Case Study: Spent Chemical and Waste Acid / Base pH Neutralization System.
Client: University Science Laboratory in Upstate NY.
Industry: Education and Research.
Installation Date: June 2009.
Objective: To safely neutralize concentrated waste acids and waste alkalis generated in a science research lab.
Criteria and Limitations: Influent flow can vary from 500 GPD to over 2,000 GPD with organic and inorganic acids and alkalis, concentrations ranging up to 20%. Safety is paramount in the design and installation.
Overview: A major Ivy League university science laboratory generates tens of gallons of waste acids and bases daily. Also produced are dilute flows from lab sinks and a scrubber. There are several known adverse reactions between the acids and bases and caution must be exercised.
It is the desire to neutralize as much of the waste acid with the waste base so as to minimize the amount of acid and base that must be purchased for the purpose of neutralization.
Since the concentration and makeup of the waste acids and bases are unknown they are kept separate with collection for inorganic acids, organic acids, and all alkalis. Lab sinks and the scrubbers all run to a common equalization system. The waste concentrates are metered in slowly to the process while temperature is closely monitored.
The entire system must be double contained so as to protect personnel in the area as well as the environment.
The Process: Digital Analysis Corp. has developed a unique process for safely mixing waste acids and bases by very closely monitoring temperature and reaction rates. The rate that the waste acids and bases mix is controlled so as to limit or prevent adverse reactions and excessive liberation of heat.
Solution: Our pHASE wastewater treatment skids are very versatile, modular, and flexible. In this application our pH10 served as the heart of the treatment system which consisted of several totally automated stages as listed below:
Waste inorganic acid collection
Waste organic acid collection
Waste alkali collection
Batch pH adjustment based upon our pHASE pH10.
Temperature monitoring and water quench
Final Effluent Monitoring.
Remote monitoring, control, and data logging
Conclusion: The key design consideration for this system was not only effluent compliance but safety. Concentrated spent chemistry is actively neutralized using, in most cases, spent chemistry. Adverse reactions are known to occur and must be controlled. Furthermore this system is installed in a location that does see frequent traffic.
The system was designed to maximize the use of spent alkalis to neutralize spent acids. This requires that we constantly monitor the rates of reaction and the temperature of the process. Chemical metering is controlled by many parameters including temperature rise. In the event of an uncontrolled temperature rise a water flush circuit is available to rapidly add cooling water, although, by design, this should never happen.
The system described here is based upon our pHASE pH10 but modified specifically for this application. In addition to the safety features of the process the system features double contained tanks and the active process is contained within a clear PVC shell such that the failure of any fluid handling component will not result in the leak of a hazardous substance.
A remote monitoring system is installed that monitors the entire system from anywhere in the world where an Internet connection is available. All of the programmable parameters, tuning variables, and setpoints are available through the remote monitoring system.