Local Discharge Limits & Surchargeable Parameters

Local Sanitary Sewer Discharge Limits

Local sanitary sewer discharge limits are established to protect against pass through and interference. These limits apply at the point where the user’s wastewater is discharged to the sanitary sewer system. All concentrations for metallic substances are for "total" metal unless indicated otherwise. 

The City-Parish may impose mass limitations in addition to, or in place of, the concentration-based limitations. Any substance exceeding the following limits based upon a thirty-day average; the average may be determined by no less than one (1) discharge monitoring test for each monitoring period as required by permit.  

If discharging to the North Wastewater Treatment Plant:

ParameterLimitation (milligrams/liters)
Oil and Grease100
Arsenic1.08
Cadmium0.86
Chromium96.01
Copper19.67
Cyanide
1.9
Lead8.58
Mercury0.63
Molybdenum
1.33
Nickel7.09
Selenium1.33
Silver6.07
Zinc21.14


If discharging to the South Wastewater Treatment Plant:

Parameter
Limitation (milligrams/liters) 
Oil and Grease
100
Arsenic
1.82
Cadmium
0.35
Chromium
99.77
Copper
25.08
Cyanide
2.62
Lead
10.86
Mercury
0.67
Molybdenum
2.68
Nickel
7.85
Selenium
1.78
Silver
8.44
Zinc
51.43

Surchargeable Parameters

ParameterLimitation (milligrams/liters)
5 Day Biochemical Oxygen Demand (BOD5)200
Total Suspended Solids (TSS)250

A surcharge means the charge for treating excessive pollutant loadings. Any discharge of BOD5 or TSS exceeding the limits in the table above based upon a thirty-day average, in which average may be determined by no less than one (1) discharge monitoring test for each monitoring period required by permit, shall be handled exclusively through surcharges as provided in Ordinance 7853.