Current through Register Vol. 48, No. 9, September 27, 2024
A public water system that uses a surface water source or a
ground water source under the direct influence of surface water, and does not
meet all of the criteria in R.61-58.10(D)(2)(C)(1) and
(2) for avoiding filtration, shall provide
treatment consisting of both disinfection, as specified in R.61-58.10(C)(1) and
(2)(D)(2), and filtration treatment which
complies with the requirements of paragraphs (1), (2), (3), or (4) of this
section by June 29, 1993, or within 18 months of the failure to meet any one of
the criteria for avoiding filtration in R.61-58.10(C)(1) and
(2)(C)(1) and (61-58.10(D)(2)), whichever is
later. Failure to meet any requirement of this section after the date specified
in this introductory paragraph is a treatment technique violation.
(1) Conventional filtration treatment or
direct filtration.
(a) For systems using
conventional filtration or direct filtration, the turbidity level of
representative samples of a system's filtered water must be less than or equal
to 0.5 NTU in at least 95 percent of the measurements taken each month,
measured as specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and
(3)(a), except that if the Department
determines that the system is capable of achieving at least 99.9 percent
removal and/or inactivation of Giardia lamblia cysts at some turbidity level
higher than 0.5 NTU in at least 95 percent of the measurements taken each
month, the Department may substitute this higher turbidity limit for that
system. However, in no case may the Department approve a turbidity limit that
allows more than 1 NTU in more than 5 percent of the samples taken each month,
measured as specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and
(3)(a).
(b) The turbidity level of
representative samples of a system's filtered water must at no time exceed 5
NTU, measured as specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and
(3)(a).
(c) Beginning January 1,
2002, systems serving at least 10,000 people must meet the requirements of
Section H(4)(a) below.
(d)
Beginning January 1, 2005, systems serving fewer than 10,000 people must meet
the turbidity requirements in Section I(6) below.
(2) Slow sand filtration.
(a) For systems using slow sand filtration,
the turbidity level of representative samples of a system's filtered water must
be less than or equal to 1 NTU in at least 95 percent of the measurements taken
each month, measured as specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d)
and (3)(a), except that if the Department determines there is no significant
interference with disinfection at a higher turbidity level, the Department may
substitute this higher turbidity limit for that system.
(b) The turbidity level of representative
samples of a system's filtered water must at no time exceed 5 NTU, measured as
specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and (3)(a).
(3) Diatomaceous earth filtration.
(a) For systems using diatomaceous earth
filtration, the turbidity level of representative samples of a system's
filtered water must be less than or equal to 1 NTU in at least 95 percent of
the measurements taken each month, measured as specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and
(3)(a).
(b) The turbidity level of representative
samples of a system's filtered water must at no time exceed 5 NTU, measured as
specified in R.61-58.10(F)(1)(d) and (3)(a)(F)(1)(d) and (3)(a).
(4) Other filtration technologies.
A public water system may use a filtration technology not
listed in paragraphs (1) through (3) of this section if it demonstrates to the
Department, using pilot plant studies or other means, that the alternative
filtration technology, in combination with disinfection treatment that meets
the requirements of Section D(2), above, consistently achieves 99.9 percent
removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal
and/or inactivation of viruses. For a system that makes this demonstration, the
requirements of paragraph (2) of this section apply. Beginning January 1, 2002,
systems serving at least 10,000 people must meet the requirements for other
filtration technologies in R.61-58.10.H(4)(b).
Beginning January 1, 2005, systems serving fewer than 10,000 people must meet
the requirements for other filtration technologies in Section I(6)
below.
