A public water system that uses a surface water source, in
whole or in part, shall provide treatment consisting of both disinfection, as
specified in paragraph (B) of rule
3745-81-72 of the Administrative
Code, and filtration treatment which complies with paragraph (A), (B), or (C)
of this rule. . Distinction between surface
water sources and ground water sources is set forth in rule
3745-81-76 of the Administrative
Code. Filtration treatment shall consistently and reliably achieve at least
ninety-nine per cent (2 log) removal of Cryptosporidium. Failure to meet any
requirement of this rule shall be a treatment technique violation and shall
require public notification as set forth in rule
3745-81-32 of the Administrative
Code.
(A) Conventional filtration
treatment
or direct filtration treatment.
All public water systems using conventional filtration treatment
or direct filtration treatment to treat
surface water shall meet the following:
(1)
Turbidity levels of representative samples of filtered water shall be less than
or equal to 0.3 nephelometric turbidity units (NTU) in at least ninety-five per
cent of the samples analyzed each month.
(2) The turbidity level of representative
samples of a public water system's filtered water shall not exceed one
NTU.
(B) Slow sand
filtration. Filtration by a public water system filtering surface water by slow
sand filtration shall meet the following:
(1)
For a public water system using slow sand filtration, the turbidity level of
representative samples of filtered water shall be less than or equal to one NTU
in at least ninety-five per cent of the samples each month.
(2) The turbidity level of representative
samples of a public water system's filtered water shall not exceed five
NTU.
(C) Alternative
filtration technologies
and direct filtration
treatment. If a public water system using a surface water source, in
whole or in part, can demonstrate to the director, using pilot plant studies or
other means, that a filtration technology not listed in paragraph (A) or (B) of
this rule, in combination with disinfection treatment that meets the
requirements of paragraph (B) of rule
3745-81-72 of the Administrative
Code, consistently and reliably achieves ninety-nine per cent (2 log) removal
of Cryptosporidium, 99.9 per cent (3 log) removal and/or inactivation of
Giardia lamblia cysts and 99.99 per cent (4 log) removal and/or inactivation of
viruses, the director may accept this alternative filtration technology for use
by the public water system. For a public water system that makes this
demonstration, the requirements of paragraph (A) of this rule apply. For a
public water system that makes this demonstration, the minimum log removal and
inactivation requirements for conventional filtration in table A of rule
3745-81-72 of the Administrative
Code shall apply. Each membrane filter which has been awarded credit for log
removal as described in this paragraph shall undergo direct integrity testing
daily to verify the log removal
the filter
it has been credited to achieve. The direct
integrity testing requirements in paragraph (K)(3) of rule
3745-81-68 of the Administrative
Code shall apply. In addition, continuous filtrate turbidity monitoring shall
be performed on each membrane filter. If the turbidity of a membrane filter
exceeds 0.15 NTU in two consecutive readings taken fifteen minutes apart, the
system shall conduct a direct integrity test on the membrane filter. A membrane
filter shall be removed from service for repairs until the membrane filter can
pass a direct integrity test to verify the log removal it has been credited to
achieve. Systems shall submit a monthly report including daily direct integrity
test results, any turbidity monitoring results which trigger direct integrity
testing, and any corrective action taken.
Notes
Ohio Admin. Code
3745-81-73
Effective:
3/23/2020
Five Year Review (FYR) Dates:
10/2/2019 and
03/23/2025
Promulgated
Under: 119.03
Statutory
Authority: 6109.04
Rule
Amplifies: 6109.03,
6109.04
Prior
Effective Dates: 12/31/1990, 09/13/1993, 01/01/2002, 01/01/2005, 01/08/2010,
10/05/2013
