5 Colo. Code Regs. § 1002-11.9

Current through Register Vol. 47, No. 11, June 10, 2024

Section 5 CCR 1002-11.9 - SURFACE WATER TREATMENT RULE: FILTER BACKWASH RECYCLE RULE

11.9(1) Applicability and Definitions

(a) For all surface water systems that use conventional filtration treatment or direct filtration treatment and that also recycle spent filter backwash water, thickener supernatant, or liquids from dewatering processes, the supplier must comply with the requirements specified in this rule.

(b) "LIQUIDS FROM DEWATERING PROCESSES" means a stream of liquids generated from a unit used to concentrate solids for disposal. Processes may consist of centrifuges, filter presses, belt presses, vacuum filters, monofills, or other sludge concentrating equipment. Such equipment may be used to dewater sludge from treatment units used in recycling processes or sludge from units found in the primary processes.

(c) "THICKENER SUPERNATANT" means a stream of liquids containing the decant from a sedimentation basin, clarifier or other unit that is used to treat water, solids, or semi-solids from the primary treatment processes. The "clear water" that exits the units after particles have been allowed to settle out is thickener supernatant (or sludge thickener supernatant).

11.9(2)Treatment Technique Requirement for Filter Backwash Recycle

The supplier must return recycled spent filter backwash water, thickener supernatant, or liquids from dewatering processes to a location within the treatment process that is before the conventional filtration treatment or direct filtration treatment or to an alternative Department-approved location.

11.9(3)Information Collection Requirements for Filter Backwash Recycle

The supplier must collect all of the following information about the recycle flow(s):

(a) A list of all recycle flows and the frequency with which they are returned.

(b) The average and maximum backwash flow rate through the filters.

(c) The average and maximum duration of the filter backwash process in minutes.

(d) The typical filter run length and a written summary of how filter run length is determined.

(e) The type of treatment provided for the recycle flow(s).

(f) If applicable, data on the physical dimensions of the equalization and/or treatment units, typical and maximum hydraulic loading rates, type of treatment chemicals used, including the average dose and frequency of use, and frequency at which solids are removed.

11.9(4)Reporting Requirements for Filter Backwash Recycle

No later than 18 months after meeting the applicability of this rule, the supplier must provide the Department with written notification that includes all of the following:

(a) A plant schematic showing all of the following:

(i) The origin of all flows which are recycled.

(ii) The hydraulic conveyance used to transport the flows.

(iii) The location where the flows are re-introduced into the treatment plant.

(b) Typical recycle flow in gallons per minute.

(c) The highest observed plant flow experienced in the previous year in gallons per minute.

(d) Design flow for the treatment plant in gallons per minute.

(e) Department-approved operating capacity for the plant.

5 CCR 1002-11.9

38 CR 07, April 10, 2015, effective 4/30/2015

41 CR 11, June 10, 2018, effective 6/30/2018

41 CR 23, December 10, 2018, effective 12/30/2018

43 CR 07, April 10, 2020, effective 4/30/2020

43 CR 17, September 10, 2020, effective 9/30/2020

45 CR 24, December 25, 2022, effective 1/14/2023