Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 590 - WATERWORKS REGULATIONS › Section 12VAC5-590-405 - Lead and copper treatment techniques

Current through Register Vol. 40, No. 24, July 15, 2024
A. Lead and copper corrosion control
				techniques.
1. Corrosion control treatment
				requirements. The owner of a community waterworks or a NTNC shall install and
				operate optimum corrosion control treatment by completing the corrosion control
				treatment requirements described below which are applicable to these waterworks
				under subdivision A 2 of this section.
a.
				Owner's proposal regarding corrosion control treatment. Based upon the results
				of lead and copper tap monitoring and water quality parameter monitoring, the
				owner of a small or a medium waterworks exceeding the lead or copper AL shall
				propose installation of one or more of the corrosion control treatments listed
				in subdivision A 1 c (1) of this section that the owner believes constitutes
				optimal corrosion control for that waterworks. The department may require the
				owner to conduct additional water quality parameter monitoring in accordance
				with
				12VAC5-590-375
				C 2 to assist the department in evaluating the proposal.
b. Applicability of studies of corrosion
				control treatment (applicable to small and medium waterworks). The department
				may require the owner of a small or a medium waterworks that exceeds the lead
				or copper AL to perform corrosion control studies under subdivision A 1 cof
				this section to identify optimal corrosion control treatment for the
				waterworks.
c. Corrosion control
				studies.
(1) The owner of a waterworks
				required by the department to perform corrosion control studies shall evaluate
				the effectiveness of each of the following treatments, and, if appropriate,
				combinations of the following treatments to identify the optimal corrosion
				control treatment for that waterworks:
(a)
				Alkalinity and pH adjustment;
(b)
				Calcium hardness adjustment; and
(c) The addition of a phosphate-based or
				silicate-based corrosion inhibitor at a concentration sufficient to maintain an
				effective corrosion inhibitor residual concentration in all test tap samples,
				such that a passivating film is formed on the interior walls of the
				pipe.
(2) The owner shall
				evaluate each of the corrosion control treatments using either pipe rig or loop
				tests, metal coupon tests, partial-system tests, or analyses based on
				documented analogous treatments with other waterworks of similar size, water
				chemistry, and distribution system configuration.
(3) The owner shall measure the following
				water quality parameters in any tests conducted under subdivision A 1 cof this
				section before and after evaluating the corrosion control treatments listed in
				subdivision A 1 c (1) of this section:
(a)
				Lead;
(b) Copper;
(c) pH;
(d) Alkalinity;
(e) Calcium;
(f) Conductivity;
(g) Orthophosphate (when an inhibitor
				containing a phosphate compound is used);
(h) Silicate (when an inhibitor containing a
				silicate compound is used); and
(i)
				Water temperature.
(4)
				The owner shall identify all chemical or physical constraints that limit or
				prohibit the use of a particular corrosion control treatment and document such
				constraints with at least one of the following:
(a) Data and documentation showing that a
				particular corrosion control treatment has adversely affected other water
				treatment processes when used by another waterworks with comparable water
				quality characteristics; or
(b)
				Data and documentation demonstrating that the owner has previously attempted to
				evaluate a particular corrosion control treatment and has found that the
				treatment is ineffective or adversely affects other water quality treatment
				processes.
(5) The owner
				shall evaluate the effect of the chemicals used for corrosion control treatment
				on other water quality treatment processes.
(6) On the basis of an analysis of the data
				generated during each evaluation, the owner shall propose in writing to the
				department that the treatment option resulting from the corrosion control
				studies constitutes optimal corrosion control treatment for that waterworks.
				The owner shall provide a rationale for the recommendation along with all
				supporting documentation specified in subdivisions A 1 c (1) through A 1 c (5)
				of this section.
d.
				Approval of optimal corrosion control treatment.
(1) Based upon consideration of available
				information including, where applicable, studies performed under subdivision A
				1 c of this section and the owner's proposed treatment alternative, the
				department shall either approve the corrosion control treatment option
				recommended by the owner, or designate alternative corrosion control treatment
				from among those listed in subdivision A 1 c (1) of this section. When
				approving optimal treatment, the department shall consider the effects that
				additional corrosion control treatment will have on water quality parameters
				and on other water quality treatment processes.
(2) The department shall notify the owner of
				the determination on optimal corrosion control treatment in writing and explain
				the basis for this determination. If the department requests additional
				information to aid an evaluation, then the owner shall provide the
				information.
e.
