Official Mexican Standard establishes new permissible pollutant limits for discharges into waters under national jurisdiction

The purpose of this NOM is to guarantee the human rights to water and sanitation provided for in the Political Constitution of the United Mexican States, as well as to establish the regulation regarding the permissible pollutant limits of wastewater discharges into receiving bodies owned by the Nation. The NOM replaces NOM-001-SEMARNAT-1996. In this regard, the most relevant changes introduced by the NOM are the following: • The Tables of Permissible Limits for wastewater discharges into receiving bodies of national ownership are amended, establishing stricter limits for Fats and Oils, Total Suspended Solids, Total Nitrogen, and Phosphorus. The foregoing encourages users to modify their processes at treatment plants in order to use wastewater in other processes or activities. • The classification of receiving bodies is amended in order to expressly include more receiving bodies subject to the NOM. Such amendment was made as follows: NOM-001-SEMARNAT-1996 NOM-001-SEMARNAT-2021 • Rivers • Reservoirs • Coastal waters • Soil (use in irrigation, natural wetlands) • Rivers, streams, canals, drains • Reservoirs, lakes, lagoons • Mexican marine zones • Soil The foregoing makes it possible to increase the bodies of water subject to the NOM and thereby create obligations for water discharges that were previously not expressly regulated under NOM-001-SEMARNAT-1996 (e.g., streams, canals, drains, lakes, etc.). • The Biochemical Oxygen Demand (BOD)1 is replaced by the Chemical Oxygen Demand (COD). The foregoing seeks to generate measurements that make it possible to establish whether microorganisms or bacteria are present in the wastewater. • The Total Organic Carbon (TOC) parameter is included as an alternative method to measure the organic pollutant load in waters with high chloride content (with a concentration greater than 1,000 mg/l of chlorides). • The fecal coliform parameter is replaced by the Escherichia Coli and Fecal Enterococci parameters. The foregoing seeks to generate a better measurement of fecal pollutants in wastewater. • The true color and acute toxicity parameters are introduced. • New parameters for the permissible limits of total pH are introduced, from 5 to 10 (pH units) to 6 to 9 (pH units). • A maximum temperature of 35 degrees is established for discharges into rivers, reducing by five degrees the parameter established by NOM-001-SEMARNAT-1996. • The permissible parameters applicable to metals and cyanides are reduced (Table 2 of the NOM). • The frequency for submitting sampling reports and returns is set on a quarterly basis in all cases (municipal and non-municipal discharges), amending the timing established in NOM-001-SEMARNAT-1996 for the submission of reports (quarterly and, in some cases, semiannual or annual). • The NOM will enter into force on April 4, 2023, with the exception of the following matters: ○ The parameters and permissible limits of Tables 1 and 2 of the NOM, as well as the Normative Appendix, will enter into force on April 3, 2023. ○ The parameters and permissible limits for true color and acute toxicity will enter into force in April 2026. Until the parameters and permissible limits enter into force, wastewater discharges will continue to be subject to NOM-001-SEMARNAT-1996. In order to comply with this NOM within the established timeframes, the obligated parties in the industrial, agricultural, and services sectors that carry out discharges into receiving bodies under national jurisdiction must implement ambitious strategies to diagnose their processes and make adjustments to them so as to be in a position to comply with the new requirements and parameters established in this NOM. At Von Wobeser y Sierra, we understand the complexity that the foregoing entails, and we can advise you in analyzing the legal alternatives and mechanisms that allow for timely and proper compliance with the obligations established in the NOM. For more information, contact our experts: Edmond Grieger, Partner: +52 (55) 5258-1048 | egrieger@vwys.com.mx Ariel Garfio, Partner: +52 (55) 5258-1048 | agarfio@vwys.com.mx Roberto Flores, Associate: +52 (55) 5258-1048 | rflores@vwys.com.mx Mariana Plowes, Associate: +52 (55) 5258-1048 | mplowes@vwys.com.mx Elena Gutiérrez, Associate: +52 (55) 5258-1048 | egutierrez@vwys.com.mx

PDF