“…The beneficial effect of addition of readily biodegradable carbon sources, such as glucose or fermentation products from primary sludge anaerobic digesters, such as short-chain fatty acids or their salts (in this paper they were abbreviated to SCFA) has been recognised in the literature [5][6][7]. However, until now most of the studies on carbon substrate affecting EBPR are focused on acetate or glucose [1,3,[8][9][10][11][12]. The investigation on other SCFA such as propionic acid influencing EBPR performance is limited [13][14][15][16][17].…”