The reduction of pollutants in water has been significant in Monterrey, thanks to the new tariff agreement that has increased fees for total suspended solids, fats and oils, and biochemical oxygen demand (BOD). According to Juan Ignacio Barragán, general director of Water and Drainage Services of Monterrey (SADM), companies, mainly the large ones, have managed to reduce BOD by 78% over a one-year period.
Barragán highlighted that these reductions refer to the excess kilograms of BOD, and that the total discharge of pollutants has decreased significantly, from 498,940 to 111,087 kilograms between November 2023 and November 2024. This reduction has been the result of greater compliance by companies, especially in the food industry sector.
Regarding the change in tariffs for the provision of services related to discharges and the use of wastewater, Barragán mentioned that they have worked with companies to ensure compliance regarding fats and oils. It was mentioned that the maximum allowed concentration of oils is 225 mg/l; however, some establishments such as restaurants, butcher shops, and slaughterhouses exceeded this limit, reaching up to 2,500 mg/l in their discharges.
On the other hand, the official explained that the adjustment in tariffs was due to previous costs being low and permissible limits very high. These conditions led SADM to incur significant costs due to the discharge of fats and oils in its sewage system. The implementation of the Expediente Charge on residential user bills since December has generated discussions, to which Barragán clarified that this concept is aligned with the social objectives of the institution and supported by regulations established decades ago.
