Section NR 106.36 - Alternative whole effluent toxicity monitoring for certain discharges of ammonia(1)In addition to water quality based effluent limitations for ammonia, the department may establish whole effluent toxicity testing requirements and limitations pursuant to ss. NR 106.08 and 106.09.(2)Chronic fathead minnow whole effluent toxicity test samples may be modified to remove ammonia prior to testing when all of the following conditions are met: (a) The whole effluent toxicity test is being conducted during a period when ammonia effluent limitations based on early life stage absent criteria are in effect.(b) The permittee has demonstrated compliance with applicable acute and chronic water quality based effluent limitations for ammonia during the testing period.(c) Total ammonia measured in whole effluent toxicity test effluent samples is less than the applicable chronic water quality based effluent limitation contained in the WPDES permit, but greater than the "ammonia threshold number", determined as follows: 1. Measure the pH of the whole effluent toxicity test effluent sample after the sample has been warmed to the test temperature. Note: Effluent samples should not be aerated to remove supersaturation of dissolved oxygen prior to use in the whole effluent toxicity test. The measured pH value shall be rounded to the nearest one-tenth of a unit.
2. Using the pH value of the sample as determined in subd. 1., determine the value of the ammonia multiplier in Table 1 for the pH range corresponding to the effluent pH.3. Divide 100 by the appropriate in-stream waste concentration, as a percentage, contained in the WPDES permit; then multiply the resulting value by the ammonia multiplier determined in subd. 2. to obtain the ammonia threshold number.(3)If all of the criteria in sub. (2) have been met, ammonia may be removed from the test sample. Effluent pH (s.u., after warming) | Ammonia Multiplier (mg/l total ammonia) |
6.0 - 6.5 | 30 |
6.6 - 7.0 | 25 |
7.1 - 7.5 | 15 |
7.6 - 8.0 | 5 |
8.1 - 9.0 | 1 |
Wis. Admin. Code Department of Natural Resources § NR 106.36
CR 03-050: cr. Register February 2004 No. 578, eff. 3-1-04.Amended by, CR 15-085: am. Table 1 (title), r. (4) Register August 2016 No. 728, eff. 9/1/2016