MBR membrane integrated wastewater treatment process

Overview

The MBR membrane bioreactor integrated equipment is a new water treatment technology that combines membrane separation technology with biotechnology. It uses membrane separation equipment to trap active sludge and macromolecular organic matter in the biochemical reaction tank, eliminating the need for a secondary sedimentation tank. The membrane-bioreactor process significantly enhances the function of the bioreactor through membrane separation technology, greatly increasing the concentration of active sludge, and allowing for separate control of the hydraulic retention time (HRT) and sludge retention time (SRT).

Features

1) High removal rate of pollutants, strong resistance to sludge expansion, stable and reliable effluent water quality, no suspended solids in the effluent.

2) The membrane bioreactor achieves separate control of the reactor sludge retention time (SRT) and hydraulic retention time (HRT), thereby significantly simplifying its design and operation.

3) The membrane's mechanical retention function prevents the loss of microorganisms, allowing for high sludge concentration within the bioreactor. This enables an increase in volume load and a reduction in sludge load, exhibiting strong shock resistance.

4) Due to the long SRT, the bioreactor also acts as a "sludge nitrification pond," significantly reducing sludge production, resulting in low residual sludge output and low sludge treatment costs.

5) The membrane's flow control effect prolongs the SRT, creating an environment conducive to the growth of slow-proliferating microorganisms, such as nitrifying bacteria. This enhances the system's nitrification capacity and benefits the treatment efficiency of difficultly degradable macromolecular organic matter, promoting its complete decomposition.

6) The active sludge in the MBR aeration tank does not wash out with the effluent. During operation, the active sludge varies due to changes in organic matter concentration, achieving a dynamic equilibrium. This characteristic ensures stable effluent quality and resistance to shock loads.

7) The large hydraulic cycle results in uniform mixing of wastewater, thus providing excellent dispersion for the active sludge, significantly increasing the specific surface area of the sludge. The highly dispersed active sludge in the MBR system is another reason for the improvement in water treatment efficiency. This is something that the conventional biochemical water treatment technology, which forms larger floc, struggles to achieve.

8) Membrane bioreactors are easy to integrate, facilitate automatic control, and are convenient for operation and management.

9) The MBR process omits the secondary sedimentation tank, reducing the land area required.

Application

1. The membrane bioreactor is a novel and efficient wastewater treatment technology that combines membrane separation with biological treatment. The nitrogen removal mechanism of industrial nitrogen-containing wastewater includes two fundamental processes: nitrification and denitrification. Nitrification refers to the conversion of ammonia nitrogen to nitrate nitrogen, a process primarily carried out by two types of aerobic autotrophic bacteria: nitrosomonas and nitrobacter.

2. The MBR membrane technology first removes biodegradable organic pollutants from water using activated sludge, followed by the use of membrane modules to forcibly retain the activated sludge and the vast majority of suspended solids within the bioreactor. This achieves separation of the treated water and the solid-liquid activated sludge, thereby enhancing the biochemical reaction and improving the wastewater treatment efficiency and effluent water quality.

3. The MBR treatment process shows significant COD removal effectiveness in the nitrogen fertilizer industry wastewater. The cultivation and acclimatization stage of the biochemical strain is relatively short, demonstrating stable results from the third day; both the stable treatment phase and normal operation phase maintain a high COD removal rate, generally above 90%; the average COD export is controlled below 30 mg/L.