REPLACEMENT AND SCREENING OF OLD FILTER MEDIA AT VARIOUS SCHEMES UNDER DISTRIC DN. JAISALMER

Silt clearance from Sedimentation cum storage tank with all lift and lead up to 50 Mtr. Silt to be disposed outside the Headworks boundaries. Disposed silt to be levelled and neatly dressed including stacking of useful material if any available during excavation for all kind of soil. Silt clearance is to be carried out by means of mechanical system i.e. Tractor craw/Trolley or any other mechanical system. No extra payment shall be done for lift . This work also involves dressing of bottom which is to be done manually and there shall be no damage to lining and LDPE film of tank. Work is to be done as per direction of Engineer In Charge and technical specifications.

Labour charges for screening of old sand (received from filter beds) through the standard sieves, washing the sand with HCL acid of required concentration as directed by the Engineer- In- Charge, so as to remove all the mud and other deposits from sand grains and then clean with water till the sand is as neat and clean that it impart no colour to clean while washing. It also includes placing this washed filter media (sand) in filter beds in layer as instructed by the Engineer- In- Charge. (RGF, SSF)

Labour charges for screening of old gravel (received from filter beds) through the standard different sizes sieves for required sizes of gravel, washing the gravel with HCL acid of required concentration as directed by the Engineer- In- Charge, so as to remove all the mud and other deposits from gravel grains and then clean with water till the gravel is as neat and clean that it impart no colour to clean while washing. It also includes placing this washed gravel in filter beds in layer as instructed by the Engineer- In- Charge. (RGF, SSF)

Removing & Re-fixing of pipes for under drainage system including cleaning of one end plugged pipes and fixing /embedded in CM 1:4 on one end and fixing other end in collecting channel with CM 1:4 with all Material etc.(Excl.cost of pipes) This job, also, includes Making 4mm dia holes if required in pipes @15 cm c/c in zig-zag pattern.

Providing and Placing of new filter media as (i) Sand shall be hard and resistant quartz or quartzite and free of clay, fine particles, soft grains and dirt of any description. (ii) Effective size shall be 0.20 to 0.30 mm. (iii) Uniformity Coefficient not be more than 5.0 nor less than 3.0. (iv) Ignition loss should not exceed 0.70% by weight. (v) Soluble fraction in HCL acid shall not exceed 7.0% by weight, (vi) Silica content should not be less than 95% (vii) Specific Gravity shall be in the range between 2.55 to 2.65 (viii) Wearing loss shall not exceed 3.0%. and as per specifications given in IS: 8419 (Part-I). (ix) The sand should not contain more than 2% of calcium and manganese calculated as carbonate. Filter media (fine sand and coarse sand) should be processed through. Disintegrator and dust separator in automatic plant including screening of sand to desired. Specification and washing and cleaning of sand with water by aqua wash technology at quarry site. The sand shall not contain more than 5% acid soluble matter as determined by solubility test in Appendix B of IS: 8419 (Part-I) (Fine sand 0.2 to 0.3mm and coarse sand 1.0 to 1.7mm) (For SSF)

20mm thick

80 mm