Study On The Ceramic Membrane Bioreactor For Treatment Of Raw Water With High Ammonia Concentration

This thesis aims to deal with the seasonally polluted raw water with ammoniarecently occurred in Beijiang, and to develop an integrated ceramic membranebioreactor. Submerged flat-sheet ceramic membrane was used and its pore diameterwas60nm on average. Two integrated processes were compared including ceramicmembrane bioreactor (CMBR) and coagulation-enhanced ceramic membranebioreactor (CCMBR). Major performances were investigated in terms of theremoval efficiencies of ammonia, organic matter and turbidity, and the ability incoping with the ammonia shock load.When the concentration of ammonia in raw water was about3mg/L, bothintegrated processes can biologically degrade it to less than0.5mg/L, but theCCMBR showed better performance than CMBR. Upon ammonia shock loadcoming, it took about8hours for CMBR to cope with the ammonia shock load of6.52mg/L, the ammonia concentration in effluent was less than0.36mg/L, thenitrite concentration was as high as0.786mg/L; while the concentration ofammonia in effluent from the CCMBR was quickly reduced to less than0.13mg/Lafter the ammonia shock load of6.61mg/L. The nitrite concentration was less than0.14mg/L.The results showed that both integrated processes could remove turbidity tolower than1NTU and the particles larger than2μm were less than25CNT/mL.When combined with coagulation, the removal efficiency of CCMBR for CODMnand UV254were52.8%and47.1%respectively, which was much higher than that ofCMBR. It was inferred that the reactor could perform a better removal of organicmatter, especially for those in the range of30Da to2000Da.The critical flux of ceramic membrane could be influenced by coagulation,aeration and oxidation. O3had a better enhancement effect than ClO2and NaClO.With the O3dosage of3mg/L, the critical flux could be enhanced by2.6timeshigher than that of treating raw water directly, and by2.8times higher whilecombined with coagulation and ozonation at the same time.The results showed that both CMBR and CCMBR had the excellent capabilityin coping with the ammonia shock load, believed to be useful in upgrading drinkingwater treatment plants. The identification of membrane critical flux was of significance in maintaining the stable operation of membrane modules.