Effect of the sludge recirculation rate on the performances of a two-stage anoxic-submerged membrane bioreactor (A SMBR) for the treatment of seafood wastewater Porntip Choksuchart Sridang1*, Jorge Lobos 2, and Chansongglod Kaiman3 1 Department of Environmental Science, Faculty of Science, Silpakorn University, Thailand, 73000, Membrane Technology for Hazardous Waste Management Group, Center of Excellence for Environmental and Hazardous Waste Management(EHWM), Bangkok 10330, Thailand, Satellite Center at Prince of Songkla University, Membrane Science and Technology Research Center (MSTRC) Prince of Songkla University, Thailand, 90112 2 Chemical Engineering Department, Universidad de Santiago de Chile, Av. Lib. Bernardo O’Higgins 3363, Casilla 10233, Santiago, Chile.3 3 Faculty of Resources and Environment, Kasetsart University, Thailand, 20230

บทคัดย่อ
The objective of this research is to study the effect of the sludge recirculation rate on the performance of two-stage anoxic-submerged membrane bioreactor (ASMBR) for the treatment of seafood wastewater. The seafood wastewater presents the biodegradable of containing high values of organic matter (COD around 2750 mg.L-1) and organic nitrogen compounds (TKN around 484 mg.L-1). Four values of recirculation rates, from 1/8 to 3 times the inflow rate, were studied during a long operational period. The MBR reactor was operated in subcritical flux conditions and no sludge extraction was done during the whole experimental period. The overall efficiency for the COD and nitrogen compound removal rate was on average 95+3% and 98+2% respectively. The residual COD, TKN and NO3–N concentration in the effluent were 23+4 mg.L-1, 1.2+0.9 mg.L-1 and 29+9 mg.L-1 respectively. In terms of filtration, trans-membrane pressure (TMP) showed a small and constant values in the membrane reactor with a TMP value of around 5-10 mbars. Membrane fouling appeared linked with the soluble organic compound interactions on the membrane surface (irreversible fouling).The quality of treated water met with the standard of wastewater reuse for all classes (A to D) issued by USEPA.

คำสำคัญ: Denitrification, Membrane bioreactor, Nitrification, Sludge recirculation, Water reuse