Sludge Stabilisation and Disinfection by Means of Autothermal Aerobic Digestion with Oxygen

Research at pilot-scale was undertaken into autothermal aerobic digestion of sludge using oxygen to demonstrate that sufficiently high temperatures can be achieved to ensure the degree of disinfection that would satisfy the health authorities. The ova of the helminth Ascaris lumbricoides were used in the disinfection studies and the dissolved oxygen level in the sludge was used as a means of controlling oxygen consumption.

The results achieved indicate that the system very rapidly attained a stable temperature which could be easily maintained and which effectively ensured disinfection of the sludge at the 2 and 4 day retention periods tested, that the treated sludge readily ferments anaerobically, that the sludge will not readily settle and is very difficult to dewater.