is specified or extended aeration type where
eventual conversion to step aeration is contemplated.
**************************************************************************
**************************************************************************
NOTE: Delete reference to chain-and-flight type
when complete mixing type is specified, or for
extended aeration type plants of less than 1.76 L/s
40,000 GPD capacity.
**************************************************************************
**************************************************************************
NOTE: Delete second sentence for plants below 1.31
L/s 30,000 GPD capacity.
**************************************************************************
[Rectangular settling tanks shall have [chain-and-flight type or] traveling
reciprocating type sludge collectors]. [Circular tanks shall have rotating
type sludge collectors.] All settling tank walls with slopes less than
1.05 rad 60 degrees with the horizontal shall be scraped by the sludge
collector.
2.9.3.1
Chain-and-Flight Type Sludge Collector
**************************************************************************
NOTE: Delete paragraph and subparagraphs thereto
when step aeration type or complete mixing type is
specified, or for extended aeration type of less than
1.76 L/s 40,000 GPD capacity or extended aeration
type where eventual conversion to step aeration is
contemplated.
On the project drawings, show:
1. Type of plant: (Extended aeration, Step
Aeration, or Complete Mixing).
2.
Design flow.
3.
5-day BOD loading.
4.
Suspended solids loading.
5. Whether a comminutor is needed for plants 1.09
L/s 25,000 GPD or less in size.
6.
Whether mechanical aerator should be allowed.
7. Whether plant should be concrete only, steel
only, or either concrete or steel at Contractor's
option.
8.
Whether piling is required for foundations.
9. Whether hypochlorinator or whether chlorinator
should be used for plants in 4.38 to 6.57 L/s
100,000 to 150,000 GPD range.
10.
Whether raw sewage recirculation box
SECTION 11375N
Page 44
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