Microwave Disintegration Of Sludge As A Method Of Accelerating The Aerobic Stabilization Process

This paper presents the results of aerobic stabilization tests, controlled by total dissolved solids and total organic solids (TOS), for three process temperatures (12 degrees C +/- 1 degrees C, 15 degrees C +/- 1 degrees C and 22 degrees C +/- 1 degrees C) and five ratios of the share of sludge subjected to initial microwave disintegration (1:0, 3: 1, 1:1, 1:3, 0:1). As expected, the disintegration process preceding the sludge stabilization process increases COD and BOD5 in the supernatant liquid. As the proportion of disintegrated sludge in the stabilized liquid increases, these values are higher. The process of aerobic sludge stabilization was carried out for 35 d. Constant aeration of the sludge resulted in a decreasing mass of TOS in the following days of stabilization. At the same time, faster sludge stabilization at higher process temperatures was confirmed. Research has shown the acceleration of the sludge stabilization process with an increase in the share of disintegrated sludge (from 0% to 50%). This effect is more pronounced at a lower temperature (12 degrees C, 15 degrees C) than at a higher temperature (22 degrees C). Regardless of the temperature of aerobic stabilization, a decrease in process efficiency and extension of stabilization time was observed when the disintegrated sludge content was above 50%. Research has shown a beneficial effect of the share of disintegrated sludge in the proportion of 1:1 (50%) on the reduction of TOS in the process of aerobic stabilization. For this proportion, a potential energy gain of up to 18% was obtained, and the stabilization time was shortened by about 3 d when conducting the process at 22 degrees C and by about 10 d at 12 degrees C. This should be taken into account in the economic assessment of the treatment of sewage sludge at wastewater treatment plants.