Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 613 - REGULATIONS FOR ALTERNATIVE ONSITE SEWAGE SYSTEMS › Part II - Performance Requirements › Section 12VAC5-613-100 - Performance requirements; laboratory sampling and monitoring

Current through Register Vol. 40, No. 24, July 15, 2024
A. Laboratory
				  sampling is not required for any small AOSS with an installed soil treatment
				  area that is sized for septic tank effluent and complies with the requirements
				  of 12VAC5-610 for septic tank effluent.
B. All effluent samples must be taken at the
				  end of all treatment, prior to the point where the effluent is discharged to
				  the soil treatment area unless changed pursuant to
				  12VAC5-613-90 or
				  12VAC5-613-210. The designer shall
				  identify the sampling points. When required, the sampling point for chlorine
				  disinfection shall be at the end of the chlorine contact tank if TRC is to be
				  used to measure compliance.
C. All
				  sampling and monitoring shall be conducted according to procedures approved
				  under 40 CFR Part 136 or alternative methods approved by the U.S. Environmental
				  Protection Agency unless other procedures have been specified in this
				  chapter.
D. The owner of each small
				  AOSS must ensure that an initial grab sample of the effluent from the treatment
				  unit is collected within 180 days of system operation. The sample must be
				  analyzed in accordance with 40 CFR Part 136 or alternative methods approved by
				  the U.S. Environmental Protection Agency within the first 180 days of
				  operation. Thereafter, if the treatment unit has received general approval, a
				  grab sample is required once every five years. Samples shall be analyzed for
				  BOD5 and, if disinfection is required, fecal coliform.
				  Treatment units utilizing chlorine disinfection may alternatively sample for
				  TRC instead of fecal coliform. Sample results shall be submitted to the local
				  health department by the 15th of the month following the month in which the
				  sample was taken.
E. For small
				  AOSSs that utilize a treatment unit that has not received general approval, in
				  addition to the initial sample required by subsection D of this section, four
				  additional grab samples of the effluent from the treatment unit shall be
				  collected, analyzed, and submitted to the department within the first two years
				  of operation and annually thereafter. The interval for collecting the samples
				  shall not be less than quarterly or more than semiannually. Sample results
				  shall be submitted to the local health department by the 15th of the month
				  following the month in which the sample was taken. After two years of sampling
				  in accordance with this subsection, the owner may submit a request to the
				  department to reduce the sampling frequency to once every five years. The
				  department shall grant such requests if the mean of five or more consecutive
				  samples complies with the applicable performance requirements of this
				  chapter.
F. Sampling and monitoring
				  requirements for AOSS treatment systems with flows greater than 1,000 GPD are
				  contained in Table 3:
Table 3 Sampling and Monitoring for Large
							 AOSSs
PLANT SIZE
>2.0 MGD
>1.0 - to 2.0 MGD
> 100,000 GPD to 1.0 MGD
> 40,000 GPD to 100,000 GPD
>10,000 GPD to 40,000 GPD
>1,000 GPD to 10,000 GPD
Flow
Totalizing, Indicating, & Recording
Totalizing, Indicating, & Recording
Totalizing, Indicating, & Recording
Totalizing, Indicating, & Recording
Measured
Measured or Estimate
BOD5, TSS
24-HC* 1/day
24-HC 5 days/wk
8-HC 3 days/wk
4-HC 1 day/wk
Grab quarterly
Grab 1/yr
Total Nitrogen
24-HC weekly
24-HC weekly
8-HC monthly
4-HC quarterly
Grab quarterly
Grab 1/yr
TRC, End of Contact Tank**
Grab daily
Grab daily
Grab weekly
Grab weekly
Grab weekly
Grab 1/yr
Fecal Coliform***
Grab weekly
Grab weekly
Grab monthly
Grab monthly
Grab quarterly
Grab 1/yr
*HC - hourly, flow weighted composite samples
**if disinfection required and chlorine used
***if disinfection required and a disinfectant other than
					 chlorine used
G. Systems
				  with direct dispersal to ground water as described in
				  12VAC5-613-90 C shall comply with
				  the following:
1. Small AOSS treatment
				  systems:
a. Shall incorporate a method to
				  remotely monitor the operation of treatment units and processes, including the
				  status of the disinfection unit, and automatically notify the operator and
				  local health department if an alarm condition occurs;
b. Shall be sampled quarterly in accordance
				  with 12VAC5-613-90 C and as defined in
				  the renewable operating permit; and
c. No treatment units or systems shall be
				  deemed generally approved.