310 C.M.R. 22.20E – Filter Backwash Recycling Rule

(1) Applicability. Each supplier of water using a surface water source or ground water source under direct influence of surface water that employs conventional filtration, direct filtration, softening, or contact clarification treatment and that recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes shall meet the requirements in 310 CMR 22.20E(2) through (4).
(2) Reporting. Each supplier of water using a surface water source or ground water source under direct influence of surface water that employs conventional filtration, direct filtration, softening, or contact clarification treatment shall notify the Department in writing by December 8, 2003, if the system recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes. This notification shall include, at a minimum, the information specified in 310 CMR 22.20E(2)(a) and (b).
1. (a) A plant schematic showing the origin of all flows that are recycled (including, but not limited to, spent filter backwash water, thickener supernatant, and liquids from dewatering processes), the hydraulic conveyance used to transport them, and the location where they are re-introduced back into the treatment plant.
2. (b) Typical recycle flow in gallons per minute (gpm), the highest observed plant flow experienced in the previous year (gpm), design flow for the treatment plant (gpm), and Department-approved operating capacity for the plant where the Department has made such determinations.
(3) Treatment Technique Requirement. Each supplier of water using a surface water source or ground water source under direct influence of surface water that employs conventional filtration, direct filtration, softening, or contact clarification treatment that recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes must return these flows through the processes of a system's existing conventional filtration, direct filtration, softening, or contact clarification system or at an alternate location approved by the Department by June 8, 2004. If capital improvements are required to modify the recycle location to meet this requirement, all capital improvements shall be completed no later than June 8, 2006.
(4) Recordkeeping. The system shall collect and retain on file recycle flow information specified in 310 CMR 22.20E(4)(a) through (f) for review and evaluation by the Department beginning June 8, 2004:
1. (a) Copy of the recycle notification and information submitted to the Department under 310 CMR 22.20E(2),
2. (b) List of all recycle flows and the frequency with which they are returned,
3. (c) Average and maximum backwash flow rate through the filters and the average and maximum duration of the filter backwash process in minutes,
4. (d) Typical filter run length and a written summary of how filter run length is determined,
5. (e) The type of treatment provided for the recycle flow, and
6. (f) Data on the physical dimensions of the equalization and/or treatment units, typical and maximum hydraulic loading rates, type of treatment chemicals used and average dose and frequency of use, and frequency at which solids are removed, if applicable.