Combination of nejayote and swine wastewater as a medium for Arthrospira maxima and Chlorella vulgaris production and wastewater treatment

Nejayote and swine wastewater are highly pollutant effluents and a source of organic matter load that sometimes released into water bodies (rivers or lakes), soils or public sewer system, with or without partial treatments. Nejayote is a wastewater product of alkaline cooking of maize, whereas, swine wastewater results from the primary production of pigs for the meat market. Owing to the presence of environmentally related pollutants, both sources are considered the major cause of pollution and thus require urgent action. Herein, we report a synergistic approach to effectively use and/or treat Nejayote and swine wastewater as a cost-effective culture medium for microalgae growth, which ultimately induces the removal of polluting agents. In this study, the strains Arthrospira maxima and Chlorella vulgaris were grown using different dilutions of Nejayote and swine wastewater. Both wastewaters were used as the only source of macronutrients and trace elements for growth. For A. maxima, the treatment of 10% nejayote and 90% of water (T3)resulted in a cell growth of 32 × 10 4 cell/mL at 12 days (μ max = 0.27/d). While, a mixture of 25% swine wastewater, 25% nejayote and 50% water (T2)produced 32 × 10 4 cell/mL at 18 days (μ max = 0.16/d). A significant reduction was also noted as 92% from 138 mg/L of TN, 75% from 77 mg/L of TP, and 96% from 8903 mg/L of COD, among different treatments. For C. vulgaris, the treatment of 10% swine wastewater and 90% water (T1)gave a cell growth of 128 × 10 6 cell/mL (μ max = 0.57/d)followed by T3 yielded 62 × 10 6 cell/mL (μ max = 0.70/d)and T2 yielded 48 × 10 6 cell/mL (μ max = 0.54/d). Up to 91% reduction from 138 mg/L of TN, 85% from 19 mg/L of TP and 96% from 4870 mg/L of COD was also recorded. These results show that microalgae can be used to treat these types of wastewater while at the same time using them as a culture media for microalgae. The resultant biomass can additionally be used for getting other sub-products of commercial interest. © 2019 Elsevier B.V.This work was financially supported by Tecnologico de Monterrey, Bioprocess Research Chair ( 0020209I13 ), CONACYT-Mexican National Council for Research and CONACYT-Innovate UK project Phycopigments (grant #268792 ). The Technology Scholarship to I. Lopez #637424 and A. Silva CVU #888365 by CONACYT is also thankfully acknowledged. The authors also thank Mr. Jose Luis Tamez who kindly provided the swine wastewater used in this study.Peer reviewe