PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
PACKAGE : I Bid Document VOLUME : II - Public Health Engineering
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Slow Start :<br />
Following cleansing operations, the contractor shall allow in his arrangements and<br />
operating instructions, for manually controlled slow start of the filters.<br />
Wash water gutters :<br />
Materials for wash water gutters shall be concrete. The upper edge of the gutter<br />
shall be placed sufficient near to the surface of the sand so that a large quantity of<br />
dirty water is not left in the filter after the completion of washing. The edge of the<br />
trough shall be slightly above the highest elevation of the sand as expanded in<br />
washing. The maximum water level in the gutter shall be 50mm below the gutter<br />
upper edge. The trough, shall be designed as free falling weirs as spill ways.<br />
21.21 Outlet chamber.<br />
Each compartment of every filter adjacent to filtrate outlet shall be connected to the<br />
common filter water collection channel. The chambers shall be covered with sheet<br />
glass, fixed in a removable aluminum frame with a lighting arrangement to see the<br />
quality of water.<br />
The flooring for inspection chamber shall be in white glazed tiles. The walls of the<br />
inspection chamber shall be covered with white glazed tiles for full height.<br />
The minimum capacity of chamber shall be 1.00 m . Each chamber shall discharge<br />
in to the channel over a sharp edge weir plate within the chamber, the contractor<br />
shall provide an adjustable wall mounted calibrated brass gauge to enable the<br />
operators to estimate the approximate filter discharge rate.<br />
Each filter bed shall be provided with rate of flow cum loss of head indicators.<br />
Each filter bed shall be provided with high water level indicator for start of back<br />
wash.<br />
21.22 Filter gallery and filter machinery hall pipe works (general).<br />
Filter gallery water carrying pipe work shall be in either steel or cast iron with<br />
flanged connections, with a provision of detachable flanged couplings to facilitate<br />
maintenance of valves and fittings. The filter gallery and machinery hall pipe work<br />
shall be arranged for ease of operation, access for maintenance to minimize<br />
undesirable head losses in the works.<br />
DTS : Detailed Tender Specification. Page 253
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