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Virginia Administrative Code
Title 9. Environment
Agency 25. State Water Control Board
Chapter 790. Sewage Collection and Treatment Regulations
1/19/2020

9VAC25-790-970. Operational Testing and Control.

A. Minimum tests and frequency. Table D-l contains the typical minimum sampling and testing program for operational control of treatment works greater than 40,000 gallons per day.

B. Sampling instructions. The following sampling instructions should be followed when taking samples:

1. When samples are taken for BOD5, COD, volatile suspended solids, and suspended solids on influent and effluent streams, they should be composite samples.

2. All other samples should be grab samples.

TABLE D-1. RECOMMENDED OPERATIONAL AND CONTROL TESTING.

Unit Process Parameters

Testing Location/Frequencies
(see key for description)

1. Primary

a) DOB5/TSS/TVS

1/bw; 2,3/2

b) settleable solids

2, 3/d

c) pH

2,3,8/d

2. Suspended Growth Reactor

a) BOD5/nutrients

1/bw; 2/w; 3/bw

b) TSS/TVSS

6/d; 13/w

c) 30 minute SSV/pH/DO

6/d

d) microscopic exam.

6/w

3. Attached Growth Reactors

a) BOD5/nutrients

1/bw; 2/w; 3/bw

b) TSS/TVS/microscopic exam.

14/w

c) pH, DO

1/d; 2/w

4. Ponds of Lagoons

a) BOD5/nutrients

1/w; 2/w

b) TSS/microscopic exam.

1/w; 2/w; 7/w

c) pH/DO/temperature

1/d; 7/d

5. Anaerobic Digestion

a) TS/TVS

6,11,12/w; 8,9,10,13/bw

b) pH/alkalinity/temp.

6,12/d; 11,15/bw; 6/w; 13/bw

6. Aerobic Digestion

a) TS/TVS

6,11,12/w; 13/bw

b) settleable solids

6/d

c) pH/temperature

6/d; 15/bw

d) microscopic exam.

6/w; 13/bw

7. Sludge Thickening

a) TS/TVS

1,2/d

b) settleable solids

6/d

8. Sludge Dewatering

a) TS/TVS

1,2,4,12/q

b) pH/alkalinity

15/q

9. Chemical Clarification

a) BOD5/COD/TSS/TYS

1,2/w

pH/alkalinity

1,2,3,4,6/d

b) settleable solids/flocculation

1,2,6/d

c) nutrients

1,2/q

10. Tertiary Filtration

a) BOD5/TSS

1,2/w

b) pH/alkalinity

1,2/d

c) nutrients

1,2/q

TABLE D-1 - KEY

FREQUENCY

SAMPLING LOCATION

d - Daily

1. Process Influent

w - Weekly

2. Process Effluents

bw - Biweekly

3. Influent plus Return Waste Streams

q - Daily when in operation

4. Following Chemical Addition

5. Filtered Effluent

CONVENTIONAL PARAMETERS

6. Contents of Reactor

BOD5 - 5-day biochemical oxygen demand

7. All Cells of Each Lagoon or Pond

SS - Suspended solids

8. Raw Sludge

TS - Total solids

9. Primary Sludge

VS - Volatile solids

10. Secondary Sludge

DO - Dissolved oxygen

11. Digester Influent

NUTRIENTS - Forms of phosphorus and nitrogen as required by the certificate CTO issued.

12. Treated Sludge

13. Return Sludge

14. Attached Growth

15. Process Supernatant

Statutory Authority

§ 62.1-44.19 of the Code of Virginia.

Historical Notes

Former 12VAC5-581-1030 derived from Volume 18, Issue 10, eff. February 27, 2002; amended and adopted as 9VAC25-790-970, Virginia Register Volume 20, Issue 09, eff. February 12, 2004.

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