The paper presents the results of the evaluation of sludge decomposition ability from a municipal wastewater treatment plant by an aerobic process on the Mishimax device (MK-50). The principle of the process was based on the microorganisms activated by the bulking agent as a bio-carrier to decompose organics composition and increase the evaporation by heating. An average sludge amount of 30 kg/day was added into MK-50, with the moisture of 80.2 – 83.6 %, with the C/N ratio of around 22 - 35. The heated air with 50 oC in temperature was supplied into a rotary bioreactor during the experiment period. After every 30 days of fermentation, the results from three experiments showed that the sludge volume decreased from 83 - 85 %, the stabilization efficiency by dry weight of sludge reached at 32 - 39 %, corresponding to the average decomposition rate is 12 g/kg.day, the evaporation efficiency was more than 95 %. Sludge after stabilization process had the colour of brown-grey, pH of about 6.5 - 7.2, the humus particles with the size of less than 1 mm accounted for over 60 %, the evaluation of product indexes according to nutrients like TOC, T-N meet the standard of 10TCN 526:2002/BNN&PTNT. The stabilized sludge was used for growth plant test and compared to a market organic fertilizer under the same conditions of cultivation and monitoring. The initial results of this study were a basis for research of sludge treatment technology approaches to waste recycling orientation in urban areas in Vietnam.
STUDY ON SLUDGE TREATMENT BY THE AEROBIC STABILIZATION PROCESS COMBINES WITH BULKING AGENT AND HEATED AIR SUPPLY
