New Helical Membrane Module And Its Application In Water Treatment

The MBR-technology has biodegradation and effective membrane separation. It has been used for wastewater treatment because of the advantages it offers over conventional treatment processes, such as:smaller footprint, advantageous effluent quality and better process control. In the development of Membrane Bioreactor (MBR) technology, the properties and costs of membrane material and membrane module were the key to MBR's development and application, because biodegradation process was a mature method. Membrane module was basic unit to MBR, and the different types determined performances of MBR. Accordingly, the optimal design of membrane module is very significant to reduce membrane fouling and enhance membrane permeation flux, the aeration energy consumption would also be reduced at the same time.In view of shortcoming of existing membrane modules, we designed a nature-inspired new helical module according to bionics principle, which reduced filtration resistance, decay rate of flux obviously, and kept higher limiting flux value through intensify influence of gas and fluid to membrane module.Helical membrane modules of different rotation angles and length-width were tested respectively and compared with that of flat membrane modules, to prove the effect on rotation angle and length-width to its performance. Then collisions and reciprocity between bubbles and curved surface of membrane were researched by two-phase fluid mechanics and bubble dynamics. Finally, for better clarify the practical operations of helical membrane module, it was tested in MBR to treat simulant domestic sewage.The results showed that helical membrane modules had better filtration and anti-fouling abilities than numal flat membrane module. The cake layer of helical membrane was looser, so effluent quality was improved and irreversible fouling was reduced effectively. In aeration test, mass transfer coefficient of helical module increased more quickly than that of flat module when aeration strength was enhanced. In addition,flux of helical module declined much slower when aeration strength was reduced. It was fully proved that helical membrane module had great potential in energy saving.