Ultrasonic Pre-Treatment of Wastewater Sludge From a Meat Processing Industry

Abstract

This investigation deals with ultrasonic disintegration of sludge taken from a meat processing wastewater treatment plant. Different specific energy inputs ranging between 0 and 100 MJ/kg Total Solids (TS) were used in the study. The effect of ultrasonic pre-treatment on anaerobic biodegradability and filterability characteristics of sludge were evaluated using lab-scale experiments. 30 MJ/kg TS of supplied energy is efficient for cell lyses. Ultrasonic pre-treatment significantly enhanced the biodegradability of sludge. Biochemical methane potential test results also supported this result. For 30 MJ/kg TS, 2.4 times higher methane production was achieved compared to raw sludge. Sludge's supernatant characteristics were also affected by the ultrasonic pre-treatment. For 30 MJ/kg TS, oil content, total nitrogen and total phosphorus in the sludge supernatant increased by 3.8 times, 58 times, and 12 times, respectively. The other result is that ultrasonic treatment adversely affected filterability characteristics of sludge even for very low specific energy levels.

A Review on Sonochemistry and Its Environmental Applications

“…Figure 2 represents a typical layout of an activated sludge process and options for bio-mass disintegration. Ultrasound de-agglomerates biological flocs and disrupts large organic particles into smaller size particles by the formation and implosion of cavitation bubbles [44]. The shear forces produced by high pressure waves break down bacterial cell walls and release intracellular substances into the aqueous phase [42].…”