aeration tank. For installations in which all
sewage has passed through a comminutor and bar
screen upstream of the plant, a comminutor and bar
screen unit need not be provided as a part of the
plant equipment.
**************************************************************************
**************************************************************************
NOTE: Delete reference to influent distribution
channel for extended aeration type.
**************************************************************************
**************************************************************************
NOTE: Delete requirement for aeration tank
detention time when complete mixing type is
specified.
**************************************************************************
**************************************************************************
NOTE: For detention time in aeration tank, insert
24 hours for extended aeration type and 5.0 to 7.5
hours for step aeration type.
**************************************************************************
**************************************************************************
NOTE: For organic loading in aeration tank, insert
5.67 kg 12.5 pounds, 5 day BOD for extended aeration
type, 13.6 to 22.1 kg 30 to 50 pounds, 5-day BOD for
step aeration type, and 52.16 kg 115 pounds, 5-day
BOD for complete mixing type mixing type. Organic
loadings used in this specification are those for
sewage strength of 200 mg/1. Organic loadings for
higher strength sewage would be proportional.
Insert value for 5 day BOD loading. This value
should be based on tests of the sewage to be
treated; however, if this cannot be obtained, use
200 mg/L.
**************************************************************************
**************************************************************************
NOTE: Delete requirement for settling tank
detention time when complete mixing type is
specified.
**************************************************************************
**************************************************************************
NOTE: For detention time in settling tank for
extended aeration type, insert 4.0 hours for plants
of less then 2.19 L/s 50,000 GPD, 3.6 hours for
plants from 2.19 L/s 50,000 GPD to 6.57 L/s 150,000
GPD capacity, and 3.0 hours for plants of 6.57 L/s
150,000 GPD capacity and above. For step aeration
type, insert 3.0.
**************************************************************************
**************************************************************************
NOTE: For extended aeration type, insert 0.013 L/s
300 GPD for 6.57 L/s 150,000 GPD capacity and less;
SECTION 11375N
Page 96
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