Pennsylvania Operator Classes, Subclasses & Process Control Authority

Pennsylvania operator certification uses both classes and subclassifications to define an operator's authority. The class reflects the size or special type of system, while subclasses identify the treatment technologies or specialized functions for which the operator is qualified.

To make process-control decisions at a regulated water or wastewater system, an operator must be appropriately certified for that system. This means the operator must hold a class that is sufficient for the system and must also hold the treatment subclassifications that apply to the technologies being operated.

Class and Subclass Are Different

A certification class and a certification subclass answer different questions.

• Class: Is the operator certified for a system of this size or special system type?
• Subclass: Is the operator certified for the treatment technology or function used at this system?

An operator can have the correct class but still lack authority to make process-control decisions if the necessary subclassification is missing.

Likewise, an operator can hold the correct treatment subclass but still need a higher class for a larger system.

Standard Drinking Water and Wastewater Classes

For standard drinking water and wastewater treatment systems, Pennsylvania uses Classes A through D.

• Class A: greater than 5 MGD.
• Class B: greater than 1 MGD but no more than 5 MGD.
• Class C: greater than 100,000 gallons per day but no more than 1 MGD.
• Class D: no more than 100,000 gallons per day.

The system classification is based on hydraulic design capacity.

An operator may make process-control decisions at a smaller system if the operator's certification class is equal to or higher than the system class and the operator also holds the required treatment subclasses.

Example of Class Authority

Suppose a wastewater treatment plant has a hydraulic design capacity of 0.75 MGD.

That falls within Class C.

A properly subclassified Class C operator may make process-control decisions there. A Class B or Class A operator may also satisfy the class requirement because those certifications are higher than Class C.

A Class D operator would not satisfy the class requirement for that Class C system.

Special Wastewater Class

Pennsylvania also identifies a wastewater Class E certification for a satellite collection system with a pump station.

This certification is associated with wastewater Subclassification 4, which covers a single-entity collection system.

Wastewater collection certification should not be confused with treatment certification. Collection-system responsibilities and treatment-system responsibilities are related but distinct.

Special Drinking Water Classes

Pennsylvania drinking water certification also includes special classes.

Class E applies to distribution and consecutive water systems.

Class Dc applies only when all specified DEP conditions are met, including:

• the system serves fewer than 500 individuals or has no more than 150 connections, whichever is less;
• the source is exclusively groundwater;
• the system requires only disinfection;
• the system is not in violation of DEP rules and regulations.

Class Dn applies to systems meeting the Dc conditions that do not have disinfection.

These special classes have specific eligibility conditions and should not be treated as interchangeable with standard Class D certification.

Wastewater Subclassifications

Pennsylvania currently identifies five wastewater subclassifications.

• Subclass 1, Activated Sludge: includes technologies such as conventional activated sludge, extended aeration, sequencing batch reactors, contact stabilization, step-feed systems, and oxidation ditches.
• Subclass 2, Fixed-Film Treatment: includes processes such as trickling filters and rotating biological contactors.
• Subclass 3, Treatment Ponds and Lagoons: includes aerated, anaerobic, facultative, lagoon, pond, and certain wetland-type processes.
• Subclass 4, Single-Entity Collection System: applies to qualifying wastewater collection systems connected to treatment owned by the same owner.
• Subclass 5, Laboratory Supervisor: applies to qualified laboratory supervisors meeting the applicable experience and certification requirements.

Wastewater Laboratory Supervisor Subclass

The wastewater Laboratory Supervisor subclass is not a substitute for normal wastewater treatment certification.

DEP requires the applicant to already hold a Class A, B, C, or D wastewater treatment certification before adding the Laboratory Supervisor subclass.

The role also requires qualifying hands-on analytical testing experience and the knowledge and skills necessary to supervise laboratory procedures and reporting.

Drinking Water Subclassifications

Pennsylvania currently identifies fifteen drinking water subclassifications.

• Subclass 1: Conventional Filtration
• Subclass 2: Direct Filtration
• Subclass 3: Diatomaceous Earth Filtration
• Subclass 4: Slow Sand Filtration
• Subclass 5: Cartridge or Bag Filtration
• Subclass 6: Membrane Filtration
• Subclass 7: Corrosion Control and Sequestering
• Subclass 8: Chemical Addition
• Subclass 9: Ion Exchange and Greensand
• Subclass 10: Aeration and Activated Carbon Adsorption
• Subclass 11: Gaseous Chlorination Disinfection
• Subclass 12: Non-Gaseous Chemical Disinfection
• Subclass 13: Ultraviolet Disinfection
• Subclass 14: Ozonation
• Subclass 15: Laboratory Supervisor

A drinking water system may have several treatment subclassifications at the same time.

One Plant Can Require Multiple Subclasses

A plant is not necessarily represented by a single technology subclass.

For example, a drinking water plant may use:

• conventional filtration;
• chemical addition;
• corrosion control;
• non-gaseous chemical disinfection.

An operator responsible for process-control decisions involving those technologies must hold the required corresponding subclasses.

Having only the filtration subclass would not automatically authorize independent process-control decisions for every other treatment technology at the facility.

What Is a Process-Control Decision?

DEP describes a process-control decision as a decision or action that maintains or changes the quantity or quality of water being treated in a manner that may affect public health or the environment.

Examples can include decisions involving:

• chemical feed rates;
• treatment-process adjustments;
• pump or flow changes that affect treatment;
• aeration or biological-process settings;
• filter operation;
• disinfection operation;
• solids wasting;
• other operational changes affecting treatment performance.

The exact significance of an action depends on the system and operating conditions.

Who May Make Process-Control Decisions?

