This thesis presents an assessment of the availability and quality of biomass from the wastewaters in a traditional corn mill in Mexico City for biogas production. To date, these wastewaters (called nejayote) are discharged untreated to the sewer with a chemical composition that surpasses the maximum permissible levels of pollutants established in the Official Mexican Standards (NOMs). From the study case four scenarios were proposed to tackle this problem: 1) separate the suspended solids (SS) by sedimentation in order to reduce the organic content of nejayote, 2) recover a protein-rich microbial biomass for animal feed through the aerobic treatment of these wastewaters, 3) produce biogas to cover part of the energy demand of the corn mill under study, and 4) switch to the alkaline extrusion of corn as an alternative the traditional corn-cooking technique known as nixtamalization. Despite their environmental benefits, none of the proposed scenarios offer, separately, the economic incentives to change the business as usual in this traditional corn mill. Yet, biogas production can be combined with other alternatives like the alkaline extrusion of corn in a two-stage technological package. This processing technology would completely eliminate nejayote while preserving the nutritive value of the nixtamal dough and most importantly, the organoleptic uniqueness of the traditionally-made tortillas.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-142262 |
| Date | January 2011 |
| Creators | Soria Baledón, Mónica |
| Publisher | Linköpings universitet, Tema vatten i natur och samhälle, Linköpings universitet, Filosofiska fakulteten |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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