Integration of submerged microfiltration and cold plasma for high-strength livestock excreta

Highlights: • Cold plasma (CP) oxidizes potential foulants by supplying reactive chemical species. • CP with membrane filtration (MF) enhances livestock urine and manure treatment. • Low membrane resistance supports improved transmembrane pressure and permeate flux. • Technical convergence of CP and MF contributes to viable livestock waste management. Numerous biological treatment techniques have been studied for better management of high-strength livestock urine and manure (LUM) but it is still challenging. To gain an advanced option for LUM management, this study proposes a physicochemical process combining microfiltration (MF) and cold plasma (CP). Experimental design applying single CP, single MF, and the integrated system coupling CP and MF (CP + MF) evaluates the performances of the configurations while reducing hydraulic retention time (HRT) from 3 d to 1 d. Results demonstrate that the CP + MF can maximize the removal efficiencies of total nitrogen (72.4 %), total phosphorus (57.8 %), NH₄-N (73.3 %), turbidity (99.1 %), dissolved organic carbon (71.3 %), suspended solids (98.7 %) at HRT 3 d. It was verified that CP, even at the lowest HRT (1 d), significantly reduces membrane resistance (0.4 × 10¹⁴ m⁻¹) compared to the control (1.5 × 10¹⁴ m⁻¹) which leads to lower transmembrane pressure (TMP, 45.6 kPa) and inclined flux (4.4 L/m²/h) than those of the control (45.6 kPa TMP and 2.2 L/m²/h). These results contribute to the advanced treatment of LUM with a cost-effective and environmentally friendly strategy via technical convergence.