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Virginia Administrative Code
Title 9. Environment
Agency 25. State Water Control Board
Chapter 790. Sewage Collection and Treatment Regulations
7/8/2020

9VAC25-790-300. Reliability.

Article 3
Requirements for Sewerage Systems and Treatment Works Reliability

A. Additional operation and maintenance documentation may be necessary where performance reliability has not been established or worker safety and public health protection is questioned.

B. Operability. Independently operated essential equipment or components of sewerage systems and treatment works shall be provided with sufficient duplication or alternative operation so that the average daily design flow may be transported, stored, treated or otherwise managed in accordance with reliability requirements with the largest component out of service. Sufficient spare parts to ensure continuous operability of essential unit operations and equipment shall be kept in a central storeroom located at the treatment works or at other readily accessible locations, and the minimum quantities shall be in accordance with the operation and maintenance manual. The need for spare parts should be determined from review of manufacturer's recommendations, evaluation of past maintenance requirements, etc. A spare parts inventory shall be included in the operation and maintenance manual. The inventory shall list the minimum and maximum quantities of the spare parts to be kept on hand, the equipment in which they are used, their storage location, replacement procedures and other pertinent information. A suggested spare parts inventory system is contained in Part IV (9VAC25-790-940 et seq.) of this chapter.

C. Maintenance. A regular program of preventive maintenance shall be adhered to. The Operations and Maintenance Manual shall contain a system of maintenance requirements to be accomplished.

1. A minimum preventive maintenance system shall be provided in accordance with the Operations and Maintenance Manual. Such a system should provide for advanced scheduling of preventive maintenance and should be continually assessed in order to reflect increased service requirements as equipment ages or flow rates increase.

2. Adequate records, files and inventories to assist the operator in his task should also be maintained.

3. A schedule for testing the integrity of all auxiliary standby power equipment, portable pumps, automatic electrical switchover gear, and diversion piping should be developed and adhered to on a regular basis. A suggested maintenance system is outlined in this chapter. In cases where certain components of the treatment process may be damaged by flooding from natural events in such a manner as to cause excessive delays in restoring the treatment process to the design operating level, the means of removal of such components prior to flooding should be described in the Operational and Maintenance Manual.

D. Personnel. The recommended attendance hours by a licensed operator and the minimum daily hours that the treatment works should be manned by operating staff are contained in Table 1. The number of operating staff provided daily at a treatment works depends upon these requirements, as well as upon the permit compliance status and the operational conditions, such as:

1. The design capacity (flow);

2. The quality of the effluent;

3. The complexity of the treatment processes used; and

4. The fact that only a licensed operator may be specified as the individual in charge of overseeing permit compliance.

In instances where the recommended hours of attendance by a licensed operator are less than the daily hours the treatment works is to be manned by operating staff (see Table 1), a licensed operator is not required to be physically located at the treatment works site during the remaining designated manning hours, provided that the licensed operator is able to respond to requests for assistance in a satisfactory manner, as described in the Operation and Maintenance Manual.

E. Conditions. The objective of treatment works operation should be to provide the most reliable and efficient performance that can be practically achieved in compliance with permit requirements, while providing for safe working conditions. Operational health and safety provisions are critical. Cross media pollution prevention measures should be evaluated and developed where practical, and material safety data sheets for toxic chemicals used should be readily available.

1. Alternate operating provisions shall be utilized as necessary in accordance with the reliability classification. An all-weather road shall be provided to permit access to and from the treatment works during normal weather conditions. Escape routes and methods should be established for emergency situations.

2. Pretreatment requirements as set forth in the State Water Control Board's Regulations should be established and monitored in accordance with local regulations specific to such requirements.

3. Local standards and specifications approved in accordance with this chapter shall provide for the construction methods, as necessary in accordance with the local owner's sewer line maintenance program, to minimize excessive amounts of infiltration and inflow and prevent the accumulation of solids or debris that would interfere with the transmission of flow resulting in overflows, bypassing, or offline flow surcharges such as in service connections.

4. Odor control measures should be established in accordance with site specific features and weather patterns. Development of objectionable odors shall be addressed by the best available odor control technology.

TABLE 1.
CLASSIFICATION OF TREATMENT WORKS AND RECOMMENDED MINIMUM HOURS OF ATTENDANCE BY LICENSED OPERATORS AND OPERATING STAFF(1).


Treatment Works Classification & Treatment Required Classification of the Operator in responsible charge

Treatment Works Capacity (MGD)

Treatment Process Methods

Recommended Attendance by a Licensed Operator(2,3) Time-Hrs.

