| Compared with the traditional activated sludge method,the aerobic granular sludge technology has the characteristics of abundant biological phase,strong resistance to shock loading and simultaneous denitrification and phosphorus removal,and has good prospects for specific application in practical engineering.However,the application of aerobic granular sludge is limited by the fact that it is difficult to cultivate and tends to disintegrate during the wastewater treatment process.This thesis explores the effect of different influent organic loading conditions on sludge activity and sludge granulation trends using an SBR reactor with aerobic flocculated sludge as the inoculum sludge.The effect of adding two different media on aerobic flocculated sludge granulation culture was investigated and an attempt was made to store the two successfully cultured granulated sludge in two different media to explore the appropriate storage method for granulated sludge.Finally,two types of granular sludge successfully cultured with two different media were used to treat actual domestic wastewater to explore the application of granular sludge.From the experimental study,the following conclusions were drawn from this thesis:(1)The use of an organic load of 1.5 to 4.5 kg CODCr/(m~3·d)in the influent water is more suitable for sludge cultivation.Instead,operating conditions with an influent organic load of 5 to 5.5 kg CODCr/(m~3·d)resulted in a large secretion of PS,which was not conducive to the subsequent cultivation of aerobic granular sludge.(2)During the cultivation of granular sludge with the addition of mixed activated carbon,the granular activated carbon had little effect on the granulation of the sludge culture,the sludge was mainly nucleated with powdered activated carbon and the aerobic granular sludge was successfully cultivated on day 34.The addition of PFS to aerobic granular sludge resulted in greater secretion of PN compared to the addition of mixed activated carbon,and the aerobic granular sludge was successfully cultured on day 25.The aerobic granular sludge system successfully cultured with the addition of PFS and the addition of mixed activated carbon had a removal rate of 93%-94%and 81%-84%for CODCr,68%-77%and 60%-65%for TN,and 89%-92%and 63%-68%for TP,respectively,from the 34 to 49d of incubation.(3)aerobic granular sludge incubated with mixed activated carbon was less structurally stable after storage and all sludge disintegrated after 15d of recovery incubation.In contrast,the structural stability of aerobic granular sludge cultured with the addition of PFS is relatively better.The aerobic granular sludge stored in PBS has better structural stability and removal of CODCr,TN and TP from wastewater than its aerobic granular sludge stored in pure water.(4)Disintegration of sludge in the reactor due to low CODCr concentration in domestic wastewater and excessive aeration time.Adjusting the operation strategy to increase the duration of the anoxic period and reduce the duration of the aerobic period,the aerobic granular sludge cultured with PFS was more effective than the aerobic granular sludge cultured with mixed activated carbon in removing CODCr and TN from the wastewater after the reactor had stabilised.The lack of sludge removal from both reactors makes them less effective in removing TP.Experimental studies in one cycle have shown the presence of short-course nitrification denitrification in SBR reactors.The growth of NOB can be inhibited during reactor operation by controlling the duration of the anoxic and aerobic periods and controlling the DO content in the reactor,thus achieving short-range nitrification and denitrification.The results of this thesis may provide some technical reference for the operational regulation of the cultivation,preservation and application process of granular sludge. |
