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    Alkaline Wastewater


What is Alkaline Wastewater?
Alkaline is defined as having a pH of more than 7. Other terms for alkaline are high pH and basic. The pH scale measures how acidic or alkaline (base) a substance is.
What are the Concerns with Alkaline Wastewater?
Wastewater with a pH above 12.5 is considered corrosive and is labeled as hazardous. In terms of evaporation, high pH wastewater poses a few concerns.

1. One is that alkaline wastewater has a higher tendency to foam. As you can see in the listing of common alkaline wastewaters above, many of those wastewaters contains soaps and detergents, so the possibility of foaming is to be expected.

2. The other concern is that, depending on the type of alkalinity of the water, it may have a higher tendency to scale. Calcium, strontium, barium, and magnesium based salts can be rather insoluble and may scale.

Using our SCTCRISTS for Alkaline Wastewaters
In our years of providing technology, we have found the solutions below to be very effective.

1. Elementary pH Adjustment: Just as alkaline wastewater has a higher tendency to foam, using elementary pH adjustment to lower the pH to neutral or slightly acidic often minimizes or eliminates the tendency to foam.

2. Antifoam: Using a high temperature antifoam or defoamer can be a simple and economical way to greatly reduce or eliminate foam. There are many antifoam chemistries available and they can be formulated to target specific applications. Most high temperature antifoams use silica to pop the foam bubbles while also reducing the surface tension that allows the foam to form in the first place.

3. Reduce Heat Input (BTU rate) on Burners: Some foams are exacerbated by the vigor of the boil itself. Soapy water is an example of this type. Reducing the BTU rate to the burner will reduce the vigor of the boil and often greatly reduce or eliminate this type of foam. Reduced heat input will reduce the system evaporation rate, but many of our customers have excess evaporation capacity thereby making this form of foam control feasible.

If our SCTCRISTS is right for you
The centerpiece of our consultative approach is the wastewater qualification process. Not all waste streams are good candidates for evaporation. We believe it’s better to find that out in our laboratory than on your factory floor.

This free analysis determines how appropriate the waste stream is for evaporation and how it will function in our SCTCRISTS. This analysis also helps determine materials of construction and allows us to determine operating procedure recommendations. If more detailed analysis of specific parameters is needed, SCTCRISTS can prepare appropriate samples and send them for outside lab analysis for a nominal cost (prices for analytical tests vary).

Once the analysis is complete, your SCTCRISTS Sales Engineer will deliver a report detailing the results to you. This report includes material of construction and pH adjustment recommendations, if needed. This allows you to make an informed decision if our SCTCRISTS is right for you.