Domestic waste waters

These waters are produced by the mere acts of living such as using the bathroom, doing laundry, or washing the dishes. These wastes are normally handled by the sanitation department, which eliminates pathogens before disposal.

Process waste waters

These waters are produced by some industrial processes and include the undesired liquid product of any unit operation. The major concern with these wastes is the reactions that may occur with the environment being either direct or indirect. Some may rob oxygen from the environment, while others may be toxic.

Cooling waste waters

These waters are produced as a result of some sort of heat exchanger where heat is removed from the product. Waters can be used once or recycled. Recycling creates the necessity for periodic cleaning, where at least some may be released into the environment. This is the least dangerous the waste waters, but because of leaks within the process, could contaminate the surroundings. This type of waste must also be monitored and often treated, and is also a major factor in thermal pollution of water sources.


There isn’t a standard design to treat all wastewaters due to the characteristics of the process specific waste. Each site requires a design specific to the process at hand, but some combination of the following pretreatment, primary treatment, secondary treatment, and processing is normally used. As a rule of thumb, we would like to separate several pollutants in one step and use several steps to increase the degree of treatment.

  • Equalization
  • Neutralization
  • Oil Removal
  • Toxin Removal
  • Grit Chambers
  • Gravity Sedimentation
  • Chemical Precipitation
  • Biological Treatment
  • Activated Sludge
  • Aeration
  • Sedimentation Tanks
  • Anaerobic/Anoxic Sludge
  • Trickling Filters