Research On The Dynamic Membrane Coupled With A Bioreactor For Domestic Wastewater Treatment

The membrane bioreactor (MBR) is a new wastewater biological treatment technology which combined with the membrane separation technology, and it has been investigated very deep in the recent 30 years. However, there are still two main problems blocking the wide application of this process, one is the filtration modules are too expensive, and the other is the membrane fouling control is difficult. In order to solve these problems, many researchers have done a lot of work for MBR reclamation, and the dynamic membrane technology would be one of the approaches to settle the problems.In this thesis, the membrane module was made up of common filter cloth, and the self-forming bio-dynamic membrane (SFDM) was studied in the first because of its simple and convenient manipulation. Its filtration capability was investigated through dosing different concentration powdered activated carbon (PAC) into DMBR. The results show:(1) The optimal PAC dosage is about 2.0 g·L^-1 in a single filtration period under the constant membrane flux. The operational period of 15 days with 2 g·L^-1 PAC dosage in the DMBR is 2.5 times longer than that of 6 days without PAC, and the dominant sludge particle diameter of 100 μm with PAC dosage is greater than that of 80 μm without PAC.(2) The SEM shows that the gel layer is the main factor of the membrane fouling without PAC, while the cake layer is the main factor of the membrane fouling with 2.0 g·L^-1 PAC dosage in the DMBR. The latter's membrane fouling can be cleaned easily, and its membrane flux can also be recovered easily.Although the SFDM has simple and convenient manipulation, its single filtration period is still very short which limits the application in the engineering field. So we studied the precoated dynamic membrane (PDM) for its better technology performance, and its steady preparation, properties characterization and long-time operational performance was investigated. The results show:(1) The suitable precoated thickness was controlled around 0.3 mm through studying the separation performance and the relationship between the thickness and the tap water filter resistance of the different thickness PDMs.(2) The experiment ran for 153 days with the stable operational performance. In the case of the membrane flux was 13.7 L·m^-2·h^-1, HRT was 10 h, the COD removal efficiency was 90.43%, NH₄⁺-N removal efficiency was 96.83%. The SEM show that the gel layer was the...