				Installation of optimal corrosion control. The owner shall properly install and
				operate throughout the waterworks the optimal corrosion control treatment
				approved by the department under subdivision A 1 d of this section. A
				construction permit is required before installation of any treatment in
				accordance with
				12VAC5-590-200.
f. The department's evaluation of treatment
				and specification of the optimal water quality control parameters shall consist
				of the following:
(1) The department shall
				evaluate the results of all lead and copper tap samples and water quality
				parameter samples submitted by the owner and determine whether the owner has
				properly installed and operated the optimal corrosion control treatment
				approved by the department under subdivision A 1 d of this section. Upon
				evaluating the results of tap water and water quality parameter monitoring by
				the owner, both before and after the owner installs optimal corrosion control
				treatment, the department shall designate:
(a) A minimum value or a range of values for
				pH measured at each entry point to the distribution system;
(b) A minimum pH value, measured in all tap
				samples. The value shall be equal to or greater than 7.0, unless the department
				determines that meeting a pH level of 7.0 is not technologically feasible or is
				not necessary for the owner to optimize corrosion control;
(c) If a corrosion inhibitor is used, then a
				minimum concentration or a range of concentrations for the inhibitor, measured
				at each entry point to the distribution system and in all tap samples, that the
				department determines is necessary to form a passivating film on the interior
				walls of the pipes of the distribution system;
(d) If alkalinity is adjusted as part of the
				optimal corrosion control treatment, then a minimum concentration or a range of
				concentrations for alkalinity, measured at each entry point to the distribution
				system and in all tap samples; or
(e) If calcium carbonate stabilization is
				used as part of the corrosion control, then a minimum concentration or a range
				of concentrations for calcium, measured in all tap samples.
(2) The values for the applicable water
				quality control parameters listed in subdivision A 1 c (3) of this section
				shall be those that the department determines to reflect optimal corrosion
				control treatment for the waterworks. The department may designate values for
				additional water quality control parameters determined by the department to
				reflect optimal corrosion control for the waterworks. The department shall
				notify the owner in writing of these determinations and explain the basis for
				the decisions.
g.
				Continued operation and monitoring. The owner of a waterworks optimizing
				corrosion control shall continue to operate and maintain optimal corrosion
				control treatment, including maintaining water quality parameters at or above
				minimum values or within ranges designated by the department under subdivision
				A 1 f of this section as verified by all samples collected under
				12VAC5-590-375
				C 4,12VAC5-590-375
				C 5, and
				12VAC5-590-375
				C 6. Compliance with the requirements of this subdivision shall be determined
				every six months, as specified under
				12VAC5-590-375
				C 4. The waterworks is out of compliance with the requirements of this
				subdivision for a six-month period if excursions occur for any
				department-specified parameter on more than nine days during the period. An
				excursion occurs whenever the daily value for one or more of the water quality
				parameters measured at a sampling location is below the minimum value or
				outside the range designated by the department. The department has discretion
				to delete results of obvious sampling errors from this calculation. Daily
				values shall be calculated as follows:
(1) On
				days when more than one measurement for the water quality parameter is
				collected at the sampling location, the daily value shall be the average of all
				results collected during the day regardless of whether they are collected
				through continuous monitoring, grab sampling, or a combination of
				both.
(2) On days when only one
				measurement for the water quality parameter is collected at the sampling
				location, the daily value shall be the result of that measurement.
(3) On days when no measurement is collected
				for the water quality parameter at the sampling location, the daily value shall
				be the daily value calculated on the most recent day on which the water quality
				parameter was measured at the sample site.
h. Modification of the department's treatment
				decisions. Upon the department's initiative or in response to a request by an
				owner or other interested party, the department may modify the determination of
				the optimal corrosion control treatment under subdivision A 1 d of this section
				or optimal water quality control parameters under subdivision A 1 f of this
				section. A request for modification by an owner or other interested party shall
				be in writing, explain why the modification is appropriate, and provide
				supporting documentation. The department may modify the determination where it
				is concluded that the change is necessary to ensure that the waterworks
				continues to optimize corrosion control treatment. A revised determination
				shall be made in writing, set forth the new treatment requirements, explain the
				basis for the department's decision, and provide an implementation schedule for
				completing the treatment modifications.