Swine wastewater treatment by combined process of iron carbon microelectrolysis-physical adsorption-microalgae cultivation

Abstract

Combined treatments were designed based on iron-carbon micro-electrolysis treatment (ICME), physical adsorption (PA) with zeolite (Z) or vermiculite (V) and microalgae cultivation (MC, Chlorella vulgaris) for removing pollutants from swine wastewater (SW): ICME + MC (IM), ICME + Z + MC (IZM) and ICME + V + MC (IVM). Results showed that the minimum total nitrogen (TN) of 43.66 mg L−1, NH4+-N of 1.33 mg−1 and total phosphorus (TP) of 0.14 mg−1 were obtained by IVM, while the minimum chemical oxygen demand (COD) was 105 mg−1 via IM. During the process of combined treatments, ICME contributed most to the removal of TN (84.52% by IZM), TP (97.78% by IVM and IZM) and COD (62.44% by IVM), and maximum NH4+-N removal (55.64%) was obtained by MC procedure in IM process. Vermiculite performed better than zeolite during all the combined treatments. Besides, the maximum cell dry weight (CDW, 0.74 g−1) of C. vulgaris was obtained by IM on day 13. The results provide an efficient integrated method for swine wastewater treatment. HIGHLIGHTS Process combining iron-carbon microelectrolysis, vermiculite adsorption and microalgae cultivation was the most efficient for treatment on TN, NH4+-N, TP removal.; Iron carbon micro-electrolysis combined with microalgae cultivation was the most efficient treatment for COD removal.; The maximum biomass harvest was observed on day 13 via combined iron-carbon microelectrolysis and microalgae cultivation.;

Keywords

• adsorption
• microalgae
• micro-electrolysis
• wastewater