Current through Register Vol. 41, No. 3, September 23, 2024
A. The
monitoring requirements for the standards provided under
9VAC25-740-70
A, are as follows:
1. Turbidity analysis:
a. Analysis shall be performed by a
continuous, on-line turbidity meter equipped with an automated data logging or
recording device and an alarm to notify the operator when the CAT for turbidity
in the standard for Level 1 has been reached. Compliance with the average
turbidity standard shall be determined daily, based on the arithmetic mean of
hourly or more frequent discrete measurements recorded during a 24-hour period.
Monitoring for the turbidity CAT shall be continuous.
b. Should the on-line turbidity meter go out
of service for either planned or unplanned repair, the permittee shall be
allowed to manually collect samples for turbidity analysis at four-hour
intervals up to a maximum of five days. Following the five-day period of
repair, continuous, on-line monitoring with a turbidity meter shall
resume.
2. Sampling and
analysis for residual concentrations of disinfectants, including total residual
chlorine (TRC):
a. For Level 1:
(1) Shall be continuous on-line monitoring,
equipped with an automated data logging or recording device and an alarm to
notify the operator when the CAT for the disinfectant has been reached. For
disinfectants other than chlorine, continuous on-line monitoring shall be
provided at the point of compliance monitoring. For TRC, continuous on-line
monitoring shall be provided at the end of the contact tank or contact period.
Monitoring for the TRC CAT shall be continuous.
(2) Should the on-line disinfectant
monitoring equipment go out of service for either planned or unplanned repair,
the permittee shall be allowed to manually collect samples for disinfectant
analysis at four-hour intervals up to a maximum of five days. Following the
five-day period of repair, continuous, on-line disinfectant monitoring shall
resume.
b. For Level 2,
shall be based on the designated design flow of the reclamation system and be
the same sampling type and frequency as specified for sewage treatment works in
the Sewage Collection and Treatment Regulations (9VAC25-790). For chemical
disinfectants other than TRC, monitoring shall be provided at the point of
compliance in accordance with
9VAC25-740-70
B. For TRC, monitoring shall be provided at the end of the contact tank or
contact period.
3.
Sampling for TSS and BOD5 or
CBOD5 shall be at least weekly or more frequently based
on the designated design flow of the reclamation system, and shall be the same
sampling type and frequency as specified for sewage treatment works in the
Sewage Collection and Treatment Regulations (9VAC25-790). Compliance with the
monthly average TSS and BOD5 or
CBOD5 standards shall be determined monthly, based on
the arithmetic mean of all samples collected during the month. Compliance with
the maximum weekly average TSS and BOD5 or
CBOD5 standards shall be determined monthly, using the
same procedures applied in the VPDES permit program for point source
discharges.
4. Sampling for fecal
coliform, E. coli or enterococci:
a. Shall for
Level 1, be grab samples collected at a time when wastewater characteristics
are most representative of the treatment facilities and disinfection processes
for water reuse, and at the frequencies provided in Table 80-A. Compliance with
the geometric mean standards for fecal coliform, E. coli, or enterococci shall
be determined monthly, based on all bacteriological monitoring results for that
month. Monitoring of the CAT for fecal coliform, E. coli, or enterococci shall
be based on the bacteriological monitoring results determined for each day a
sample is collected.
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Table 80-A
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Reclamation System Designated Design Flow
(MGD)(1)
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Bacterial Sampling
Frequency(2)
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>0.500
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Daily with the ability to reduce to no less than
four days per week(3)
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0.050 to 0.500
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Four days per week with the ability to reduce to
no less than three days per week(3)
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<0.050
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Three days per week with no reduction
allowed
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(1)MGD means million
gallons per day.
(2)For reclamation
systems treating municipal wastewater, bacterial samples shall be collected
between 10 a.m. and 4 p.m. to coincide with peak flows to the reclamation
system. An exception to this requirement may be approved upon demonstration to
the department that peak flows to the reclamation system occur outside this
period.
(3)Monitoring
frequency may be reduced after demonstrating compliance with bacterial
standards for Level 1 and adequate correlation between bacterial monitoring
results and measurements for surrogate disinfection parameters, such as TRC and
turbidity.
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b.
Shall for Level 2, be based on the designated design flow of the reclamation
system and be the same sampling type and frequency as specified for sewage
treatment works in the Sewage Collection and Treatment Regulations
(9VAC25-790). Compliance with the geometric mean standard and monitoring of the
CAT for fecal coliform, E. coli or enterococci shall be in accordance with the
same procedures specified for Level 1 in subdivision 4 a of this
subsection.
5. Samples
for pH shall be grab samples collected at least daily. Compliance with the
range of the pH standard shall be determined daily based on the pH of the
samples.
B. Samples
collected for TSS, BOD5 or CBOD5,
and fecal coliform, E. coli or enterococci analyses, shall be analyzed by
laboratory methods accepted by the department.
C. A reclamation system that produces
reclaimed water intermittently or seasonally shall monitor only when the
reclamation system discharges to a reclaimed water distribution system, a
nonsystem storage facility, or directly to a reuse.
D. Monitoring of reclaimed water held in
system storage for a period greater than 24 hours at a reclamation system or
SRS may be required by the department where (i) the system storage facility
discharges to a reclaimed water distribution system, a nonsystem storage
facility, or directly to a reuse; and (ii) conditions exist at the facility to
degrade the reclaimed water to a quality failing to comply with applicable
minimum reclaimed water standards for the intended reuses of that water. When
monitoring of reclaimed water in or from system storage is required, monitoring
parameters and frequencies shall be determined by the department on a
case-by-case basis.
E. Monitoring
other than or in addition to that described under subsection A of this section
may be required for treatment of reclaimed water that is provided pursuant to
9VAC25-740-70
D and
9VAC25-740-70
E.
Statutory Authority: § 62.1-44.15 of the Code of
Virginia.