Pennsylvania requires process-control decisions to be made by an appropriately certified available operator.

An appropriately certified operator has:

• a certification class equal to or higher than the system class;
• the required subclassifications for the system's treatment technologies.

A worker who does not meet both requirements is not independently authorized to make those process-control decisions.

Non-Certified Operators

Not every worker at a treatment system must hold certification.

Non-certified personnel may perform many operational, maintenance, sampling, laboratory, inspection, and support duties under the facility's organization and procedures.

However, DEP states that non-certified personnel cannot independently make process-control decisions.

An applicant gaining experience before certification may assist a certified operator and perform qualifying work, but the certified operator retains process-control authority.

Available Operators

Pennsylvania regulations use the term available operator for an appropriately certified operator available to make required process-control decisions.

The operator does not necessarily need to remain physically at the treatment plant at all times.

DEP states that an appropriately certified operator may be available for contact when a process-control decision is required.

Specific staffing, availability, reporting, and owner responsibilities are discussed in a later Study Guide article.

How Process-Control Decisions May Be Made

Under 25 Pa. Code Chapter 302, process-control decisions may be made in several ways when the applicable requirements are satisfied.

They may be made:

• onsite;
• from a remote location;
• through approved Standard Operating Procedures under an operator in responsible charge;
• through qualifying PLC or SCADA systems as provided by the regulations.

This does not eliminate certified-operator responsibility. Automation and written procedures must operate within the certification framework established by Chapter 302.

Operator in Responsible Charge

An operator in responsible charge has additional responsibilities when a system owner chooses to use Standard Operating Procedures to facilitate process-control decision making.

The operator in responsible charge is not simply the most senior employee on a shift. The designation has a specific role under the certification regulations.

The relationship among SOPs, process control, non-certified operators, and operators in responsible charge is addressed in a separate article.

Higher Class Does Not Replace Missing Subclasses

One of the most important exam concepts is that class and subclass requirements work together.

Consider a Class A wastewater operator certified only for Fixed-Film Treatment.

That operator has a class high enough for any standard Class A-D treatment-system size, but the operator does not automatically have Activated Sludge authority.

If the plant uses activated sludge, the operator must also hold Wastewater Subclass 1.

Subclass Does Not Replace Insufficient Class

The reverse is also true.

A Class D operator who holds the correct treatment subclass cannot independently make process-control decisions at a Class B treatment system merely because the technology matches.

The class requirement and subclass requirement must both be satisfied.

Class Upgrade Versus Subclass Upgrade

DEP treats class upgrades differently from adding a new subclass.

For a class upgrade, the operator generally demonstrates the additional qualifying experience required for the higher class. DEP states that operators do not normally retake certification exams simply to increase the size class.

To add a new subclass, the operator must pass the applicable treatment technology-specific examination and satisfy the current experience requirements for that subclass before Board approval.

Certification Follows the Operator

An operator certificate is not automatically limited to the facility where the operator earned experience.

An operator can work at another system when:

• the operator's class is equal to or higher than the new system class;
• the operator holds all required treatment subclasses.

The new facility should therefore be evaluated by both system class and treatment technologies.

Examples

Example 1: A Class B wastewater operator with Activated Sludge Subclass 1 wants to work at a Class C activated sludge plant.

The class requirement is satisfied because Class B is higher than Class C. The subclass also matches. The certification is appropriate for those qualifications.

Example 2: A Class A wastewater operator with only Fixed-Film Subclass 2 wants to independently control an activated sludge process.

The class is sufficient, but the subclass does not match. Activated Sludge Subclass 1 is still required.

Example 3: A Class D drinking water operator holds the correct disinfection subclass but wants to make process-control decisions at a Class B treatment plant.

The treatment subclass may match, but the class is too low. A class upgrade would be required.

Common Class and Subclass Mistakes

• Assuming Class A means the operator can operate every type of plant.
• Ignoring technology subclasses because the operator holds a high class.
• Assuming a subclass alone authorizes work at any size system.
• Confusing wastewater collection certification with wastewater treatment certification.
• Confusing drinking water distribution certification with treatment certification.
• Assuming every employee at a facility must be certified.
• Allowing a non-certified employee to independently make a process-control decision.
• Choosing certification exams without first identifying the system technologies.
• Assuming automation removes the need for certified-operator oversight.

A Practical Way to Determine Authority

1. Identify whether the system is drinking water or wastewater.
2. Determine the system class.
3. Identify every treatment technology used.
4. Determine the corresponding subclasses.
5. Compare the operator's certificate class with the system class.
6. Confirm that all required subclasses are present.
7. Determine whether the planned action is a process-control decision.
8. Ensure an appropriately certified available operator makes or controls that decision as required.

What to Remember for the Exam

• Operator class and treatment subclass are separate certification requirements.
• The standard Classes A-D are based on hydraulic design capacity.
• Class A is greater than 5 MGD.
• Class B is greater than 1 MGD through 5 MGD.
• Class C is greater than 100,000 gpd through 1 MGD.
• Class D is 100,000 gpd or less.
• Pennsylvania also has special drinking water and wastewater classes.
• Wastewater currently has five subclasses.
• Drinking water currently has fifteen subclasses.
• A system may require more than one treatment subclass.
• An operator's class must equal or exceed the system class.
• The operator must also hold every required treatment subclass relevant to the process-control decisions being made.
• A higher class does not replace a missing subclass.
• A correct subclass does not replace an insufficient class.
• Non-certified personnel cannot independently make process-control decisions.
• An available operator must make required process-control decisions.
• Process-control decisions may be made onsite, remotely, through qualifying SOPs, or through qualifying PLC/SCADA arrangements when regulatory requirements are satisfied.