Recommended Daily Hours That Works Should Be Manned(2,3)

I

Greater than 10 MGD

Biological Treatment Methods

(A) Suspended Growth Reactors

24

24

(B) Aerated Lagoons or Constructed Wetlands

16

24

(C) Filters or Other Attached Growth Contactors

24

24

(D) Processes Utilizing Biological Nutrient Control

24

24

(E) Processes Utilizing Land Treatment

During Land Application

- -

I

Equal to or less than 10 MGD but greater than 5 MGD

Biological Treatment Methods

(A) Suspended Growth Reactors

16

24

(B) Aerated Lagoons or Constructed Wetlands

8

16

(C) Filters or Other Attached Growth Contactors

16

24

(D) Processes Utilizing Biological Nutrient Control

16

24

(E) Processes Utilizing Land Treatment

During Land Application

- -

I

Greater than 5 MGD

Advanced Waste Treatment (AWT)

(A) Ammonia Stripping

24

24

(B) Breakpoint Chlorination

24

24

(C) Carbon Adsorption

24

24

(D) Chemical Coagulation, Flocculation, Precipitation

24

24

(E) Filtration

24

24

(F) Demineralization (Ion Exchange, Reverse Osmosis, Electrodialysis)

24`

24

I

Equal to or less than 5 MGD but greater than 2.5 MGD

Advanced Waste Treatment

(A) Ammonia Stripping

16

24

(B) Breakpoint Chlorination

16

24

(C) Carbon Adsorption

16

24

(D) Chemical Coagulation, Flocculation, Precipitation

16

24

(E) Filtration

16

24

(F) Demineralization (Ion Exchange, Reverse Osmosis, Electrodialysis)

16

24

(G) Microstraining/Screening

16

24

II

Greater than 2.5 MGD but equal to or less than 5.0 MGD

Biological Treatment Methods

(A) Suspended Growth Reactors

8

24

(B) Aerated Lagoons or Constructed Wetlands

8

26

(C) Filters or Other Attached Growth Contactors

8

24

(D) Processes Utilizing Biological Nutrient Control

8

24

(E) Processes Utilizing Land Treatment

During Land Application

- -

II

Greater than 0.5 MGD but equal to or less than 2.5 MGD

Biological Treatment Methods

(A) Suspended Growth Reactors

8

16

(B) Aerated Lagoons

4

8

(C) Filters or Other Attached Growth Contactors

8

16

(D) Processes Utilizing Biological Nutrient Control

8

16

(E) Processes Utilizing Land Treatment

During Land Application

- -

II

Greater than 0.1 MGD but equal to or less than 2.5 MGD

Advanced Waste Treatment

(A) Ammonia Stripping

8

16

(B) Breakpoint Chlorination

8

16

(C) Carbon Adsorption

8

16

(D) Chemical Coagulation, Flocculation, Precipitation

8

16

(E) Filtration

8

16

(F) Demineralization (Ion Exchange, Reverse Osmosis, Electrodialysis)

8

16

III

Greater than 0.04 MGD but Equal to or less than 0.5 MGD

Biological Treatment Methods

(A) Suspended Growth Reactors

8

8

(B) Aerated Lagoons or Constructed Wetlands

8

8

(C) Filters or Other Attached Growth Contractors

8

8

(D) Processes Utilizing Biological Nutrient Control

8

8

(E) Processes Utilizing Land Treatment

During Land Application

- -

III

Greater than 1.00 MGD

Natural Treatment Methods

4

8

III

Greater than 0.001 MGD but equal to or less than 0.1 MGD

Advanced Waste Treatment

(A) Ammonia Stripping

8

8

(B) Breakpoint Chlorination

8

8

(C) Carbon Adsorption

8

8

(D) Chemical Coagulation, Flocculation, Precipitation

8

8

(E) Filtration

8

8

(F) Demineralization (Ion Exchange, Reverse Osmosis, Electrodialysis)

8

8

IV

Greater than 0.001 MGD but equal to or less than 0.04 MGD

Biological Mechanical Methods(4)

4(5)

4(5)

IV

Greater than 0.001 MGD but equal to or less than 1.00 MGD

Natural Treatment Methods(4)

4(5)

4(5)

Notes:

(1)Specific requirements for the number of licensed operators and the number and qualifications of the operating staff specified in accordance with this chapter and in consultation with and concurrence by the director are to be evaluated on a case-by-case basis in accordance with operational reliability and permit compliance data. Such requirements are to be included in the Operation and Maintenance Manual.

(2)If a particular treatment unit or units are discontinued or not in use for a significant period of time and the remaining treatment processes result in a lower classification for the treatment works, the licensed operator and operating staff requirements during that period may be reduced to that required for the type and classification of treatment process remaining in service, after concurrence by the director.

(3)If more than one sewage treatment process is used, the more stringent requirements among the processes will apply. In some cases, complexity of operation for several AWT processes in sequence may require more than the minimum coverage.

(4)Mechanical treatment processes are defined as those containing aerated and mixed flows using electrical or outside energy sources.

(5)An operator is not required unless the facility is designated as a wastewater treatment works by DEQ.

Statutory Authority

§ 62.1-44.19 of the Code of Virginia.

Historical Notes

Former 12VAC5-581-360 derived from Volume 18, Issue 10, eff. February 27, 2002; amended and adopted as 9VAC25-790-300, Virginia Register Volume 20, Issue 09, eff. February 12, 2004.

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