The Research On MBR For Water Reuse Of Expressway Service Area

Aiming at the current situation and problem of the wastewater treatment of highway service area, the view of using MBR (Membrane Bioreactor) wa s prefer to be the main treatment technology for water reuse of expressway ser v-ice area. Via the pilot study, we explored the feasibility of MBR, and the nec-essary operating parameters were given to the demonstration Project of wa ter reuse for Hunan expressway service area.Firstly, artificially prepared sewage of the highway service area was used. Then according to the removal efficiency of relevant water-quality index, th e operational parameters(HRT and water-gas ratio) which is suitable for sewag e quality of expressway service area were selected. Then the membrane flux---c r-itical flux of actual project was determined and at last the membrane foulin g mechanism and cleaning methods were explored.The experiments testify that the removal of the COD, BOD, NH3-N, TN and TP by MBR (Membrane Bio-Reactor) respectively reaches to95.1%,98.5%,93.4%,50.5%, and40.4%under the optimum operating condition in which the HRT (Hydraulic Retention Time) is10hours and the gas-water rate is70:1. Consequently, the outflow water after the treatment of MBR process achieves the miscellaneous water quality standard. With the variation of HRT from6hours to12hours, the removal of COD, BOD and NH3-N changes scarcely, while the removal of the TN ascends to63%from54.4%and the TP descends from40%to30%. And with the variation of gas-water rate from80:1to50:1, the changes in removal of COD and BOD appear considerably slight; on the other hand the changes happen in the removal of NH3-N and TN, respectively with the removal of NH3-N falling from95%to87.5%, the removal of TN rising from40%to60%and TP from20%to40%. In the experiment, the threshold of the MBR flux is taken as22L/(m2·h), while aeration and outflow backwash can slow down the pollution of the MBR to some degrees, and the operating cycle is extended with the MBR flux recovered by chemical rinse.Via the technical, and Economic Analysis of Water Reuse of Guiyang service area of Chenning expressway in which way MBR was used, the water reuse operating costs of MBR is2.38yuan/m3,and water reuse has a better benefits of social environment.