Biological treatment of fish processing wastewater:A case study from Sfax City(Southeastern Tunisia)

The present work presents a study of the biological treatment of fish processing wastewa at salt concentration of 55 g/L. Wastewater was treated by both continuous stirred-ta reactor(CSTR) and membrane bioreactor(MBR) during 50 and 100 days, respectively. Th biological processes involved salt-tolerant bacteria from natural hypersaline environme at different organic loading rates(OLRs). The phylogenetic analysis of the correspond excised DGGE bands has demonstrated that the taxonomic affiliation of the most domin species includes Halomonadaceae and Flavobacteriaceae families of the Proteobacteria(Gamm proteobacteria class) and the Bacteroidetes phyla, respectively. The results of MBR w better than those of CSTR in the removal of total organic carbon with efficiencies from 97 to 98.6%. Nevertheless, salinity with increasing OLR aggravates fouling that requires m cleaning for a membrane in MBR while leads to deterioration of sludge settleability a effluent quality in CSTR.