Study On Relationship Between Characteristics Of Electro-osmotic Dewatering And Growth Environment For Sludge

With the rapid increase of the number of sewage treatment plants as well as the more thorough regulations for sludge treatment and disposal in China,it is significant to explore a cost-effective and efficient technology.In this paper,we explored the relationship between the characteristics of electro-osmotic dewatering for sewage sludge and the growth environment for the sludge,which further enriches the research category of electro-osmotic dewatering for sludge.In addition,the correlation between the basic properties of sludge and the effect of electro-osmotic dewatering was studied through analysis of experimental data from different sludge,to provide guidelines for the evaluation of applicable object of electro-osmotic dewatering technology.Firstly,the effects of initial sludge thickness,initial voltage gradient and mechanical pressure on electro-osmotic dewatering effect,current and energy consumption were investigated.The effectiveness of the electro-osmotic technology for the further dewatering of sludge was validated by the study.The optimal operating conditions were:the initial sludge thickness of 8 mm,the initial voltage gradient of 30 V/cm,the mechanical pressure of 75 kPa.Under this condition,the water content of the sludge could be reduced to 56.29%after 10 min of electro-osmotic dewatering,and the energy consumption for removal of 1 kg water was 0.1877 kW·h.Secondly,this study explored the relevance between different culture conditions of activated sludge(C/N of the influent,whether oxygen,culture temperature)and activated sludge properties,settling performance,mechanical dewatering performance,electro-osmotic dewatering performance and energy consumption.The experimental results showed that the increase or decrease of C/N in influent would increase the effect of mechanical and electro-osmotic dewatering.In particular,it was obvious that increasing C/N was beneficial to the improvement of mechanical dewatering.For the effect of sludge settling,mechanical dewatering and electro-osmotic dewatering,anaerobic sludge was better than aerobic sludge.What is more,in the field of current and energy consumption of electro-osmotic dehydration,anaerobic sludge was lower than aerobic sludge.Sludge domesticated at 35?was superior to it at 25?in the effect of sludge settling and mechanical dewatering.After fifteen,twenty two days'domestication,during electro-osmotic dewatering,sludge domesticated at 35?was better than it at 25?,but removal of1 kg of water for sludge domesticated at 35?required more energy than it at25?.The effect of oxygen supply and incubation temperature on the electro osmotic dehydration was more obvious.Finally,we used the linear fitting method to study the correlation between the basic nature(initial water content,organic matter,conductivity and p H)of sewage sludge,which got from different sewage treatment plant and cultured in different conditions,and the effect,current and energy consumption of electro-osmotic dewatering.In the results,there was a positive correlation between the water content of sludge after the mechanical dewatering and the water content of sludge after the electro-osmotic dewatering,so was the organic matter content and the water content of sludge after the electro-osmotic dewatering.There was a certain linear relationship,R~2 was 0.5121 and 0.7036 respectively.There was a relatively linear relationship between the conductivity and water content of sludge,current and energy consumption of the sludge after electro-osmosis dewatering.R~2 of them were all in 0.4-0.5.