GRANULE PRODUCTION FROM RAW WASTE ACTIVATED-SLUDGE

Granulation is an important characteristic of sludges used in upflow a naerobic sludge blanket (UASB) reactors. As the UASB technology is rap idly spreading, there is a need of granular sludge for inoculation of new reactors, particularly in those countries where anaerobic technolo gies have been just recently accepted. Alternative sources of inocula are digested sludge, digested manure, septic tank sludges and pond sed iments. Raw waste activated sludges have also been identified as a con venient material for reactor seeding, with previous treatment In this work, anaerobic flocculant sludge obtained from raw waste activated sl udge has been granulated with hydraulic stress, in a lab-scale column under different upflow velocities (1 to 50 m h(-1)). A methodology is proposed for enhancing the quality of non granular anaerobic sludges i n batch treatments of less than 8 hours. The granular sludge produced was used as inoculum for a UASB lab scale reactor. The seed sludge imp roved all its characteristics and maintained the granulation, in spite of the low velocity (0.08 m h(-1)) applied.