Effect Of Sludge Synergist On Treatment Performance Of MBR

To improve the characteristics of mixed liquor suspended solids is the key of further strengthening processing capabilities and reducing membrane fouling of MBR.In this paper a mixture of bio-ferric and PAC was added in MBR and a composite processing of synergist-MBR was proposed from this angle.This paper compared the characteristics of two different types of MBR,the synergist membrane bio-reactor and the submerged membrane bio-reactor,through the treatment of domestic wastewater.Batch experiments were carried out to make studies on the optimal dosing quantity.In the continuous experiments,the effect of pollutant removal in long-term operation,the pollutant degradation rate,the reduction of membrane fouling and some characteristics of mixed liquor such as EPS and so on were studied.Main results are as follows:In the SBR experiments,it was proved that the optimal dosing quantities of bio-ferric and PAC were 10%of activated sludge and 1200mg/L separately.Through long-term experiment,the removal rate of COD,NH4+-N and turbidity with these two different reactors were better,but both the removal rate of TN were relatively different,which was made increased by 10%with synergist. The synergist made characteristics of the mixed liquor better,such as EPS,supernatant SMP,Zeta potential,viscosity and membrane fouling.The supernatant SMP and the zeta potential was reduced with synergist addition.The sludge flocs were enlarged because of accelerating the aggregation between the colloids and sludge flocs,which was beneficial to oxygen transmission and increase membrane filtration flux.the corresponding changes among SMP,Zeta and EPS indicated that the synergist addition enhanced the activity of the sludge.The COD degradation rates with operating time were developed by Eckenfelder model.The maximum degradation rates of COD were 2.68 for MBR with operating time=47d and 2.91 for synergist-MBR with operating time=56d.According to the laboratory results,the content of EPS per unit volume of activated sludge had good correlation with the constant K1 of COD degradation rate.The higher the EPS content, the faster the degradation rate and the better the activity of sludge.