Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 590 - WATERWORKS REGULATIONS › Section 12VAC5-590-411 - Disinfection byproduct precursors, disinfection byproducts, and maximum residual disinfection level treatment techniques

Current through Register Vol. 40, No. 24, July 15, 2024
A. Treatment technique for control of DBPPs.
1. Applicability.
a. The owner of a community waterworks or a
				NTNC shall comply with treatment techniques for the control of DBPPs.
b. A waterworks that uses a surface water
				source, a GUDI source, or both using conventional filtration treatment shall
				operate with enhanced coagulation or enhanced softening to achieve the TOC
				percentage removal levels specified in subdivision A 2 of this section unless
				the waterworks meets at least one of the alternative compliance criteria listed
				in subdivision A 1 c or A 1 d of this section.
c. Alternative compliance criteria for
				enhanced coagulation and enhanced softening waterworks. A waterworks that uses
				a surface water source, a GUDI source, or both provided with conventional
				filtration treatment may use the alternative compliance criteria in
				subdivisions A 1 c (1) through A 1 c (6) of this section to comply with this
				section instead of complying with subdivision A 2 of this section. The owner
				shall comply with monitoring requirements in 12VAC5-590-374 I.
(1) The waterworks' source water TOC level is
				less than 2.0 mg/L, calculated quarterly as an RAA.
(2) The waterworks' treated water TOC level
				is less than 2.0 mg/L, calculated quarterly as an RAA.
(3) The waterworks' source water TOC level is
				less than 4.0 mg/L, calculated quarterly as an RAA; the source water alkalinity
				is greater than 60 mg/L (as CaCO3), calculated quarterly
				as an RAA; and no TTHM and HAA5 LRAAs are greater than 0.040 mg/L and 0.030
				mg/L, respectively.
(4) No TTHM and
				HAA5 LRAAs are greater than 0.040 mg/L and 0.030 mg/L, respectively, and the
				waterworks uses only chlorine for primary disinfection and maintains a residual
				in the distribution system.
(5) The
				waterworks' source water SUVA, before any treatment and measured monthly, is
				less than or equal to 2.0 liters per milligram-meter (L/mg-m), calculated
				quarterly as an RAA.
(6) The
				waterworks' finished water SUVA, measured monthly, is less than or equal to 2.0
				L/mg-m, calculated quarterly as an RAA.
d. Additional alternative compliance criteria
				for softening waterworks. A waterworks practicing enhanced softening that
				cannot achieve the TOC removals required by subdivision A 2 b of this section
				may use the alternative compliance criteria in subdivisions A 1 c (1) and A 1 c
				(2) instead of complying with subdivision A 2 of this section. A waterworks
				shall comply with monitoring requirements in 12VAC5-590-374 [ J ].
(1) Softening that results in lowering the
				treated water alkalinity to less than 60 mg/L (as CaCO3), measured monthly and
				calculated quarterly as an RAA.
(2)
				Softening that results in removing at least 10 mg/L of magnesium hardness (as
				CaCO3), measured monthly and calculated quarterly as an RAA.