In addition to the definitions set forth in 40 CFR part 401, the following definitions apply to this part:
(a) ``Sulfide'' shall mean total sulfide as measured by the potassium ferricyanide titration method described in appendix A or the modified Monier-Williams method described in appendix B.
(b) ``Hide'' means any animal pelt or skin as received by a tannery as raw material to be processed.
(c) ``Retan-wet finish'' means the final processing steps performed on a tanned hide including, but not limited to, the following wet processes: retan, bleach, color, and fatliquor.
(d) ``Hair pulp'' means the removal of hair by chemical dissolution.
(e) ``Hair save'' means the physical or mechanical removal of hair which has not been chemically dissolved, and either selling the hair as a by-product or disposing of it as a solid waste.
(f) ``Chrome tan'' means the process of converting hide into leather using a form of chromium.
(g) ``Vegetable tan'' means the process of converting hides into leather using chemicals either derived from vegetable matter or synthesized to produce effects similar to those chemicals.
(h) ``Raw material'' means the hides received by the tannery except for facilities covered by subpart D and subpart I where ``raw material'' means the hide or split in the condition in which it is first placed into a wet process.
(i) ``Monthly average'' means the arithmetic average of eight (8) individual data points from effluent sampling and analysis during any calendar month.
(j) ``Interference'' means the discharge of sulfides in quantities which can result in human health hazards and/or risks to human life, and an inhibition or disruption of POTW as defined in 40 CFR 403.3(i). [47 FR 52870, Nov. 23, 1982, as amended at 53 FR 9181, Mar. 21, 1988]