Bacterial 16S rRNA genes were amplified and sequenced using 454 GS                 FLX Titanium for fouled UF membrane.target gene : bacterial 16S rRNA target                 subfragment:V1-V3 pcr primers : Forward: GAGT TTGA TCMT GGCT CAG Reverse: WTTA CCGC                 GGCT GCTG G multiplex identifiers :CACG TGTC GC adapters : Forward: CCTA TCCC CTGT                 GTGC CTTG GCAG TC Reverse: CCAT CTCA TCCC TGCG TGTC TCCG AC pcr conditions 95                 degrees C for 5 min; 30 cycles at 95 degreesC for 30 s, 55 degreesC for 30 s and 72                 degreesC for 30 s, with a final extension at 72 degreesC for 7                 min.