|Other Abstract||The membrane bioreactor (MBR) technology, which has the advantages of small footprint, high treatment effect and easy management, was widely applied to the high concentration and non-biodegraded wastewaters. However, its low removal rates of nitrogen and phosphorus hinder its wide application in some circumstances. The chemical measurements for removing phosphorus were easy for application and could improve the phosphorus removal rate effectively.
The submerged membrane bioreactor (SMBR) was chosen as the typical representative. The removal efficiencies for MBR under optimal operational conditions, the studies of optimal chemical coagulant, together with the effects of Al2 (SO4)3 on the purification effects of wastewater in a continuous SMBR system, were studied.
The exact results were as following:
Firstly, under the optimal operational conditions(MLSS=7g·L-1, JV = 10L·m-2·h-1, Qgas=6m3·h-1, tp/tb= 4min/min, Ar/Ad=1.7m2/m2, temperature=25~35℃), most of the chemical parameters of the effluent in the SMBR could meet with the requirements for Class I of integrated wastewater discharge standard(GB18918-2002), while the average removal rate of TP was only 55.6% , and the phosphorus concentration of effluent was over 1mg/L.
Secondly, four different coagulants: Al2 (SO4)3, FeCl3, PAC and PAM were studied for their phosphorus removal abilities in batch test. It showed that Al2 (SO4)3 was the best choice for the removal of phosphorus, with the advantages of stable and high treatment performance. The optimal operating condition was mixed with 200 rpm in 1-2 minutes; and the main forms for removal of phosphorus were SRP and PP.
Thirdly, the removal effects of phosphorus in the SMBR was studied by continuous addition of certain concentration of Al2 (SO4)3, the results indicated that the addition of Al2 (SO4)3 could significantly improve the removal ability for phosphorus, and the concentrations of phosphorus in the effluent during the experimental period were within 1mg/L, which met with the requirements for Class I of integrated wastewater discharge standard (GB18918-2002). Meanwhile, the average removal rates of COD, ammonia and TN were 97%, 96.6% and 67.7%, respectively.|