Influences of dissolved organic matters on tetracyclines transport in the process of struvite recovery from swine wastewater

Due to the extensive existence of tetracyclines (TCs), struvite (MgNH4PO4·6H2O) recovery from swine wastewater will pose TCs-pharmacological threats to the agricultural planting and environment. This study investigated the influences of dissolved organic matters (DOM), as an important medium in the wastewater, on TCs transport during struvite recovery from swine wastewater. Compared to TCs concentrations of 1.49–2.16 μg/g in the solids obtained from synthetic wastewater, the existence of DOM significantly enhanced TCs contents in the products with the values of 360–742 μg/g. DOM was fractionated into four size fractions with different molecular weight cut-off, i.e. FDOM1 (30 kDa-0.45 μm), FDOM2 (5–30 kDa), FDOM3 (1–5 kDa) and FDOM4 (