NIT No-21 EE (SDW) II/ (19-20) Item No. 9

Renovation of Primary Settling Tank of 15 MGD (A unit of 37 MGD ) STP, Okhla by carrying out following works:- Isolating the PST by operating sluice gate and providing gunny bags to ensure no low in the PST. Dewatering the PST with the help of sump pumps and D.G. Set cleaning the PST with the help of machines/manually for exaction of work.

Dismantling of electric motor, primary gear box and other mechanical accessories from the top of center mechanism and shifting to workable place.

Making temporary platform as safety measures on the side of the central cage as per site requirement for dismantling of derive head.

Dismantling of central cage & turn table, lifting & taking out from the PST & shifting to ground level etc.

Dismantling the damaged structure of the both side scrapper arm structure and shifting the same to a workable place with the help of mobile crane & heavy Labour tec.

Renovation of centre drum i/c replacement of the damaged stiffeners of the drum and making required patch work with 6 mm thick M.S. sheet with the help of electric welding as per site requirement.

Renovation and strengthening of scrapper arms structure by way of providing / fixing new elements of the structure made out of M.S. angle iron of size 65x65x6 mm approx 40 meter & 50x50x5 mm approx 50 meter by using new fasteners and homogenous electric arc wending and balancing the both side arm with the help of tie rod and with adjustment bolts.

Replacement / Renovation of the bottom scrapper made out from 8 mm thick M.S. sheet of size 200x1700 mm approx. i/c replacement of the rubber squeezers with M.S. flat after making holes at equal distance and fastening through the nut bolts.

Replacement of turn table balls of size 38 mm approx.

Replacement of strip liner of high quality spring steel of centre mechanism.

Dismantling of worn out V-notch of rusted not bolts with the help of gas cutter, all tools & tackles. .

Providing the S.S nut bolts as per sample for fixing the ‘V’ notch.

Re fixing the V-notch with the new nut bolts as per sample for fixing in PST after drilling in RCC with power hammer including all civil work with all tools and tackles.

Fabrication the scum box (size 1800x1500 mm approx) made out of 6 mm thick M.S. sheet i/c providing the heavy duty out let pipe of 200 mm dia and 8 mm thick, including flange with nut bolts &gasket. Fixing the box at site with the help of angle / channel after alignment the scum box with the help of all tools and tackles and loading, unloading

Providing/ fixing of MS chequered sheet, 8 mm thick, 0.950 Mtr. Wide in a length of 16 Mtr. Apprx by cutting of old rusted / corroded sheet & fixing of new sheet with welding work.

Painting of the complete structure after removing the rust from the structure with the wire brush. Painting the surface with the one coat of red oxide primer and two coat of anti corrosive paint.

Assembling, testing & commissioning of complete unit on NO load / full load after removing gunny bags and temporary plate form.

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