pH Adjustment Systems

Applied Mechanical Technology is an industry leader in industrial wastewater treatment components and systems.  Since 1997 we’ve been designing and building industrial equipment and systems for variety of industries. 

We design and build all our core technology equipment in-house. Our complete line of equipment includes:

  • Oil Water Separators,
  • DAF Dissolved Air Flotation,
  • Inclined plate Clarifiers,
  • Multimedia filters
  • Controls Packages.

These are the core of our complete systems packages.  We complete our systems with strategic OEM relationships for all the other necessary components such as instruments, pumps, valves etc. 

As we design and manufacture our core equipment and systems in our own shop we have the flexibility and the ability to configure our systems as needed to meet the most stringent project specifications while exceeding customer’s expectations.

Principal of Operation – pH Adjusting Systems

pH is the measurement of how basic or acidic something is. pH actually stands for Potential Hydrogen and is a measurement of the activity of the hydrogen ion.  Typical pH range is 0-14 but actual pH levels can exceed these theoretical limits. pH adjustment is the alteration of pH or Potential Hydrogen by adding a pH reagent such as using an acid to drive pH downward or using a caustic or other alkaline substance to drive pH upward.  Sulfuric acid and sodium hydroxide (caustic) are most commonly used.  Caution must be used for pH adjust applications as an exothermic reaction will occur generating heat.  The more severe the application the more heat generated.  For example;  pH adjusting tap water will create very little heat and is a non-issue.  Neutralizing solutions with a high percentage acidic or bases can generate significant heat and therefore must be considered in design and materials.

pH Adjusting Systems are used for a variety of water treatment purposes including:

  • pH adjustment is employed standalone if pH control is the only thing required. In other words no other discharge prohibited items are in the water such as metals, oil and grease etc.  Discharge limits for pH vary but are typically between 5 and 11 pH units.
    Rapid mixing and about 5-10 minutes dwell time is generally sufficient to complete the reaction.
  • Metals insolubility. pH adjustment can be used in combination with metals removal to create ideal insolubility conditions for metals to precipitate as metal hydroxides. See Metals Hydroxides. 
    Rapid mixing and about 10-15 minutes dwell time is generally sufficient to complete the reaction.
  • Oily Emulsion breaking. pH can also be used for oily emulsion breaking by acidifying the wastewater to pH 3, then allowing time for emulsions to crack, then running the wastewater thru and oily water separator. Post Oil Water Separator pH adjustment upward is then needed to meet discharge regulations. 
    Rapid mixing and about 10-15 minutes dwell time is generally sufficient to complete the reaction.
  • Chrome reduction. pH adjustment is also used to help convert hexavalent chromium to trivalent chrome reduction which is required to precipitate chrome (Cr) as hex chrome is highly soluble.
    Rapid mixing and about 20-30 minutes dwell time is generally sufficient to complete the reaction.
  • Cyanide oxidation. pH adjustment is used to reduce cyanide to cyanate by alkaline chlorination. pH is adjusted to between 10-11.5 pH and strong oxidizer such as sodium hypochlorite is added.  Rapid mixing and about 30-40 minutes dwell time is generally sufficient to complete the reaction.
  • Organics destruction/reduction. pH is often used in a variety of organic reduction regimes where a chemical compound is broken down into the basic elements or into a set of elements or into a different set of compounds. Residence and reaction time can vary greatly depending on the goal.

pH Adjustment chamber residence times are important to ensure reaction completion Not all applications are the same.  pH adjustment reaction times are typically 10-15 minutes but can vary from there depending on the application.  In some cases simultaneous reactions are conducted while pH is adjusted.  Certain coagulants and other precipitators are used in combination with pH adjustment which in some cases can require extended reaction times to as much as 30-40 minutes.
Reaction times are dictated by the specific reaction required and by the water buffering capacity.  Buffering capacity is essentially how long and how much pH reagent is needed to affect pH to the desired level.  For example, tap water requires very little acid to get pH a significant change while a bold and thick wastewater would take considerable more reagent to affect pH.  This is due to the affect the other “stuff” in the water has on the pH reagent. Reagents may be consumed by other chemicals etc before they have a chance to affect pH so more reagent and or more reaction time is needed to overcome this phenomenon.

There are many configurations of pH adjustment systems that are selected by the application and by the desired results. Applied Mechanical Technology makes all our pH adjust systems to several standard designs as well as custom configurations to meet project specifics.  Different types of pH systems include:

  • Single Stage pH Adjustment. Flow thru system. Used for simple pH adjust applications with little buffering capacity.  Also used for basic pH adjustment where precise pH is not required such as simple pH adjust to meet discharge range (5-11 pH typically). These systems typically include tanks, mixers, sensors, dosing pumps and controls.
  • Two Stage pH Adjustment. Flow thru system. Used for more difficult pH adjustment where significant buffering capacity exists or where precise pH adjustment is needed to hit a specific pH target such as specific metal precipitation. Not all metals precipitate at the same pH. These systems typically include tanks, mixers, sensors, dosing pumps and controls.
  • Batch pH Adjustment. This system is similar to the flow thru system in overall design except that in this case, batches are held and pH adjusted as long as needed to reach the pH set point. Once that is achieved and maintained it will allow the batch to be discharged.  These systems typically include tanks, mixers, sensors, dosing pumps and controls.
  • Flow Thru – In Pipe or In Line. This type of system is used for basic and fairly easy pH adjustment applications where there is not a lot of buffering or precise pH control is needed. In this system, pH is measured in-pipe while flowing,  pH adjustment reagent is injected into the pipe.  The pipe includes static mixing elements, sensor and chemical fittings, dosing pumps and controls package.

Our pH Adjust Systems are found in a variety of industries including but not limited to:

  • Laboratory waste
  • Oily wastewater emulsification and coagulation
  • Metal Forging press pit oily wastewater
  • Metal plating and conversion coating
  • Food processing.
  • Groundwater remediation
  • Solids removal
  • Turbidity reduction
  • Chemical Etch bath rinse waters
  • Bottom fly ash sluice water
  • Scrubber water
  • Cooling tower water

Typical Options Include:

  • Plastic, Fiberglass, Mild or Stainless Steel construction
  • Temperature monitor and controls
  • Vapor capture and venting systems
  • XP Explosion proof electrical components
  • Complete control packages
  • Pump skids, inlet and effluent
  • Chemical dosing and FFM Flash-Floc-Mixing Systems for emulsion breaking
  • Operator platforms
  • Special coatings for highly corrosive application
  • Effluent filters

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We use only the highest quality materials, pumps, instruments, valves and controls components to ensure you the heavy duty robust performance you demand in today’s highly competitive market environment.  All our systems are built to the highest standards of craftsmanship and are extensively tested throughout the fabrication process. We perform a variety of NDE testing including PQR, UT, XT, full hydro, dye penetrant, ASME pressure testing and of course visual inspections and functional testing both in-shop and in the field.


Our operator controls interface scheme is the most advanced in the wastewater industry.  We offer basic simplified controls to full featured controls systems that use SQL database platforms permitting the generation, archiving and managed all trending and effluent data.  Our most advanced controls offer operator input of bench treatability testing that then allow the system.We design and build all our own controls in-house to UL-508A Industrial Control Panel standards with strict conformance to NEC ANSI/NFPA 70 regulations.  All panels are built to UL standards and are individually UL certified if required.

Tankwash Systems

Our Industrial Tankwash Division designs and builds Railcar and Tank Trailer Internal wash systems to wash everything from Crude oil to Edible oils, from Chemicals to Corn Starch and everything in between.  When you wash an industrial tank, you create an industrial wastewater and we take care of that too.