Performance of membrane bioreactor system with sludge ozonation process for minimization of excess sludge production

Holistic sludge management through ozonation: A critical review

“…By contrast, other studies found that increasing ozone dosage enhanced (Song et al, 2003) or did not change (Bougrier et al, 2006;Zhang et al, 2009) floc size. According to Song et al (2003), ozonated sludge had larger particles (60 µm) than non-ozonated sludge (30 µm) due to the coagulation and eventual re-flocculation of solids after ozonation. Discrepancies between different studies are possibly due to variations in sludge properties and experimental conditions (e.g., range of ozone dosages).…”

“…Some studies found that increasing ozone dosage decreased sludge floc size, which pertains to floc destruction (Demir & Filibeli, 2012;Park et al, 2003). By contrast, other studies found that increasing ozone dosage enhanced (Song et al, 2003) or did not change (Bougrier et al, 2006;Zhang et al, 2009) floc size. According to Song et al (2003), ozonated sludge had larger particles (60 µm) than non-ozonated sludge (30 µm) due to the coagulation and eventual re-flocculation of solids after ozonation.…”

“…For instance, ozonation at 100 mg O 3 /g TSS resulted in the conversion of lysates (products of cell lysis) into volatile fatty acids (e.g., lactic acid) and sulphate (Chu et al, 2009b;Song et al, 2003). These compounds rapidly consume radicals and interfere with sludge reduction (Chu et al, 2009b;Song et al, 2003), and have potential to decrease sludge solubilisation efficiency. Radical scavengers are discussed in more detail in Section 3.1.…”

“…Generally, ozonation increases effluent COD due to sludge solubilisation (Section 2.1). In spite of this, many studies demonstrate that the overall COD removal efficiency was unaffected (Demir & Filibeli, 2014;Huysmans et al, 2001;Naso et al, 2008;Nie et al, 2014;Paul et al, 2012;Richardson et al, 2009;Song et al, 2003;Tsuno et al, 2008) or underwent a minor decrease (5-10%) (Albuquerque et al, 2008;Nagare et al, 2008;Qiang et al, 2015), and therefore effluent COD was maintained at satisfactory levels. This was because the majority of the solubilized COD was biodegradable, and was rapidly consumed when ozonated sludge was returned to the aerobic reactor (Dytczak & Oleszkiewicz, 2008;Nagare et al, 2008).…”

“…Ozonation can increase soluble nitrogen concentration, however, many studies have also shown that adequate overall TN removal efficiency of the main bioreactor/s can still be achieved (Arakawa et al, 2011;Nie et al, 2014;Qiang et al, 2015;Song et al, 2003;Sui et al, 2014;Tsuno et al, 2008). Stable reactor performance could be achieved when sludge acclimatizes to continuous ozonation (Qiang et al, 2015;Sui et al, 2014).…”