Study Of Sludge Bio-drying Process

Sludge drying is one of the important methods of excess sludge reduction process. Thermal drying and natural drying which are widely used exists problems of high energy consumption or time-consuming. While the sludge bio-drying using their own biomass heat to discharging the water, has broad prospect for sludge treatment technologies. However, the study and application of this technology is still in its initial stage, some basic problems need to be solved. In this paper, we use dewatering sludge from Shenyang Northern Sewage Treatment Plant as the object of study, studied effect of conditioners, different ventilation rates and different ventilation modes on bio-drying sludge. In parallel experiments, we set the ventilation rate from 2 to 10 in each group respectively, ventilation cycle unified set to 6 days. Experimental results show that, when the ventilation rate is 6, between 26 h to 92 h the temperature rise gradient of the sludge matrix is the maximum, and at 86h the maximum temperature reached 82.3?, temperatures stay above 60? for about 78h, the final temperature was maintained at about 40.8?. Water content decreased significantly began to appear from the third day, to the sixth day of experiment water rate dropped to 43.40% from 85.7%, which has dropped 42.3%. Comparing the amount of ventilation in the paper, when the ventilation rate is 6, sludge matrix drying has the highest efficiency and has the most obvious effect, is the recommended ventilation under stable continuous ventilation, inoculation specific strains conditions. According to the bio-drying has a great relationship with drying time, we recommend in the early feeding reduce the ventilation, in second phase when microbial metabolic reactions in the most exuberant set the maximum ventilation, after that corresponding decrease ventilation in the third phase, control the ventilation process base on the situation of sludge bio-drying, the articles set four different ventilation strategy to be compared, in which a relatively better group compared with the group were maintained throughout the test period temperature has risen 7.3% and water content reduce 9.37%. Results of this study may provide scientific evidence for sludge bio-drying technology further optimization and promotion, and provide the basis for sludge dewatering further treatment and disposal of Shenyang wastewater treatment plant.