Technical Articles

 

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Technical Articles

This section of the site is an ever evolving list of technical articles ranging from the architecture of a typical glass pH electrode, to pH system architecture, to wastewater control technology and theory. The list will continue to grow over time and we hope that some find this to be of some use. There are other articles that we have available upon request that are not published to the internet. Feel free to call and request these papers. A list of selected articles follows :

  • pH Probe Architecture This article provides a description of how a pH electrode functions. Simple pH probe calibration procedures are also included.
  • pH Probe Calibrations This article discusses the fundamental procedure for cleaning and calibrating the most common pH electrodes used in industry today which are also the most common pH probes that we use on our systems.
  • pH Probes Used in Wastewater Treatment Systems This article discusses the types of pH probes and pH electrodes used in industry. Also covered are pH transmitters and pH controllers.
  • pH Adjustment - The Basics: A technical discussion providing a definition for pH, and continuing through the pH scale, acids and bases, acidity and alkalinity, and the concept of pH neutralization. Also covered are two basic system designs including continuous flow through, and batch pH adjustment systems.
  • Limestone for pH Adjustment This article clears up many misgivings regarding the use of limestone for pH adjustment systems. Thinking about using limestone for pH adjustment? Read this first.
  • Chemicals Used for pH Adjustment The various choices for acid and base neutralizing chemicals are discussed here. If you are curious as to which chemical you should be using for your pH neutralization system then this discussion may be of help.
  • Sulfuric Acid Neutralization  Sulfuric acid is one of the most commonly produced chemicals in the world and, consequently, is the single largest source of acidity in industrial wastewater streams. The neutralization of sulfuric acid is quite similar to any of the mineral acids, however, it is not without potential hazards.
  • Fluoride Removal Systems for Industry Fluoride Removal Systems. These are automated systems that are designed to remove fluorides from industrial wastewater streams.
  • Fluoride Removal From Industrial Wastewater The nature of fluorides, why fluorides are hazardous, and how fluorides are neutralized and removed from effluent wastewater streams.
  • Heavy Metal Reduction from Industrial Wastewater Removal of various heavy metals from industrial wastewater streams including Cr, Cu, Ni, Pb, Zn and more. This technical discussion covers hydroxide and sulfide precipitation, ion exchange, and more. 
  • Principles of Ion Exchange. The removal of heavy metals through the use of ion exchange can be very effective in some applications. This article explores the basics of ion exchange for the removal of heavy metals from wastewater.




Case Studies

  • Fluoride Reduction This case study examines a duplex fluoride reduction system designed to remove fluorides from a semiconductor fab wastewater effluent stream. Fluorides are reduced from very high levels to as low as 2ppm.
  • HF Neutralization and Fluoride Removal System This case study examines a 200 GPM continuous flow through fluoride removal and pH neutralization system.
  • Waste Acid Neutralization Waste acids and bases, usually in a concentrated form, present a significant challenge to the designer and operator of an automated system. Very dangerous reactions can run out of control resulting in the liberation of a hazardous amount of chemical. This case study examines a typical waste acid / waste alkali neutralization system for a major university science lab.
  • Spent Chemical Neutralization: A Hazardous Waste Management company providing cradle to grave waste handling solutions for local industry handles many thousands of gallons of spent chemicals each month. Many of these can be safely neutralized rendering completely harmless by products. This case study provides a synopsis for a typical spent chemical neutralization system.




White Papers

White Papers Request



We offer, upon request, an ever growing list of white papers covering various aspects of industrial wastewater treatment including pH neutralization, heavy metal reduction, fluoride reduction, and more. All papers are available upon request at the phone numbers and email addresses list on this page including: mailto:info@digital-analysis.com

The following is a list of some of the papers that we have available:

  • Optimization: The design of conventional pH neutralization systems is plagued by the designer's failure to recognize that pH is not a simple parameter to monitor and control. The design of any well functioning system must recognize that tank geometry is critical, pH probes do not react quickly and require extensive service, chemical injection must be precise and repeatable, chemicals do not mix quickly and react even slower, controls must address the very non-linear control curves and must accommodate for aging pH probes, deficiencies in chemical injection, and ever changing wastewater characteristics. "Optimization" discusses our approach to all of these design concerns and more. Paper is available upon request.
  • Fluoride Reduction in Industrial Wastewater Streams: In some areas of the country tight limits exist on total fluorides discharged to the environment or a POTW. The reduction of fluorides from wastewater is not easy as some of the available technologies, such as ion exchange or membrane filtration, simply do not lend themselves very well to fluoride removal. Furthermore conventional technologies such as precipitation only work if the nature of fluorides in industrial wastewater is understood. This white paper details the precautions that must be taken and outlines our approach. White papers covering batch and continuous systems are available.
  • Heavy Metal Reduction from Industrial Wastewaters: One of the most commonly encountered toxins in industrial wastewater includes heavy metals such as Ag, Cd, Cr (Cr+3 and Cr+6), Cu, Hg, Ni, Pb, Zn and more. There are many technologies available to us with the economics of treatment usually governing which approach we take. As Best Available Technologies improve the limits imposed by the local or governing authorities become increasingly stricter. This technical paper describes the most commonly used technologies including precipitation and ion exchange. The chemistry, implementation, and cost of operation are examined and compared.
  • Principles of Ion Exchange: One of the best available technologies for the removal of specific hazardous species (such as all heavy metals)  from industrial wastewaters is ion exchange. However, efficacy must be examined, the process must be understood, and the cost of operation must be considered. Although not necessarily the cheapest system to own and operate the effluent quality can exceed all other technologies. All of these considerations are discussed in this paper.