Section 810.44. Treatment performance toolbox components.

 

(1)   Combined filter performance. Public water systems using conventional filtration treatment or direct filtration treatment receive an additional 0.5-log Cryptosporidium treatment credit during any month the system meets the criteria in this subsection. Combined filter effluent (CFE) turbidity shall be less than or equal to 0.15 NTU in at least 95% of the measurements. Turbidity shall be measured as described in s. NR 809.113 (1) , Tables A and B.

(2)   Individual filter performance. Public water systems using conventional filtration treatment or direct filtration treatment receive 0.5-log Cryptosporidium treatment credit, which may be in addition to the 0.5-log credit under sub. (1) , during any month the system meets the criteria in this subsection. Compliance with these criteria shall be based on individual filter turbidity monitoring as described in s. NR 809.113 (1) Tables A and B, as applicable.

(a) The filtered water turbidity for each individual filter shall be less than or equal to 0.15 NTU in at least 95% of the measurements recorded each month.

(b) No individual filter may have a measured turbidity greater than 0.3 NTU in 2 consecutive measurements taken 15 minutes apart.

(c) Any system that has received treatment credit for individual filter performance and fails to meet the requirements of par. (a) or (b) during any month does not receive a treatment technique violation under s. NR 810.35 (3) if the department determines the following:

1. The failure was due to unusual and short-term circumstances that could not reasonably be prevented through optimizing treatment plant design, operation, and maintenance.

2. The system has experienced no more than 2 such failures in any calendar year.

(3)   Demonstration of performance. The department may approve Cryptosporidium treatment credit for drinking water treatment processes based on a demonstration of performance study that meets the criteria in this subsection. This treatment credit may be greater than or less than the prescribed treatment credits in s. NR 810.35 or ss. NR 810.43 to 810.46 and may be awarded to treatment processes that do not meet the criteria for the prescribed credits.

(a) Systems cannot receive the prescribed treatment credit for any toolbox box option in ss. NR 810.43 to 810.46 if that toolbox option is included in a demonstration of performance study for which treatment credit is awarded under this subsection.

(b) The demonstration of performance study shall follow a department-approved protocol and shall demonstrate the level of Cryptosporidium reduction the treatment process will achieve under the full range of expected operating conditions for the system.

(c) Approval by the department shall be in writing and may include monitoring and treatment performance criteria that the water supplier for the system shall demonstrate and report on an ongoing basis to remain eligible for the treatment credit. The department may designate the criteria where necessary to verify that the conditions under which the demonstration of performance credit was approved are maintained during routine operation.

History: CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10.