Industrial Wastewater FAQs

Certificate of Analysis Definitions

MB - Method Blank
MB2 - Second Method Blank, for BOD only
LCS - Laboratory Control Standard
CCV - Continuing Calibration Verification
MS - Matrix Spike
RPD - Relative Percent Difference
MS2 - 2nd Matrix Spike

Who do I contact if I have a question about my results, or the certificate of analysis?

Oklahoma City Utilities Department, Wastewater Quality Division, (405) 297-1610
Oklahoma City Utilities Department, Environmental Laboratory ( 405) 297-3280

Where can I find my permit limits? 

Your permit limits can be found on page 4 of your Industrial Wastewater Discharge. For industrial users who have a small permit, it can be found on page 2. 

What is the difference between "mg/L" and "ug/L."

 mg/L (also called parts per million, or ppm) is a standard of measurement meaning "milligrams per liter." The limits found in your permit should be shown in "mg/L."

ug/L (also called parts per billion or ppb) is a standard of measurement meaning "micrograms per liter."

To convert ug/L to mg/L in order to determine whether you are in compliance, divide ug/L by 1,000.  

Do I still have to self-monitor my wastewater?

Yes. If your permit requires it.  

How often does the City sample my wastewater? 

This depends on a number of factors, including the type of industry, volume of discharge and/or strength of waste. 

How does the City determine permit limits? 

The U.S. Environmental Protection Agency (EPA) sets limits for Categorical Industrial Users such as metal finishers, pharmaceutical manufacturers, centralized waste treatment plants and similar industrial users. For all other industries, the City evaluates the limits every five (5) years to ensure that the treatment plants are not being over-loaded by the strength of the waste. This evaluation incorporates the receiving streams of the plants as well as many other factors to determine permit limits.