2.        Add a section that states the following or something similar:

“All treatment units used for an intermittent use facility, such as a seasonal cottage, cabin, home, church, school, camp or other such facility, shall demonstrate the ability to perform under intermittent use conditions.”

Reason: Some treatment units do not perform adequately when intermittently loaded.  In some cases, they will not even meet the ≤60 mg/l BOD5 referenced in 12VAC5-613-80.10.d. in order to qualify for increased soil loading rates.  Therefore, the designer should show calculations and operating requirements in order to meet expected performance requirements.

3.        Add a section that states the following or something similar:

“Timed dosing, preceding the treatment unit, or effluent by-pass protection shall be incorporated into all treatment units meeting TL-3.”

Reason: Per the Sewage Handling and Disposal Regulations (12 VAC 5-610-800):

“Where an activated sludge process is used to produce a secondary effluent, provisions shall be made to protect the drainfield from bulking solids.”  Since TL-3 is used on more marginal sites than TL-2, it is imperative that the public health and the environment (and the drainfield) is adequately protected through a fail-safe mechanism.  Also, TL-3 effluent needs to be assured through our comment #1 above.  Lastly, NSF Standard 40 make the following statement on influent dosing regimen:

8.2.2.1 Design loading note
NOTE – The individual dosage shall be no more than 10 gallons per dose, unless the dosage system is based
on a continuous flow, and be uniformly applied over the dosing periods.

4.        Modify section 10. to incorporate Table 1 soil loading rates from GMP #147 for TL-3 and create an additional table for soil loading rates for TL-2 in a format like GMP #147.

           Reason: Many designers are unsure about soil loading rates for other types of dispersal, like pads.  Adding additional tables will provide clarity for designers.

5.        An alternative to field verification specified in 12VAC5-613-70 (repealing this section) is the acceptance of third party test center data or third party field data to establish minimum performance threshold for meeting TL-3 for the requirements of Table 1 soil loading rates.  This is similar to what many other states do for establishing performance.  Two other state tables were submitted via email to VDH.