| abstract |
The invention relates to a novel integral process for the treatment of wastewater, commonly known as nejayote, from the nixtamal, masa and tortilla industry, comprising an improved method for removing the insoluble fraction and a filtration system for separating and concentrating the fractions forming the nejayote. The method comprises the steps of: (a) neutralising the nejayote; (b) enzymatically hydrolysing the starch granules; (c) flocculating and separating the insoluble fraction. The system comprises the steps of (a) microfiltration; (b) ultrafiltration for concentrating long-chain carbohydrates; (c) ultra/nano filtration for concentrating medium-size compounds; (d) nanofiltration/reverse osmosis for concentrating small molecules and obtaining water of sufficient quality that it can be re-used or safely discharged into the environment. In one embodiment of the invention, in order to remove unwanted phenolic compounds, the process includes a method comprising the steps of: (a) acidifying the effluents at pH <4; (b) flocculating and separating the unwanted insoluble fraction. |