| High-efficiency, energy-saving and equipment-miniaturization are developing tendency for current wastewater biological treatment and sludge granulation is an important method to realize this goal. Anaerobic granule sludge has widely been studied and applied. However, thus far culture condition, formation mechanism and characteristics of denitrifying granule sludge have rarely been reported.Denitrifying granular sludge can be successfully achieved in short time using glucose as carbon source after aerobic active sludge is inoculated.Sludge inoculated appear wadding and they have complex structures and plenty of microorganisms. Mature granular sludge have stable structure and good setting velocity of 45-50 m·h-1. Its humid density is 1.0223 g·cm-3 and water containing accounts for 95.6% (as total weight).The whole formation period can be composed of two phases, One is sandy sludge formation period and another is granulation period.Both heavy microorganism and high nitrate rate can be achieved in USB. When up-flow velocity is 3.3 m·h-1, MLSS and MLVSS can reach 27.5 g·L-1与 23.1 g·L-1 respectively. When nitrate load is 19.1 gN.L-1·d-1, removal rate is 98.4% (as N); when COD load is 91.3 gCOD·L-1·d-1, removal rate is 91.1% (as COD). The maximal denitrification rate is 0.98 gN.gVSS-1·d-1(as MLVSS) at 30℃.The paper proved that with ratio of organic matter to nitrate consumed, denitrification stoichiometric equation could be established to calculate reasonable carbon tonitrogen ratio and actual sludge yield. YHobs=0.614R-1.755(gVSS·gN-1)...
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