Advanced Sewage Treatment with Ozone Under Excess Sludge Reduction, Disinfection and Removal of EDCs

Holistic sludge management through ozonation: A critical review

“…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).…”

“…Arakawa et al, (2011) reportedly recovered phosphorous from the effluent of ozonated anaerobic/anoxic/aerobic system by chemical precipitation and consequently maintained the final TP discharge below 1 mg/L. Several studies have demonstrated that highly concentrated waste streams, such as ozonated sludges and digestates, are ideal targets for nutrient recovery schemes (Qiang et al, 2015;Tsuno et al, 2008) which will be discussed in greater detail in Section 5.1.…”

“…Inert solids could comprise 25-50% of the TSS of primary or secondary sludge depending on influent characteristics and operation conditions (Turovskiy & Mathai, 2005). The mineralisation or conversion of inert solids into more biodegradable forms (Saktaywin et al, 2005;Tsuno et al, 2008) further contributes to the overall decrease of sludge mass.…”

“…Significant research effort has been devoted to the application of ozonation in sludge reduction (Chu et al, 2009b) or removal of emerging contaminants (Gerrity & Snyder, 2011), but there is only a few studies linking the two together (Qiang et al, 2015;Tsuno et al, 2008). Meanwhile, the use of ozonation in resource recovery is an emerging topic that is worthy of further investigation (Qiang et al, 2015;Saktaywin et al, 2005).…”