A Common Problem

The Washington State Department of Health's state testing facility was in need of replacing a deteriorated acid neutralization system. The system that had been in-place since the building opened was a traditional neutralization system that experienced traditional problems.

Interaction with the corrosive waste stream caused the limestone caustic to become non-reactive and ineffective. The dilution tanks effectively served as traps in the waste stream for solids, creating a need for routine hazardous clean-up in a confined space. The lack of satisfactory treatment resulted in significant infrastructure deterioration due to contact with the unsatisfactorily neutralized waste. Additionally, a staff chemist was required nearly full-time to manually neutralize waste prior to discharge.

A Unique Solution

Through collaboration with the technical staff, the facility planner and the industrial hygienist, an active neutralization system was developed to better suite the needs of the facility.

First, a ventilated disposal station was provided, allowing safe disposal of waste into a dilution bath. Then, a monitoring system was utilized to track waste quantity and to activate an automatic neutralization sequence.

During this sequence, the corrosive waste and dilution bath are continually mixed while caustic powder is added. Solution pH is monitored and, through an algorithm that anticipates the non-linear reaction of the solution to the caustic, controls the quantity of caustic introduced.

Once the acceptable pH is reached, the solution is then discharged to the waste system. At the time of discharge, the pH of the solution is measured and documented to confirm compliance with local hazardous waste requirements.

The Results

The facility now has an acid neutralization system that actually neutralizes acid, and allows the technical staff to focus on their testing and other technical procedures. The discharge stream is reliably within required pH ranges, and documentation is automatically generated for verification.