Vivianite Occurrence and Remediation Techniques in Biosolids Pre-treatment Process

Ionic strength of the liquid phase of different sludge streams in a wastewater treatment plant

“…Volatile Fatty Acids (VFA) concentration can strongly increase, especially during prefermentation, due to the decomposition of organic matter (Roldán et al 2020) that mainly takes place during the first two days of fermentation (Soares et al 2010;Yuan et al 2011). The VFA produced, composed of Table 1 | Ranges for the compounds whose concentration is identical in all non-digested streams Low Typical High 50-80% of acetate (Astals et al 2012), explains why the pH of thickened sludge is usually lower than in influent/effluent (Bouzas et al 2002;Pathak et al 2018).…”

“…The release of K þ is usually more noticeable than the release of Ca 2þ and Mg 2þ since these latter can precipitate in sludge, for example with phosphate (Wilfert et al 2016;Roldán et al 2020). The extend of the release of PO 3À 4 , K þ , Ca 2þ and Mg 2þ is very dependent on the advancement of the fermentation (Barajas et al 2002;Martí et al 2010;Wilfert et al 2016;Pathak et al 2018). This phenomenon should be even more important for EBPR sludge than for CPR sludge, since more PO 3À 4 , Mg 2þ and K þ were accumulated by PAO's in the first place in EBPR sludges (Jardin & Pöpel 1994;Bouzas et al 2002;Roldán et al 2020).…”

Ionic Strength of the Liquid Phase of Different Sludge Streams in a Wastewater Treatment Plant

“…Volatile Fatty Acids (VFA) concentration can strongly increase, especially during prefermentation, due to the decomposition of organic matter (23) that mainly takes place during the first two days of fermentation (31,36). The VFA produced, composed of 50-80% of acetate (35), explains why the pH of thickened sludge is usually lower than in influent/effluent (7,37).…”

Ionic Strength of the Liquid Phase of Different Sludge Streams in a Wastewater Treatment Plant

“…Volatile Fatty Acids (VFA) concentration can strongly increase, especially during prefermentation, due to the decomposition of organic matter ( 23) that mainly takes place during the first two days of fermentation (31,36). The VFA produced, composed of 50-80% of acetate ( 35), explains why the pH of thickened sludge is usually lower than in influent/effluent (7,37).…”

“…fermentation(4,7,24,40). This phenomenon should be even more important for EBPR sludge than for CPR sludge, since more PO4 3-, Mg 2+ and K + were accumulated by PAO's in the first place in EBPR sludges(23,29,37).…”