Dyestuff wastewater treatment by combined SDS-CuO/TiO_2 photocatalysis and sequencing batch reactor

Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor(SBR) were applied to treating dyestuff wastewater.Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment.SDS-CuO/TiO2 photocatalyst was prepared by modification of nano-TiO2 using CuO and sodium dodecyl sulfate(SDS).Results show that the SDS-CuO/TiO2 photocatalyst contains two kinds of crystals,including TiO2 and CuO.The band gap of this photocatalyst is 1.56 eV,indicating that it can be excited by visible light(λ<794.87 nm).And characterization also shows that there are alkyl groups on its surface.It takes 40 min to improve the biodegradability of dyestuff wastewater.Five-day biochemical oxygen demand(BOD5) and dehydrogenase activity(DHA) of wastewater reach the maximum value when dissolved oxygen is higher than 2.97 mg/L.SBR reactor was used to treat this biodegradability improved wastewater.Chemical oxygen demand(COD) and colority decline to 72 mg/L and 20 times,respectively,when the sludge loading is 0.179 kg(COD)/[kg(MLSS)?d],dissolved oxygen is 4.09 mg/L and aeration time is 10 h.

Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor （SBR） were applied to treating dyestuff wastewater. Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment. SDS-CuO/TiO2 photocatalyst was prepared by modification of nano-TiO2 using CuO and sodium dodecyl sulfate （SDS）. Results show that the SDS-CuO/TiO2 photocatalyst contains two kinds of crystals, including TiO2 and CuO. The band gap of this photocatalyst is 1.56 eV, indicating that it can be excited by visible light （2〈794.87 nm）. And characterization also shows that there are alkyl groups on its surface. It takes 40 rain to improve the biodegradability of dyestuff wastewater. Five-day biochemical oxygen demand （BODs） and dehydrogenase activity （DHA） of wastewater reach the maximum value when dissolved oxygen is higher than 2.97 mg/L. SBR reactor was used to treat this biodegradability improved wastewater. Chemical oxygen demand （COD） and colority decline to 72 mg/L and 20 times, respectively, when the sludge loading is 0.179 kg（COD）/[kg（MLSS）＇d], dissolved oxygen is 4.09 mg/L and aeration time is 10 h.