabilities in reactor performance ocurred:
COD and TSS removals, and CH4 production decreased and total volatile acids
concentration increased.