[Code of Federal Regulations] [Title 40, Volume 29] [Revised as of July 1, 2007] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR463.21] [Page 548-549] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 463_PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY --Table of Contents Subpart B_Cleaning Water Subcategory Sec. 463.21 Specialized definitions. For the purpose of this subpart: (a) The ``average process water usage flow rate'' of a cleaning water process in liters per day is equal to the volume of process water (liters) used per year by a process divided by the number of days per year the process operates. The ``average process water usage flow rate'' for a plant with more than one plastics molding and forming process that uses cleaning water is the sum of [[Page 549]] the ``average process water usage flow rates'' for the cleaning processes. (b) The ``volume of process water used per year'' is the volume of process water that flows through a cleaning process and comes in contact with the plastic product over a period of one year.