Rhode Island Code of Regulations › Title 216 - Department of health › Chapter 50 - Environmental health › Subchapter 05 - Water Quality › Part 1 - Public Drinking Water (216-RICR-50-05-1) › Section 216-RICR-50-05-1.6 - Filtration and Disinfection

Current through June 14, 2024
1.6.1
General
				  Requirements
A. The requirements of
				  this Section constitute Rhode Island's primary drinking water regulations. This
				  Part establishes criteria under which filtration is required as a treatment
				  technique for PWS supplied by a surface water source, or a groundwater source
				  under the direct influence of surface water also referred to as §
											1.6   PW S.
				  This Part establishes treatment technique requirements in lieu of maximum
				  contaminant levels for the following contaminants: Giardia lamblia, viruses,
				  heterotrophic plate count bacteria, Legionella, Cryptosporidium, and turbidity.
				  Each §
											1.6   PW S must provide treatment of that source water that complies
				  with these treatment technique requirements.
B. The treatment technique requirements
				  consist of installing and properly operating water treatment processes which
				  reliably achieve:
1. At least 99.9 percent
				  (3-log) removal and/or inactivation of Giardia lamblia cysts between a point
				  where the raw water is not subject to recontamination by surface water runoff
				  and a point downstream before or at the first customer, and
2. At least 99.99 percent (4-log) removal and
				  or inactivation of viruses between a point where the raw water is not subject
				  to recontamination by surface water runoff and a point downstream before or at
				  the first customer.
3. At least 99
				  percent (2-log) removal of Cryptosporidium between a point where the raw water
				  is not subject to recontamination by surface water runoff and a point
				  downstream before or at the first customer for filtered PWS, or Cryptosporidium
				  control under the watershed control plan for unfiltered PWS.
4. Compliance with the profiling and
				  benchmark requirements under the provisions of §1.6.3(G) of this
				  Part.
C. A §
											1.6   PW S
				  is considered to be in compliance with the requirements of §1.6.1(B) of
				  this Part, if:
1. It meets the requirements
				  for avoiding filtration in §1.6.2 of this Part and the disinfection
				  requirements in §1.6.3 of this Part; OR
2. It meets the filtration requirements in
				  §1.6.4 of this Part and the disinfection requirements in §1.6.3 of
				  this Part.
D. Each
				  §
											1.6   PW S must be operated by qualified personnel who meet the
				  requirements of the Rules and Regulations Pertaining to the Certification of
				  Public Drinking Water Treatment and Transmission and Distribution Operators
				  promulgated pursuant to the authority set forth in R.I. Gen Laws Chapter
				  23-65.
E.
											§
											1.6   PW S that
				  served fewer than ten thousand (10,000) people beginning January 1, 2002 but
				  currently serve or will serve at least ten thousand (10,000) people before
				  January 1, 2005 must comply with all the requirements listed in this Filtration
				  and Disinfection Document for PWSs serving at least ten thousand (10,000)
				  people as soon as those PWS begin serving at least ten thousand (10,000)
				  people. These PWS must also consult with the Director to establish a
				  disinfection benchmark. If a significant change is made to the disinfection
				  practice, these PWS must consult with the Director prior to making such change
				  as stated in §1.6.3(G)(4) including, but not limited to,
				  §§1.6.3(G)(4)(a)(1) through (4) of this Part.
F. Recycle Provisions: All §
											1.6   PW S
				  that employ conventional filtration or direct filtration treatment and that
				  recycle spent filter backwash water, thickener supernatant, or liquids from
				  dewatering processes must meet the requirements in §§1.6.1(F)(1) and
				  1.6.8(D) of this Part.
1. Treatment Technique
				  Requirement. Any PWS that recycles spent filter backwash water, thickener
				  supernatant, or liquids from dewatering processes must return these flows
				  through the processes of a PWS's existing conventional or direct filtration
				  system as defined in
				   40 C.F.R. §
													141.2  or at an alternate
				  location approved by the Director.