Guidelines for wastewater discharges This document presents two tables of guidelines for wastewater discharges, consisting in its maximum permissible levels of pollution. To have national and international references for pollution limits in wastewater discharges, the guidelines presented are: The “Mexican policies for wastewaters discharges” and the Environmental, Health, and Safety (EHS) General Guidelines from the International Finance Corporation (World Bank Group). Mexican policies for wastewaters discharges Because of the location of Sucroliq’s industrial facilities the best option for discharge the waste water is into sewage systems. The Mexican policies which regulate this kind of discharge are the NOM-002-ECOL-1996 and the NOM-001-ECOL-1996. These policies have different pollution limits for each kind of water receptor body (e.g. ground, rivers, reservoirs and coastal waters). The receptor bodies are classified as: (A) for the coastal exploitation waters and water receptor bodies for agricultural use; (B) for rivers, streams and estuaries and (C) for lakes and dams. (Mexican federal law of water rights, 2014). (Table 1) Table 1. Maximum permissible levels of pollution in the Mexican policies for wastewater discharges into sewage systems. Parameter Units Maximum permissible levels of pollution pH pH units 5.5-10 Temperature °C 40 Greases and oils mg/L 15 Floating materials mg/L 0 Settleable soilds ml/L 5 Total suspended solids mg/L 150 BOD5 mg/L 150 ( A ) / 75 ( B )/ 30 ( C ) Arsenic mg/L 0.5 Cadmium mg/L 0.5 Cyanide mg/L 1 Copper mg/L 10 Hexavalent chromium mg/L 0.5 Mercury mg/L 0.01 Nickel mg/L 4 Lead mg/L 1 Zinc mg/L 6 (A), (B) and (C): Classification of wastewater receptor bodies, according to the Mexican federal law of water rights. (A) For the coastal waters; (B) for rivers, streams and estuaries and (C)for lakes and dams. Environmental, Health, and Safety Guidelines The Environmental, Health, and Safety Guidelines are technical reference documents with general examples of good International industry practice which include maximum permissible levels of pollution in sanitary sewage discharges, for that reason are used as our international environmental references. (International Finance Corporation, 2007). (Table 2) Table 2. Environmental, Health, and Safety Guidelines for Sanitary Sewage Discharges. Parameter Units maximum permissible levels of pollution pH pH units 6-9 BOD5 mg/L 30 COD mg/L 125 Total nitrogen mg/L 10 Total phosphorus mg/L 2 Oil and greases mg/L 10 Total suspended solids mg/L 50 Total coliform bacteria MPN/ 100 ml 400 References International Finance Corporation (2007). Environmental, Health, and Safety General Guidelines. The World Bank Group. March 07, 2015. Secretary of economy, Mexico. (1996) Norma official Mexicana NOM-001-ECOL-1996. Secretary of economy, Mexico. March 07, 2015. Secretary of economy, Mexico. (1996) Norma official Mexicana NOM-002-ECOL-1996. Secretary of economy, Mexico. March 17, 2015. National Commission for Water (CONAGUA) (2014). Mexican federal law of water rights. National Commission for Water (CONAGUA), Mexico. March 17, 2015.
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