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.