[Code of Federal Regulations]
[Title 40, Volume 26]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR423.11]

[Page 654-655]
 
                TITLE 40-PROTECTION OF ENVIRONMENT
 
      CHAPTER I-ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 423-STEAM ELECTRIC POWER GENERATING POINT SOURCE CATEGORY--Table of Contents
 
Sec. 423.11  Specialized definitions.

    In addition to the definitions set forth in 40 CFR part 401, the 
following definitions apply to this part:
    (a) The term total residual chlorine (or total residual oxidants for 
intake water with bromides) means the value obtained using the 
amperometric method for total residual chlorine described in 40 CFR part 
136.
    (b) The term low volume waste sources means, taken collectively as 
if from one source, wastewater from all sources except those for which 
specific limitations are otherwise established in this part. Low volume 
wastes sources include, but are not limited to: wastewaters from wet 
scrubber air pollution control systems, ion exchange water treatment 
system, water treatment evaporator blowdown, laboratory and sampling 
streams, boiler blowdown, floor drains, cooling tower basin cleaning 
wastes, and recirculating house service water systems. Sanitary and air 
conditioning wastes are not included.
    (c) The term chemical metal cleaning waste means any wastewater 
resulting from the cleaning of any metal process equipment with chemical 
compounds, including, but not limited to, boiler tube cleaning.
    (d) The term metal cleaning waste means any wastewater resulting 
from cleaning [with or without chemical cleaning compounds] any metal 
process equipment including, but not limited to, boiler tube cleaning, 
boiler fireside cleaning, and air preheater cleaning.
    (e) The term fly ash means the ash that is carried out of the 
furnace by the gas stream and collected by mechanical precipitators, 
electrostatic precipitators, and/or fabric filters. Economizer ash is 
included when it is collected with fly ash.
    (f) The term bottom ash means the ash that drops out of the furnace 
gas stream in the furnace and in the economizer sections. Economizer ash 
is included when it is collected with bottom ash.
    (g) The term once through cooling water means water passed through 
the main cooling condensers in one or two passes for the purpose of 
removing waste heat.
    (h) The term recirculated cooling water means water which is passed 
through the main condensers for the purpose of removing waste heat, 
passed through a cooling device for the purpose of removing such heat 
from the water and then passed again, except for blowdown, through the 
main condenser.
    (i) The term 10 year, 24/hour rainfall event means a rainfall event 
with a probable recurrence interval of once in ten years as defined by 
the National Weather Service in Technical Paper No. 40. Rainfall 
Frequency Atlas of the United States, May 1961 or equivalent regional 
rainfall probability information developed therefrom.
    (j) The term blowdown means the minimum discharge of recirculating 
water for the purpose of discharging materials contained in the water, 
the further buildup of which would cause concentration in amounts 
exceeding

[[Page 655]]

limits established by best engineering practices.
    (k) The term average concentration as it relates to chlorine 
discharge means the average of analyses made over a single period of 
chlorine release which does not exceed two hours.
    (l) The term free available chlorine shall mean the value obtained 
using the amperometric titration method for free available chlorine 
described in Standard Methods for the Examination of Water and 
Wastewater, page 112 (13th edition).
    (m) The term coal pile runoff means the rainfall runoff from or 
through any coal storage pile.