NPDES Stormwater & Construction Pollution


  • Introduction
  • Suspended Particles
  • Existing Contamination
  • Construction Pollution Chemicals
  • Stormwater Pollution Prevention Plan (SWPPP)
  • Conclusion

Introduction – Construction Pollution

Clearing and developing construction sites disturbs soil and other materials, creating construction pollution. This pollution may be from the site itself, or from the procedures and materials used on the site. Stormwater runoff from rainfall can carry these materials off site. As a result, these materials pollute receiving surface waters. This is because the runoff may be toxic to fish, wildlife, and plants in the receiving water. However, Construction NPDES Stormwater Permits (see our recent blog article at minimize this construction pollution and these impacts.

Suspended Particles

construction pollution in receiving water
Construction pollution in receiving water

Digging, grading, drilling, and dewatering operations create particles from soil, clays, sand, organic matter, and debris. Stormwater runoff picks them up, then they become suspended. As a result, in the receiving surface water these suspended particles block off sunlight from plants and deplete oxygen. Once that occurs, the receiving water can become polluted and devoid of life. However, turbidity measurements determine if the suspended particles are excessive and capable of causing pollution.

Existing Contamination

In comparison to susended particles, construction operations do not cause existing contamination. On the contrary, existing contamination is caused by past usage of the site, legally or illegally, and includes several types of pollution. These types include gasoline, diesel fuel, oil, agricultural materials, or hazardous wastes. The contamination’s location and its concentration may be well documented and the contractor can be forewarned. On the other hand, it may not be and the contractor may discover it after disturbing it. Therefore, the contractor must prepare a plan to handle unknown pollution, including a list of emergency response contractors.

Construction Pollution Chemicals

These chemicals may come from developing the site, working on the equipment, or construction of buildings. For example, they may include, gas, oil, diesel fuel, paint, solvents, grease, fertilizer, pesticides, and sewage, and come from several sources including ordinary use, misuse, storage, leaks, spills, or vandalism.

Stormwater Pollution Prevention Plans

Stormwater Pollution Prevention Plans (aka SWPPPs) prevent construction pollution and eliminate or reduce the impact on receiving waters in several ways. Firstly, they identify operations which will cause pollution. Secondly, they result in a change of the operations. Thirdly, they identify effective controls and provide a schedule for implementation. Most importantly, prepare an effective SWPPP using resources such as the web site of the U.S. Environmental Protection Agency (


Environmental Safety Consultants, Inc.
Environmental Safety Consultants, Inc.

Stormwater runoff from construction sites does not have to pollute receiving surface waters. If you need any assistance, ESC is here. The firm holds a Florida engineering business license and has a licensed Professional Engineer (P.E.) on staff. ESC’s staff scientists hold bachelors and masters degrees and have over seventy (70) years of combined experience in the stormwater, surface water pollution, and environmental permits field. ESC has been providing NPDES stormwater permits services to its clientele for over thirty (30) years. We have the credentials and experience to help you with your stormwater permits needs. Contact us today ( We strive to reply to all contacts promptly!

Engineering Sewer Discharges

Engineering Sewer Discharges

Engineering sewer discharges goes on inside the plant.
Engineering sewer discharges cannot usually be seen from the outside.

In this blog post, we continue our series on environmental engineering for industrial wastewater.  Specifically, we discuss engineering sewer discharges for acceptance at off-site sewer plants.  On the other hand, we do not address discharges to surface waters, on-site treatment facilities, or ground water.

How do you use engineering to clean up your industrial wastewater before discharging it?  First, perform a mass balance calculation.  To explain, identify and quantify all chemicals and materials.  Basically, mass balance means what goes in must come out.  Secondly, list the waste water’s chemical properties.  Finally, determine if the discharge is acceptable to the sewer plant. And that is very important.  Why?  Because the U.S. Environmental Protection Agency (EPA, requires it.  But the County usually enforces it.  How? By using a Sewer Use Ordinance. 

Engineering Sewer Discharges? 

There are good reasons to worry about engineering sewer discharges from your plant.  For starters, the discharge could be toxic.  As a result, it could kill micro-organisms at the treatment plant.  What’s more, the discharge might be flammable or explosive.  As a result, it could cause a fire or explosion at the plant.  Additionally, it could cause the sewer plant’s discharge to pollute surface or ground water.  Finally, it could violate the County Sewer Use Ordinance.  Consequently, your plant could get bad publicity and be fined.

Will They Know Where the Toxic Sewer Discharge is Coming from?

The County may not know where the toxic sewer discharge is coming from but they can do sewer discharge tracing to find out.  First, they inspect and test the wastewater at lift stations.  Second, they use the results to identify which lift station is causing the problem.  Third, they determine which plants discharge to that lift station.  Fourth, they decide which plant is the most likely suspect.  Fifth, they knock on your door, ask questions, and test your discharge.  It is not that difficult!

Clean Up the Sewer Discharge

So, before the County comes knocking, clean up your sewer discharge.  First, read the County Sewer Use Ordinance closely.  Second, determine if  banned chemicals could be in your discharge.  If so, test the discharge.  If the results confirm a problem, you are dead in the water, right?  No, now explore the following treatment options:

  • Change the process 
  • Substitute chemicals 
  • Remove hazardous wastes 
  • Pre-treat the sewer discharge
  • Get help from an environmental engineer or the County 

After you have fixed the problem, run a bench scale test on the sewer discharge.  Good results mean start the treatment.  Bad results mean you adjust the treatment, retest, and then start the treatment.

Environmental Safety ConsultantsSo, there is a discussion of the engineering sewer discharges of industrial wastewater! If you need any assistance, ESC ( is here. We are a Florida licensed environmental engineering firm with a P.E. on staff. We have the credentials and experience to help you with your engineering sewer discharges. Contact us today ( We strive to reply to all contacts promptly!