A "Green" Company Since 1990

Continuous Flow pH Neutralization Systems

The HydroFlo continuous flow pH neutralization systems are designed to neutralize the pH of highly acidic and highly alkaline process or waste streams, to a specific set point.  They are designed to constantly process flow rates up to a maximum of 2,000 GPM.

HydroFlo systems are completely automated, requiring no operator attention other than periodic system maintenance. Remote monitoring is available via SCADA, building management, or dial-up link .

Every HydroFlo system is robust in design and construction and is built to work continuously, problem free, day in and day out.  Everything needed is included: pumps, mixers, controls, etc. Sophisticated controls continuously monitor pH levels and seamlessly adjust pump outputs, assuring that your effluent meets the desired levels.


Continuous flow pH Neutralization systems are typically simple in concept and yet, (depending on application), complex in execution.

HydroFlo's pH neutralization systems are very versatile in that they can adjust the pH of process or wastewater to a specific required set point, regardless of swings in the influent pH.

Standard Features:

  • Skid mounted

  • Stand alone operation
  • Compact design for small footprint
  • Epoxy coated ASTM A-36 carbon steel skid
  • Factory tested
  • Pre-piped
  • Pre-wired
  • Seamlessly integrates with other HydroFlo offered wastewater products
  • State of the art NEMA-4X, UL 508 electrical enclosure
  • Standard units can be manufactured to treat batches from 50 to 10,000 gallons
  • TEFC motors

Available Options:

  • Access platforms with ladder or stairs

  • Available in epoxy coated carbon steel, stainless steel, polypropylene, FRP, exotic alloys and all thermoplastics for long life and superior corrosion resistance
  • Duplex systems for redundancy
  • Effluent monitoring
  • Effluent sampling
  • Explosion-proof design
  • Influent equalization
  • Influent / effluent lift stations
  • On board reagent storage (day tanks)
  • Potable water design
  • SCADA system monitoring
Equipment Design Data & Sizing Calculations

Chemical Pump Dosing

Chemical Compatibility


General Arrangement

Standard Process and
  Instrumentation Diagram


• Standard Engineering

"Common" Engineering
  Applicable to all HydroFlo
  Manufactured Equipment

Installation, Operation & Maintenance Manuals

Standard IO&M Manual

Process Description

HydroFlo Continuous Flow pH Neutralization Systems are designed to constantly process flow rates up to a maximum of 2,000 GPM. As the water flows through the system, chemicals for pH control (such as acid or caustic), and other required chemicals, are injected automatically and continuously, based on flow rate and sensor outputs.  The treated water typically flows to another device for the separation of precipitated contaminants

A pretreatment option is available for the equalization tank. This option allows for coarse treatment of the equalization tank contents.

The Equipment:

The basic system is comprised of a single flat bottom reaction tank, a mixer, a series of chemical metering pumps, a pH indicator/controller, and a control panel.


A steel skid is provided for supporting the entire system. The skid  features a welded 4" steel "C" channel frame and a 1/4" steel deck plate. The entire skid is blasted to an SSPC-SP6, and coated with a 2 part self priming epoxy finish for corrosion resistance. The skid color is OSHA Safety Blue, unless otherwise specified.

Optional Containment Pan: As an option, a containment / drip pan can be provided for protecting the steel skid from leaking or spilled corrosive fluids. A drain connection is provided for plumbing the containment pan to a suitable location. The pan can be fabricated from polypropylene, stainless steel, etc. and features 8" high walls.

The Reaction Tank:

There are many items to consider when choosing the reaction tank.  What is the retention time required for proper pH adjustment buffering?  What is your average flow?  What is your peak flow?  What chemical processes are going to be applied?  Will the reaction be exothermic (create heat)?   If so, how much heat will be generated?

HydroFlo addresses all of these items, as well as others, in order to properly size the system and choose the correct materials of construction for the application.

Reagent Storage Tanks:

Chemicals for treatment are pumped directly from 55 gallon DOT drums.  An alternate to pumping directly from DOT drums is utilization of day tanks, which can be automatically refilled from the customer's bulk chemical delivery system within the plant. Redundant level sensors and redundant fill valves provide protection against overfilling.


All ball valves are true union, field serviceable valves. All diaphragm valves are flange mounted. Elastomers are EPDM and Teflon, except on concentrated acid lines where the elastomers are Viton and/or Teflon.


All recirculation, transfer and discharge lines are fabricated from solvent welded, PVC SCH 80 pipe. All reagent delivery lines are flexible PFA tube, double contained within a clear  flexible PVC hose, clamped at each end to seal leaks.

The Mixer:

The mixer is one of the key elements of the system.  The system will not generate consistent results without a properly designed mixer.  In a typical continuous flow system, different mixers (size, speed, etc.) handle different chemical reaction processes.

Chemical Metering Pumps:

Properly sizing the chemical metering pumps is important in order to achieve the correct chemical reactions.  Also, metering pump sizing has an impact on total chemical consumption.  Properly sized pumps will help you reduce overall chemical costs.

Control Package:

All HydroFlo continuous flow pH neutralization systems are fully automated.  Control packages (depending on your specific requirements) are available in either basic relay logic controls, or a full state of the art PLC with touch screen HMI and our sophisticated treatment algorithms. The relay logic controls package allows basic reconfiguration of the original system settings, while the PLC based package allows maximum flexibility to change the process parameters, as well as tight control that minimizes chemical usage. We can include a variety of options including digital data logging of critical process parameters, ethernet access to process data, communication with Building Management Systems, and even remote system access using cellular wireless technology.

All enclosures are NEMA 4X.  Where metallic enclosures are used, they are provided with epoxy or polyester finishes for corrosion resistance. All conduit is plastic coated, where possible. Low voltage 24VDC is used throughout to minimize service personnel exposure to high voltage. All panels are OSHA, LOTO and NFPA 79 compliant.  UL-508 listing is available.

Effluent Monitoring: As mandated by the local controlling authority, the effluent quality must be continuously monitored. A two pen recorder is to be used to monitor effluent flow rate and pH. The recorder is to be equipped with a flow totalizer. Any effluent pH deviations will trigger an alarm and system discharge will be halted.

System Packaging:

The system is supplied as a completely fabricated "turnkey" package. All devices are pre-wired and plumbed.

You need to make the plumbing connections to and from the system and a single electrical connection point for incoming power.  The disconnect on the MCP provides OSHA Lock Out/Tag Out and NFPA 79 compliance. Systems requiring compressed air, also require only one connection  and the valve is supplied for OSHA LOTO.

Additional Information

For specific equipment information, contact us directly. We can provide the specifying engineer with a formatted specification package that thoroughly describes any of our systems for bidding purposes. This includes detailed drawings, and detailed equipment specifications.