Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 611 - PRIMARY DRINKING WATER STANDARDS › Subpart I - DISINFECTANT RESIDUALS, DISINFECTION BYPRODUCTS, AND DISINFECTION BYPRODUCT PRECURSORS › Section 611.385 - Treatment Technique for Control of Disinfection Byproduct (DBP) Precursors

Current through Register Vol. 48, No. 28, July 12, 2024
a)
				Applicability
1) A Subpart B system supplier
				using conventional filtration treatment (as defined in Section
				611.101 ) must
				operate with enhanced coagulation or enhanced softening to achieve the TOC
				percent removal levels specified in subsection (b) unless the supplier meets at
				least one of the alternative compliance standards listed in subsection (a)(2)
				or (a)(3).
2) Alternative
				compliance standards for enhanced coagulation and enhanced softening systems. A
				Subpart B system supplier using conventional filtration treatment may use the
				alternative compliance standards in subsections (a)(2)(A) through (a)(2)(F) to
				comply with this Section in lieu of complying with subsection (b). A supplier
				must comply with monitoring requirements in Section
				611.382(d).
A) The supplier's source water TOC level,
				measured according to Section
				611.381(d)(3),
				is less than 2.0 mg/l, calculated quarterly as a running annual
				average.
B) The supplier's treated
				water TOC level, measured according to Section
				611.381(d)(3),
				is less than 2.0 mg/l, calculated quarterly as a running annual
				average.
C) The supplier's source
				water TOC level, measured according to Section
				611.381(d)(3),
				is less than 4.0 mg/l, calculated quarterly as a running annual average; the
				source water alkalinity, measured according to Section
				611.381(d)(1),
				is greater than 60 mg/l (as CaCO3), calculated quarterly
				as a running annual average; and either the TTHM and HAA5 running annual
				averages are no greater than 0.040 mg/l and 0.030 mg/l, respectively; or prior
				to the effective date for compliance in Section
				611.380(b),
				the system has made a clear and irrevocable financial commitment, not later
				than the effective date for compliance in Section
				611.380(b),
				to use technologies that will limit the levels of TTHMs and HAA5 to no more
				than 0.040 mg/l and 0.030 mg/l, respectively. A supplier must submit evidence
				of a clear and irrevocable financial commitment, in addition to a schedule
				containing milestones and periodic progress reports for installation and
				operation of appropriate technologies, to the Agency for approval. Failure to
				install and operate these technologies by the date in the approved schedule
				will constitute a violation of an NPDWR.
D) The TTHM and HAA5 running annual averages
				are no greater than 0.040 mg/l and 0.030 mg/l, respectively, and the supplier
				uses only chlorine for primary disinfection and maintenance of a residual in
				the distribution system.
E) The
				supplier's source water SUVA, prior to any treatment and measured monthly
				according to Section
				611.381(d)(4),
				is less than or equal to 2.0 l/mg-m, calculated quarterly as a running annual
				average.
F) The supplier's finished
				water SUVA, measured monthly according to Section
				611.381(d)(4),
				is less than or equal to 2.0l/mg-m, calculated quarterly as a running annual
				average.
3) Additional
				Alternative Compliance Standards for Softening Systems. A supplier practicing
				enhanced softening that cannot achieve the TOC removals required by subsection
				(b)(2) may use the alternative compliance standards in subsections (a)(3)(A)
				and (a)(3)(B) in lieu of complying with subsection (b). A supplier must comply
				with monitoring requirements in Section
				611.382(d).
				The alternative compliance standards are as follows:
A) The supplier may undertake softening that
				results in lowering the treated water alkalinity to less than 60 mg/l (as
				CaCO3), measured monthly according to Section
				611.381(d)(1)
				and calculated quarterly as a running annual average; and
B) The supplier may undertake softening that
				results in removing at least 10 mg/l of magnesium hardness (as
				CaCO3), measured monthly according to Section
				611.381(d)(6)
				and calculated quarterly as a running annual average.